砂土地基和粉质黏土地基基坑悬臂开挖离心模型试验
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摘要
分别开展砂土和粉质黏土两种典型土质条件下基坑悬臂式开挖离心模型试验,详细叙述试验过程中所要解决的关键问题,并提出合理的解决方案。通过对比分析两组试验结果,得到以下结论:非饱和土地基制备中参数控制困难,分层夯实法有待进一步改进,而砂雨法制备的砂土地基参数可控性更好;两组试验的结果有差异,砂土地基试验所呈现的土压力、地基变形、支护弯矩的变化规律更好,因此,岩土离心试验可适当考虑以砂土代替非饱和土;对于采用悬臂式支护结构的基坑,开挖引起的地表沉降曲线在砂土中呈指数型,而在粉质黏土中呈直线型;开挖引起的粉质黏土地基土体位移范围较砂土地基更大;开挖引起的砂土中挡墙弯矩较粉质黏土更大,砂土和粉质黏土中最大弯矩位置都随开挖逐渐下移;在砂土试验中开挖引起主动区土压力各处均减小,而在粉质黏土试验中开挖引起土压力在挡墙底有增大趋势。该基坑工程离心模型试验过程及数据处理方法可为进一步试验提供参考。
Two centrifuge model tests on foundation pit engineering with cantilever retaining wall in sand and silty clay ground are carried out respectively. Test procedures and some feasible solutions to the key problems in the tests are introduced, and results of the two tests are listed and compared in this paper. It can be summarized that the preparation of unsaturated soil ground is difficult because it is hard to control parameters of remolded soil. Therefore, stratified compaction method needs to be improved. In contrast, sand ground prepared by sand-rain method is easier to control parameters.Evolution of soil pressure, foundation deformation, and bending moment in the sand ground test is better than that in the silty clay ground test. Therefore, geotechnical centrifuge model tests in unsaturated soil ground can be replaced by the tests in sand ground appropriately. In foundation pit engineering with cantilever supporting structures, the induced surface settlement curve is an exponential pattern in sand ground but a linear pattern in silty clay ground according to test results, and the induced ground deformation range is larger in silty ground than that in sand ground. The induced bending moment of the retaining wall is larger in sand ground than that in silty ground, and the positions of the maximum bending moment for both grounds move down during the excavations. In sand ground, soil excavation causes decrease of the earth pressure behind the retaining wall, while in silty clay ground, there is an increase at the bottom of the wall. The complete test procedures and data processing methods presented in this study provide technical premises and guidance for further tests.
Two centrifuge model tests on foundation pit engineering with cantilever retaining wall in sand and silty clay ground are carried out respectively. Test procedures and some feasible solutions to the key problems in the tests are introduced, and results of the two tests are listed and compared in this paper. It can be summarized that the preparation of unsaturated soil ground is difficult because it is hard to control parameters of remolded soil. Therefore, stratified compaction method needs to be improved. In contrast, sand ground prepared by sand-rain method is easier to control parameters.Evolution of soil pressure, foundation deformation, and bending moment in the sand ground test is better than that in the silty clay ground test. Therefore, geotechnical centrifuge model tests in unsaturated soil ground can be replaced by the tests in sand ground appropriately. In foundation pit engineering with cantilever supporting structures, the induced surface settlement curve is an exponential pattern in sand ground but a linear pattern in silty clay ground according to test results, and the induced ground deformation range is larger in silty ground than that in sand ground. The induced bending moment of the retaining wall is larger in sand ground than that in silty ground, and the positions of the maximum bending moment for both grounds move down during the excavations. In sand ground, soil excavation causes decrease of the earth pressure behind the retaining wall, while in silty clay ground, there is an increase at the bottom of the wall. The complete test procedures and data processing methods presented in this study provide technical premises and guidance for further tests.
