高速铁路穿透型CFG桩复合地基沉降计算修正系数分析

Research on settlement calculation empirical coefficient of end-bearing CFG pile composite foundation

为掌握铁路工程CFG桩复合地基在路堤荷载作用下的沉降计算修正系数变化特点,基于武汉-广州高速铁路24个路堤断面的地基沉降测试数据,结合地勘和设计参数,分析了地基沉降计算修正系数的变化规律及工后沉降的时间效应特征,结果表明,软弱土层浅薄的穿透型CFG桩复合地基具有优良的沉降控制效果,对应的地基沉降计算修正系数在0.63～0.17之间,较当量压缩模量相当的《铁路工程地基处理技术规范》推荐值偏低约1/3;地基沉降表现出显著的时间效应特征,地基工后沉降占最终沉降的比值有随时间逐渐降低的趋势;路堤填筑速率加快和地基布桩间距加大,对穿透型CFG桩复合地基工后沉降占最终沉降的比值有明显增大作用,地基沉降稳定所需的时间更长。

In order to adequately master settlement calculation empirical coefficient of CFG pile composite foundation under embankment load,an analysis is taken out based on foundation information,subgrade design parameters and settlement field test data of 24 sections in Wuhan-Guangzhou high-speed railway.Empirical coefficient of settlement calculation＇s variation and time effect features of settlement after construction are studied.The conclusions are as follows.Under embankment load,penetrating high-strength CFG pile composite foundation has outstanding deformation resistance,and its corresponding empirical coefficient changes between 0.63 and 0.17,which is lower than recommended value in Technical Code for Ground Treatment of Railway Engineering by 30 percent;foundation settlement shows a significant time effect features;and ratio of settlement after construction to final settlement decreases with time;the ratio of penetrating high-strength CFG pile composite foundation and time before stable of foundation settlement increases obviously with faster embankment filling rate and larger pile spacing.