CFG桩复合地基加筋褥垫层作用机理数值分析

摘要

Aiming at the problem of whether geo-grid reinforced cushion can improve the settlement and distribution of pile-soil stress of CFG pile composite foundation under embankment load in municipal road engineering of Wanbei Road in Pingtan ,Fujian Province ,the numerical simulation of CFG pile composite foundation based on the finite difference software&FLAC3D was conducted .The numerical simulation of vertical compressive load test of single CFG pile was car-ried out with FLAC3D software ,and the Q-s curve of vertical compressive load test of single pile obtained by numerical simulation with FLAC3D was compared with which obtained by field test .In addition ,the analysis of the pile body stress and settlement deformation of CFG pile composite foundation was performed under the condition that the cushion is rein-forced by geo-grid or not .The results show that the Q-s curve of vertical compressive load test of single pile obtained by numerical simulation with FLAC3D agree well with the field test ones ,which proves that the model has certain rational-ity .The geo-grid reinforced cushion can improve the settlement of foundation by increasing the pile body force ,but the effect is unconspicuous ,however the safety margin of composite foundation was improved .%针对福建平潭万北路市政道路工程土工格栅加筋褥垫层是否能够改善CFG桩复合地基在路堤荷载作用下的沉降及桩土应力分配的问题 ,提出了基于有限差分软件FLAC3D的CFG桩复合地基的数值模拟.应用FLAC3D软件进行CFG桩单桩竖向抗压静载试验模拟 ,并将数值模拟所得的 Q- s曲线与现场试验所得进行了对比 ,对路堤荷载下有无土工格栅对褥垫层加筋处理两种工况下的复合地基进行了桩身应力及沉降的分析.结果表明 ,数值模拟与现场试验所得的单桩竖向抗压静载试验 Q- s曲线吻合较好 ,证明了该模型具有一定的合理性 ;土工格栅加筋褥垫层通过增大桩身受力来改善地基沉降 ,但改善效果不明显 ,主要起提高安全储备的作用.