饱和黏土剪切变形与强度特性试验研究  

Experimental study of shear and strength behavior of saturated clay

作　　者：齐剑峰[1] 栾茂田[1] 聂影[1] 范庆来[1] 马太雷[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室

出　　处：《大连理工大学学报》2008年第4期551-556,共6页Journal of Dalian University of Technology

基　　金：国家自然科学基金资助项目(50579006重点项目50639010,50439010);教育部跨世纪优秀人才培养计划研究基金资助项目(教技函[1999]2号)

摘　　要：针对由真空抽吸制样技术制备的饱和重塑黏土，在0．0002～0．1mm／s剪切速率范围内，进行了多组应变控制的UU和CU三轴剪切试验，通过对比试验系统地探讨了围压和剪切速率对饱和黏土的应力-应变关系及其强度特性的影响．试验结果表明，饱和黏土的应力．应变关系在低剪切速率下发生应变强化，而在高剪切速率下出现峰值强度和应变软化，不排水强度随剪切速率的增加而增大，增长幅度可达70％，但当应变超过10％以后的最终残余强度趋于相等．同时试验还发现，在UU试验条件下黏土应力-应变关系与强度特性不受围压的影响，而受剪切速率的影响较为显著．通过归一化，建议了不排水强度与剪切速率之间的线性拟合公式，在确定拟合参数以后，在一定的剪切速率范围内可以同时估计UU和CU试验条件下各剪切速率下的强度．A series of undrained （UU） and consolidated-undrained （CU） triaxial tests are carried out to systematically inves and strength behavior tig of ate the effect of shearing rate and confining pressure on stress-strain relation saturated clay. Sheari mm/s. Experimental data indicate that strain softening occurs after peak strength at high different shearing rates will tend to be identica the clay increases with the increase of shearing ng rate is controlled to vary between 0.000 2 and 0.1 hardening appears at low shearing rate while strain shearing rate. Nevertheless, the deviatoric stress at 1 after the strain exceeds 10%. Undrained strength of rate. The increase of shear strength of about 70% may be attained. In addition, it is revealed that stress-strain relation and strength behavior are mainly affected by shearing rate. However, they are almost independent on confining pressure under the condition of UU tests. An empirical linear relation which correlates shear strength and shearing rate is established and can be used to estimate the undrained strength at different shearing rates and under UU or CU condition.

关 键 词：饱和黏土 三轴试验 应力-应变关系 剪切强度 剪切速率 

分 类 号：TU432[建筑科学—岩土工程]