软土地基电渗固结理论分析与数值模拟

Theoretical analysis and numerical simulation of electroosmosis consolidation for soft clay

电渗固结是加速软土固结、提高地基承载力的有效技术。传统的电渗固结理论假设土体的物理力学、水力学和电学特性均匀稳定,其理论解答与试验结果差别较大。针对电渗固结处理过程,对土体位移场、渗流场和电场的耦合特征进行了理论分析,根据电荷守恒原理、水流连续原理和Biot固结理论,建立了电渗固结过程的多场耦合控制方程;考虑土体相关特性参数的非线性关系,开发了有限元软件用于分析电渗过程中电场强度、土体位移以及超静孔隙水压力的变化特征。计算结果与理论数据吻合较好,能够反映土体相关特性参数非线性关系对结果的影响。软件能够为电渗固结系统设计提供参考依据。

Electroosmosis consolidation provides a potentially attractive soil improvement technique, which involves the application of a direct current potential across electrodes embedded in the soil and cause the flow of pore water from the anode toward the cathode. The traditional electroosmosis theory cannot provide satisfied solution due to the hypothesis of constant parameters of mechanical and electrical properties of soils. In this paper, FEM soiiware is developed to couple the Laplace equation for electrical field with Biot＇s equation for consolidation; and the displacement of soil mass and pore water pressure can be obtained during electroosmosis process. The nonlinear relationship among electrical resistivity, void ratio and effective stress is incorporated in the control equations. The calculation results of both one and two dimensional model agree well with the analytical solutions. The software can simulate complicated boundary conditions and predict the settlement process of the soil layers. Furthermore, the software can provide useful data for system design of electroosmosis treatment technique.