引文
[1]李连祥,符庆宏,张海平.基坑工程离心模型试验进展及关键技术[J].工业建筑,2015,45(10):142-149.LI Lian-xiang,FU Qing-hong,ZHANG Hai-ping.Progress and key technology of centrifugal model tests on foundation pit engineering[J].Industrial Construction,2015,45(10):142-149.
[2]张建红,张雁,濮家骝,等.土钉支护的离心模型试验研究[J].土木工程学报,2009,42(1):76-80.ZHANG Jian-hong,ZHANG Yan,PU Jia-liu,et al.Centrifuge modelling of soil nail reinforcements[J].China Civil Engineering Journal,2009,42(1):76-80.
[3]周秋娟,陈晓平,徐光明.软土基坑离心模型试验及数值模拟研究[J].岩石力学与工程学报,2013,32(11):2342-2348.ZHOU Qiu-juan,CHEN Xiao-ping,XU Guang-ming.Centrifugal model test and numerical simulation of soft soil foundation pit[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(11):2342-2348.
[4]RICHARDS D J,POWRIE W.Centrifuge model tests on doubly propped embedded retaining walls in overconsolidated kaolin clay[J].Géotechnique,1998,48(6):833-846.
[5]BOLTON M D,POWRIE W.The collapse of diaphragm walls retaining clay[J].Géotechnique,1987,37(3):335-353.
[6]BOLTON M D,POWRIE W.Behaviour of diaphragm walls in clay prior to collapse[J].Géotechnique,1988,38(2):167-189.
[7]马险峰,张海华,朱卫杰,等.软土地区超深基坑变形特性离心模型试验研究[J].岩土工程学报,2009,31(9):1371-1377.MA Xian-feng,ZHANG Hai-hua,ZHU Wei-jie,et al.Centrifuge model tests on deformation of ultra-deep foundation pits in soft ground[J].Chinese Journal of Geotechnical Engineering,2009,31(9):1371-1377.
[8]徐前卫,马险峰,朱合华,等.软土地基超深基坑开挖的离心模型试验研究[J].土木工程学报,2009,42(12):154-161.XU Qian-wei,MA Xian-feng,ZHU He-hua,et al.Centrifugal model test on extra-deep foundation pit excavations in soft ground[J].China Civil Engineering Journal,2009,42(12):154-161.
[9]LEUNG C F,CHOW Y K,SHEN R F.Behavior of pile subject to excavation-induced soil movement[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2000,126(11):947-954.
[10]LEUNG C F,LIM J K,SHEN R F,et al.Behavior of pile groups subject to excavation-induced soil movement[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2003,129(1):58-65.
[11]ONG D E L,LEUNG C F,CHOW Y K.Pile behavior due to excavation-induced soil movement in clay.I:Stable wall[J].Journal of and Geoenvironmental Geotechnical Engineering,ASCE,2006,132(1):36-44.
[12]LEUNG C F,ONG D E L,CHOW Y K.Pile behavior due to excavation-induced soil movement in clay.II:Collapsed wall[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2006,132(1):45-53.
[13]梁发云,褚峰,宋著,等.紧邻地铁枢纽深基坑变形特性离心模型试验研究[J].岩土力学,2012,33(3):657-664.LIANG Fa-yun,CHU Feng,SONG Zhu,et al.Centrifugal model test research on deformation behaviors of deep foundation pit adjacent to metro stations[J].Rock and Soil Mechanics,2012,33(3):657-664.
[14]丁春林,孟晓红.承压水基坑离心模型试验与现场实测分析[J].同济大学学报(自然科学版),2008,36(1):22-26.DING Chun-lin,MENG Xiao-hong.Centrifuge model test and field measurement analysis for foundation pit with confined water[J].Journal of Tongji University:(Natural Science),2008,36(1):22-26.
[15]李镜培,张飞,梁发云,等.承压水基坑突涌机制离心模型试验与数值模拟[J].同济大学学报(自然科学版),2012,40(6):837-842.LI Jing-pei,ZHANG Fei,LIANG Fa-yun,et al.Centrifugal model tests and numerical simulation on hydraulic heave mechanism in excavation with confined water[J].Journal of Tongji University(Natural Science),2012,40(6):837-842.
