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Editor Work2007 Vol. 15, No. 3
Previous Issue
2007, 15(3): 289-313.
Abstract
The internal structures of geomaterials including soil,rock,asphalt concrete and cement concrete are complicated.The internal constitutions and structure of a geomaterial determine the stress and strain distribution and control the failure mechanism and process of that geomaterial when it is subject to loading.As a tool of precise measurement and digital representation for the actual spatial distribution of the different materials and components in geomaterials,digital images have been gaining more and more applications in the internal structural analysis of geomaterials at the micro and meso-levels since 1995.This paper gives a literature review of 175 papers published in the relevant literatures on the subject.Based on the literature review,this paper analyzes and investigates the development and status of digital image processing techniques(DIP) in quantitative analysis and associated numerical simulation of the geomaterials.It includes(a) quantitative analysis of particle shapes,(b) quantitative analysis of internal structures of soil,rock,asphalt concretes and cement concrete,(c) quantitative analysis of macro-structures of rock mass in the ground,and(d) numerical modeling and simulation of geomaterials by taking into account their actual internal structures.Based on the review results,the paper discusses the development history and future trend of the utilization of the digital images and associated techniques in soil and rock.Due to the facts that they are a measuring tool of spatial distributions and a digital representation way,the digital images have a great potential for further developments and utilizations.They can be used to realize the establishment of new theories and methods for analyzing geomaterial internal structures and for taking them into account in the numerical prediction of the geomaterials under external loading.
The internal structures of geomaterials including soil,rock,asphalt concrete and cement concrete are complicated.The internal constitutions and structure of a geomaterial determine the stress and strain distribution and control the failure mechanism and process of that geomaterial when it is subject to loading.As a tool of precise measurement and digital representation for the actual spatial distribution of the different materials and components in geomaterials,digital images have been gaining more and more applications in the internal structural analysis of geomaterials at the micro and meso-levels since 1995.This paper gives a literature review of 175 papers published in the relevant literatures on the subject.Based on the literature review,this paper analyzes and investigates the development and status of digital image processing techniques(DIP) in quantitative analysis and associated numerical simulation of the geomaterials.It includes(a) quantitative analysis of particle shapes,(b) quantitative analysis of internal structures of soil,rock,asphalt concretes and cement concrete,(c) quantitative analysis of macro-structures of rock mass in the ground,and(d) numerical modeling and simulation of geomaterials by taking into account their actual internal structures.Based on the review results,the paper discusses the development history and future trend of the utilization of the digital images and associated techniques in soil and rock.Due to the facts that they are a measuring tool of spatial distributions and a digital representation way,the digital images have a great potential for further developments and utilizations.They can be used to realize the establishment of new theories and methods for analyzing geomaterial internal structures and for taking them into account in the numerical prediction of the geomaterials under external loading.
2007, 15(3): 314-321.
Due to the complexity of debris flow dynamic process,difficulties exist on the study of its constitutive model and dynamics simulation.This review begins with a survey of a number of literatures on constitutivemodelsand numerical simulation of debris flow process.Next,some important aspects are discussed.They included :(1) principle of existing constitutive models for debris flow and their applicability;(2) implement of numerical models and their application;(3) effect of environmental factors on debris flow dynamicprocess, such as stress redistribution and propagationas a result of complex geomorphological and geohydrological conditions.Finally,the potential practicability of GIS simulation for debris flow simulationis discussed.
Due to the complexity of debris flow dynamic process,difficulties exist on the study of its constitutive model and dynamics simulation.This review begins with a survey of a number of literatures on constitutivemodelsand numerical simulation of debris flow process.Next,some important aspects are discussed.They included :(1) principle of existing constitutive models for debris flow and their applicability;(2) implement of numerical models and their application;(3) effect of environmental factors on debris flow dynamicprocess, such as stress redistribution and propagationas a result of complex geomorphological and geohydrological conditions.Finally,the potential practicability of GIS simulation for debris flow simulationis discussed.
2007, 15(3): 322-327.
Panlongdong Cave,located at Huangyan county of Zhejiang Proveince,is a large-scale underground cave group left by ancient quarrying,and has been explored to be Jinxiu-Huangyan scenery site.Indicated by practical measurements,the No.3 cave of the cave group is up to the height of 64.3m,which is the highest one of known large-scale ancient underground projects in the world.In the present paper,the authors analyze possible reasons of the ancient project maintaining several hundred years of stability,and discover some ancient simple scientific ideas and lofty quarrying techniques contained in this ancient project.
