摘要
为研究交通荷载作用下筋箍碎石桩复合地基的工作性状,开展了一系列循环荷载作用下筋箍碎石桩单桩复合地基室内模型试验。通过复合地基中埋设的各类传感器,监测了桩顶平面处桩–土应力、地基累积沉降、超孔隙水压力和桩体鼓胀变形情况,探讨了地基加固形式、土工格栅套筒拉伸强度和砂垫层厚度对复合地基动力响应的影响。试验结果表明,桩–土应力分布取决于桩–土刚度差异,竖向加筋套筒能有效提高桩体刚度,水平加筋格栅能进一步将荷载传递至桩顶,而砂垫层将荷载分担至桩周土中。地基累积沉降随加筋套筒拉伸模量的提高而减小,基于沉降控制设计,工程中应选用拉伸模量高的土工格栅作为加筋套筒。复合地基超孔隙水压力的累积随桩周土中应力的增加而增大。筋箍碎石桩的鼓胀变形取决于桩体承受的竖向荷载和加筋套筒的拉伸模量。
To study the behaviors of geosynthetic-encased stone column-improved composite foundation under traffic loads,a series of laboratory tests on composite foundation reinforced by single geosynthetic-encased stone column subjected to cyclic loads are conducted.The composite foundation is instrumented to monitor the stress distribution between piles and soils,accumulated settlement,excess pore water pressure and column bulging deformation.The influences of the reinforcement configuration,tensile strength of geogrid encasement and thickness of sand bed on the cyclic behaviors of the composite foundation are investigated.The test results indicate that the pile-soil stress distribution is stiffness-dependent,and the vertical reinforced encasement improves the plie stiffness.The horizontal reinforced geogrid can further increase the loads to pile top,while the sand bed increases the loads to transfer to the surrounding soils.The accumulated settlement reduces with the increase of the tensile modulus of geosynthetic-encasement.Based on the settlement control,the geogrid with high tensile modulus should be selected as the geosynthetic encasement.The accumulation of pore water pressure in the composite foundation increases with the increase of the stress in the surrounding soils.The bulging deformation depends on the vertical loads on piles and the tensile modulus of the geosynthetic encasement.
作者
张玲
徐泽宇
赵明华
ZHANG Ling;XU Ze-yu;ZHAO Ming-hua(Institute of Geotechnical Engineering,Hunan University,Changsha 410082,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第12期2198-2205,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(52078205,51678231)
湖南省自然科学基金优秀青年基金项目(2020JJ3013)。
关键词
筋箍碎石桩
复合地基
模型试验
循环荷载
geogrid-encased stone column
composite foundation
model test
cyclic load
