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1
2019, 27(2): 415-425.
Abstract
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On October 11, 2018, a massive landslide occurred in Baige Village, Boluo Town, Jiangdacounty, Changdu city, Tibet. About 3, 165×104 cubic meter of a mountain mass rushed into the Jinsha River at a high speed, thus forming a barrier dam. At 9:00 on October 13, the body of the barrier dam was washed away by natural aerial drainage and the threat of forming a barrier lake was resolved. On November 3, only 23 days later, the high slip mass of 215×104 cubic meter at the back edge of the landslide occurred sliding failure again. The high-speed slip mass scraped the slope along the way and then rushed into the Jinsha River, forming a barrier dam again. This paper held the view that the landslide happened in Baige Village was thought to be mainly controlled by the next branch margin thrust fault f2, then finally generated buckling failure of the overall instability of the landslide with the influence of a long-term gravity unloading, rainfall and repeated infiltration of groundwater. The process of slip deformation and failure can be divided into five stages:trailing creep and settlement under the fault phase(Ⅰ), slope crack development, penetration stage(Ⅱ), overall launch of the "locking-fix end" cutting stage(Ⅲ), a stage with high moving speed(Ⅳ), collided, crushing and dam accumulation stage(Ⅴ). The failure mode of the first-stage deformation and failure mechanism can be summed up as creep-slip type-down fault type-shearing type-ski-jump type, and the failure mode is shown as the thrust type. In the later stage, the free surface condition of the slope is better, and the traction type can remain as the main failure mode. On this basis, combined with the residual strong deformation block(K1, K2, K3) and morphological characteristics and deformation signs of the surrounding influence zone, this paper predicted and analyzed the deformation and failure characteristics and development trend of the block, deeming that strong deformation areas can be destroyed by gradual disintegration. And these research findings can provide some reference for the monitoring, survey and governance of the future plan making and implementation.
On October 11, 2018, a massive landslide occurred in Baige Village, Boluo Town, Jiangdacounty, Changdu city, Tibet. About 3, 165×104 cubic meter of a mountain mass rushed into the Jinsha River at a high speed, thus forming a barrier dam. At 9:00 on October 13, the body of the barrier dam was washed away by natural aerial drainage and the threat of forming a barrier lake was resolved. On November 3, only 23 days later, the high slip mass of 215×104 cubic meter at the back edge of the landslide occurred sliding failure again. The high-speed slip mass scraped the slope along the way and then rushed into the Jinsha River, forming a barrier dam again. This paper held the view that the landslide happened in Baige Village was thought to be mainly controlled by the next branch margin thrust fault f2, then finally generated buckling failure of the overall instability of the landslide with the influence of a long-term gravity unloading, rainfall and repeated infiltration of groundwater. The process of slip deformation and failure can be divided into five stages:trailing creep and settlement under the fault phase(Ⅰ), slope crack development, penetration stage(Ⅱ), overall launch of the "locking-fix end" cutting stage(Ⅲ), a stage with high moving speed(Ⅳ), collided, crushing and dam accumulation stage(Ⅴ). The failure mode of the first-stage deformation and failure mechanism can be summed up as creep-slip type-down fault type-shearing type-ski-jump type, and the failure mode is shown as the thrust type. In the later stage, the free surface condition of the slope is better, and the traction type can remain as the main failure mode. On this basis, combined with the residual strong deformation block(K1, K2, K3) and morphological characteristics and deformation signs of the surrounding influence zone, this paper predicted and analyzed the deformation and failure characteristics and development trend of the block, deeming that strong deformation areas can be destroyed by gradual disintegration. And these research findings can provide some reference for the monitoring, survey and governance of the future plan making and implementation.
2
2019, 27(5): 1153-1163.
The research area of this paper is located from Diexi Township to Shidaguan Township, Maoxian County, Sichuan Province. Ten impact factors are selected according to the field data and the basic conditions of the study area. They are the slope, slope direction, section curvature, elevation, undulation, stratum, distance from the river, distance from the fault, land type and vegetation coverage. Using GIS technology as the operating platform, three methods are used to evaluate the sensitivity of landslide hazard in the study area. They are the deterministic coefficient+analytic hierarchy process(CF-AHP), the deterministic coefficient+logistic regression method(CF-LR) and the deterministic coefficient+multi-layer perceptron method of neural network(CF-MLP), The landslide hazard in this area is divided into four categories:extremely low, low, medium and high sensitive areas. The effect of the model is tested by receiver operating characteristic curve(ROC). The under-line area(AUC) of the ROC curves of the CF-AHP, CF-LR and CF-MLP combined models are 0.850, 0.884 and 0.867, respectively. The CF-LR combination model works best. In the CF-LR combination model, the areas of high, medium, low and extremely low sensitive area account for 11.3%, 25.1%, 22.5% and 41.1% of the total area of the study area, respectively. The results show that the high sensitive area is mainly located around the main water system and fault-developed area. The calculated sensitivity zoning results are close to the actual situation in field. Thus, the results are valuable for risk assessment of geological disasters.
The research area of this paper is located from Diexi Township to Shidaguan Township, Maoxian County, Sichuan Province. Ten impact factors are selected according to the field data and the basic conditions of the study area. They are the slope, slope direction, section curvature, elevation, undulation, stratum, distance from the river, distance from the fault, land type and vegetation coverage. Using GIS technology as the operating platform, three methods are used to evaluate the sensitivity of landslide hazard in the study area. They are the deterministic coefficient+analytic hierarchy process(CF-AHP), the deterministic coefficient+logistic regression method(CF-LR) and the deterministic coefficient+multi-layer perceptron method of neural network(CF-MLP), The landslide hazard in this area is divided into four categories:extremely low, low, medium and high sensitive areas. The effect of the model is tested by receiver operating characteristic curve(ROC). The under-line area(AUC) of the ROC curves of the CF-AHP, CF-LR and CF-MLP combined models are 0.850, 0.884 and 0.867, respectively. The CF-LR combination model works best. In the CF-LR combination model, the areas of high, medium, low and extremely low sensitive area account for 11.3%, 25.1%, 22.5% and 41.1% of the total area of the study area, respectively. The results show that the high sensitive area is mainly located around the main water system and fault-developed area. The calculated sensitivity zoning results are close to the actual situation in field. Thus, the results are valuable for risk assessment of geological disasters.
3
2019, 27(1): 21-28.
