基坑突涌机理研究
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摘要
当基坑下部有承压水存时基坑很容易发生突涌,事故一旦产生对整个基坑工程会造成严重影响,因此含承压水基坑设计时抗突涌计算越来越引起大家的重视。目前已有的基坑突涌计算理论主要有以下几种:压力平衡理论、土体剪切破坏理论、土体挠曲破坏理论、综合考虑土体强度和刚度理论和统计预测法等,这些方法从不同角度推测基坑突涌破坏机理,但是这些方法均存在一些不足之处,对于基坑突涌破坏过程和基坑破坏机理还没有准确的认识。
本文借鉴土石坝心墙水力劈裂理论解释基坑突涌破坏机理,在下部高承压水作用下基坑粘土隔水层内部孔隙水压力和土体有效应力会发生改变,同时隔水层自身隆起变形也会降低基坑边缘底部土应力,通过水力劈裂理论可知隔水层底部会产生裂缝,在底部持续高水压作用下裂缝会逐渐从下向上扩展,最终形成突涌通道。
为了观测基坑突涌破坏过程并验证突涌破坏机理,本文进行了一系列模型试验,并对模型试验进行全过程有限元数值模拟计算,试验现象和数值计算结果均表明基坑突涌破坏是基坑隔水层在水力劈裂作用下产生的。本文同时考察了基坑存在缺陷情况下突涌破坏特点,这些现象也表明水力劈裂理论可以正确揭示基坑突涌破坏机理。
Bottom piping may occur in the foundation pit under the confined water pressure, which will make great damage to the engineering. How to control bottom piping in the foundation pit engineering becomes a common problem. Based on the failure mechanism of bearing resistance water foundation pit, the existing calculation methods of inrushing for confined water foundation pit are summarized as followed, balance of the water press and the soil?s weight, considering the shearing and cementation strength, considering the stiffness of the pit, overall consideration of the stiffness and the strength of the pit and neural network model for gush of foundation pit. The mechanism of piping is seen from different points of view in these methods, but these methods don?t make the mechanism exactly and clear.
In this paper hydraulic fracturing will be introduced into the study of piping in foundation pit. Effective stress and pore pressures in impervious aquiclude will change under the confined water pressure, at the same time, the deformation will increase, which will reduce the stress in the clay. By the theory of hydraulic fracturing, fissures would emerge in the clay where effective stress is small. The fissures will develop from down to up till it runs through the impervious aquiclude, then inrushing of soil and water will occurs.
A series of model experiments is performed to determine the type of failure in the foundation pit to observe the course of piping and prove the applicability of hydraulic fracturing in foundation engineering. Then numerical simulations for the experiments are made, and the results indicate that hydraulic fracturing can be used to explicate piping in foundation pit. At last, an analysis of foundation with weaknesses is made, whose result also prove the conclusion above.
本文借鉴土石坝心墙水力劈裂理论解释基坑突涌破坏机理,在下部高承压水作用下基坑粘土隔水层内部孔隙水压力和土体有效应力会发生改变,同时隔水层自身隆起变形也会降低基坑边缘底部土应力,通过水力劈裂理论可知隔水层底部会产生裂缝,在底部持续高水压作用下裂缝会逐渐从下向上扩展,最终形成突涌通道。
为了观测基坑突涌破坏过程并验证突涌破坏机理,本文进行了一系列模型试验,并对模型试验进行全过程有限元数值模拟计算,试验现象和数值计算结果均表明基坑突涌破坏是基坑隔水层在水力劈裂作用下产生的。本文同时考察了基坑存在缺陷情况下突涌破坏特点,这些现象也表明水力劈裂理论可以正确揭示基坑突涌破坏机理。
Bottom piping may occur in the foundation pit under the confined water pressure, which will make great damage to the engineering. How to control bottom piping in the foundation pit engineering becomes a common problem. Based on the failure mechanism of bearing resistance water foundation pit, the existing calculation methods of inrushing for confined water foundation pit are summarized as followed, balance of the water press and the soil?s weight, considering the shearing and cementation strength, considering the stiffness of the pit, overall consideration of the stiffness and the strength of the pit and neural network model for gush of foundation pit. The mechanism of piping is seen from different points of view in these methods, but these methods don?t make the mechanism exactly and clear.
In this paper hydraulic fracturing will be introduced into the study of piping in foundation pit. Effective stress and pore pressures in impervious aquiclude will change under the confined water pressure, at the same time, the deformation will increase, which will reduce the stress in the clay. By the theory of hydraulic fracturing, fissures would emerge in the clay where effective stress is small. The fissures will develop from down to up till it runs through the impervious aquiclude, then inrushing of soil and water will occurs.
