固结不排水条件下初始应力各向异性结构性土的力学特性  

Mechanical properties of artificially structured soils with stress-induced anisotropy under undrained conditions

作　　者：陈亚军[1] 罗开泰[1] 刘恩龙[1] 张树祎[1] 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,水利水电学院,四川成都610065

出　　处：《水利学报》2015年第4期460-470,共11页Journal of Hydraulic Engineering

基　　金：国家自然科学基金资助项目(51009103)

摘　　要：天然土都具有结构性和各向异性,这使得天然土与重塑土的力学性质有很大区别,对其进行研究可为建筑物的设计和施工提供理论依据。对人工制备的初始应力诱发各向异性结构性土样进行了4组不同围压下的固结不排水三轴压缩试验,并建立了初始应力诱发各向异性结构性土的强度准则。结果表明:(1)结构性土在低围压下结构性较为明显,但是在高围压下由于土的结构性被破坏而表现为接近于重塑土的性质。且初始应力诱发各向异性结构性土的结构性强于初始均质结构性土的结构性;(2)初始应力诱发各向异性结构性土的强度包线呈现非线性,且初始应力诱发各向异性结构性土的抗剪强度要略高于初始均质结构性土的抗剪强度。当应力水平低于结构屈服应力时强度包线呈外凸的曲线,当应力水平较高且超过结构屈服应力时强度包线呈直线;(3)与试验结果的对比表明,本文所建议的初始应力各向异性结构性土的强度准则具有良好的适用性。During the process of sedimentation, natural soils are structured and anisotropic, which lead to the great differences of mechanical features between natural soils and remoulded soils. Studying the mechani- cal properties of these kinds of natural soils can provide the support for the design and construction of buildings. The consolidated undrained triaxial compression tests of artificial structured soils with stress-in- duced anisotropy with 4 different cell pressures were carried out, and a new strength criterion for the struc- tured soils with stress-induced anisotropy was established. The following conclusions are reached： （1） the structured soils samples have a strong structured under lower cell pressures, but behave as the remoulded samples under higher cell pressures occurring to the damage of their structures. Further, compared with ini- tially homogeneous structured soils samples, the structured soils samples with stress-induced anisotropy have more strong structures; （2） the strength envelop of the initially stress-induced structured soils sam- ples was non-linear and their shear strength envelop was higher than that of the initially homogeneous struc- tured soils samples. When the stress level was lower than the structure yield stress, the strength envelop was a convex curve; on the other hand, the strength envelop was a straight line when the stress level was higher than the structure yield stress; （3） Comparing the computed results to the experiment ones demon- strates that the suggested strength criterion has a good usability.

关 键 词：各向异性 结构性土 固结不排水试验 强度准则 

分 类 号：TU431[建筑科学—岩土工程]