Panlongdong Cave,located at Huangyan county of Zhejiang Proveince,is a large-scale underground cave group left by ancient quarrying,and has been explored to be Jinxiu-Huangyan scenery site.Indicated by practical measurements,the No.3 cave of the cave group is up to the height of 64.3m,which is the highest one of known large-scale ancient underground projects in the world.In the present paper,the authors analyze possible reasons of the ancient project maintaining several hundred years of stability,and discover some ancient simple scientific ideas and lofty quarrying techniques contained in this ancient project.
2007, 15(3): 328-337.
Neutrino Underground Laboratory is a special underground rock engineering project.Its site selection and operation put very rigorous on engineering geological conditions and engineering environment.A key question of the experiment is to find out the neutrino mixing angle(13) for particle physics,nuclear physics,celestial bodies physics and cosmography in the world.Nowadays,Reactor Neutrino Measurement of 13 is a question under discussion worldwide.The site is adjacent to Daya bay reactor with high powers of Daya Bay Nuclear Power plant.The laboratories are planed at the south foot of the Paiya Mountain with highly altitude and the enough overburden for decreasing the background.This environment is benefit to the precision of Neutrino Measurement of 13.This paper presents the analysis and assessment of engineering geological conditions.The works are based on data got from topographic survey,geologic investigation,geophysical exploration,drilling,borehole tests including geostress measurement,and lab tests etc.As a result,it is known that the rocks and tectonic conditions are simple,massive granite is with high strength,relative low geostress,groundwater is mainly limited in fissures with a low permeability coefficient.The four experiment caverns are located in rocks of Ⅰ~Ⅱ class,and the connection tunnel is sit in rocks with 81% of Ⅲ or above Ⅲ classes.After evaluation of engineering geological conditions,it is indicated that the Daya Bay neutrino underground lab will become a optimum location for measure 13 in the world because of the low investment and the high measurement precision.
Neutrino Underground Laboratory is a special underground rock engineering project.Its site selection and operation put very rigorous on engineering geological conditions and engineering environment.A key question of the experiment is to find out the neutrino mixing angle(13) for particle physics,nuclear physics,celestial bodies physics and cosmography in the world.Nowadays,Reactor Neutrino Measurement of 13 is a question under discussion worldwide.The site is adjacent to Daya bay reactor with high powers of Daya Bay Nuclear Power plant.The laboratories are planed at the south foot of the Paiya Mountain with highly altitude and the enough overburden for decreasing the background.This environment is benefit to the precision of Neutrino Measurement of 13.This paper presents the analysis and assessment of engineering geological conditions.The works are based on data got from topographic survey,geologic investigation,geophysical exploration,drilling,borehole tests including geostress measurement,and lab tests etc.As a result,it is known that the rocks and tectonic conditions are simple,massive granite is with high strength,relative low geostress,groundwater is mainly limited in fissures with a low permeability coefficient.The four experiment caverns are located in rocks of Ⅰ~Ⅱ class,and the connection tunnel is sit in rocks with 81% of Ⅲ or above Ⅲ classes.After evaluation of engineering geological conditions,it is indicated that the Daya Bay neutrino underground lab will become a optimum location for measure 13 in the world because of the low investment and the high measurement precision.
2007, 15(3): 338-345.
This paper presents the evaluation of the engineering geological conditions for a large tunnel crossing Yellow River at Zhongwei.The tunnel is to transport gas from the western China to-the eastern China and is 1197.7 7m long and 4.3 m high and 5.6 m wide.The elevation of the tunnel ceiling is 1130 m above the sea level and 100 m below the Yellow River.The surrounding rocks are the Cambrian rocks,Mopanjing Formation and include celadon and silver-gray metamorphic medium heavy bedded fine-granular feldspar quartz sandstone and phyllitic slate and sericite phyllite.The class of the surrounding rock quality is III-IV.The permeable ratio is between 4 and 67 Lu,the P-wave velocity is from 500 to 3300 ms-11.The BQ value is between 300 and 400.Modulus of deformation is between 6.11 and 9.22 GPa.Poissons ratio is between 0.14 and 0.24.The internal friction angle（） is between 42.1 and 44.7.The groundwater is the water in fissures of the bedrock.The aquifer supplied by atmospheric precipitated water is the agnostogenic rocks of the Cambrian system.The seepage capacity of a signle well is 1.0 ～50 m3 per day.The traverse rock tunnel axis is from relative intact to relative broken rocks,and has no active faults.The alignment and depth of the tunnel design is adequate and feasible.The construction and long-term operation are safe.
