2003 Vol. 11, No. 3
2003, 11(3): 225-229.
Engineering-geological zoning of plateau permafrost area by using remote sensing technique has great advantage. Qinghai-Tibeten plateau permafrost area is divided into three engineering-geological zones and ten sub-zones. The selecting Qingzang railway line is used as an example to illustrate the effectiveness of remote sensing interpretation in engineering-geological zoning of plateau permafrost area.The interpreted features of the Qingzang plateau permafrost area are systematically expounded.
Engineering-geological zoning of plateau permafrost area by using remote sensing technique has great advantage. Qinghai-Tibeten plateau permafrost area is divided into three engineering-geological zones and ten sub-zones. The selecting Qingzang railway line is used as an example to illustrate the effectiveness of remote sensing interpretation in engineering-geological zoning of plateau permafrost area.The interpreted features of the Qingzang plateau permafrost area are systematically expounded.
2003, 11(3): 230-238.
The boundary river bank collapse is a main and special geologic hazard in Heilong jiang Prorince. This problem is must be resolved as soon as possible.In this paper, we summarize the river banks collapse situation of the two main rivers, Heilongjiang and Wusuli rivers in Heilongjiang Province, find the distribution regularities of the band collapses of the boundary river banks collapses, identifized, discussed the formation mechanism of the collapses and analysed the causes for the boundary river banks collapses. Finally, a series of the morphologic types prevention and control measures is suggested for the boundary river banks collapses.
The boundary river bank collapse is a main and special geologic hazard in Heilong jiang Prorince. This problem is must be resolved as soon as possible.In this paper, we summarize the river banks collapse situation of the two main rivers, Heilongjiang and Wusuli rivers in Heilongjiang Province, find the distribution regularities of the band collapses of the boundary river banks collapses, identifized, discussed the formation mechanism of the collapses and analysed the causes for the boundary river banks collapses. Finally, a series of the morphologic types prevention and control measures is suggested for the boundary river banks collapses.
2003, 11(3): 239-243.
Based on the past classification of preferred plane, a gray cluster method is used for evaluating preferred plane controlling the regional stability in this paper. Compared with the previous elevation method, the gray cluster evaluation overcomes the strict numerical value limits and is a valuable evaluation method.
Based on the past classification of preferred plane, a gray cluster method is used for evaluating preferred plane controlling the regional stability in this paper. Compared with the previous elevation method, the gray cluster evaluation overcomes the strict numerical value limits and is a valuable evaluation method.
2003, 11(3): 244-249.
Using linear elastic finite element model for piles and pile cap, elastic-plastic finite element model for piles-surrounding soil under pile cap, linear elastic infinite element model for soil around pile group, and mounting interface element on the pile-soil interfaces, 3-D elastic-plastic finite element method is used to analyzing the pile-soil-cap interaction. It is found that under pile cap, the distribution law of the pile-top load is behaves as follow: the load exerted to the corner piles is largest to the side piles next, and to the middle pile lowest. The pile-top loads are uniformly distributed along with increasing load exerted on the pile cap, the skin friction of piles gradually develops from the pile-end towards the pile-top. The pile cap has a weakening effect on the skin friction of piles upside. To verify the results, a static load test on a nine pile group under pile cap performed. It is found that the obtained results from the proposed are matched for the results of the experimental test.
Using linear elastic finite element model for piles and pile cap, elastic-plastic finite element model for piles-surrounding soil under pile cap, linear elastic infinite element model for soil around pile group, and mounting interface element on the pile-soil interfaces, 3-D elastic-plastic finite element method is used to analyzing the pile-soil-cap interaction. It is found that under pile cap, the distribution law of the pile-top load is behaves as follow: the load exerted to the corner piles is largest to the side piles next, and to the middle pile lowest. The pile-top loads are uniformly distributed along with increasing load exerted on the pile cap, the skin friction of piles gradually develops from the pile-end towards the pile-top. The pile cap has a weakening effect on the skin friction of piles upside. To verify the results, a static load test on a nine pile group under pile cap performed. It is found that the obtained results from the proposed are matched for the results of the experimental test.
2003, 11(3): 250-257.