[16]孙玉永,周顺华.基于离心模型试验的基坑突涌模式及机制研究[J].岩石力学与工程学报,2012,29(12):2551-2557.SUN Yu-yong,ZHOU Shun-hua.Mode and mechanism of bursting foundation pit based on centrifugal model test[J].Chinese Journal of Rock Mechanics and Engineering,2012,29(12):2551-2557.
[17]李连祥,符庆宏.临近基坑开挖复合地基侧向力学性状离心试验研究[J].土木工程学报,2017,50(6):85-94.LI Lian-xiang,FU Qing-hong.Lateral mechanical behavior of composite ground due to adjacent excavation:Centrifuge model test[J].China Civil Engineering Journal,2017,50(6):85-94.
[18]杨俊杰,柳飞,丰泽康南,等.砂土地基承载力离心模型试验中的粒径效应研究[J].岩土工程学报,2007,29(4):477-483.YANG Jun-jie,LIU Fei,TOYOSAWAY,et al.Particle size effects on bearing capacity of sandy ground in centrifugal tests[J].Chinese Journal of Geotechnical Engineering,2007,29(4):477-483.
[19]李荣建,于玉贞,吕禾,等.饱和砂土地基上抗滑桩加固边坡的动力离心模型试验研究[J].岩土力学,2009,30(4):897-902.LI Rong-jian,YU Yu-zhen,LüHe,et al.Dynamic centrifuge modeling of piles-reinforced slope on saturated sandy foundation[J].Rock and Soil Mechanics,2009,30(4):897-902.
[20]陈胜立,张建民,张丙印,等.软土地基上土工织物加筋堤的离心模型试验研究[J].岩土力学,2006,27(5):803-806.CHEN Sheng-li,ZHANG Jian-min,ZHANG Bing-yin,et al.Centrifugal modeling of reinforced embankments on soft clay[J].Rock and Soil Mechanics,2006,27(5):803-806.
[21]王爱霞,邢占清,张嘎,等.海上风机筒型基础黏土地基离心模型试验研究[J].岩土工程学报,2015,37(增刊1):41-45.WANG Ai-xia,XING Zhan-qing,ZHANG Ga,et al.Centrifugal model tests on bucket foundation in clay for offshore wind turbine[J].Chinese Journal of Geotechnical Engineering,2015,37(Supp.1):41-45.
[22]李连祥,符庆宏,张海平,等.复合地基侧向力学性状离心模型试验方案研究与设计[J].重庆交通大学学报(自然科学版),2016,35(2):92-100.LI Lian-xiang,FU Qing-hong,ZHANG Hai-ping,et al.Research and design of centrifuge model tests on lateral mechanics properties of composite foundation[J].Journal of Chongqing Jiaotong University(Natural Science),2016,35(2):92-100.
[23]中国建筑科学研究院.JGJ94-2008建筑桩基技术规范[S].北京:中国建筑工业出版社,2008.China Academy of Building Research.JGJ94-2008Technical code for building pile foundation[S].Beijing:China Architecture&Building Press,2008.
[24]李连祥,符庆宏,张永磊,等.基坑离心模型试验开挖方法研究与应用[J].岩石力学与工程学报,2016,35(4):856-864.LI Lian-xiang,FU Qing-hong,ZHANG Yong-lei,et al.Research and application of a new excavation method in centrifuge model test on foundation pit engineering[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(4):856-864.
[25]WHITE D J,TAKE W A,BOLTON M D.Soil deformation measurement using particle image velocimetry(PIV)and photogrammetry[J].Géotechnique,2003,53(7):619-631.
[26]PECK R B.Deep excavation and tunneling in soft ground[C]//Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering.Mexico City:State of the Art Volume,1969:225-290.
