褥垫层参数对CFG桩复合地基承载特性的影响研究

为研究褥垫层物理参数对CFG桩复合地基承载特性的影响，采用Midas/GTS建立了某工程CFG桩复合地基有限元模型，分析了不同工况下的地基沉降量和桩土应力比。研究结果表明，随着上部荷载的增大，地基沉降量和桩身应力比也呈增大的趋势，褥垫层能降低地基沉降量。垫层厚度越大，地基沉降量越小，桩土应力比越大；垫层模量越大，地基沉降量越小，桩土应力比越大。选择合理的褥垫层参数有利于调节桩土荷载分担比例，充分发挥地基承载性能。考虑经济效益和安全性能范围内，该工程褥垫层厚度宜取值为400 mm，模量宜取值70 MPa，实际工程的合理设计具有指导作用。

Study on Influence of Cushion Parameters on Bearing Characteristics of CFG Pile Composite Foundation

In order to study the influence of physical parameters of cushion on bearing characteristics of CFG pile composite foundation, a finite element model of CFG pile composite foundation for a project is established by using MIDAS /GTS, and the settlement of foundation and the pile-soil stress ratio under different working conditions are analyzed. The results show that the foundation settlement and pile stress ratio increase with the increase of the upper load, and the cushion can reduce the foundation settlement. The larger the cushion thickness is, the smaller the foundation settlement is and the larger the pile-soil stress ratio is. The larger the cushion modulus is, the smaller the foundation settlement is and the larger the pile-soil stress ratio is. The selection of reasonable cushion parameters is helpful to adjust the proportion of pile-soil load sharing and give full play to the bearing capacity of foundation. Considering the range of economic benefit and safety performance, the cushion thickness of the project should be 400 mm, and the modulus should be 70 MPa. The reasonable design of the actual project has a guiding role.