Based on the theory of engineering geomechanics of rock mass founded by Professor Gu Dezhen, a concept of mine hydrogeological structure was proposed based on the idea of hydrogeological structure. The types of mine water hazards was reclassified based on the concept of mine hydrogeological structure, combined with the macroscopic geological background of mines in China and foundations of mine water disaster research and controlling. The analysis of the responses of mine hydrogeological structure on mining activity provides a new idea to mine water hazard prevention and safe mining from the points of groundwater sources, pathways and mining influence, combining with the study of case histories, such as water and sand inrush, groundwater inrush from seam floor. This study shows that engineering geomechanics of rock mass plays an important role and has a strong guiding role in research of hydrogeological and engineering geological issues for coal mines.
Based on the theory of engineering geomechanics of rock mass founded by Professor Gu Dezhen, a concept of mine hydrogeological structure was proposed based on the idea of hydrogeological structure. The types of mine water hazards was reclassified based on the concept of mine hydrogeological structure, combined with the macroscopic geological background of mines in China and foundations of mine water disaster research and controlling. The analysis of the responses of mine hydrogeological structure on mining activity provides a new idea to mine water hazard prevention and safe mining from the points of groundwater sources, pathways and mining influence, combining with the study of case histories, such as water and sand inrush, groundwater inrush from seam floor. This study shows that engineering geomechanics of rock mass plays an important role and has a strong guiding role in research of hydrogeological and engineering geological issues for coal mines.
4
2019, 27(1): 55-68.
Natural gas hydrate, a pollution-free clean energy, is buried in sediments of the shallow geosphere and widely distributed, therefore considered as the most likely potential substitute resource in the oil and gas sector. Field scale exploitation of gas hydrate have been tried of 5 countries including China, especially the successful offshore production tests in Shenhu area, South China Sea, making a record of gas producing time and cumulative production. Nevertheless, there is no mature solution to realize economical and large-scale exploitation because of the special physical properties and occurrence environment of gas hydrate. In this paper, the offshore production tests carried out by China and Japan are introduced and analyzed according to fundamental understanding of gas hydrate. Our results indicated that:(1)the current production methods could be summarized into two types:in situ decomposition and stratum excavation methods. (2)The exploitation data suggested the temperature and pressure are the main constrain conditions for gas production and they works differently in different stages of production. (3)The first exploitation data of Japan showed that there's fine relevance between production rate and pressure/temperature driving force. The decomposition model based on coupled driving force were proposed using a comprehensive parameter named "distance to phase equilibrium curve". (4)According to the judgments of drastic-rapid and phased-slow depressurization methods, we presented that efficient heat injection are possibly one necessary condition for long-term exploitation of gas hydrate. Furthermore, convection heat supply and depressurization method were proposed according to the integration of hydraulic fracturing horizontal well technology in shale exploitation and the heat convection exchange cycle in hot dry rock exploitation.
Natural gas hydrate, a pollution-free clean energy, is buried in sediments of the shallow geosphere and widely distributed, therefore considered as the most likely potential substitute resource in the oil and gas sector. Field scale exploitation of gas hydrate have been tried of 5 countries including China, especially the successful offshore production tests in Shenhu area, South China Sea, making a record of gas producing time and cumulative production. Nevertheless, there is no mature solution to realize economical and large-scale exploitation because of the special physical properties and occurrence environment of gas hydrate. In this paper, the offshore production tests carried out by China and Japan are introduced and analyzed according to fundamental understanding of gas hydrate. Our results indicated that:(1)the current production methods could be summarized into two types:in situ decomposition and stratum excavation methods. (2)The exploitation data suggested the temperature and pressure are the main constrain conditions for gas production and they works differently in different stages of production. (3)The first exploitation data of Japan showed that there's fine relevance between production rate and pressure/temperature driving force. The decomposition model based on coupled driving force were proposed using a comprehensive parameter named "distance to phase equilibrium curve". (4)According to the judgments of drastic-rapid and phased-slow depressurization methods, we presented that efficient heat injection are possibly one necessary condition for long-term exploitation of gas hydrate. Furthermore, convection heat supply and depressurization method were proposed according to the integration of hydraulic fracturing horizontal well technology in shale exploitation and the heat convection exchange cycle in hot dry rock exploitation.
5
2019, 27(1): 202-207.
Coral reef is a kind of special geotechnical medium. From the perspective of engineering geology, it can be divided into two types:coral sandstone and coral reef limestone. This paper reviews the basic history of coral reef research for 30 years, focusing on the exploration and research results of the static mechanical properties, dynamic properties, low particle strength and other special mechanical properties of the coral sand soil and the engineering properties of the pile foundation. Taking the development and construction of coral reef islands in the South China Sea as a guide, more research scholars are called upon to join the research team of coral reefs to jointly promote the development of coral reef engineering geology.
Coral reef is a kind of special geotechnical medium. From the perspective of engineering geology, it can be divided into two types:coral sandstone and coral reef limestone. This paper reviews the basic history of coral reef research for 30 years, focusing on the exploration and research results of the static mechanical properties, dynamic properties, low particle strength and other special mechanical properties of the coral sand soil and the engineering properties of the pile foundation. Taking the development and construction of coral reef islands in the South China Sea as a guide, more research scholars are called upon to join the research team of coral reefs to jointly promote the development of coral reef engineering geology.
6
2019, 27(5): 966-972.
Under the long-term of water-rock interaction, the red-bed soft rock shows the characteristics of poor diagenesis, easy weathering and softening, which brings challenges to the soft rock engineering design and construction. Firstly, in order to analyze the mechanical properties of soft rock, uniaxial and triaxial compression tests are carried out on the samples of mudstone taken from the red-bed soft rock area of central Yunnan in the natural state and saturated state. Then the microstructure of soft rock in different water-bearing states is studied by X-ray diffraction. Finally, based on the experimental results, the softening mechanism is discussed. The results show that the mechanical properties of soft rock are obviously deteriorated under the action of hydro-rock, and the compressive strength of rock peak value is significantly reduced, the failure degree of rock mass increases. When the soft rock clay minerals absorb water, the microstructure changes from compact granular structure to loose and porous irregular flake structure. Clay mineral particles such as illite react with water, resulting in uneven stress and a large number of micropores, which causes the destruction of the internal structure of soft rock. The water-softening mechanism of red-bed soft rock includes the dissolution and secondary action of soft rock minerals, the water-absorbing expansion and disintegration of clay minerals, and the failure of intergranular bonding caused by the interaction between soft rock and water.
