巨厚填土场地地基用垫层法处理时对地基缺陷的评价

Evaluation of groundwork defect in site foundation filled with large-thickness soil and processed with cushion approach

采用数值模拟的方法对3种巨厚(10m以上)人工堆填土场地的地基缺陷进行评价.模型以基底位移为目标,考虑几个因素:缺陷类型(位置、面积)、基础形式、荷载大小及垫层厚度.模拟结果表明:最优的基础形式是筏板基础;缺陷面积相同时缺陷分布越集中对垫层的危害越大;增加垫层厚度是有效的方法,但增大到一定值时效果有所下降;因此建议垫层最佳厚度可通过计算选取,同时应将改善垫层材料的整体性(刚度)作为首要因素考虑.

The method of numerical simulation was used to access three kinds of groundwork defects in site foun- dation artificially filled with thick soil （10 m and over）. Taking the displacement of its bottom as objective of mod- el, following factors were taken into consideration, defect type （location, area）, foundation type, load and cushion thickness. It was shown by the simulation result that the raft foundation was the optimal form of the foundation. For the cushion with identical defect area, the more the defect concentration was, the greater the harm to the cush- ion would be. Thickening the cushions was effective to decrease the base displacement, however, it effect would decrease as the thickening attained to some extent. So it was suggested that the optimum cushion thickness could be selected by means of calculation, and the integrity （rigidity） of the cushion material should be taken as the pri- mary influence factor in consideration.