CFG桩复合地基的试验研究

Experimental Study on CFG Pile Composite Foundation

本文介绍了一个CFG桩加固软土地基的工程实例。结合该工程,对CFG桩复合地基的设计方法进行了简要阐述;采用有限元ANSYS程序对CFG桩复合地基的应力传递特性进行了分析;对CFG桩体的强度和弹性模量进行了测试,对CFG桩体、CFG桩复合地基进行了静载荷试验,对桩间土进行了标准贯入试验。试验和分析结果表明:CFG桩能够把荷载传递到深层土上;CFG桩复合地基与天然地基的变形比随面积置换率m的增大而减小,且当m<10%时,效果显著;经CFG桩处理后的复合地基的承载力高达天然地基承载力的2.5倍以上,打桩过程的振动作用和挤密作用可以消除或降低桩间土的液化。

This paper presents a real engineering project by using cement flyash gra vel(CFG)pile for reinforcing soft foundation in north China.In combin ation with the project,the design me thod of CFG pile composite foundatio n has been expounded briefly.The characteristics of loading transmission of the CFG pile composite foundation has been an-alyzed by use of the ANSYS program.The cubic strength and elastic modulus of CFG mixture have been tested and th e site loading tests of CFG pile and CFG pile composite foundation together with the standard penetration test o f soil be-tween piles have been performed.The results of tests and analysis indicate that CFG pile can transfer the load ing into deep soil,the higher the replacing r atio m,the smaller the deformation ratio,and when m<10%,increasing m will effectively result in decreasing th e deformation of composite foundati on while the bearing capacity of CFG p ile composite foundation can be over 2.5times more than that of natural soil.Furthermo re,the vibration and compaction eff ects during pile driving may eliminate liquefac tion of the soil between piles.