Under the long-term of water-rock interaction, the red-bed soft rock shows the characteristics of poor diagenesis, easy weathering and softening, which brings challenges to the soft rock engineering design and construction. Firstly, in order to analyze the mechanical properties of soft rock, uniaxial and triaxial compression tests are carried out on the samples of mudstone taken from the red-bed soft rock area of central Yunnan in the natural state and saturated state. Then the microstructure of soft rock in different water-bearing states is studied by X-ray diffraction. Finally, based on the experimental results, the softening mechanism is discussed. The results show that the mechanical properties of soft rock are obviously deteriorated under the action of hydro-rock, and the compressive strength of rock peak value is significantly reduced, the failure degree of rock mass increases. When the soft rock clay minerals absorb water, the microstructure changes from compact granular structure to loose and porous irregular flake structure. Clay mineral particles such as illite react with water, resulting in uneven stress and a large number of micropores, which causes the destruction of the internal structure of soft rock. The water-softening mechanism of red-bed soft rock includes the dissolution and secondary action of soft rock minerals, the water-absorbing expansion and disintegration of clay minerals, and the failure of intergranular bonding caused by the interaction between soft rock and water.
7
2019, 27(1): 88-97.
Some basic concepts or terminology, such as hazard, disaster vulnerability, risk identification, causes induced, deformation or failure mechanism and disaster modes, et al. are explained in this paper. For to serve effectively in disaster reduction, author puts up methods on the risk identification of landslide disasters which consists historic contrast, direct survey, indirect inversion, remote sensing and telemetering, dynamic monitoring and integrated analysis methods. The model Rt=[(f(a)+f(b)+f(c))d(t)+f(e)]f(v) is set up for integrated analysis of landslide disaster risk based on boundary forms(a), compositions and structures(b), initial states(c), induced factors(d), environmental effects(e) around slopes and disaster vulnerability(f) to objects bearing hazard and its changes to follow with time. Integrated risk analysis of two example, landslide-debris flow disaster happened in Jun. 24, 2017 at Xinmo village, Maoxian county, Sichuan province and rockfall-debris flow disaster happened in Aug. 28, 2017 at Pusa community, Nayong county, Guizhou province in China, have been done which includes its initial, induced and critical states by through suggested parameters based on author's personal experience. The results are coincidence comparatively with realistic situation.
Some basic concepts or terminology, such as hazard, disaster vulnerability, risk identification, causes induced, deformation or failure mechanism and disaster modes, et al. are explained in this paper. For to serve effectively in disaster reduction, author puts up methods on the risk identification of landslide disasters which consists historic contrast, direct survey, indirect inversion, remote sensing and telemetering, dynamic monitoring and integrated analysis methods. The model Rt=[(f(a)+f(b)+f(c))d(t)+f(e)]f(v) is set up for integrated analysis of landslide disaster risk based on boundary forms(a), compositions and structures(b), initial states(c), induced factors(d), environmental effects(e) around slopes and disaster vulnerability(f) to objects bearing hazard and its changes to follow with time. Integrated risk analysis of two example, landslide-debris flow disaster happened in Jun. 24, 2017 at Xinmo village, Maoxian county, Sichuan province and rockfall-debris flow disaster happened in Aug. 28, 2017 at Pusa community, Nayong county, Guizhou province in China, have been done which includes its initial, induced and critical states by through suggested parameters based on author's personal experience. The results are coincidence comparatively with realistic situation.
8
2019, 27(5): 1131-1145.
Water-induced landslide refers to the slope instability events directly caused by water-related factors(including rainfall, fluctuation of reservoir level, surface runoff, groundwater activities and others). Southwest China is a high-incidence area of water-induced landslides, especially for reservoir landslides. The water-induced landslides directly threaten the safety of human life, property and infrastructure, and may cause far-reaching secondary disasters. It is extremely urgent to improve the level of monitoring, early warning, comprehensive control and emergency disposal of water-induced landslides. Water-induced landslide can be induced in loose accumulated formation, broken rock mass, soft rock and rock slope with soft rock interlayer or weak structural plane. Long-term evolution of geological environment, hydrological conditions and human disturbance play key roles in the development of water-induced landslide. Under uninterrupted alternation of various adverse factors, the slope gradually produces deformation and local failure with the decrease of stability and tends to the limit instability state. Finally, the short-term change of hydrological conditions makes a large-scale slope instability. The dynamic process of landslide after slope instability is very complex, especially the large-scale landslide in high elevation, which can produce strong impact disturbance fragmentation and erosion with scraping along the movement course, resulting in the change of landslide movement pattern and the increase of accumulation volume. The presence of water can intensify the erosion with scraping along the movement course and lead to the change of movement pattern to fluidization, resulting in a longer movement distance and a wider disaster-causing scope. Water-induced landslide is a complex and systematic problem. The deformation and failure processes of landslides under different geological structures and hydrodynamic conditions are quite different. Long-distance, non-contact early identification and monitoring technology, early prediction and warning method for landslide based on artificial intelligence, large data and self-learning are the important development directions in the future. The prevention and control of hydrodynamic landslide is involved with many factors such as engineering construction, economy, livelihood, and society, which needs a comprehensive application of engineering measures and non-engineering measures. In the future construction of water conservancy and hydropower engineering, much attention should be paid to the hazards of reservoir landslides, and the reconstruction facilities should be apart from the affected areas of reservoir landslides as far as possible.
Water-induced landslide refers to the slope instability events directly caused by water-related factors(including rainfall, fluctuation of reservoir level, surface runoff, groundwater activities and others). Southwest China is a high-incidence area of water-induced landslides, especially for reservoir landslides. The water-induced landslides directly threaten the safety of human life, property and infrastructure, and may cause far-reaching secondary disasters. It is extremely urgent to improve the level of monitoring, early warning, comprehensive control and emergency disposal of water-induced landslides. Water-induced landslide can be induced in loose accumulated formation, broken rock mass, soft rock and rock slope with soft rock interlayer or weak structural plane. Long-term evolution of geological environment, hydrological conditions and human disturbance play key roles in the development of water-induced landslide. Under uninterrupted alternation of various adverse factors, the slope gradually produces deformation and local failure with the decrease of stability and tends to the limit instability state. Finally, the short-term change of hydrological conditions makes a large-scale slope instability. The dynamic process of landslide after slope instability is very complex, especially the large-scale landslide in high elevation, which can produce strong impact disturbance fragmentation and erosion with scraping along the movement course, resulting in the change of landslide movement pattern and the increase of accumulation volume. The presence of water can intensify the erosion with scraping along the movement course and lead to the change of movement pattern to fluidization, resulting in a longer movement distance and a wider disaster-causing scope. Water-induced landslide is a complex and systematic problem. The deformation and failure processes of landslides under different geological structures and hydrodynamic conditions are quite different. Long-distance, non-contact early identification and monitoring technology, early prediction and warning method for landslide based on artificial intelligence, large data and self-learning are the important development directions in the future. The prevention and control of hydrodynamic landslide is involved with many factors such as engineering construction, economy, livelihood, and society, which needs a comprehensive application of engineering measures and non-engineering measures. In the future construction of water conservancy and hydropower engineering, much attention should be paid to the hazards of reservoir landslides, and the reconstruction facilities should be apart from the affected areas of reservoir landslides as far as possible.
