Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint s...Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint sets.A new method based on the space geometric and mechanical properties of the modified crack tensor is proposed,providing an analytical solution for the equivalent elastic compliance tensor of rock mass.A series of experiments validate the capability of the compliance tensor to accurately represent the deformation of rock mass with multiple persistent joint sets,based on conditions set by the basic hypothesis.The spatially varying rules of the equivalent elastic parameters of rock mass with a single joint set are analyzed to reveal the universal law of the stratified rock mass.展开更多
To investigate the influence of different joint conditions on the rockburst of a circular tunnel,a true-triaxial test of rockburst with a single set of joint conditions was conducted.The rockburst incubation and evolu...To investigate the influence of different joint conditions on the rockburst of a circular tunnel,a true-triaxial test of rockburst with a single set of joint conditions was conducted.The rockburst incubation and evolution characteristics and acoustic emission evolution characteristics under different joint directions and joint dip angles were studied.The Weibull function was used to fit rockburst debris with different particle sizes and a single set of joints to obtain statistical results.The experimental results revealed that shear fracture rockburst occurred in samples with joints aligned with the tunnel strike as well as joints with inclination angles of 45°,60°,and 90°.Slab buckling–shear fracture rockburst was more likely to occur in samples with inclination angles of 0°and 30°.Slab buckling–shear fracture rockburst occurred in samples with joints crossing the tunnel strike as well as in samples with joints with inclination angles of 0°,30°,45°,60°,and 90°.The location of the rockburst pit was influenced by the joint inclination angle when the joints aligned with the tunnel strike.In contrast,when the joints crossed the tunnel strike,the location of the rockburst pit was independent of the joint inclination angle.The cumulative absolute energy of acoustic emission(AE)exhibited an overall upward trend with the increase in joint dip angle.The cumulative absolute energy of the AE of the jointed samples was greater than that of intact samples(without joints).Loading reached the rockburst stage in the samples with joints aligned with the tunnel strike and dip angles of 45°,60°,and 90°.Moreover,the peak value of AE cumulative absolute energy was the highest.These results can elucidate the evolution mechanism of rockburst in the surrounding rock of circular tunnels with a single set of joints in deep underground engineering.展开更多
If you are representing a foreign-funded institution in setting up a foreign-funded bank or financial company in Shanghai, you should have a representative agency already established within the boundaries of China for...If you are representing a foreign-funded institution in setting up a foreign-funded bank or financial company in Shanghai, you should have a representative agency already established within the boundaries of China for more than two years, and general assets at the end of the previous year should not be less than US $ 10 billion. The country or region you are residing in should have展开更多
Tors are mound-like rock landforms,resistant to erosion,that may sometimes reach the size of several storeys of house by volume.They may develop in different climate regions and different rock types,led by granitic ro...Tors are mound-like rock landforms,resistant to erosion,that may sometimes reach the size of several storeys of house by volume.They may develop in different climate regions and different rock types,led by granitic rocks.In this study,tors developed in granitic rocks around Yaylal?village linked to Kürtün county in Gümü?hane were investigated.The study area is located in the eastern part of the Giresun mountain range in northeastern Turkey,2000-2300 m above sea level.The aim of the study is to determine the natural environmental characteristics in tor formation and to reveal the effect of bedrock on tor formation.During field studies,18 tors were selected by noting location,size and structural features,and dimensions were measured.Thin sections were first made from the rock samples taken from the tors and then the mineralogical composition was investigated by modal analysis method.As a result of this analysis,it was determined that the bedrock forming the tors is granite.During the field observations,it was determined that the intersecting vertical joints supported the formation of castle-like tors,while the horizontal joints supported the formation of pita pileshaped tors.There are also pseudokarstic shapes resembling kamenitza and karst pavement.In conclusion,joint sets causing local resistance differences directed the formation of tors,while excess slope affected surface erosion and suitability of climate conditions-controlled weathering rate.展开更多
In core logging, each joint set intersects borehole into some segments. In this research, it has been shown that length of the borehole segments created by each joint set could be computed by trigonometrical relations...In core logging, each joint set intersects borehole into some segments. In this research, it has been shown that length of the borehole segments created by each joint set could be computed by trigonometrical relations. By realizing the lengths associated with joint sets, an algorithm has been designed to compute the length of borehole pieces (created by all joint sets) and to calculate RQD. Effect of some factors have been analyzed and applied to the abstract model of the rock mass to have the most similarity to a real rock mass. The program proposed in this study, is a robust platform to calculate the RQD in all directions inside a rock mass without having to deal with the labor of core logging and wrestling with difficulties and inaccuracies of the traditional processes. This is the first algorithmic method for estimating the rock quality which could be employed to develop a new and far more reliable measurement for the degree of jointing inside a rock mass.展开更多
基金Projects(41172284,51379202) supported by the National Natural Science Foundation of ChinaProject(2013CB036405) supported by the National Basic Research Program of ChinaProject(2013BAB02B01) supported by the National Key Technologies R&D Program of China
文摘Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint sets.A new method based on the space geometric and mechanical properties of the modified crack tensor is proposed,providing an analytical solution for the equivalent elastic compliance tensor of rock mass.A series of experiments validate the capability of the compliance tensor to accurately represent the deformation of rock mass with multiple persistent joint sets,based on conditions set by the basic hypothesis.The spatially varying rules of the equivalent elastic parameters of rock mass with a single joint set are analyzed to reveal the universal law of the stratified rock mass.
