Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subj...Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.展开更多
For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model...For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model.Firstly,rocks are divided into three parts,i.e.,voids,a damaged part and an undamaged part in the course of loading.The void ratio was applied to describing the changes of voids or pores during the deformation process.Then,using statistical damage theory,a constitutive model was developed for rocks to describe their strain softening and hardening on the basis of investigating the relationship between the net stress and apparent stress,in which the influence of volume changes on rock behavior was correctly taken into account,such as the initial phase of compaction and the latter stage of dilation.Thirdly,a method of determining model parameters was also presented.Finally,this model was used to compare the theoretical results with those observed from experiments under conventional triaxial loading conditions.展开更多
基金Project(09JJ1008) supported by Hunan Provincial Science Foundation of ChinaProject(200550) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China
文摘Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.
基金Project(2006AA11Z104) supported by the National High-Tech Research and Development Program of China
文摘For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model.Firstly,rocks are divided into three parts,i.e.,voids,a damaged part and an undamaged part in the course of loading.The void ratio was applied to describing the changes of voids or pores during the deformation process.Then,using statistical damage theory,a constitutive model was developed for rocks to describe their strain softening and hardening on the basis of investigating the relationship between the net stress and apparent stress,in which the influence of volume changes on rock behavior was correctly taken into account,such as the initial phase of compaction and the latter stage of dilation.Thirdly,a method of determining model parameters was also presented.Finally,this model was used to compare the theoretical results with those observed from experiments under conventional triaxial loading conditions.