9
2019, 27(6): 1362-1370.
Numerical simulation is an important tool in the investigation of high-speed long-runout landslides. Taking the Xinmocun landslide in Maoxian as an example, this paper proposes a 3-dimensional discrete element modeling and numerical simulation method of large-scale landslide. On the basis of the micro-macro conversion formulas and numerical tests of discrete element method, it is able to get a discrete element deposition model that has similar mechanical properties as the sandstone of the landslide. Combined with the digital elevation model data and strata information, a 3-dimensional discrete element shell model is built, which follows the actual strata condition and rock mechanical properties. The initiation, high-speed sliding and accumulation process of Xinmocun landslide is simulated. The simulation results and the actual landslide accumulation are very similar in pattern and distribution, and the characteristics of velocity variation and time scale of simulated landslide coincide with the theoretical values and the measured seismic signal, which validate the reliability of the numerical simulation results and the effectiveness of the method. Source code of the numerical simulation is shared online(http://matdem.com), with which a three-dimensional model can be built quickly. This paper provides an alternative approach for the study of mechanism of high-speed long-runout landslide and the evaluation of corresponding disaster effects.
Numerical simulation is an important tool in the investigation of high-speed long-runout landslides. Taking the Xinmocun landslide in Maoxian as an example, this paper proposes a 3-dimensional discrete element modeling and numerical simulation method of large-scale landslide. On the basis of the micro-macro conversion formulas and numerical tests of discrete element method, it is able to get a discrete element deposition model that has similar mechanical properties as the sandstone of the landslide. Combined with the digital elevation model data and strata information, a 3-dimensional discrete element shell model is built, which follows the actual strata condition and rock mechanical properties. The initiation, high-speed sliding and accumulation process of Xinmocun landslide is simulated. The simulation results and the actual landslide accumulation are very similar in pattern and distribution, and the characteristics of velocity variation and time scale of simulated landslide coincide with the theoretical values and the measured seismic signal, which validate the reliability of the numerical simulation results and the effectiveness of the method. Source code of the numerical simulation is shared online(http://matdem.com), with which a three-dimensional model can be built quickly. This paper provides an alternative approach for the study of mechanism of high-speed long-runout landslide and the evaluation of corresponding disaster effects.
10
2019, 27(4): 880-889.
A method of landslide displacement prediction based on time series analysis model is proposed. It combines artificial bee colony algorithm(ABC)with support vector regression machine(SVR). The existing problems of landslide displacement prediction methods are summarized. We select Baishuihe landslide in The Gorges Reservoir area as the research object. We study the influence of landslide displacement, rainfall, reservoir water level and other factors on the change of landslide displacement with time. Firstly, the landslide displacement is decomposed into a trend term and a periodic term by time series addition model and moving average method. We use the polynomial least square method to fit and predict the trend term of landslide displacement. Then we use artificial bee colony support vector machine model to train and predict the periodic term of landslide displacement. In this paper, seven factors affecting the displacement of periodic terms are selected for the analysis. We use the grey system correlation analysis method to calculate the correlation degree between each factor and the displacement of the same period term. The total displacement prediction value of landslide is the sum of trend and periodic displacement prediction values. Compared with BP neural network and PSO-SVR model, this method has higher accuracy in landslide displacement prediction, and has better application prospects in disaster prevention and mitigation.
A method of landslide displacement prediction based on time series analysis model is proposed. It combines artificial bee colony algorithm(ABC)with support vector regression machine(SVR). The existing problems of landslide displacement prediction methods are summarized. We select Baishuihe landslide in The Gorges Reservoir area as the research object. We study the influence of landslide displacement, rainfall, reservoir water level and other factors on the change of landslide displacement with time. Firstly, the landslide displacement is decomposed into a trend term and a periodic term by time series addition model and moving average method. We use the polynomial least square method to fit and predict the trend term of landslide displacement. Then we use artificial bee colony support vector machine model to train and predict the periodic term of landslide displacement. In this paper, seven factors affecting the displacement of periodic terms are selected for the analysis. We use the grey system correlation analysis method to calculate the correlation degree between each factor and the displacement of the same period term. The total displacement prediction value of landslide is the sum of trend and periodic displacement prediction values. Compared with BP neural network and PSO-SVR model, this method has higher accuracy in landslide displacement prediction, and has better application prospects in disaster prevention and mitigation.
11
2019, 27(5): 1000-1009.
The topographic measurement of high-steep to upright slopes of complex terrain and the establishment of three-dimensional numerical models have always been puzzling geologists. In recent years, the unmanned aerial vehicle(UAV)has been widely used in geological surveys due to its small size, maneuverability, and the ability to acquire high-resolution images. This paper focuses on a new measuring and modeling method for high-steep/upright slopes with integration of UAV and many software. Firstly, on the basis of low-altitude UAV tilt photography, the Agisoft Photoscan 3D real scene modeling software and reverse engineering-based Geomagic Studio's powerful point cloud data processing function, we generate the topographic maps of high-steep/upright slope with complex terrain quickly, combine with the topographic mapping function of CASS. Subsequently, the high-steep/upright slope closed CAD surface models of complex terrain are reconstructed utilizing the CAD surface modeling function of Geomagic Studio. Then we take the advantages of the powerful geometric processing and meshing ability of Hypermesh to mesh the CAD surface models, before establishing a fine three-dimensional(3D)numerical model for high-steep/upright slopes of complex terrain. Finally, the 3D numerical model is converted into a file recognizable by FLAC3D for calculation and analysis. In order to illustrate this method in details, we take the Feitian Waterfall Scenic Spot in Shenxianju Scenic Spot in Zhejiang Province as an example. The results indicate that the use of UAV enables fast, efficient and accurate mapping and 3D modeling of high-steep/upright slopes in complex terrain. The method has the advantages of being simple and practical, fast and convenient, and strong practicality.