A series of model experiments is performed to determine the type of failure in the foundation pit to observe the course of piping and prove the applicability of hydraulic fracturing in foundation engineering. Then numerical simulations for the experiments are made, and the results indicate that hydraulic fracturing can be used to explicate piping in foundation pit. At last, an analysis of foundation with weaknesses is made, whose result also prove the conclusion above.
引文
[1]李启民,孔永,我国深基坑工程事故的综合分析,科技情报开发与经济,1999,29(2): 55-561
[2]丁春林,软土地区承压水基坑突涌稳定计算法研究综述,地下空间与工程学报,2007,3(2): 333-339
[3]王曙光,温文,深基坑工程事故分析与工程实践,地基基础工程,2000,10(6): 1-9
[4]叶琳昌,要重视基坑围护中的防水问题,中国建筑防水,2000,(1): 18-22
[5]唐业清,深基坑工程事故的预防与处理,施工技术,1997,26(1): 4-5
[6]郑剑升,张克平,承压水地层基坑底部突涌及解决措施,隧道建设,2003,23(5): 25-27
[7]刘国彬,王洪新,上海浅层粉砂地层承压水对基坑的危害及治理,岩土工程学报,2002,24(6): 790-792
[8]张兴辽,尚玉忠,郭文秀,一起令人深思的基坑突涌事件,岩土工程技术,1999,3: 63-66
[9]戴斌,卫东,压水影响深基坑工程的若干技术措施探讨,岩土工程学报,2006,28(增)
[10]《工程地质手册》编委会,工程地质手册,北京:中国建筑工业出版社,1992
[11]《建筑基坑工程技术规范》(YB 9258-97),1997.
[12]马石城,印长俊,邹银生,抗承压水基坑底板的厚度分析与计算,工程力学,2004,21(2): 204-208
[13]Eringen A C, Suhub E S. Electrodynamics, New York and London: Academic Press, 1974
[14]梁勇然,条形基坑的突涌分析,岩土工程学报,1996,18(1): 75-80
[15] VAUGHAN P R. The use of hydraulic fracturing tests to detect crack formation in embankment dam cores, London:Department of Civil Engineering, Imperial College, 1971
[16]陈五一,赵颜辉,土石坝心墙水力劈裂计算方法研究,岩石力学与工程学报:2008,27(7): 1380-1386
[17]张惠忠,刘明建,上海软土中的“微承压水”与基坑工程,岩土工程学报,2005,27(8): 944-947
[18]Independent Panel. Review cause of Teton Dam failure, Denver, Colo: US Bureau of Reclamation, 1976
[19]王俊杰,朱俊高,张辉,关于土石坝心墙水力劈裂研究的一些思考,岩石力学与工程学报,2005,24(增刊2): 5664-5668
[20]孔宪勇,左永振,姜景山,土石坝心墙水力劈裂的研究进展,岩土力学,2008,29(增刊): 215-218
[21]陈仲颐,周景星,王洪瑾,土力学,清华大学出版社,1994,36-64
[22]张丙印,李娜,李全明等,土石坝水力劈裂发生机理及模型试验研究,岩土工程学报,2005,27(11): 1277-1281
[23]张丙印,于玉贞,张建民,高土石坝的若干关键技术问题,第九届土力学及岩土工程学术会议论文集,北京:清华大学出版社,2003: 163-186
[24]朱俊高,王俊杰,张辉,土石坝心墙水力劈裂机制研究,岩土力学,2007,28(3): 487-493
[25]张云,梁永然,基于BP神经网络的基坑突涌分析,工程勘察,2001,(2): 22-25
[26]殷宗泽,朱俊高,袁俊平等,心墙堆石坝的水力劈裂分析,水利学报,2006,37(11): 1348-1353
[27]U.S. Department of the Interior Teton Dam Failure Review Group. U.S. Failure of Teton dam:a report of findings, Washington, D.C.:U.S. Department of the Interior Teton Dam Failure Review Group, 1977.
[28]曾开华,土质心墙坝水力劈裂机制及影响因素的研究,河海大学,2001
[29]黄文熙,对土石坝科研工作的几点看法,水利水电技术,1982,(4): 23-27R.
