分级加载电压下考虑有效电势变化的软黏土电渗固结理论

分级加载电压技术能够有效延长电渗处理的时间,改善地基的处理效果并能有效降低能耗。在利用分级加载电压技术开展电渗试验时,随着土体的排水固结,土体各点的电势会发生明显的变化,这与现有的电渗固结理论假设土体各点电势保持不变有所差异。利用自主设计的电渗试验仪器开展了分级加载电压下的电渗室内试验,分析了电渗过程中土体有效电势变化的规律。基于该规律并结合Esrig固结理论建立了在阳极处不排水、阴极处排水条件下考虑土体有效电势变化的电渗固结理论,得到了分级加载电压条件下考虑土体有效电势变化的超静孔隙水压力和平均固结度的解析表达式。研究表明,在电压分级加载过程中,土体有效电势变化规律表现为随时间先基本保持不变,后呈抛物线状先增后减。通过试验案例验证了考虑土体有效电势变化所求得解析解的合理性,且该数值计算结果相较于Esrig数值计算结果,前者更加接近实测值,该固结方程的建立为后续分级加载电压技术的推广应用提供了理论依据,也为实际工程提供了参考。

Electro-osmotic Consolidation Theory of Graded Loading Voltage Considering Variation in Effective Potential in Soft Soil

The time of electro-osmotic treatment can be extended effectively by using the technology of graded loading voltage.At the same time,the treatment effect can be improved and the energy consumption can be reduced effectively.When the electro-osmosis test is carried out by using graded loading voltage technique,the potential of soil is different at different positions and changes with time.This is different from the existing electro-osmotic consolidation theory,which assumed that the soil potential remains unchanged.A laboratory electro-osmosis experiment was carried out in a self-developed device,and the variety law of effective potential of soil was analyzed.The law was taken as a basic assumption,and the Esrig electro-osmotic consolidation theory was combined,the electro-osmotic consolidation equation of the situation of anode closed and cathode open was established by considering the variation of effective potential in the process of graded loading voltage.The analytic expression of excess pore water pressure and average degree of consolidation were set up.On the basis of the results of electro-osmosis indoor experiment using EKG electrodes,it was founded that the effective potential obeys the law of keeping stable first and then changing parabolically in the process of graded loading voltage.The rationality of the analytical solution considering the variation of effective potential of soil was verified by a model test.In the comparison of consolidation theory of Esrig,the former was more reasonable.It provided a theoretical foundation for the application of graded loading voltage and a reference for practical engineering.