The topographic measurement of high-steep to upright slopes of complex terrain and the establishment of three-dimensional numerical models have always been puzzling geologists. In recent years, the unmanned aerial vehicle(UAV)has been widely used in geological surveys due to its small size, maneuverability, and the ability to acquire high-resolution images. This paper focuses on a new measuring and modeling method for high-steep/upright slopes with integration of UAV and many software. Firstly, on the basis of low-altitude UAV tilt photography, the Agisoft Photoscan 3D real scene modeling software and reverse engineering-based Geomagic Studio's powerful point cloud data processing function, we generate the topographic maps of high-steep/upright slope with complex terrain quickly, combine with the topographic mapping function of CASS. Subsequently, the high-steep/upright slope closed CAD surface models of complex terrain are reconstructed utilizing the CAD surface modeling function of Geomagic Studio. Then we take the advantages of the powerful geometric processing and meshing ability of Hypermesh to mesh the CAD surface models, before establishing a fine three-dimensional(3D)numerical model for high-steep/upright slopes of complex terrain. Finally, the 3D numerical model is converted into a file recognizable by FLAC3D for calculation and analysis. In order to illustrate this method in details, we take the Feitian Waterfall Scenic Spot in Shenxianju Scenic Spot in Zhejiang Province as an example. The results indicate that the use of UAV enables fast, efficient and accurate mapping and 3D modeling of high-steep/upright slopes in complex terrain. The method has the advantages of being simple and practical, fast and convenient, and strong practicality.
12
2019, 27(2): 325-332.
The permeability and permeability coefficient of landslide bodies are great importance to the calculation of the seepage and stability of the reservoir landslides. This paper analyses the test data of 1188 test pits(samples) from 396 landslides in the Three Gorges Reservoir Area. It gets the following conclusions:(1)According to provenance lithology of landslides in Three Gorges Reservoir Area, landslide bodies can be divided into dolomite and limestone, marlite, sand shale interbed. According to the composition structure, landslide bodies can be divided into the homogeneous fine-grained soil, soil containing gravel stone, soil clip gravel stone, crushed rock soil and fractured rock mass. (2)The permeability of landslide bodies is mainly medium and good. Moreover, it has certain regional distribution characteristics. The permeability of landslide bodies in Fengjie, Wuxi and Zhongxian is medium. And the permeability of landslide bodies in other districts is good. The permeability coefficient is positively correlated with the content of gravel stone of landslide body. The permeability of the fractured rock mass is lower than that of the crushed rock soil. (3)The average permeability coefficient of different components of landslide bodies are as follows. The permeability coefficient of homogeneous fine-grained soil is 1.28 m·d-1. The soil containing gravel stone is 1.41 m·d-1. The soil clip gravel stone is 2.56 m·d-1. The crushed rock soil is 3.84 m·d-1. And the fractured rock mass is 3.24 m·d-1.
The permeability and permeability coefficient of landslide bodies are great importance to the calculation of the seepage and stability of the reservoir landslides. This paper analyses the test data of 1188 test pits(samples) from 396 landslides in the Three Gorges Reservoir Area. It gets the following conclusions:(1)According to provenance lithology of landslides in Three Gorges Reservoir Area, landslide bodies can be divided into dolomite and limestone, marlite, sand shale interbed. According to the composition structure, landslide bodies can be divided into the homogeneous fine-grained soil, soil containing gravel stone, soil clip gravel stone, crushed rock soil and fractured rock mass. (2)The permeability of landslide bodies is mainly medium and good. Moreover, it has certain regional distribution characteristics. The permeability of landslide bodies in Fengjie, Wuxi and Zhongxian is medium. And the permeability of landslide bodies in other districts is good. The permeability coefficient is positively correlated with the content of gravel stone of landslide body. The permeability of the fractured rock mass is lower than that of the crushed rock soil. (3)The average permeability coefficient of different components of landslide bodies are as follows. The permeability coefficient of homogeneous fine-grained soil is 1.28 m·d-1. The soil containing gravel stone is 1.41 m·d-1. The soil clip gravel stone is 2.56 m·d-1. The crushed rock soil is 3.84 m·d-1. And the fractured rock mass is 3.24 m·d-1.
13
2019, 27(2): 466-476.
The deformation and failure of the loess slopes is more likely to occur during the rainfall, and have caused significant losses. In order to reduce the impact of loess landslides induced by rainfall, it is of practical significance to carry out the field experimental study on rainfall-induced landslides. The natural loess slope chosen in this article is located at Jingyang. Based on the rainfall simulation system designed by us, we designed and conducted three groups of field tests of loess slope with different rainfall intensities, aiming at investigating osmotic law and deformation and failure mode of the natural loess slopes under the different rain fall intensity. By analyzing the changes of readout of soil moisture sensors, earth pressure cells and tensiometers buried in the slope and experimental phenomenon, we obtained the deformation and failure law of field test of large loess slope under the artificial rainfall condition, and the law of water infiltration, and meanwhile we summarized deformation and failure mode of this kind of slopes. The experimental results show that, the rainfall infiltration on the loess slope present certain rules during the tests, which are:the infiltration depth and seepage rate of slope shoulder are the largest under rainfall condition, followed by slope toe, and that of middle slope location are the smallest. Moreover, the greater the rainfall intensity is, the lager the infiltration rate of loess is, the longer the infiltration time is, and the bigger the increasing range of the soil pressure and volume moisture at the same position and the decrease magnitude of the matrix suction are. Under the condition of rainfall, the deformation and failure mode of natural loess slope is:①formation and extension of erosion at the shoulder of slope; ②emergence and development of fractures in the slope surface; ③occurrence and growth of fissures at the shoulder of slope; ④local caving of the slope. If it continues to rain, some cracks at the shoulder of slope will penetrate each other gradually, the sliding surface can be subsequently formed, and landslide can occur eventually.
The deformation and failure of the loess slopes is more likely to occur during the rainfall, and have caused significant losses. In order to reduce the impact of loess landslides induced by rainfall, it is of practical significance to carry out the field experimental study on rainfall-induced landslides. The natural loess slope chosen in this article is located at Jingyang. Based on the rainfall simulation system designed by us, we designed and conducted three groups of field tests of loess slope with different rainfall intensities, aiming at investigating osmotic law and deformation and failure mode of the natural loess slopes under the different rain fall intensity. By analyzing the changes of readout of soil moisture sensors, earth pressure cells and tensiometers buried in the slope and experimental phenomenon, we obtained the deformation and failure law of field test of large loess slope under the artificial rainfall condition, and the law of water infiltration, and meanwhile we summarized deformation and failure mode of this kind of slopes. The experimental results show that, the rainfall infiltration on the loess slope present certain rules during the tests, which are:the infiltration depth and seepage rate of slope shoulder are the largest under rainfall condition, followed by slope toe, and that of middle slope location are the smallest. Moreover, the greater the rainfall intensity is, the lager the infiltration rate of loess is, the longer the infiltration time is, and the bigger the increasing range of the soil pressure and volume moisture at the same position and the decrease magnitude of the matrix suction are. Under the condition of rainfall, the deformation and failure mode of natural loess slope is:①formation and extension of erosion at the shoulder of slope; ②emergence and development of fractures in the slope surface; ③occurrence and growth of fissures at the shoulder of slope; ④local caving of the slope. If it continues to rain, some cracks at the shoulder of slope will penetrate each other gradually, the sliding surface can be subsequently formed, and landslide can occur eventually.