This paper presents the evaluation of the engineering geological conditions for a large tunnel crossing Yellow River at Zhongwei.The tunnel is to transport gas from the western China to-the eastern China and is 1197.7 7m long and 4.3 m high and 5.6 m wide.The elevation of the tunnel ceiling is 1130 m above the sea level and 100 m below the Yellow River.The surrounding rocks are the Cambrian rocks,Mopanjing Formation and include celadon and silver-gray metamorphic medium heavy bedded fine-granular feldspar quartz sandstone and phyllitic slate and sericite phyllite.The class of the surrounding rock quality is III-IV.The permeable ratio is between 4 and 67 Lu,the P-wave velocity is from 500 to 3300 ms-11.The BQ value is between 300 and 400.Modulus of deformation is between 6.11 and 9.22 GPa.Poissons ratio is between 0.14 and 0.24.The internal friction angle（） is between 42.1 and 44.7.The groundwater is the water in fissures of the bedrock.The aquifer supplied by atmospheric precipitated water is the agnostogenic rocks of the Cambrian system.The seepage capacity of a signle well is 1.0 ～50 m3 per day.The traverse rock tunnel axis is from relative intact to relative broken rocks,and has no active faults.The alignment and depth of the tunnel design is adequate and feasible.The construction and long-term operation are safe.
2007, 15(3): 346-349.
The stability of a slope in Datang Lueyang Power Plant is analyzed.This study adopts the strength-reduction theory,FLAC/SLOPE finite-difference program,elastic-plasticity Mohr-Coulomb model,as well as its failure criterion.The stability factors obtained from the study are compared with those obtained through the conventional Bishop and Janbus methods of slices.The results show that the finite-difference and strength-reduction method is more convenient and reasonable in the analysis of slope stability.It can reflect the actual slope state,and give stability factors that are closer to the actual ones.
The stability of a slope in Datang Lueyang Power Plant is analyzed.This study adopts the strength-reduction theory,FLAC/SLOPE finite-difference program,elastic-plasticity Mohr-Coulomb model,as well as its failure criterion.The stability factors obtained from the study are compared with those obtained through the conventional Bishop and Janbus methods of slices.The results show that the finite-difference and strength-reduction method is more convenient and reasonable in the analysis of slope stability.It can reflect the actual slope state,and give stability factors that are closer to the actual ones.
2007, 15(3): 350-355.
The rock mass quality classification in slopes is a complicated geology problem.It includes many factors including hydrological geology, engineering geology,rock mechanics,and excavation condition.This paper uses the fuzzy analytic hierarchy process(AHP) method for rock mass quality classification in slopes.It uses the AHP method to divided the hierarchy structure of the relevant factors,and uses the fuzzy method to compute the weight of each factor.The evaluation standards for each factor and for slope rock mass quality classification are established simultaneously.At last,the proposed method is illustrated with an example and compared with other methods.The usefulness of the proposed is verified.The proposed method can be considered as an extension of the existing method of rock mass quality classification.
The rock mass quality classification in slopes is a complicated geology problem.It includes many factors including hydrological geology, engineering geology,rock mechanics,and excavation condition.This paper uses the fuzzy analytic hierarchy process(AHP) method for rock mass quality classification in slopes.It uses the AHP method to divided the hierarchy structure of the relevant factors,and uses the fuzzy method to compute the weight of each factor.The evaluation standards for each factor and for slope rock mass quality classification are established simultaneously.At last,the proposed method is illustrated with an example and compared with other methods.The usefulness of the proposed is verified.The proposed method can be considered as an extension of the existing method of rock mass quality classification.
2007, 15(3): 356-361.
