真空预压加固软地基工程实例分析

Case study on soft-clay foundation reinforcement by vacuum preloading

对真空预压排水固结加固软基工程实例进行了具体分析,对承载力增长规律进行了定性分析。根据原位试验结果,推算了地基承载力;推导了考虑固结效应的软土地基承载力增长计算公式并进行了修正;对原位试验结果推算的地基承载力与理论公式计算的地基承载力进行了对比分析。修正公式计算的地基承载力与现场原位测试推算的地基承载力增长特性一致。用有限元程序对排水固结预压加固软基承载力增长规律进行了模拟分析。现场原位检测推算结果、理论公式计算结果与有限元模拟分析结果均表明:排水固结预压加固地基承载力的增长是非线性的,排水固结期间,前期地基承载力增长迅速,后期地基承载力增长缓慢,加固前期地基承载力增长远快于后期;随着排水固结预压时间的增加,地基承载力增长逐渐趋于极值。

Taking the soft-clay foundation reinforcement project using vacuum preloading as a study case,the growth law of bearing capacity of the foundation is studied qualitatively.According to the results of the in-site test,we presume the bearing capacity of the foundation,deduce the formula for calculating bearing capacity increment by considering consolidation effect,and correction of the formula is given as well;the bearing capacity obtained by theoretical formula and in-site test are compared.The comparative analysis show that the increasing features of bearing capacity obtained by in-site test and corrected formula are well in agreement with each other.Moreover,we conduct a FEM numerical simulation on the increasing features of bearing capacity of soft foundation strengthened by vacuum preloading.The analysis results of the in-situ measured data,theoretical formula and FEM show that the development of bearing capacity of soft-clay foundation strengthened by vacuum preloading is nonlinear;during the consolidation construction period,the bearing capacity increases faster in the early stage than that in late stage;in the later stage,the bearing capacity of soft-clay reaches to a extreme value.