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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。
The natural soil is both structural and anisotropic, which makes the mechanical properties of natural soil and remolded soil are greatly different. Studying on them can provide theoretical basis for the design and construction of buildings. Four sets of consolidated undrained triaxial compression tests under different confining pressures were carried out on the manually prepared initial stress-induced anisotropic structural soil samples, and the strength criterion of the initial stress-induced anisotropic structured soil was established. The results show that: (1) The structural soil is obviously structural under low confining pressure, but it is close to the remolded soil under high confining pressure due to the destruction of soil structure. And the structure of the initial stress-induced anisotropic structural soil is stronger than that of the initial homogeneous structural soil. (2) The strength envelope of the initial stress-induced anisotropic structured soil is nonlinear, and the initial stress-induced Shear strength of the anisotropic structured soil is slightly higher than that of the initial homogeneous structured soil. When the stress level is lower than the structural yield stress, the strength envelope curve is convex, and when the stress level is higher than the structural yield stress, the strength envelope line is straight. (3) The comparison with the experimental results shows that the proposed initial The strength criterion of stress-anisotropic structured soil has good applicability.