[30]Lo K Y, Kiny K. Hydraulic fracture in earth and rock-fill dams, Canadian Geotechnical Journal, 1990, 27(4): 496-506
[31]李广信,高等土力学,清华大学出版社,2004,190-215
[32]李广信,刘早云,温庆博,渗透对基坑水土压力的影响,水力学报,2002(5),75-80
[32]李全明,张丙印,于玉贞等,土石坝水力劈裂发生过程的有限元数值模拟,岩土工程学报,2007,29(2): 212-217
[33]王俊杰,朱俊高,堆石坝心墙抗水力劈裂性能研究,岩石力学与工程学报,2007,26(增1): 2880-2885
[34]宫必宁,童蕾,牛志国,土石坝工程的拱效应分析,岩石力学与工程学报,2004,22(245): 14-17
[35]李涛,王超,高承压水地层开挖基坑底板隆起稳定性分析,岩土工程学报,2009,31(8): 1236-1241
[36]唐红侠,周志芳,王文远,水劈裂过程中岩体渗透性规律及机制分析,岩土力学,2004,25(8): 1320-1322
[37]谢兴华,速宝玉,裂隙岩体水力劈裂研究综述,岩土力学,2004,25(2): 330-336
[38]Panah A K, Yanagisawa E, Laboratory studies on hydraulic fracturing criteria in soil, Soils and Foundations, 1989, 29(4): 14-22
[39]Alfaro M C, Wong R C K. Laboratory studies on fracturing of low-permeability soils, Canadian Geotechnical Journal, 2001,38: 303-315
[40]冯晓莹,栾茂田,徐泽平,黏土心墙坝水力劈裂发生机理及判别方法,北京工业大学学报,2009,35(4): 470-475
[41]Murdoch L C. Hydraulic fracturing of soil during laboratory experiments, Part 1. Methods and observations, Geotechnique, 1993, 43(2): 255-265
[42]张坤勇,殷宗泽,朱俊高,各向异性对土质心墙坝水力劈裂的影响,岩土力学,2005, 26(2): 243-246
[43]Lawrence C M, Mechanical Analysis of idealized shallow hydraulic fracture,Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2002, 128(6): 488-495
[44]丁春林,周顺华,张师德,基于离心试验的承压水基坑变形稳定影响因素,同济大学学报(自然科学版),2005,33(12): 1586
[45]钱家欢,殷宗泽,土工原理与计算,北京:中国水利水电出版社,1996
[46]周健,刘宁,离心模型试验技术应用新进展,上海地质,2002(1): 52
[47]Hill R, on uniqueness and stability in the theory of finiteelastic strain, J Mech. Phys Solids, 1957, 5: 227-241
[48]Toupin R A, Bernstein B, Sound waves in deformed perfectly elastic material, Acoustoelastic effect, Acoust.Soc. Amer, 1961, 33: 216-225
[49]璩继立,刘国彬,张建峰,东昌路地铁车站降承压水引起地面沉降的研究,土木工程学报,2000,35(5): 93-99
[50]柏仇勇,曹继平,周剑锋等,南京地铁三山街站基坑降水及对周边环境的影响,河海大学学报,2001,29: 268-270
[51] B. J. Brinkgreve, W. Broere , K. J. Bakker, Delf University of Technology & PLAXIS by the Netherlands: version 1-version 5
[2]丁春林,软土地区承压水基坑突涌稳定计算法研究综述,地下空间与工程学报,2007,3(2): 333-339
[3]王曙光,温文,深基坑工程事故分析与工程实践,地基基础工程,2000,10(6): 1-9
[4]叶琳昌,要重视基坑围护中的防水问题,中国建筑防水,2000,(1): 18-22
[5]唐业清,深基坑工程事故的预防与处理,施工技术,1997,26(1): 4-5
[6]郑剑升,张克平,承压水地层基坑底部突涌及解决措施,隧道建设,2003,23(5): 25-27
[7]刘国彬,王洪新,上海浅层粉砂地层承压水对基坑的危害及治理,岩土工程学报,2002,24(6): 790-792
[8]张兴辽,尚玉忠,郭文秀,一起令人深思的基坑突涌事件,岩土工程技术,1999,3: 63-66
[9]戴斌,卫东,压水影响深基坑工程的若干技术措施探讨,岩土工程学报,2006,28(增)
[10]《工程地质手册》编委会,工程地质手册,北京:中国建筑工业出版社,1992
[11]《建筑基坑工程技术规范》(YB 9258-97),1997.