From the engineering-geological data of marine soft soil in Lianyungang, statistical characteristics of physical and mechanical indexes of marine soft soil in study region are analyzed systematically in comparison with physical and mechanical indexes of soft soil in other coastal regions of China, and then the characteristics of shear strength, consolidation deformation and creep of the marine soft soil are studied. The relationship between these indexes are obtained by using linear regression analysis. Finally, some methods for treatment of the soil are put forward.
From the engineering-geological data of marine soft soil in Lianyungang, statistical characteristics of physical and mechanical indexes of marine soft soil in study region are analyzed systematically in comparison with physical and mechanical indexes of soft soil in other coastal regions of China, and then the characteristics of shear strength, consolidation deformation and creep of the marine soft soil are studied. The relationship between these indexes are obtained by using linear regression analysis. Finally, some methods for treatment of the soil are put forward.
2003, 11(3): 258-262.
In order to understand a large amount of fuzzy and uncertain factors of red slate rock materials in geotechnical engineering, an implicit constitutive model is established on the basic of ANN(artificial neural network) method and experiment on geotechnical materials. In the paper, the ANN s learning and training are done directly on the experimental results, the knowledge of mechanical behaviors of the materials can be obtained and stored in the weight structure of a multilayer feed forward back-propagation neural network, and hence we obtain an implicit constitutive model expressing stress-strain relationships of geotechnical materials.
In order to understand a large amount of fuzzy and uncertain factors of red slate rock materials in geotechnical engineering, an implicit constitutive model is established on the basic of ANN(artificial neural network) method and experiment on geotechnical materials. In the paper, the ANN s learning and training are done directly on the experimental results, the knowledge of mechanical behaviors of the materials can be obtained and stored in the weight structure of a multilayer feed forward back-propagation neural network, and hence we obtain an implicit constitutive model expressing stress-strain relationships of geotechnical materials.
2003, 11(3): 263-268.
The main factors influencing rockburst are analyzed, the complex non-linear relation between the factors are firstly simulated on neural network model and remove the influences of artificial choosing the risk indexes in traditional methods. Test result shows that the model is reliable and precise and provides basis for application of the artificial intelligence to rockburst prediction.
The main factors influencing rockburst are analyzed, the complex non-linear relation between the factors are firstly simulated on neural network model and remove the influences of artificial choosing the risk indexes in traditional methods. Test result shows that the model is reliable and precise and provides basis for application of the artificial intelligence to rockburst prediction.
2003, 11(3): 269-274.
Regarding several main factors influencing the classification of underground construction surrounding rocks as the fuzzy subsets in evaluating surrounding rock classification, and using a fuzzy inference system established for the underground works surrounding rock classification, we can obtain the result of the detemined rock types consistent with the actual local case. The result provides a basis for information design and construction of underground works.
Regarding several main factors influencing the classification of underground construction surrounding rocks as the fuzzy subsets in evaluating surrounding rock classification, and using a fuzzy inference system established for the underground works surrounding rock classification, we can obtain the result of the detemined rock types consistent with the actual local case. The result provides a basis for information design and construction of underground works.
2003, 11(3): 275-279.
Shock liquefaction of sand layers is a principal engineering geological problem for the Hadashan water conservancy project. An in-depth study has been carried out on it through numerous tests and comprehensive analysis, including SPT, GJS undisturbed sampling, OYO-3000 density log and Rayleigh wave measurement. The obtained results provide an important basis for dam foundation treatment. In this study, the Rayleigh wave measurement technique is first used for assessment of shock liquefaction of sand layers.
Shock liquefaction of sand layers is a principal engineering geological problem for the Hadashan water conservancy project. An in-depth study has been carried out on it through numerous tests and comprehensive analysis, including SPT, GJS undisturbed sampling, OYO-3000 density log and Rayleigh wave measurement. The obtained results provide an important basis for dam foundation treatment. In this study, the Rayleigh wave measurement technique is first used for assessment of shock liquefaction of sand layers.
2003, 11(3): 280-284.
An optimization method is used to design the anti-slide pile at given load or internal stress. The optimization method consider the structure cost as an object function to obtain the best designing parameters, which must satisfy the engineering operation requirements as well as the byelaw demanded in the code. Compared with the traditional designing method, the optimation result can considerably reduce the total cost of the piles.