[27]OU C Y,HSIEH P G,CHIOU D C.Characteristics of ground surface settlement during excavation[J].Canadian Geotechnical Journal,1993,30(5):758-767.
[2]张建红,张雁,濮家骝,等.土钉支护的离心模型试验研究[J].土木工程学报,2009,42(1):76-80.ZHANG Jian-hong,ZHANG Yan,PU Jia-liu,et al.Centrifuge modelling of soil nail reinforcements[J].China Civil Engineering Journal,2009,42(1):76-80.
[3]周秋娟,陈晓平,徐光明.软土基坑离心模型试验及数值模拟研究[J].岩石力学与工程学报,2013,32(11):2342-2348.ZHOU Qiu-juan,CHEN Xiao-ping,XU Guang-ming.Centrifugal model test and numerical simulation of soft soil foundation pit[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(11):2342-2348.
[4]RICHARDS D J,POWRIE W.Centrifuge model tests on doubly propped embedded retaining walls in overconsolidated kaolin clay[J].Géotechnique,1998,48(6):833-846.
[5]BOLTON M D,POWRIE W.The collapse of diaphragm walls retaining clay[J].Géotechnique,1987,37(3):335-353.
[6]BOLTON M D,POWRIE W.Behaviour of diaphragm walls in clay prior to collapse[J].Géotechnique,1988,38(2):167-189.
[7]马险峰,张海华,朱卫杰,等.软土地区超深基坑变形特性离心模型试验研究[J].岩土工程学报,2009,31(9):1371-1377.MA Xian-feng,ZHANG Hai-hua,ZHU Wei-jie,et al.Centrifuge model tests on deformation of ultra-deep foundation pits in soft ground[J].Chinese Journal of Geotechnical Engineering,2009,31(9):1371-1377.
[8]徐前卫,马险峰,朱合华,等.软土地基超深基坑开挖的离心模型试验研究[J].土木工程学报,2009,42(12):154-161.XU Qian-wei,MA Xian-feng,ZHU He-hua,et al.Centrifugal model test on extra-deep foundation pit excavations in soft ground[J].China Civil Engineering Journal,2009,42(12):154-161.
[9]LEUNG C F,CHOW Y K,SHEN R F.Behavior of pile subject to excavation-induced soil movement[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2000,126(11):947-954.
[10]LEUNG C F,LIM J K,SHEN R F,et al.Behavior of pile groups subject to excavation-induced soil movement[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2003,129(1):58-65.
[11]ONG D E L,LEUNG C F,CHOW Y K.Pile behavior due to excavation-induced soil movement in clay.I:Stable wall[J].Journal of and Geoenvironmental Geotechnical Engineering,ASCE,2006,132(1):36-44.
[12]LEUNG C F,ONG D E L,CHOW Y K.Pile behavior due to excavation-induced soil movement in clay.II:Collapsed wall[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2006,132(1):45-53.
[13]梁发云,褚峰,宋著,等.紧邻地铁枢纽深基坑变形特性离心模型试验研究[J].岩土力学,2012,33(3):657-664.LIANG Fa-yun,CHU Feng,SONG Zhu,et al.Centrifugal model test research on deformation behaviors of deep foundation pit adjacent to metro stations[J].Rock and Soil Mechanics,2012,33(3):657-664.
[14]丁春林,孟晓红.承压水基坑离心模型试验与现场实测分析[J].同济大学学报(自然科学版),2008,36(1):22-26.DING Chun-lin,MENG Xiao-hong.Centrifuge model test and field measurement analysis for foundation pit with confined water[J].Journal of Tongji University:(Natural Science),2008,36(1):22-26.
[15]李镜培,张飞,梁发云,等.承压水基坑突涌机制离心模型试验与数值模拟[J].同济大学学报(自然科学版),2012,40(6):837-842.LI Jing-pei,ZHANG Fei,LIANG Fa-yun,et al.Centrifugal model tests and numerical simulation on hydraulic heave mechanism in excavation with confined water[J].Journal of Tongji University(Natural Science),2012,40(6):837-842.
