CFG复合桩在软弱地基处理中的应用

某工程采用CFG复合桩对软弱地基土进行处理，持力层为粉质粘土，设计单桩承载力标准值180kPa，复合地基承载力标准不低于220kPa，采用沉管法施工。成桩后进行桩间土的力学性质测试发现，施工前后桩问土的强度没有提高，土的挤密度不明显；运用单桩静力载荷试验分析发现，I区的l号桩发生刺入破坏，单桩承载力标准值按比例荷载计算为105kPa，远低于理论预估值，Ⅱ区单桩承载力标准值按比例荷载计算为185kPa，与设计值相近。用单桩动测试分析发现原因是由于桩间土的差异及施工桩身的施工质量问题所致。

Application of CFG Composite Pile in Soft Ground Treatment

The CFG pile composite foundation method has used in soft ground treatment in foundation engineering. The bearing stratum is silty clay, designed single pile bearing capacity standard value 180kN, composite foundation bearing capacity standard not less than 220kN, immersed tunneling method has been used. Mechanic property testing of soil between piles after completion found that strength of soil between piles has not changed before and ＇after construction, compaction of soil is not obvious. After single pile static loading test analysis, penetrating failure has found in No.1 pile of region I, based on proportional loading estimated single pile bearing capacity standard value is 105kN and far lower than theoretic prior estimate, region II single pile bearing capacity standard value based on proportional loading is 185kN, similar to designed value. Through the single pile dynamic test found the causation is from different soil between piles and pile construction quality.