An optimization method is used to design the anti-slide pile at given load or internal stress. The optimization method consider the structure cost as an object function to obtain the best designing parameters, which must satisfy the engineering operation requirements as well as the byelaw demanded in the code. Compared with the traditional designing method, the optimation result can considerably reduce the total cost of the piles.
2003, 11(3): 285-287.
The composite pile-geonets is effective to consolidate soft foundation for some constructions which have special requirement for non-uniform settlement and residual deformation, because its interaction mechanism and loading transmission is a complex problem. In this paper the stress dispersion principle is applied to estimating the loading on geotextile and pile, then the tensile strength and secant modulus are calculated. The result provides a theoretical basis for designing pile-geonets.
The composite pile-geonets is effective to consolidate soft foundation for some constructions which have special requirement for non-uniform settlement and residual deformation, because its interaction mechanism and loading transmission is a complex problem. In this paper the stress dispersion principle is applied to estimating the loading on geotextile and pile, then the tensile strength and secant modulus are calculated. The result provides a theoretical basis for designing pile-geonets.
2003, 11(3): 288-296.
Based on the experiment, monitoring and analysis of roaded settlement, horizontal displacement, temperature, and embankment temperature in Qinghaihe Station of Qinghai-Tibet railway, this paper analyzes the effect of the widened roaded temperature field and deformation.
Based on the experiment, monitoring and analysis of roaded settlement, horizontal displacement, temperature, and embankment temperature in Qinghaihe Station of Qinghai-Tibet railway, this paper analyzes the effect of the widened roaded temperature field and deformation.
2003, 11(3): 297-301.
A new method for training the artificial neural network is presented. In this method, the genetic algorithm is used to train network with updating the weights and the valves to minimize the error between the network output and the desired output. Then the back propagation(BP) algorithm is used to further train the artificial neural network. A new method of using the course of training BP network to get mutation is expounded. For the mutation of the genetic algorithm, the choice and the mutation of the genetic algorithm is studied. As an example, the method was used to predict horizontal displacement of deformation of support structure to foundation pit . The result suggests that the method is feasible.
A new method for training the artificial neural network is presented. In this method, the genetic algorithm is used to train network with updating the weights and the valves to minimize the error between the network output and the desired output. Then the back propagation(BP) algorithm is used to further train the artificial neural network. A new method of using the course of training BP network to get mutation is expounded. For the mutation of the genetic algorithm, the choice and the mutation of the genetic algorithm is studied. As an example, the method was used to predict horizontal displacement of deformation of support structure to foundation pit . The result suggests that the method is feasible.
2003, 11(3): 302-306.
A sandy-soil sample buried at nearly 600m depth in the Juye mine area of Shandong Province was tested under, triaxial unloading at 12MPa confining pressure on triaxial test machine and the microstructural change of the sandy-soil sample in the whole process was detected by CT equipment. The CT photographs are processed and analyzed with computer image analysis method. The essential characteristics of structural change of the deep buried sand soil sampling . The deformation and failure processes under the condition of high pressure unloading test are analyzed.
A sandy-soil sample buried at nearly 600m depth in the Juye mine area of Shandong Province was tested under, triaxial unloading at 12MPa confining pressure on triaxial test machine and the microstructural change of the sandy-soil sample in the whole process was detected by CT equipment. The CT photographs are processed and analyzed with computer image analysis method. The essential characteristics of structural change of the deep buried sand soil sampling . The deformation and failure processes under the condition of high pressure unloading test are analyzed.
2003, 11(3): 307-311.
Radon measurement is a geophysical radiometry. We can use the radon measurement to investigate landslide and to study the structural characteristics, as the structural difference between slip mass and the rock and soil mass around it. The method is of low cost and short duration of exploration, and can be verified with geologic alanalys, so as to provide a basis for engineering practice.
Radon measurement is a geophysical radiometry. We can use the radon measurement to investigate landslide and to study the structural characteristics, as the structural difference between slip mass and the rock and soil mass around it. The method is of low cost and short duration of exploration, and can be verified with geologic alanalys, so as to provide a basis for engineering practice.
2003, 11(3): 312-317.
