堆载–电渗联合作用下双层地基1维固结解析解

实际地基处理中，电渗与堆载预压常常联合使用。为了解决目前综合考虑堆载和电渗作用的成层地基固结解答理论的不足，假定土体中的渗透流速可由水力坡降引起的渗透流速与电势差引起渗透流速的进行叠加，建立考虑堆载和电渗联合作用的双层地基1维固结方程；利用特征函数法获得瞬时堆载和线性堆载下双层地基1维电渗固结解析解；通过与现有解析解和电渗固结试验结果对比，验证了本文解答的可靠性。基于该解答，详细讨论了土层参数及荷载参数对双层地基固结特性的影响。结果表明：当下层土的渗透性高于上层土的渗透性时，由于电渗作用导致地基中间土层在固结初期流入的水量大于流出的水量，造成超静孔隙水压力在固结初期上升及有效应力在固结初期下降的现象；降低下层土的压缩性能够提高双层地基的沉降速率和超静孔隙水压力消散速率；与单纯电渗固结相比，电渗联合堆载作用不仅能提高地基沉降速率，还能提高固结后的地基强度，更有利于减小工后沉降和加快地基处理速率。

Analytical Solution for One-dimensional Consolidation of Double-layered Soil Under Combined Action of Load and Electro-osmosis

In actual foundation treatment, electro-osmosis is often used in combination with preloading. In order to solve the deficiency in the theory about electro-osmotic consolidation solution considering both load action and layered configuration of soil, a one-dimensional consolidation equation of double-layered soil considering the combined action of load and electro-osmosis is established, by assuming that the flow velocity in soil can be superimposed by the flow velocity caused by hydraulic gradient and the flow velocity caused by potential difference. The analytical solutions for one-dimensional electro-osmotic consolidation of double-layered soil under constant and linear loading are obtained by using the feature function method. The effectiveness of the present solution is assessed by comparing against other existing analytical solutions and electro-osmotic consolidation test results. Based on the solution, the influences of soil parameters and load parameters on the consolidation characteristics of double-layered soil are discussed in detail. The results show that when the permeability of the subsoil is greater than that of the upper soil, in the early stage of consolidation, the amount of water flowing into the soil near the middle of the foundation is greater than the amount flowing out due to electro-osmosis, resulting in the phenomenon that the excess pore water pressure increases and the effective stress decreases in the early stage of consolidation. Reducing the compressibility of subsoil can improve the settlement rate and the excess pore water pressure dissipation rate of double-layered soil. Compared with the single electro-osmosis consolidation, the combined action of the load and electro-osmosis can not only improve the settlement rate of the double-layered soil, but also improve the strength of foundation after consolidation, which is more conducive to reducing the settlement after construction and speeding up the foundation treatment rate.