14
2019, 27(4): 729-736.
Two industry by-products, soda residue(SR) and ground granulated blastfurnace slag(GGBS), and sodium silicate(SS)were utilized to stabilize dredged silt at high water content. The unconfined compressive tests and X-ray diffraction were conducted to analyze the strength characteristics and the mechanism. The results indicate that the increase in dosage of SS, SR and GGBS can increase the unconfined compressive strength for the samples with the initial water content of 110%. The order of factors for strength of 3 days curing is SS > SR > GGBS. The order changes to SS > SR > GGBS for samples cured for 7 and 28 days. SS has a significant impact on the strength of 28 days curing. When the dosage of SS is fixed and the total dosage of SR and GGBS is the same, the effect of SR is stronger than that of GGBS. The hydration reaction among SS, SR, GGBS and soil minerals produces hydration products including ettringite, calcium chloro-aluminate hydrates, gismondine, and calcium silicate hydrates. They play the filling-in and cementation effects. The solidification scheme to meet the requirement of fill construction was determined. The results can provide a theoretical basis and data support for the resource utilization of SR and GGBS as stabilizer for dredged silt at high water content.
Two industry by-products, soda residue(SR) and ground granulated blastfurnace slag(GGBS), and sodium silicate(SS)were utilized to stabilize dredged silt at high water content. The unconfined compressive tests and X-ray diffraction were conducted to analyze the strength characteristics and the mechanism. The results indicate that the increase in dosage of SS, SR and GGBS can increase the unconfined compressive strength for the samples with the initial water content of 110%. The order of factors for strength of 3 days curing is SS > SR > GGBS. The order changes to SS > SR > GGBS for samples cured for 7 and 28 days. SS has a significant impact on the strength of 28 days curing. When the dosage of SS is fixed and the total dosage of SR and GGBS is the same, the effect of SR is stronger than that of GGBS. The hydration reaction among SS, SR, GGBS and soil minerals produces hydration products including ettringite, calcium chloro-aluminate hydrates, gismondine, and calcium silicate hydrates. They play the filling-in and cementation effects. The solidification scheme to meet the requirement of fill construction was determined. The results can provide a theoretical basis and data support for the resource utilization of SR and GGBS as stabilizer for dredged silt at high water content.
15
2019, 27(3): 608-622.
The evaluation targets of geological hazard susceptibility and risk assessment are the same but the evaluation contents including time, space and intensity information of geological disasters are different. This paper combines the statistical model in the susceptibility with the physical model in the risk assessment on collapse landslides, and combines the advantages of statistical model predicting spatial location information objectively with the advantages of physical model simulation including geological disaster occurrence mechanisms. It makes up for the insufficiency of regional statistical model predicting the disaster intensity information. It also effectively controls or corrects the spatial position of the physical model simulation. Then a comprehensive analysis is completed on the susceptibility and risk level of the collapse and landslide, which achieves a refined assessment of the potential high-risk location of the regional collapse and landslide. This paper takes the Longshan community in Fuding County, Fujian Province as an example. It uses data from high-definition images, terrain, boreholes and geological disasters acquired in the field. With the combination of statistical model and physical model, the refined evaluation of potential high-risk locations is completed. The research results show that:the area that needs to be focused on governance is about 26.92% of the total area of the mountain near the community. There are five areas in the community that require centralized investigation and governance. Three of them need to be focused on key governance. The potential high-risk areas coincide with the hidden danger points in the investigation area. The five high-risk areas directly threaten the safety of 180 buildings(about 360 householders). Refining the large-scale high-risk areas is delineated in field research. The feasibility of the evaluation method system is verified. The evaluation method system provides working ideas and guidance for the refined investigation and governance of regional collapse and landslide disasters.
The evaluation targets of geological hazard susceptibility and risk assessment are the same but the evaluation contents including time, space and intensity information of geological disasters are different. This paper combines the statistical model in the susceptibility with the physical model in the risk assessment on collapse landslides, and combines the advantages of statistical model predicting spatial location information objectively with the advantages of physical model simulation including geological disaster occurrence mechanisms. It makes up for the insufficiency of regional statistical model predicting the disaster intensity information. It also effectively controls or corrects the spatial position of the physical model simulation. Then a comprehensive analysis is completed on the susceptibility and risk level of the collapse and landslide, which achieves a refined assessment of the potential high-risk location of the regional collapse and landslide. This paper takes the Longshan community in Fuding County, Fujian Province as an example. It uses data from high-definition images, terrain, boreholes and geological disasters acquired in the field. With the combination of statistical model and physical model, the refined evaluation of potential high-risk locations is completed. The research results show that:the area that needs to be focused on governance is about 26.92% of the total area of the mountain near the community. There are five areas in the community that require centralized investigation and governance. Three of them need to be focused on key governance. The potential high-risk areas coincide with the hidden danger points in the investigation area. The five high-risk areas directly threaten the safety of 180 buildings(about 360 householders). Refining the large-scale high-risk areas is delineated in field research. The feasibility of the evaluation method system is verified. The evaluation method system provides working ideas and guidance for the refined investigation and governance of regional collapse and landslide disasters.
16
2019, 27(6): 1448-1455.
The rock mass structure controls the stability of the rock mass. Therefore, the geological cataloging of rock mass structure has always been an important part of rock mass engineering geology. The conventional method of cataloging the surface structure of open pit mines has the disadvantages of high risk and low efficiency. It is necessary to introduce new technologies to achieve safe and efficient geological cataloging. With the development of drones in recent years, the photos taken with the UAV-equipped camera can be used in the Structure-from -Motion to restore the 3D structure of the rock mass with the point cloud. The coordinate information of the point cloud can be used to achieve the interpretation of the occurrence of rock mass structure. Taking an open-pit mine slope in Zhejiang as an example, this paper expounds the application method and workflow of UAV photography technology in geological cataloging, and verifies the reliability of the application by comparing the occurrence of compass measurement and the occurrence of point cloud computing. It also divides the dominant occurrence of the structural plane and provides basic data support for analyzing the slope stability.