Deformation damage due to excavation unloading is a common phenomenon.It was observed in the bottom of riverbed during the excavation of a hydropower station dam foundation in Southwest China.The depth and intension of excavation unloading and intension have become a key problem in dam construction and its longtime stability.The characteristics of deformation damage in dam foundation rock mass under condition of excavation unloading area are examined by using FLAC3D software.On the basis of the in-situ unloading fissure data,numerical analysis gives the affected depth and intensity of the riverbed dam foundation due to excavation unloading in the studied zone.This result can provide the necessary information for dam foundation integrative curing and can be use as reference data for the similar projects in the future.
Deformation damage due to excavation unloading is a common phenomenon.It was observed in the bottom of riverbed during the excavation of a hydropower station dam foundation in Southwest China.The depth and intension of excavation unloading and intension have become a key problem in dam construction and its longtime stability.The characteristics of deformation damage in dam foundation rock mass under condition of excavation unloading area are examined by using FLAC3D software.On the basis of the in-situ unloading fissure data,numerical analysis gives the affected depth and intensity of the riverbed dam foundation due to excavation unloading in the studied zone.This result can provide the necessary information for dam foundation integrative curing and can be use as reference data for the similar projects in the future.
2007, 15(3): 362-369.
The creep rock mass zone B is located in the upstream of Long-Tan hydropower station.It is the typically toppling rock slope.Because of weathering,unloading and other external stress,the slope has occurred fracture and slide deformation.Then the slope stability was paid much attention by engineers.The purpose of this paper is to investigate the structural feature of the reservoir area,and to analyse the slope stability from rock mass,and then to offer the scientific evidences for slope stability in qualitative or quantitative analysis.The paper also discusses the assessment methods about rock mass quality,and proposes the concept for dynamic evaluation of rock mass quality.
The creep rock mass zone B is located in the upstream of Long-Tan hydropower station.It is the typically toppling rock slope.Because of weathering,unloading and other external stress,the slope has occurred fracture and slide deformation.Then the slope stability was paid much attention by engineers.The purpose of this paper is to investigate the structural feature of the reservoir area,and to analyse the slope stability from rock mass,and then to offer the scientific evidences for slope stability in qualitative or quantitative analysis.The paper also discusses the assessment methods about rock mass quality,and proposes the concept for dynamic evaluation of rock mass quality.
2007, 15(3): 370-373.
This paper presents the geological investigation on the characteristics of the faults observed in the engineering tunnels around Daliushu hydropower dam site.The faulting materials were used to test the latest activity age of the fault.The samples are dated younger than 120Ka by ESR dating method in laboratory.The dating results illustrate that the faults observed in the engineering tunnels around Daliushu hydropower site have not been active faults since late Pleistocene.
This paper presents the geological investigation on the characteristics of the faults observed in the engineering tunnels around Daliushu hydropower dam site.The faulting materials were used to test the latest activity age of the fault.The samples are dated younger than 120Ka by ESR dating method in laboratory.The dating results illustrate that the faults observed in the engineering tunnels around Daliushu hydropower site have not been active faults since late Pleistocene.
2007, 15(3): 374-379.
A debris flow was occurred in Yangliu stream at the Xiaotiandu hydropower station on July 11,2001.It caused severe economic losses and also affected the lower lock site of Xiaotiandu hydropower station.This paper presents the development and movement characteristics of the debris flow in Liufang stream.The examination was carried out by field investigation and computer analysis.The impact of the debris flow to the hydropower station is analyzed under different design probabilities.
A debris flow was occurred in Yangliu stream at the Xiaotiandu hydropower station on July 11,2001.It caused severe economic losses and also affected the lower lock site of Xiaotiandu hydropower station.This paper presents the development and movement characteristics of the debris flow in Liufang stream.The examination was carried out by field investigation and computer analysis.The impact of the debris flow to the hydropower station is analyzed under different design probabilities.
2007, 15(3): 380-383.
Actual values of shear strength parameters are important to rock mass as bedrock foundation of hydropower station dam.This paper presents large shear tests to measure the shear strength parameter values of the bedding planes sandstone in laboratory.The sandstone is excavated from the bedrock of a hydropower station dam.By means of the large shear tests,the characters of shear strength about sandstone structural planes are examined.Therefore good results are obtained.The tests show that the characters of the shear deformation curves are strain hardening and the displacements are up to 8.9 mm～44.5 mm before reaching to the peak points of shear strength.At the same time,the basic friction angle of the bedding plane is 31.4 .The average undulant angle of the bedding is 6.3.
