摘要
利用SDT-20型动三轴仪在双向循环荷载下探究了黄土的动变形特性,分析了初始循环偏应力、径向动荷载幅值和预剪应力对黄土动变形发展的影响。试验结果表明:双向循环荷载作用下,初始动应力状态对黄土破坏模式有重要影响,初始循环偏应力小于0 k Pa时,黄土呈受拉破坏,初始循环偏应力大于0 k Pa时,黄土呈受压破坏。初始循环偏应力、径向动荷载幅值和预剪应力对黄土的动剪切变形均有明显的影响,初始循环偏应力和径向动荷载幅值的增大均加快了黄土的动剪切变形发展,使土体的破坏更迅速。预剪应力对土体起到预压密作用,黄土的动剪切变形的发展随预剪应力的增大而减缓。当剪切动荷载幅值保持不变时,拉压动荷载幅值的增大明显地加速了黄土动剪切变形的发展,其对土体动剪切变形的影响和剪切动荷载是一致的。
The dynamic deformation properties of loess under bidirectional cyclic loads are explored by SDT-20 dy- namic triaxixal apparatus, and effects of initial cyclic deviator stress, radial vibration amplitude and initial shear stress on development of loess dynamic deformation are analyzed. The test results show that initial dynamic stress states have significant effects on failure mode of loess under bidirectional cyclic loads. When the value of initial cy- clic deviator stress is less than 0 kPa, loess is in the mode of tensile failure, and loess is in the mode of compres- sive failure when the value of initial cyclic deviator stress is lager than 0 kPa. Initial cyclic deviator stress, radial vibration amplitude and initial shear stress have obvious effects on the dynamic shear deformation of loess. Develop- ment of loess dynamic shear deformation becomes faster with the increase of initial cyclic deviator stress and radial vibration amplitude. Initial shear stress plays a role of preconsolidation on loess, consequently, development of lo- ess dynamic shear deformation slows down with the increase of initial shear stress. When the amplitude of shear dy- namic load remains constant, increase of amplitude of tension ＆ compression dynamic load accelerates the develop- ment of loess dynamic shear deformation, which means that tension ＆ compression dynamic load has the similar effect on loess dynamic shear deformation with shear dynamic load.
出处
《地震工程与工程振动》
CSCD
北大核心
2016年第1期186-192,共7页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(51178392)~~