The rock mass structure controls the stability of the rock mass. Therefore, the geological cataloging of rock mass structure has always been an important part of rock mass engineering geology. The conventional method of cataloging the surface structure of open pit mines has the disadvantages of high risk and low efficiency. It is necessary to introduce new technologies to achieve safe and efficient geological cataloging. With the development of drones in recent years, the photos taken with the UAV-equipped camera can be used in the Structure-from -Motion to restore the 3D structure of the rock mass with the point cloud. The coordinate information of the point cloud can be used to achieve the interpretation of the occurrence of rock mass structure. Taking an open-pit mine slope in Zhejiang as an example, this paper expounds the application method and workflow of UAV photography technology in geological cataloging, and verifies the reliability of the application by comparing the occurrence of compass measurement and the occurrence of point cloud computing. It also divides the dominant occurrence of the structural plane and provides basic data support for analyzing the slope stability.
17
2019, 27(6): 1395-1404.
Two large landslide-debris avalanches occurred in Jinsha River at the junction of Baige Village, Bolo Township, Jiangda County, Tibet and Sichuan Province in October and November 2018, respectively. The volumes of the two landslides were about 2400×104 m3 and 850×104 m3, respectively. The two landslides moved down an average distance of 1400 m, blocked the Jinsha River and formed a barrier lake. The first natural outburst of the dam caused no casualties. However, the second landslide blocked the natural crater of the first landslide and resulted in a rapid increase in the storage capacity of the barrier lake to 3.85×108 m3. The government immediately carried out emergency measures to discharge floods by building spillways, which greatly reduced the risk of flood. In this article, a particle flow code in three dimensions(PFC3D) is adopted to simulate the occurrence, movement and accumulation of the two landslides. Based on the inversion results, we predict the movement path and accumulation scope of the potential dangerous sliding mass in Baige landslide, as well as evaluate its risk scientifically. The results show the follows. (1) Under gravity, in addition to being affected by the initial potential energy, the micro-geomorphology of the landslide is also one of the key factors determining the movement path and the distance of the particles. (2) The PFC3D particle flow numerical simulation method is suitable for landslides similar to the debris avalanche type such as Baige landslide, and the accumulation scope and thickness obtained from the two simulated landslides are basically consistent with these of the reality. (3) Using the parameters obtained from the inversion of the two events, we predict the instability process of the potentially unstable part of the source area. The unstable slope bodies can collapse and form a barrier dam with a thickness of about 70 m at the Jinsha River, which is possible to block the river again.
Two large landslide-debris avalanches occurred in Jinsha River at the junction of Baige Village, Bolo Township, Jiangda County, Tibet and Sichuan Province in October and November 2018, respectively. The volumes of the two landslides were about 2400×104 m3 and 850×104 m3, respectively. The two landslides moved down an average distance of 1400 m, blocked the Jinsha River and formed a barrier lake. The first natural outburst of the dam caused no casualties. However, the second landslide blocked the natural crater of the first landslide and resulted in a rapid increase in the storage capacity of the barrier lake to 3.85×108 m3. The government immediately carried out emergency measures to discharge floods by building spillways, which greatly reduced the risk of flood. In this article, a particle flow code in three dimensions(PFC3D) is adopted to simulate the occurrence, movement and accumulation of the two landslides. Based on the inversion results, we predict the movement path and accumulation scope of the potential dangerous sliding mass in Baige landslide, as well as evaluate its risk scientifically. The results show the follows. (1) Under gravity, in addition to being affected by the initial potential energy, the micro-geomorphology of the landslide is also one of the key factors determining the movement path and the distance of the particles. (2) The PFC3D particle flow numerical simulation method is suitable for landslides similar to the debris avalanche type such as Baige landslide, and the accumulation scope and thickness obtained from the two simulated landslides are basically consistent with these of the reality. (3) Using the parameters obtained from the inversion of the two events, we predict the instability process of the potentially unstable part of the source area. The unstable slope bodies can collapse and form a barrier dam with a thickness of about 70 m at the Jinsha River, which is possible to block the river again.
18
2019, 27(5): 1019-1026.
Soil water characteristic curve(SWCC) is a basic physical-mechanical relation of unsaturated soils and changes the physical index of water content to the mechanical index of forces among soil particles. Soil water characteristic curve is controlled by soil structures. To investigate the effect of soil structure on the SWCC, the compacted loess samples are made with three different moisture contents in the study. They are less than the optimum 8%, at the optimum 17%, and more than the optimum 19%. Mercury intrusion poroimetry(MIP) and scanning electronic method(SEM)as well as filter paper method are respectively used to explore the pore size distribution(PSD), the soil water characteristics(SWCC) and the microstructure of the compacted loess at difference water contents. It can be observed from the SWCCs and PSds that compacted loess at different moisture contents have a significant impact on the microstructure and soil water characteristics. In low suction zone, the SWCCs of three compacted loess are significantly different. The SWCC of dry of optimum is the steepest. It tends to be the same in the high suction region. The PSD varies greatly in the macro-pores and is almost the same in the micro-pores, which is similar to the SWCC. By comparing the SWCC and PSD, it is found that the pore distribution of loess compacted with different moisture content is tightly related to SWCC. The larger the pore size density, the steeper slope of SWCC. SEM imagines also show the typical characters of the three compacted soils as follows:(1)the specimen with the less optimum moisture content is dominated with large inter-particle pores; (2)the specimen with more than the optimum moisture content is dominated with smaller inter-particle pores; and (3)the specimen at the optimum has a wide range of pore distribution.
Soil water characteristic curve(SWCC) is a basic physical-mechanical relation of unsaturated soils and changes the physical index of water content to the mechanical index of forces among soil particles. Soil water characteristic curve is controlled by soil structures. To investigate the effect of soil structure on the SWCC, the compacted loess samples are made with three different moisture contents in the study. They are less than the optimum 8%, at the optimum 17%, and more than the optimum 19%. Mercury intrusion poroimetry(MIP) and scanning electronic method(SEM)as well as filter paper method are respectively used to explore the pore size distribution(PSD), the soil water characteristics(SWCC) and the microstructure of the compacted loess at difference water contents. It can be observed from the SWCCs and PSds that compacted loess at different moisture contents have a significant impact on the microstructure and soil water characteristics. In low suction zone, the SWCCs of three compacted loess are significantly different. The SWCC of dry of optimum is the steepest. It tends to be the same in the high suction region. The PSD varies greatly in the macro-pores and is almost the same in the micro-pores, which is similar to the SWCC. By comparing the SWCC and PSD, it is found that the pore distribution of loess compacted with different moisture content is tightly related to SWCC. The larger the pore size density, the steeper slope of SWCC. SEM imagines also show the typical characters of the three compacted soils as follows:(1)the specimen with the less optimum moisture content is dominated with large inter-particle pores; (2)the specimen with more than the optimum moisture content is dominated with smaller inter-particle pores; and (3)the specimen at the optimum has a wide range of pore distribution.
