关键词: CFG桩复合地基, 褥垫层, 数值模拟, 现场试验

Abstract: This paper presents a case study of the improvement effect of the CFG columns in soft soils. The numerical simulation of the CFG column composite soil is established by using FLAC3D finite difference software. At the same time, the in-situ tests are also performed. The engineering characteristics of the cushion and the influence of the loading level, the area replacement ratio, the column strength and other conditions on the composite soil settlement and deformation are also evaluated. The in-situ static quick load and sustained static load tests are performed to compare and to analyze the deformation characteristics of the composite soils under the two static load test methods. The final settlement value of the composite is quickly predicted and validated by the sustained static load test. The conclusions are as follows: (1) according to the numerical analysis results, the settlement and deformation of the composite soil can be effectively controlled by changing the cushion thickness and materials. The optimal cushion thickness therefore be determined in order to achieve the best settlement control effect. (2) by comparing the in-situ loading tests using the elastic cushion method and the code method, it is concluded that the elastic cushion method is closer to the actual loading condition of the foundation. (3) the settlement of the composite soil can be effectively predicted by the sustained static load test, and the results meet the code requirements.

Key words: CFG Column Composite Ground, Cushion, Numerical Simulation, Field Tests