基金funded by the National Natural Science Foundation of China(Grant Nos.52364005,51934003)Yunnan major scientific and technological special project(202202AG050014).This support is gratefully acknowledged.
文摘To investigate the influence of different joint conditions on the rockburst of a circular tunnel,a true-triaxial test of rockburst with a single set of joint conditions was conducted.The rockburst incubation and evolution characteristics and acoustic emission evolution characteristics under different joint directions and joint dip angles were studied.The Weibull function was used to fit rockburst debris with different particle sizes and a single set of joints to obtain statistical results.The experimental results revealed that shear fracture rockburst occurred in samples with joints aligned with the tunnel strike as well as joints with inclination angles of 45°,60°,and 90°.Slab buckling–shear fracture rockburst was more likely to occur in samples with inclination angles of 0°and 30°.Slab buckling–shear fracture rockburst occurred in samples with joints crossing the tunnel strike as well as in samples with joints with inclination angles of 0°,30°,45°,60°,and 90°.The location of the rockburst pit was influenced by the joint inclination angle when the joints aligned with the tunnel strike.In contrast,when the joints crossed the tunnel strike,the location of the rockburst pit was independent of the joint inclination angle.The cumulative absolute energy of acoustic emission(AE)exhibited an overall upward trend with the increase in joint dip angle.The cumulative absolute energy of the AE of the jointed samples was greater than that of intact samples(without joints).Loading reached the rockburst stage in the samples with joints aligned with the tunnel strike and dip angles of 45°,60°,and 90°.Moreover,the peak value of AE cumulative absolute energy was the highest.These results can elucidate the evolution mechanism of rockburst in the surrounding rock of circular tunnels with a single set of joints in deep underground engineering.
文摘If you are representing a foreign-funded institution in setting up a foreign-funded bank or financial company in Shanghai, you should have a representative agency already established within the boundaries of China for more than two years, and general assets at the end of the previous year should not be less than US $ 10 billion. The country or region you are residing in should have
文摘Tors are mound-like rock landforms,resistant to erosion,that may sometimes reach the size of several storeys of house by volume.They may develop in different climate regions and different rock types,led by granitic rocks.In this study,tors developed in granitic rocks around Yaylal?village linked to Kürtün county in Gümü?hane were investigated.The study area is located in the eastern part of the Giresun mountain range in northeastern Turkey,2000-2300 m above sea level.The aim of the study is to determine the natural environmental characteristics in tor formation and to reveal the effect of bedrock on tor formation.During field studies,18 tors were selected by noting location,size and structural features,and dimensions were measured.Thin sections were first made from the rock samples taken from the tors and then the mineralogical composition was investigated by modal analysis method.As a result of this analysis,it was determined that the bedrock forming the tors is granite.During the field observations,it was determined that the intersecting vertical joints supported the formation of castle-like tors,while the horizontal joints supported the formation of pita pileshaped tors.There are also pseudokarstic shapes resembling kamenitza and karst pavement.In conclusion,joint sets causing local resistance differences directed the formation of tors,while excess slope affected surface erosion and suitability of climate conditions-controlled weathering rate.
文摘In core logging, each joint set intersects borehole into some segments. In this research, it has been shown that length of the borehole segments created by each joint set could be computed by trigonometrical relations. By realizing the lengths associated with joint sets, an algorithm has been designed to compute the length of borehole pieces (created by all joint sets) and to calculate RQD. Effect of some factors have been analyzed and applied to the abstract model of the rock mass to have the most similarity to a real rock mass. The program proposed in this study, is a robust platform to calculate the RQD in all directions inside a rock mass without having to deal with the labor of core logging and wrestling with difficulties and inaccuracies of the traditional processes. This is the first algorithmic method for estimating the rock quality which could be employed to develop a new and far more reliable measurement for the degree of jointing inside a rock mass.
