垫层土拱效应试验与计算方法  

Experiments and calculation methods of soil arching in cushion

作　　者：朱小军[1] 龚维明[1] 赵学亮[1] 徐国平[2] 

机构地区：[1]东南大学土木工程学院,南京210096 [2]中交公路规划设计院有限公司,北京100088

出　　处：《东南大学学报（自然科学版）》2013年第5期957-961,共5页Journal of Southeast University：Natural Science Edition

基　　金："十二五"国家支撑计划资助项目(2011BAG07B01);国家重点研究基础发展计划(973计划)资助项目(2013CB036304);国家自然科学基金资助项目(51079030)

摘　　要：为了研究刚性桩复合地基垫层土拱效应的作用机理,通过可视化模型箱对不同桩间距及垫层厚度的刚性桩复合地基进行室内模型试验,并对加载过程中桩顶及桩间土压力进行测试.利用数码相机拍摄数字照片观测垫层土体的变形,由垫层土体的位移场得出垫层内土拱几何形状,提出了二维土拱分析模型,运用二维力学方法对土拱分析模型进行计算,求解出桩顶及桩间土应力,并利用室内模型试验数据对理论解进行验证.结果表明,土拱分析模型计算结果与试验数据吻合较好,当垫层厚度与桩间距之比达到0.7时,垫层内部开始产生土拱.土拱分析模型的建立对于土拱效应作用机理和刚性桩复合地基垫层受力机理的揭示具有一定的参考价值.In order to investigate the effect mechanism of the soil arching of cushion in rigid-pile composite foundation, laboratory experiments of rigid pile composite foundation were carded out in a tempered glass box with different pile spacing and cushion thickness. The stresses of pile top and soil between piles were measured during the loading process. The soil deformation of the cushion was investigated by observing the digital picture shot by digital camera. On the basis of the soil deformation in the cushion, the geometrical shape of soil arch in the cushion was described, and an analytical model of two-dimensional soil arch was put forward. Two-dimensional mechanics was applied to calculate the analytical model of soil arch. The stresses of pile top and soil between piles were solved, and the theoretical solutions were verified by the data from the laboratory model tests. The results show that the calculation results of the analytical model agree well with the experimental data. The soil arch appears in the cushion when the ratio of the cushion thickness to the pile spacing reaches 0.7. The establishment of soil arch analytical model is helpful to reveal the soil arching mechanism and bearing mechanism of the cushion in rigid-pile composite foundation.

关 键 词：垫层 土拱效应 模型试验 分析模型 

分 类 号：TU473[建筑科学—结构工程]