包裹碎石群桩模型试验分析  

Model test analysis on group of geosynthetic encased stone columns

作　　者：欧阳芳[1] 张建经[1] 韩建伟[1] 毕俊伟 杜林[1] 

机构地区：[1]西南交通大学土木工程学院,成都610031

出　　处：《东南大学学报（自然科学版）》2015年第5期952-957,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金重点资助项目(41030742);国防基础科研计划资助项目(B0220133003)

摘　　要：为了研究包裹碎石桩群桩的承载性能,开展了具有不同面积置换率的包裹碎石群桩模型试验.采用百分表和土压力盒监测包裹碎石桩复合地基的应力和位移关系、端阻力以及桩侧应力分布等,并根据试验中包裹碎石桩承载特性推导其承载力计算公式.试验结果表明,包裹碎石桩能明显提高软弱土的承载力,在承压板顶面产生相同位移时,面积置换率为14%的包裹碎石桩复合地基承受的应力相比未加固地基提高约3.5倍,且置换率较大者应力提高的倍数也较大.桩体底端与顶端应力之比随承压板顶面位移的增大而减小,直至承压板顶面产生的位移大于7%,应力比基本稳定在17%左右.包裹碎石桩侧向应力影响深度较碎石桩大,其分布与面积置换率有关.To study the bearing capacity of the group of geosynthetic encased stone columns,a series of laboratory model tests with different area replacement rates were carried out.The relationship of the pressure and the settlement,the resistance at the column tip,and the distributions of the radial stress of geosynthetic encased stone columns were monitored by dial indicators and earth pressure cells.The calculation formula of the bearing capacity of geosynthetic encased stone columns was deduced according to bearing capacity characteristics in tests.The experimental results indicate that the geosynthetic encased stone columns can effectively improve the bearing capacity of soft soil.With the same settlement,the pressure on the geosynthetic encased stone columns with the area replacement rate of 14% is about 3.5 times higher than that of the unreinforced foundation;moreover,the foundation with larger area replacement rate behaves even better.With the increase of the settlement, the ratio of the pressure at the column bottom to the pressure at the column top decreases,and when the settlement is larger than 7%,the ratio stabilizes at about 17%.The depth influenced by the lateral stress along the geosynthetic encased stone columns is deeper than that of the stone columns,and the distribution of the lateral stress is influenced by the area replacement rate.

关 键 词：包裹碎石桩 承载力 位移 面积置换率 

分 类 号：TU473[建筑科学—结构工程]