成层结构性软土一维非线性固结半解析分析

为了研究变荷载作用下土体结构性对成层软土固结性状的影响，基于结构性软土压缩性和渗透性的非线性变化规律，以及结构屈服应力随土体深度变化等特征，对结构性软土非线性固结问题进行了分析. 首先采用三折线压缩模型、e-lg k_v渗透模型，详细分析了结构性软土在不同排水工况下的固结过程；其次，利用半解析法，建立一维固结方程，并编制程序进行求解，与目前已有的非线性固结结果进行了对比分析，验证了本文计算方法的可靠性；最后以某四层软土地基为工程背景，研究了变荷载、结构性等因素对固结性状的影响. 研究结果表明:成层结构性软土一维非线性固结过程中，当最终荷载相同，加荷速率不同时，固结前期，按应力定义的固结度大于按沉降定义的固结度，固结后期则相反；当加荷速率相同，最终荷载不同时，按应力定义和按沉降定义的固结度在固结前期均随着最终荷载的增大而减小，而在固结后期，随着最终荷载的增大而增大；考虑结构性时，按应力定义的固结度明显大于不考虑结构性的计算值，固结前期相差较大，随着固结的进行，差值逐渐减小. 

Semi-analytical Analysis of One-Dimensional Nonlinear Consolidation of Multi-layered Structured Soft Clay

To study the impact of structural properties on the consolidation behavior of multi-layered soft clay under time-dependent loading, the problem of nonlinear consolidation of structured soft clay was addressed by analyzing the nonlinear variable permeability and compressibility of structured soft clay and the variation of the yield stress with depth. First, the consolidation process in different drainage situations was analyzed in detail using the structured soft clay trilinear compression model and e-lg k_v permeability model. Then, one-dimensional consolidation equations were established by semi-analytical method. A calculation procedure was developed to solve the problem, and the effectiveness of the proposed method was verified by comparison with the existing nonlinear consolidation results. Finally, in the engineering background of a four-layer soft clay ground, influences of time-dependent loading and structural properties on the consolidation behavior of multi-layered soft clay were investigated. The results show that when the ultimate load is fixed while loading rates are varying, the degree of consolidation defined in terms of effective stress (U_p) is larger than that defined in terms of settlement (U_s) at the early stage, but the opposite will occur at the late stage. On the other hand, when the loading rate is fixed but the ultimate loads are different, with the ultimate load increasing, the values of U_s and U_p decrease at the early stage but increse at the late stage. At the early stage of cosolidation, the U_p obtained by the nonlinear consolidation analysis considering structural properties is significantly larger than that without considering structural properties, but the discrepancy decreases gradually as the consolidation proceeds.