The effects of the elastic-plastic parameters of a buried weak layer on seismic ground motion amplification are modelled. It is found that significant amplification would occur at certain frequencies when the shear wave velocity in the weak layer is no higher than 30% of that in surrounding layers. It is found that shear wave velocity mainly affects the amplification strength of the buried weak layer, while other elastic parameters, such as density and quality factor, have no significant effects on it. It is also found that the strength is controlled by a certain relationship between the shear wave velocity and the thickness of the weak layer. Further analytical study is yet required to reveal the relationship.
The effects of the elastic-plastic parameters of a buried weak layer on seismic ground motion amplification are modelled. It is found that significant amplification would occur at certain frequencies when the shear wave velocity in the weak layer is no higher than 30% of that in surrounding layers. It is found that shear wave velocity mainly affects the amplification strength of the buried weak layer, while other elastic parameters, such as density and quality factor, have no significant effects on it. It is also found that the strength is controlled by a certain relationship between the shear wave velocity and the thickness of the weak layer. Further analytical study is yet required to reveal the relationship.
2003, 11(3): 318-322.
In order to study the deformation cause of reactivated landslide in a high seismic intensity area, the authors firstly systematically analyze the dynamic properties of soil in slide zone in cyclic triaxial test . The disturbed soil samples, physical properties of which are prepared to be field test index are tested on triaxial compressor under unconsolidated-undrained condition, with confining pressure of 100kPa, 200kPa and 300kPa and a step by step increasing dynamic load. Analyzing the environmental condition of the landslide in combination with high seismic intensity in the region, the seismic response properties of soil in slide zone are systematically sdutied. The result shows that there is a lot of difference between the dynamic and the static properties, for example, the nonlinear relation between dynamic stress and strain, dynamic elasticity modulus and dynamic strength of the soil markedly reduce, but damping ratio increases. The study provides an important theoretical basis for evaluating the sliding of the landslide.
In order to study the deformation cause of reactivated landslide in a high seismic intensity area, the authors firstly systematically analyze the dynamic properties of soil in slide zone in cyclic triaxial test . The disturbed soil samples, physical properties of which are prepared to be field test index are tested on triaxial compressor under unconsolidated-undrained condition, with confining pressure of 100kPa, 200kPa and 300kPa and a step by step increasing dynamic load. Analyzing the environmental condition of the landslide in combination with high seismic intensity in the region, the seismic response properties of soil in slide zone are systematically sdutied. The result shows that there is a lot of difference between the dynamic and the static properties, for example, the nonlinear relation between dynamic stress and strain, dynamic elasticity modulus and dynamic strength of the soil markedly reduce, but damping ratio increases. The study provides an important theoretical basis for evaluating the sliding of the landslide.
2003, 11(3): 323-327.
Based on the laboratory geomechanical model test, the interaction mechanism between landslide deformation and tunnels, the variation regularities of the pressure in surrounding rocks and lining,the deformation features of landslides and tunnels are studied. The interaction relationship between landslide deformation and tunnels during sliding plane softening with water and creep occur is emphatically studied. The study result provides a scientific basis for prediction and treatment of the deformed tunnel.
Based on the laboratory geomechanical model test, the interaction mechanism between landslide deformation and tunnels, the variation regularities of the pressure in surrounding rocks and lining,the deformation features of landslides and tunnels are studied. The interaction relationship between landslide deformation and tunnels during sliding plane softening with water and creep occur is emphatically studied. The study result provides a scientific basis for prediction and treatment of the deformed tunnel.
2003, 11(3): 328-333.
Taking the soft soil on river beach as research object and settlement plates,deflection inclinometer, and piezometer as testing apparatus, the stability and settlement of representative sections of the beach were observed for more than one year. By analysis of the observed data, a settlement regularity was found and its coefficient - ms was calculated. The obtained result it will be of significanace in construction of high-grade highway on the beach soft soil in the future.
Taking the soft soil on river beach as research object and settlement plates,deflection inclinometer, and piezometer as testing apparatus, the stability and settlement of representative sections of the beach were observed for more than one year. By analysis of the observed data, a settlement regularity was found and its coefficient - ms was calculated. The obtained result it will be of significanace in construction of high-grade highway on the beach soft soil in the future.
2003, 11(3): 334-336.