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为研究结构性土在不排水条件下的力学特性,开展固结不排水条件下初始应力各向异性结构性土、各向同性结构性土及重塑土在25,50,100,200及400 k Pa共5种围压下的三轴加卸载试验,并利用二元介质概念对试验现象进行了分析。结果表明:结构性土在固结应力较低时结构性保持较好,存在明显的结构屈服强度,不同应力循环中平均模量无明显变化;固结应力较高时结构性减弱,表现为与重塑土相似的特性,受结构性减弱及正孔压等因素影响,平均模量随εa增加而减小;结构性土胶结元破损率与摩擦元中土颗粒间距随轴向应变增加而增大,卸载时体缩趋于明显。
In order to study the mechanical properties of structured soil under undrained conditions, the initial stress-anisotropy constitutive soil, isotropic structured soil and remodeled soil under undrained consolidation conditions were developed at 25, 50, 100, 200 and 400 kPa Three-axis loading and unloading test under confining pressure was carried out, and the phenomenon of test was analyzed by using the concept of binary medium. The results show that the structural soil maintains well under the low consolidation stress and has obvious structural yield strength with no obvious change of the average modulus in different stress cycles. The structure weakens when the consolidation stress is high, The similar properties of remolded soil are affected by structural weakening and positive pore pressure. The average modulus decreases with the increase of εa. The damage rate of structural soil cement and the intergranular particle spacing of friction element increase with the increase of axial strain Large, unloaded body contraction tends to be obvious.