用真空加固软土地基的机制与计算方法

本文结合用真空加固软土地基的实际工程问题,通过固结模型分析了真空对软基的作用机制,明确了土体在负压作用下发生的排水-变形过程与在正压荷载作用下的固结过程是相似的,都是通过孔隙水应力的变化将外荷载传递给土骨架的过程;二者的区别在于孔隙水应力的初始条件与边界条件不同,因此也可以用固结理论进行设计计算。在三轴仪中进行的上样在负压作用下的固结试验验证了这一结论。在计算方法上,本文给出负压作用下一维固结方程的理论解以及二维问题的有限单元分析方法,并与试验或工程实测数据进行了比较。

Mechanism and Calculation Methods of Vacuum Stabilization of Soft Clay

In this paper, the mechanism of vacuum stabilization of soft clay was studied based on the establishment of the model of consolidation under the action of negative pressure. By comparison with the model of consolidation under the action of positive pressure, it can be concluded that the dewatering-displacement process of the soft clay under negative pressure is the same as that under positive pressure, and thus can also be discribed and calculated by consolidation theories.To verify this conclusion, consolidation tests under the action of negative pressure were carried out in traxial equipment.A finite element program of computers is presented to evaluate the stress, pore pressure and displacemet of subsoils when acted by vacuum, and was used in engineering practice.