[16]孙玉永,周顺华.基于离心模型试验的基坑突涌模式及机制研究[J].岩石力学与工程学报,2012,29(12):2551-2557.SUN Yu-yong,ZHOU Shun-hua.Mode and mechanism of bursting foundation pit based on centrifugal model test[J].Chinese Journal of Rock Mechanics and Engineering,2012,29(12):2551-2557.
[17]李连祥,符庆宏.临近基坑开挖复合地基侧向力学性状离心试验研究[J].土木工程学报,2017,50(6):85-94.LI Lian-xiang,FU Qing-hong.Lateral mechanical behavior of composite ground due to adjacent excavation:Centrifuge model test[J].China Civil Engineering Journal,2017,50(6):85-94.
[18]杨俊杰,柳飞,丰泽康南,等.砂土地基承载力离心模型试验中的粒径效应研究[J].岩土工程学报,2007,29(4):477-483.YANG Jun-jie,LIU Fei,TOYOSAWAY,et al.Particle size effects on bearing capacity of sandy ground in centrifugal tests[J].Chinese Journal of Geotechnical Engineering,2007,29(4):477-483.
[19]李荣建,于玉贞,吕禾,等.饱和砂土地基上抗滑桩加固边坡的动力离心模型试验研究[J].岩土力学,2009,30(4):897-902.LI Rong-jian,YU Yu-zhen,LüHe,et al.Dynamic centrifuge modeling of piles-reinforced slope on saturated sandy foundation[J].Rock and Soil Mechanics,2009,30(4):897-902.
[20]陈胜立,张建民,张丙印,等.软土地基上土工织物加筋堤的离心模型试验研究[J].岩土力学,2006,27(5):803-806.CHEN Sheng-li,ZHANG Jian-min,ZHANG Bing-yin,et al.Centrifugal modeling of reinforced embankments on soft clay[J].Rock and Soil Mechanics,2006,27(5):803-806.
[21]王爱霞,邢占清,张嘎,等.海上风机筒型基础黏土地基离心模型试验研究[J].岩土工程学报,2015,37(增刊1):41-45.WANG Ai-xia,XING Zhan-qing,ZHANG Ga,et al.Centrifugal model tests on bucket foundation in clay for offshore wind turbine[J].Chinese Journal of Geotechnical Engineering,2015,37(Supp.1):41-45.
[22]李连祥,符庆宏,张海平,等.复合地基侧向力学性状离心模型试验方案研究与设计[J].重庆交通大学学报(自然科学版),2016,35(2):92-100.LI Lian-xiang,FU Qing-hong,ZHANG Hai-ping,et al.Research and design of centrifuge model tests on lateral mechanics properties of composite foundation[J].Journal of Chongqing Jiaotong University(Natural Science),2016,35(2):92-100.
[23]中国建筑科学研究院.JGJ94-2008建筑桩基技术规范[S].北京:中国建筑工业出版社,2008.China Academy of Building Research.JGJ94-2008Technical code for building pile foundation[S].Beijing:China Architecture&Building Press,2008.
[24]李连祥,符庆宏,张永磊,等.基坑离心模型试验开挖方法研究与应用[J].岩石力学与工程学报,2016,35(4):856-864.LI Lian-xiang,FU Qing-hong,ZHANG Yong-lei,et al.Research and application of a new excavation method in centrifuge model test on foundation pit engineering[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(4):856-864.
[25]WHITE D J,TAKE W A,BOLTON M D.Soil deformation measurement using particle image velocimetry(PIV)and photogrammetry[J].Géotechnique,2003,53(7):619-631.
[26]PECK R B.Deep excavation and tunneling in soft ground[C]//Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering.Mexico City:State of the Art Volume,1969:225-290.
[27]OU C Y,HSIEH P G,CHIOU D C.Characteristics of ground surface settlement during excavation[J].Canadian Geotechnical Journal,1993,30(5):758-767.