19
2019, 27(4): 803-810.
This paper aims to examine the collapsible loess in Xining area. The burial depth and humidifying water content are analyzed with the confined compression tests for the change regularity in the collapsible deformation and compressive deformation of loess under humidifying conditions. Qualitative analysis is carried out on the microstructure of different humidification loess samples by means of scanning electron microscopy. Macro-microscopic analysis is further carried out for the relationship between the microstructure of the loess sample and the collapse deformation. The results show the follows. (1)With the increase of water content, the amount of collapse deformation and compression under the same pressure gradually become smaller. The soil will be compressed, the strength will be increased, the compressibility will be weakened, and the collapsibility will be weakened or there will be no collapsibility when the water content increases to a certain extent. (2)Due to the influence of loess stress history on its structure and collapsibility, with the increase of burial depth and water content, the 5m loess exhibits less humidification and deformation and compressive deformation than the 3m loess. (3)With the increase of water content before and after immersion, the arrangement of pores tends to be stable, the particle distribution is gradually concentrated. The degree of agglomeration becomes higher, the proportion of pore area gradually decreases, the pore morphology gradually becomes narrow and the macroscopic humidifying deformation of loess before and after water immersion consistent performance.
This paper aims to examine the collapsible loess in Xining area. The burial depth and humidifying water content are analyzed with the confined compression tests for the change regularity in the collapsible deformation and compressive deformation of loess under humidifying conditions. Qualitative analysis is carried out on the microstructure of different humidification loess samples by means of scanning electron microscopy. Macro-microscopic analysis is further carried out for the relationship between the microstructure of the loess sample and the collapse deformation. The results show the follows. (1)With the increase of water content, the amount of collapse deformation and compression under the same pressure gradually become smaller. The soil will be compressed, the strength will be increased, the compressibility will be weakened, and the collapsibility will be weakened or there will be no collapsibility when the water content increases to a certain extent. (2)Due to the influence of loess stress history on its structure and collapsibility, with the increase of burial depth and water content, the 5m loess exhibits less humidification and deformation and compressive deformation than the 3m loess. (3)With the increase of water content before and after immersion, the arrangement of pores tends to be stable, the particle distribution is gradually concentrated. The degree of agglomeration becomes higher, the proportion of pore area gradually decreases, the pore morphology gradually becomes narrow and the macroscopic humidifying deformation of loess before and after water immersion consistent performance.
20
PROBABILITY OF COSEISMIC LANDSLIDES: A NEW GENERATION OF EARTHQUAKE-TRIGGERED LANDSLIDE HAZARD MODEL
2019, 27(5): 1122-1130.
The probability of the occurrence of coseismic landslides is basically blank. In this study, the Bayesian Probability Method and the Machine Model are used to carry out the real probability of coseismic landslides of China. The first generation of coseismic landslide hazard probability map of China is produced on the basis of nine earthquake cases. They include 1999 Chi-chi, Taiwan, 2005 Kashmir, 2008 Wenchuan, 2010 Yushu, 2013 Lushan, 2013 Minxian, 2014 Ludian, 2015 Nepal, and 2017 Jiuzhaigou earthquakes. Seven of the nine earthquakes occurred in China. The 2005 Kashmir and the 2015 Nepal quakes occurred in China's neighboring areas, which can better control the accuracy of the model. All these earthquake events have detailed and complete coseismic landslide inventories. They include 306 435 landslide polygons. Considering the real earthquake landslide occurrence area, the difference of landslide size, the ratio of landslide to non-slip sample ratio, a total of 5 117 000 samples are selected. A total of 13 factors are selected. They are absolute elevation, relative elevation, slope angle, slope aspect, slope curvature, slope position, topographic humidity index, land cover, vegetation coverage percentage, fault distance, stratum, average annual precipitation, and peak ground acceleration. The Bayesian probability method is combined with the machine learning model to establish a multi-factor impact model for the probability of earthquake-triggered landslide. Then the weights of each continuous factor and the weight of each class of the classification factor are obtained. The model is applied in China considering the peak ground acceleration as the triggering factor of landslides and considering the real probability of earthquake landslides in China under different peak ground accelerations(0.1~1 g, one result per 0.1 g, a total of 10 results). In addition, combined with Seismic Ground Motion Parameters Zonation Map of China, the corresponding true probability of earthquake-triggered landslides of China is generated.
The probability of the occurrence of coseismic landslides is basically blank. In this study, the Bayesian Probability Method and the Machine Model are used to carry out the real probability of coseismic landslides of China. The first generation of coseismic landslide hazard probability map of China is produced on the basis of nine earthquake cases. They include 1999 Chi-chi, Taiwan, 2005 Kashmir, 2008 Wenchuan, 2010 Yushu, 2013 Lushan, 2013 Minxian, 2014 Ludian, 2015 Nepal, and 2017 Jiuzhaigou earthquakes. Seven of the nine earthquakes occurred in China. The 2005 Kashmir and the 2015 Nepal quakes occurred in China's neighboring areas, which can better control the accuracy of the model. All these earthquake events have detailed and complete coseismic landslide inventories. They include 306 435 landslide polygons. Considering the real earthquake landslide occurrence area, the difference of landslide size, the ratio of landslide to non-slip sample ratio, a total of 5 117 000 samples are selected. A total of 13 factors are selected. They are absolute elevation, relative elevation, slope angle, slope aspect, slope curvature, slope position, topographic humidity index, land cover, vegetation coverage percentage, fault distance, stratum, average annual precipitation, and peak ground acceleration. The Bayesian probability method is combined with the machine learning model to establish a multi-factor impact model for the probability of earthquake-triggered landslide. Then the weights of each continuous factor and the weight of each class of the classification factor are obtained. The model is applied in China considering the peak ground acceleration as the triggering factor of landslides and considering the real probability of earthquake landslides in China under different peak ground accelerations(0.1~1 g, one result per 0.1 g, a total of 10 results). In addition, combined with Seismic Ground Motion Parameters Zonation Map of China, the corresponding true probability of earthquake-triggered landslides of China is generated.
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