[12]马石城,印长俊,邹银生,抗承压水基坑底板的厚度分析与计算,工程力学,2004,21(2): 204-208
[13]Eringen A C, Suhub E S. Electrodynamics, New York and London: Academic Press, 1974
[14]梁勇然,条形基坑的突涌分析,岩土工程学报,1996,18(1): 75-80
[15] VAUGHAN P R. The use of hydraulic fracturing tests to detect crack formation in embankment dam cores, London:Department of Civil Engineering, Imperial College, 1971
[16]陈五一,赵颜辉,土石坝心墙水力劈裂计算方法研究,岩石力学与工程学报:2008,27(7): 1380-1386
[17]张惠忠,刘明建,上海软土中的“微承压水”与基坑工程,岩土工程学报,2005,27(8): 944-947
[18]Independent Panel. Review cause of Teton Dam failure, Denver, Colo: US Bureau of Reclamation, 1976
[19]王俊杰,朱俊高,张辉,关于土石坝心墙水力劈裂研究的一些思考,岩石力学与工程学报,2005,24(增刊2): 5664-5668
[20]孔宪勇,左永振,姜景山,土石坝心墙水力劈裂的研究进展,岩土力学,2008,29(增刊): 215-218
[21]陈仲颐,周景星,王洪瑾,土力学,清华大学出版社,1994,36-64
[22]张丙印,李娜,李全明等,土石坝水力劈裂发生机理及模型试验研究,岩土工程学报,2005,27(11): 1277-1281
[23]张丙印,于玉贞,张建民,高土石坝的若干关键技术问题,第九届土力学及岩土工程学术会议论文集,北京:清华大学出版社,2003: 163-186
[24]朱俊高,王俊杰,张辉,土石坝心墙水力劈裂机制研究,岩土力学,2007,28(3): 487-493
[25]张云,梁永然,基于BP神经网络的基坑突涌分析,工程勘察,2001,(2): 22-25
[26]殷宗泽,朱俊高,袁俊平等,心墙堆石坝的水力劈裂分析,水利学报,2006,37(11): 1348-1353
[27]U.S. Department of the Interior Teton Dam Failure Review Group. U.S. Failure of Teton dam:a report of findings, Washington, D.C.:U.S. Department of the Interior Teton Dam Failure Review Group, 1977.
[28]曾开华,土质心墙坝水力劈裂机制及影响因素的研究,河海大学,2001
[29]黄文熙,对土石坝科研工作的几点看法,水利水电技术,1982,(4): 23-27R.
[30]Lo K Y, Kiny K. Hydraulic fracture in earth and rock-fill dams, Canadian Geotechnical Journal, 1990, 27(4): 496-506
[31]李广信,高等土力学,清华大学出版社,2004,190-215
[32]李广信,刘早云,温庆博,渗透对基坑水土压力的影响,水力学报,2002(5),75-80
[32]李全明,张丙印,于玉贞等,土石坝水力劈裂发生过程的有限元数值模拟,岩土工程学报,2007,29(2): 212-217
[33]王俊杰,朱俊高,堆石坝心墙抗水力劈裂性能研究,岩石力学与工程学报,2007,26(增1): 2880-2885
[34]宫必宁,童蕾,牛志国,土石坝工程的拱效应分析,岩石力学与工程学报,2004,22(245): 14-17
[35]李涛,王超,高承压水地层开挖基坑底板隆起稳定性分析,岩土工程学报,2009,31(8): 1236-1241
[36]唐红侠,周志芳,王文远,水劈裂过程中岩体渗透性规律及机制分析,岩土力学,2004,25(8): 1320-1322
[37]谢兴华,速宝玉,裂隙岩体水力劈裂研究综述,岩土力学,2004,25(2): 330-336
[38]Panah A K, Yanagisawa E, Laboratory studies on hydraulic fracturing criteria in soil, Soils and Foundations, 1989, 29(4): 14-22
[39]Alfaro M C, Wong R C K. Laboratory studies on fracturing of low-permeability soils, Canadian Geotechnical Journal, 2001,38: 303-315
[40]冯晓莹,栾茂田,徐泽平,黏土心墙坝水力劈裂发生机理及判别方法,北京工业大学学报,2009,35(4): 470-475
[41]Murdoch L C. Hydraulic fracturing of soil during laboratory experiments, Part 1. Methods and observations, Geotechnique, 1993, 43(2): 255-265
[42]张坤勇,殷宗泽,朱俊高,各向异性对土质心墙坝水力劈裂的影响,岩土力学,2005, 26(2): 243-246
[43]Lawrence C M, Mechanical Analysis of idealized shallow hydraulic fracture,Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2002, 128(6): 488-495
[44]丁春林,周顺华,张师德,基于离心试验的承压水基坑变形稳定影响因素,同济大学学报(自然科学版),2005,33(12): 1586
[45]钱家欢,殷宗泽,土工原理与计算,北京:中国水利水电出版社,1996
[46]周健,刘宁,离心模型试验技术应用新进展,上海地质,2002(1): 52
[47]Hill R, on uniqueness and stability in the theory of finiteelastic strain, J Mech. Phys Solids, 1957, 5: 227-241
[48]Toupin R A, Bernstein B, Sound waves in deformed perfectly elastic material, Acoustoelastic effect, Acoust.Soc. Amer, 1961, 33: 216-225
[49]璩继立,刘国彬,张建峰,东昌路地铁车站降承压水引起地面沉降的研究,土木工程学报,2000,35(5): 93-99
[50]柏仇勇,曹继平,周剑锋等,南京地铁三山街站基坑降水及对周边环境的影响,河海大学学报,2001,29: 268-270
[51] B. J. Brinkgreve, W. Broere , K. J. Bakker, Delf University of Technology & PLAXIS by the Netherlands: version 1-version 5