砂岩地基上地下结构浮力特性研究%
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摘要
为了研究砂岩地基上地下结构抗浮设计折减问题,通过室内模型试验与现场监测试验,进行砂岩地基上地下结构浮力特性研究,分析地下水渗流规律。结果表明:砂岩为不透水材料,渗流条件、渗透压、渗流时间对基础所受浮力均有影响,三者贡献程度不同,渗流条件影响最大;渗流条件变化时,渗透压、渗流时间对浮力的影响程度随之变化;砂岩地基上的地下结构浮力可进行安全折减,折减系数视基底与地基接触关系而定,二者仅简单接触、接触四周做封闭处理但砂岩内部存在裂隙、接触四周做封闭处理且砂岩完整3种情况下水压力折减系数分别为0.82～0.91,0.63～0.73,0.31～0.50;基坑回填时宜在地下结构四周一定范围内采用不透水材料形成隔水层,改变渗流路径,增加折减效果,放宽抗浮设计要求。研究结果旨在为地下空间结构抗浮设计提供一些依据。
The buoyancy characteristics of underground structures on sandstone foundation are studied for anti-floating design and the seepage laws of groundwater are analyzed by indoor model tests and field monitoring tests. Results show that since sandstone is impervious,seepage condition,seepage pressure,and seepage time could all affect the buoyancy acting on sandstone structure,among which seepage condition has the largest impact. The influence of seepage pressure and seepage time on buoyancy changes with the variation of seepage condition. The buoyancy of underground structure on sandstone foundation can be reduced safely,and the reduction coefficient depends on the contact between basement and ground. The reduction coefficients in three contact conditions( simple contact,contact with sealing treatment in the peripheral and fractures inside the sandstone,and contact with sealing treatment in the peripheral and no fracture inside the sandstone) are 0.82-0.91,0.63-0.73,0.31-0.50,respectively.It is recommended to ease the anti-floating requirements and adopt impermeable materials surrounding underground to alter seepage path and enhance reduction effect during foundation backfill.
The buoyancy characteristics of underground structures on sandstone foundation are studied for anti-floating design and the seepage laws of groundwater are analyzed by indoor model tests and field monitoring tests. Results show that since sandstone is impervious,seepage condition,seepage pressure,and seepage time could all affect the buoyancy acting on sandstone structure,among which seepage condition has the largest impact. The influence of seepage pressure and seepage time on buoyancy changes with the variation of seepage condition. The buoyancy of underground structure on sandstone foundation can be reduced safely,and the reduction coefficient depends on the contact between basement and ground. The reduction coefficients in three contact conditions( simple contact,contact with sealing treatment in the peripheral and fractures inside the sandstone,and contact with sealing treatment in the peripheral and no fracture inside the sandstone) are 0.82-0.91,0.63-0.73,0.31-0.50,respectively.It is recommended to ease the anti-floating requirements and adopt impermeable materials surrounding underground to alter seepage path and enhance reduction effect during foundation backfill.
引文
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[2]梅国雄,宋林辉,宰金珉.地下水浮力折减试验研究[J].岩土工程学报,2009,31(9):1476-1480.
[3]袁正如.地下工程的抗浮设计[J].地下空间与工程学报,2004,24(1):41-43.
[4]熊欢.地下结构抗浮设计中浮力的研究[D].长沙:中南大学,2013.
[5]章胜南.成层土中围护结构所受水土压力的计算[J].岩土工程学报,1998,20(4):95-97.
[6]孙保卫,徐宏声,张在明.孔隙水压力测试与建筑抗浮水压力的确定[J].工程勘察,1998,(3):31-35.
[7]张在明,孙保卫,徐宏声.地下水赋存状态与渗流特征对基础抗浮的影响[J].土木工程学报,2001,34(1):73-78.
[8]宋林辉,梅国雄,宰金珉.黏土地基上基础模型抗浮试验研究[J].工程勘察,2008,6(6):26-30.
[9]张乾,宋林辉,梅国雄.黏土地基中的基础浮力模型试验[J].工程勘察,2011,(9):37-41.
[10]GB 50021-2001,岩土工程勘察规范[S].北京:中国标准出版社,2001.
[11]林在贯,高大钊,顾宝和,等.岩土工程手册[M].北京:中国建筑工业出版社.1994.
[12]GB 50069-2002,给水排水工程构筑物结构设计规范[S].北京:中国标准出版社,2001.
[13]宋林辉,刘益,梅国雄,等.粘土地基中的水浮力试验研究[J].水文地质工程地质,2008,(6):80-84.
[14]孙广利,高涛,安征.某工程地下水抗浮折减试验研究[J].吉林建筑工程学院学报,2013,30(2):12-14.
[15]张第轩,陈龙珠.地下结构抗浮计算方法试验研究[J].四川建筑科学研究,2008,34(3):105-108.
[16]张第轩.地下结构抗浮模型试验研究[D].上海:上海交通大学,2007.
[17]崔岩,崔京浩,吴世红.地下结构浮力模型试验研究[J].特种结构,1999,16(1):32-39.
[18]崔岩,崔京浩,吴世红,等.浅埋地下结构外水压折减系数试验研究[J].岩石力学与工程学报,2000,19(1):82-84.
[19]张豫川,潘增志,王祖耀,等.砂岩与砂质泥岩渗透性能试验研究[J].地下空间与工程学报,2017,13(2):301-306.