堆载预压与真空堆载联合预压技术在软基处理中的对比分析

堆载预压和真空堆载联合预压是软基处理中的常用技术，两者均通过荷载作用将土体中的孔隙水排出，使作用于土骨架上的有效应力增加，加速土体沉降固结，以增强其力学性能（变形、强度和稳定性等）。从两种预压方式的力学原理上分析了其异同点，采用非线性有限元方法对两种预压加载模式下软土地基的力学响应做了应力渗流耦合分析计算。着重研究了软基粘土孔隙比、有效应力、超孔隙水压和变形在两种预压模式下的变化规律。研究发现，真空堆载联合预压的加固范围较堆载预压的大，处理深度更深，固结沉降量也更大。真空荷载的施加还可有效地减小软基的水平

Comparative Analysis on Technical Application of Surcharge Preloading and Vacuum Combined Surcharge Preloading in Soft Foundation Treatment

The technologies of surcharge preloading and vacuum combined surcharge preloading are commonly used in soft foundation treatment，both of which works in such manner that，through loading，pore water is drained from soil，leading to increased effective stress on soil skeleton and accelerated settlement consolidation of soil，hence the mechanical properties（stiffness，strength and stability）are enhanced.This paper，in relation to the mechanical principal of the two preloading methods，analyzed their similarities and differences and，by non-linear FEM，studied the stress-seepage coupling response of soft foundation to these two preloading modes，with the emphasis laid on the change laws of void ratio，effective stress，excess pore water pressure and deformation of soft soil foundation.Through the research，we find out that the reinforcement range，treating depth and consolidation subsidence in respect of vacuum combined surcharge preloading are greater than those of surcharge preloading；and the application of vacuum load may reduce horizontal deformation of soft foundation，making for its stability.