基坑开挖对邻近桩基影响的室内试验研究
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摘要
基坑开挖过程中,支护结构后土体中会产生水平方向和竖直方向的位移,进而对基坑周边的邻近结构物产生较大的影响,甚至会危及结构物的正常使用.设计了轴向加载和基坑开挖作用下单桩和群桩的模型试验,支护结构设定为悬臂式地下连续墙,选取不同工况分析了在轴向荷载和土体位移共同作用下桩基础的位移和弯矩的变化,并与数值模拟计算结果进行了分析对比.试验结果表明:桩基础的弯矩与位移同时受到竖向荷载和土体变形的影响,随着竖向荷载和基坑开挖深度的不断增大,单桩和群桩的弯矩和位移均增大,桩基础中前桩对后桩有明显的遮拦作用,在邻近建筑物密集的地区施工基坑,可采用在基坑与建筑物之间增设围护桩的方法来增加邻近建筑物的安全.
In the process of foundation pit excavation,the displacement of horizontal and vertical direction will occur in the soil behind the retaining structure,which will have a great influence on the adjacent structure around the foundation pit,and even endanger the normal use of the structure.In this paper,the model tests of single pile and group piles under axial loading and excavation of foundation pit are designed,and the supporting structure is set as cantilever type underground continuous wall.The variation of pile foundation displacement and bending moment under the combined action of axial load and soil displacement are analyzed under different working conditions,and the results are compared with those of numerical simulation.The test results show that the bending moment and displacement of pile foundation are affected by both vertical load and soil deformation.The bending moment and displacement of single pile and group piles increase with the increase of vertical load and excavation depth of foundation pit.The front pile in pile foundation has an obvious blocking effect on the rear pile.In the construction of foundation pit in the area with dense buildings,the method of adding retaining piles between the foundation pit and the building can be adopted to increase the safety of the adjacent buildings.
In the process of foundation pit excavation,the displacement of horizontal and vertical direction will occur in the soil behind the retaining structure,which will have a great influence on the adjacent structure around the foundation pit,and even endanger the normal use of the structure.In this paper,the model tests of single pile and group piles under axial loading and excavation of foundation pit are designed,and the supporting structure is set as cantilever type underground continuous wall.The variation of pile foundation displacement and bending moment under the combined action of axial load and soil displacement are analyzed under different working conditions,and the results are compared with those of numerical simulation.The test results show that the bending moment and displacement of pile foundation are affected by both vertical load and soil deformation.The bending moment and displacement of single pile and group piles increase with the increase of vertical load and excavation depth of foundation pit.The front pile in pile foundation has an obvious blocking effect on the rear pile.In the construction of foundation pit in the area with dense buildings,the method of adding retaining piles between the foundation pit and the building can be adopted to increase the safety of the adjacent buildings.
引文
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[10] 魏丽敏,辛学忠,何群,等.邻近开挖对桥梁桩基变形与内力影响分析[J].铁道工程学报,2017,34(5):38-44.
[11] 王恒,陈福全,林海.基坑开挖对邻近桥梁桩基的影响与加固分析[J].地下空间与工程学报,2015,11(5):1257-1265.
[12] 马学宁,赵双喜,艾昕.地下连续墙深基坑支护结构振动台模型试验研究[J].兰州交通大学学报,2015,34(1):1-5.
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[14] 马勤国,严松宏,醋经纬.新建王府酒店对既有地铁隧道的变形影响分析[J].兰州交通大学学报,2014,33(1):154-157.
[15] 陈志敏,欧阳康淼.地铁站基坑开挖对相邻建筑物影响性分析[J].兰州交通大学学报,2009,28(4):25-29.
[2] POULOS H G,CHEN L T.Pile response due to excavation-induced lateral soil movement[J].Journal of Geotechnical and Geoenvironmental Engineering,1997,123(2):94-99.
[3] 杨敏,周洪波,杨桦.基坑开挖与临近桩基相互作用分析[J].土木工程学报,2005,38(4):91-96.
[4] 郑刚,颜志雄,雷华阳,等.基坑开挖对临近桩基影响的实测及有限元数值模拟分析[J].岩土工程学报,2007,29(5):638-643.
[5] 张爱军,莫海鸿,李爱国,等.基坑开挖对邻近桩基影响的两阶段分析方法[J].岩石力学与工程学报,2013,32(增刊1):2746-2750.
[6] 姚国圣.土体侧移作用下既有轴向受荷桩性状模型试验与数值分析[D].上海:同济大学,2009.
[7] 刘念武,龚晓南,楼春晖.软土地基中地下连续墙用作基坑围护的变形特性分析[J].岩石力学与工程学报,2014,33(增刊1):2707-2712.
[8] 梁发云,姚国圣,陈海兵,等.土体侧移作用下既有轴向受荷桩性状的室内模型试验研究[J].岩土工程学报,2010,32(10):1603-1609.
[9] 徐长节,金飚,孙凤明,等.桩基施工及基坑开挖对邻近建筑物联合影响研究[J].岩土工程学报,2013,35(增刊2):809-813.
[10] 魏丽敏,辛学忠,何群,等.邻近开挖对桥梁桩基变形与内力影响分析[J].铁道工程学报,2017,34(5):38-44.
[11] 王恒,陈福全,林海.基坑开挖对邻近桥梁桩基的影响与加固分析[J].地下空间与工程学报,2015,11(5):1257-1265.
[12] 马学宁,赵双喜,艾昕.地下连续墙深基坑支护结构振动台模型试验研究[J].兰州交通大学学报,2015,34(1):1-5.
[13] 何海鹏,杨有海.兰州某基坑变形监测与数值模拟[J].兰州交通大学学报,2015,34(6):38-44.
[14] 马勤国,严松宏,醋经纬.新建王府酒店对既有地铁隧道的变形影响分析[J].兰州交通大学学报,2014,33(1):154-157.
[15] 陈志敏,欧阳康淼.地铁站基坑开挖对相邻建筑物影响性分析[J].兰州交通大学学报,2009,28(4):25-29.
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