Actual values of shear strength parameters are important to rock mass as bedrock foundation of hydropower station dam.This paper presents large shear tests to measure the shear strength parameter values of the bedding planes sandstone in laboratory.The sandstone is excavated from the bedrock of a hydropower station dam.By means of the large shear tests,the characters of shear strength about sandstone structural planes are examined.Therefore good results are obtained.The tests show that the characters of the shear deformation curves are strain hardening and the displacements are up to 8.9 mm～44.5 mm before reaching to the peak points of shear strength.At the same time,the basic friction angle of the bedding plane is 31.4 .The average undulant angle of the bedding is 6.3.
2007, 15(3): 384-390.
Undisturbed clay samples were taken from the Juye coal mine of 300 to 600 m below the ground surface in Shandong province.These undisturbed sample and their re-mould samples are tested in triaxial apparatus under unloading test with high pressures.The different deformation characteristics between the undisturbed and the re-mould clay samples are analyzed.A method and a structural parameter to describe the change in the deformation and strength properties of deep soil during unloading process at high pressure are put forward.Based on the results of triaxial unloading test of the clays,the structural parameter is determined.The structural constitutive model which can describe the high pressure unloading process is set up.
Undisturbed clay samples were taken from the Juye coal mine of 300 to 600 m below the ground surface in Shandong province.These undisturbed sample and their re-mould samples are tested in triaxial apparatus under unloading test with high pressures.The different deformation characteristics between the undisturbed and the re-mould clay samples are analyzed.A method and a structural parameter to describe the change in the deformation and strength properties of deep soil during unloading process at high pressure are put forward.Based on the results of triaxial unloading test of the clays,the structural parameter is determined.The structural constitutive model which can describe the high pressure unloading process is set up.
2007, 15(3): 391-394.
There are vast non-consolidated alluvia deposits freshly formed in estuary area of Yangtze River and nearby coastal area.The deposits contribute to land subsidence.Based on their distribution,two subsidence volumes of different kinds of deposits are respectively calculated due to their consolidation and underlayer soil consolidation.It is found that the subsidence induced by the deposits has a larger ratio of the total surface subsidence.And also the suggestions for the in-depth study on deposits are discussed in this paper.
There are vast non-consolidated alluvia deposits freshly formed in estuary area of Yangtze River and nearby coastal area.The deposits contribute to land subsidence.Based on their distribution,two subsidence volumes of different kinds of deposits are respectively calculated due to their consolidation and underlayer soil consolidation.It is found that the subsidence induced by the deposits has a larger ratio of the total surface subsidence.And also the suggestions for the in-depth study on deposits are discussed in this paper.
2007, 15(3): 395-398.
Conventional drainage hole technique used in geotechnical engineering is often encountered with mud or sand-induced drainage jamming.After jammed with mud or sand,the drainage hole will not have its normal function of long-term and effective drainage.For this reason,the authors present a new drainage technique of long-term drainage efficiency,i.e.fiber bundle seepage-guiding drainage hole technique.Seen from laboratory tests of comparisons,the purpose of long-term and effective drainage can be realized by using the new technique,even for an occurrence of mud or sand-induced drainage jamming.Compared with conventional drainage hole,the new-type drainage hole has the almost same cost,having a broad application foreground in geotechnical engineering.
Conventional drainage hole technique used in geotechnical engineering is often encountered with mud or sand-induced drainage jamming.After jammed with mud or sand,the drainage hole will not have its normal function of long-term and effective drainage.For this reason,the authors present a new drainage technique of long-term drainage efficiency,i.e.fiber bundle seepage-guiding drainage hole technique.Seen from laboratory tests of comparisons,the purpose of long-term and effective drainage can be realized by using the new technique,even for an occurrence of mud or sand-induced drainage jamming.Compared with conventional drainage hole,the new-type drainage hole has the almost same cost,having a broad application foreground in geotechnical engineering.
2007, 15(3): 399-402.
Using the method of extenics,a grade system for expansive soils is developed.The expansive soil at Jingmeng power plant area is examined with the method of extenics.By constriction,the estimated result is compared well with the result from the analytical method of grading distortion in the criterion.the result shows the extenics based grade system is applicable.
