黏土在低水力坡降下偏离达西定律的现象及应力历史对土体变形的影响已为人们所认识,但能够同时考虑非达西渗流及应力历史影响的土体固结理论还很鲜见。在传统太沙基一维固结理论基础上,引入经典的Hansbo渗流模型,并考虑土体在不同应力状态下的变形特性,建立实际变荷载作用下土体的非线性固结模型。利用有限差分法对模型进行数值求解。在保证数值解可靠性的基础上,着重分析非达西渗流对超固结土固结性状的影响及非达西渗流下应力状态对固结性状的影响,并分析比较其异同点。结果表明:非达西渗流下超固结土的固结速率要比达西定律下慢,且随非达西渗流模型参数m、i1值的增大,固结速率的减慢愈加明显;对考虑非达西渗流的不同应力状态土体而言,超固结土的固结速率最快,且超固结土在外荷载作用下产生的地基最终沉降值最小;对考虑非达西渗流的超固结土而言,前期固结压力越大、回弹再压缩指数越小,则土的固结速率越快,地基土的最终沉降值越小。
The deviation of water flow from Darcy's flow law and the influence of stress history on the settlement of soil have been recognized by many researchers, but the theory of consolidation with the considerations of non-Darcian flow and stress history was rarely reported. Based on Terzaghi's consolidation theory and classical Hansbo's flow model, a nonlinear model of consolidation is developed by considering different settlement characteristics of soil with different stress states and time-dependent load in practical engineering. The finite difference method is adopted to obtain numerical solutions for this model. Based on the reliability of numerical solutions, the influences of non-Darcy flow on consolidation behavior of over consolidated soil and the influences of stress history on over consolidated soil with non-Darcy flow are intensively analyzed, and similarities and differences of consolidation behaviors are compared. The results show that the consolidation rate of over consolidated soil with non-Darcian flow is slower than that with Darcy's flow. In addition, the consolidation rate evidently decreases with an increase in the value ofm or il. Among different stress states of soil with non-Darcian flow, the consolidation rate of over consolidated soil is the fastest, and the final settlement of over consolidated soil under external load is the smallest. When non-Darcy flow in an over consolidated soil layer is considered, a large preconsolidation pressure and a small rebound- or recompression-index always result in a rapid consolidation rate and a small final settlement.