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为研究复杂应力状态下粉质黏土结构性演化规律,利用TSW-40型土壤真三轴仪,开展一系列不同围压、含水量和中主应力系数条件下粉质黏土的真三轴试验,探究真三维应力状态下粉质黏土应力比结构性参数的变化规律。研究结果表明:粉质黏土的广义剪应力-广义剪应变(q-ε)曲线主要表现为应变硬化型。应力比结构性参数mη与广义剪应变ε呈拟合度较高的对数关系。应力比结构性参数mη随广义剪应变、含水量、固结围压和中主应力系数的增大而降低。剪切作用初始阶段,mη下降较快;当ε达到5%左右后,mη逐渐趋于平稳;试样达到破坏标准时mη接近于1。数据分析结果表明:固结围压对土体结构性的影响最大,其次为中主应力,含水率对土体结构性的影响相对较小。
In order to study the structural evolution of silty clay in complex stress conditions, a series of true triaxial tests of silty clay under different confining pressures, water contents and medium principal stress coefficients were carried out using TSW-40 soil true triaxial apparatus. The variation regularity of structural parameters of the stress ratio of silty clay under true three-dimensional stress state was explored. The results show that the generalized shear strain (q-ε) curve of silty clay is mainly strain hardening. The logarithmic relationship between the structural parameters mη and the generalized shear strain ε shows a good fit. The stress ratio structural parameter mη decreases with the increase of generalized shear strain, water content, consolidation confining pressure and middle main stress coefficient. In the initial stage of shearing, mη decreased rapidly; when η reached about 5%, mη gradually became stable; when the sample reached the failure criterion, mη was close to 1. The results of data analysis show that the consolidation confining pressure has the strongest influence on the soil structure, followed by the middle principal stress, and the influence of water content on the soil structure is relatively small.