Using the method of extenics,a grade system for expansive soils is developed.The expansive soil at Jingmeng power plant area is examined with the method of extenics.By constriction,the estimated result is compared well with the result from the analytical method of grading distortion in the criterion.the result shows the extenics based grade system is applicable.
2007, 15(3): 403-406.
Ground water is the key factor that does more harm to the foundation pit project.How to analyze and examine the effect of ground water on the project is a challenging and important subject.This paper,analyzes the change of interface with the variety of ground water by taking into account the destruction effect of ground water.It derives the equation to calculate the critical angel of planar slide under saturated condition.When the area of interface A* and are smaller,the critical angel of failure is smaller.However,the increase of ground water pressure can reduce the area of interface A*,which shows the ground water pressure makes the soil mass is easier to fail.
Ground water is the key factor that does more harm to the foundation pit project.How to analyze and examine the effect of ground water on the project is a challenging and important subject.This paper,analyzes the change of interface with the variety of ground water by taking into account the destruction effect of ground water.It derives the equation to calculate the critical angel of planar slide under saturated condition.When the area of interface A* and are smaller,the critical angel of failure is smaller.However,the increase of ground water pressure can reduce the area of interface A*,which shows the ground water pressure makes the soil mass is easier to fail.
2007, 15(3): 407-411.
The author in this paper analyzed the cracking forms of walls over ground fissures with non-linear finite element method.The originated position,dip direction,dip angle and later mode of the cracks on walls are accomplished when the walls crossing over ground fissures with three-dimensional activity,and the changing law varying with different ratio of sedimentation and tensor are got.The results show that,there are two types of cracks generating on walls: the vertical cracks on top of walls located in footwall and the skew cracks at the bottom of walls just above ground fissures.The dip direction of the skew cracks is opposite to that of ground fissures.When the activity of ground fissures is mainly the tensor,the skew cracks at the bottom of walling expand upward with high angel;but when the activity is mainly the sedimentation,then the skew cracks expand upward with low angel.The walls could be broken so long as there was minute dislocation,generally 2～3 mm distance,occurred to the ground fissures.And the cracks expand quickly that several millimeters dislocation can make the cracks expand tens of centimeters,even finally breakthrough the walls.At the early developmental stage,the skew cracks are relatively flat,but with the quick expansion of cracks,the dip angles become lower.The later mode of the cracks likes a flexural arc.
The author in this paper analyzed the cracking forms of walls over ground fissures with non-linear finite element method.The originated position,dip direction,dip angle and later mode of the cracks on walls are accomplished when the walls crossing over ground fissures with three-dimensional activity,and the changing law varying with different ratio of sedimentation and tensor are got.The results show that,there are two types of cracks generating on walls: the vertical cracks on top of walls located in footwall and the skew cracks at the bottom of walls just above ground fissures.The dip direction of the skew cracks is opposite to that of ground fissures.When the activity of ground fissures is mainly the tensor,the skew cracks at the bottom of walling expand upward with high angel;but when the activity is mainly the sedimentation,then the skew cracks expand upward with low angel.The walls could be broken so long as there was minute dislocation,generally 2～3 mm distance,occurred to the ground fissures.And the cracks expand quickly that several millimeters dislocation can make the cracks expand tens of centimeters,even finally breakthrough the walls.At the early developmental stage,the skew cracks are relatively flat,but with the quick expansion of cracks,the dip angles become lower.The later mode of the cracks likes a flexural arc.
2007, 15(3): 412-415.
The technique of anti-sliding piles with prestressed cable anchors is an effective measure in landslide treatment.Compared with common anti-sliding piles,anti-sliding piles with prestressed cable anchors result in a more reasonable force bearing state.This paper,on the basis of simple hypothesis,presents the physical model and computing diagram of piles with with prestressed cable anchors,derives the anchor in the pile body free position formula,establishes a simple procedure realization moment and stress computational scheme.This method can be used to determine the most superior anchor angle and the most superior position,which will effectively reduce the anti-slide pile moment and fully display anchor function.Finally,a case of the BaoTa mountain of Yanan landslide treatment is given and the practical result is discussed.
The technique of anti-sliding piles with prestressed cable anchors is an effective measure in landslide treatment.Compared with common anti-sliding piles,anti-sliding piles with prestressed cable anchors result in a more reasonable force bearing state.This paper,on the basis of simple hypothesis,presents the physical model and computing diagram of piles with with prestressed cable anchors,derives the anchor in the pile body free position formula,establishes a simple procedure realization moment and stress computational scheme.This method can be used to determine the most superior anchor angle and the most superior position,which will effectively reduce the anti-slide pile moment and fully display anchor function.Finally,a case of the BaoTa mountain of Yanan landslide treatment is given and the practical result is discussed.
2007, 15(3): 416-421.
The author in this paper introduces the treatment design of the mountainside high steep soft soil subgrade of No.2 worksit of No.9 contract section of Ruian Longtou-Cangnan Shuiguan in Ning-Tai-Wen express highway.This geology condition of this worksite is special,half of the subgrade Is located on a slope hillside with better geology condition;and the other half is located in the paddy field with mainre deposit,the thickness of the silt seam is 3.2～7.2m.
The author in this paper introduces the treatment design of the mountainside high steep soft soil subgrade of No.2 worksit of No.9 contract section of Ruian Longtou-Cangnan Shuiguan in Ning-Tai-Wen express highway.This geology condition of this worksite is special,half of the subgrade Is located on a slope hillside with better geology condition;and the other half is located in the paddy field with mainre deposit,the thickness of the silt seam is 3.2～7.2m.
2007, 15(3): 422-427.
Presently,in tunnel surrounding rockmass stress field, elastoplasticanalysis often uses the Mohr-Coulomb criterion,which doesnt consider the principal stress.The paper selects the II kind of rock materialin Miller,R.Ps experiment.Taking the circular tunnel as the research object which has integrity formationin rockmass.Then inferred circular tunnel newelastoplastic solution,such as the stress of surrounding rockmass,plastic area radius by using the unification theory of strength. and ,the introduction parameter,get their expression in two strength indexessystem ,fc and c,.Then,author has analyzed the relationship among strength indexs by curves.The solutions based onmodifiedFenner formulaand Kastner formulais the reduced forms of new elastoplastic solusions in b=0 situation.Finally,some new conclusions has obtained,which doesthe good guiding sense to the project practice.
Presently,in tunnel surrounding rockmass stress field, elastoplasticanalysis often uses the Mohr-Coulomb criterion,which doesnt consider the principal stress.The paper selects the II kind of rock materialin Miller,R.Ps experiment.Taking the circular tunnel as the research object which has integrity formationin rockmass.Then inferred circular tunnel newelastoplastic solution,such as the stress of surrounding rockmass,plastic area radius by using the unification theory of strength. and ,the introduction parameter,get their expression in two strength indexessystem ,fc and c,.Then,author has analyzed the relationship among strength indexs by curves.The solutions based onmodifiedFenner formulaand Kastner formulais the reduced forms of new elastoplastic solusions in b=0 situation.Finally,some new conclusions has obtained,which doesthe good guiding sense to the project practice.
2007, 15(3): 428-432.
The three-dimensional laser scan technology.also named the real-life scenery duplication technique,is another important technological revolution in surveying and mapping field after the Global Position System(GPS) technology.It has high efficiency and high precision.The three-dimensional point cloud data of the scanned object surface can be acquired by using the three-dimensional laser scan technology.Therefore,the technology can be used in gaining digital terrain models(DTM) with high accuracy and resolution.This paper will discuss the method of using the technology in quickly gaining DTM.A cut slope project is used as example.The method includes acquiring,aligning,coordinate adjusting,,de-noising and formating of digital elevation model.It is feasibility that the high accurate and resolution digital terrain model can be acquired using the technology within certain space.
The three-dimensional laser scan technology.also named the real-life scenery duplication technique,is another important technological revolution in surveying and mapping field after the Global Position System(GPS) technology.It has high efficiency and high precision.The three-dimensional point cloud data of the scanned object surface can be acquired by using the three-dimensional laser scan technology.Therefore,the technology can be used in gaining digital terrain models(DTM) with high accuracy and resolution.This paper will discuss the method of using the technology in quickly gaining DTM.A cut slope project is used as example.The method includes acquiring,aligning,coordinate adjusting,,de-noising and formating of digital elevation model.It is feasibility that the high accurate and resolution digital terrain model can be acquired using the technology within certain space.
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