深基坑开挖全过程的数值模拟及工程实践
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摘要
利用非线性弹性模型中的Duncan-Chang双曲线模型及数值分析方法,对比研究在开挖区外有和没有附加荷载的场地土在开挖全过程中的应力变化,探索这些荷载对开挖全过程的影响。通过模拟分析开挖区外有建筑物等附加荷载作用的深基坑开挖工程实例,得出了一个重要结论:在附加荷载作用下,土体会在靠近附加荷载侧边附近形成一个变形模量明显变小的‘软弱区’,随着开挖的进行,此处任何微小的荷载变化均可产生大量沉降,并揭示了在这些荷载作用下开挖全过程产生变化的原因和机理。
This paper is using both the Duncan-Chang hyperbolic model of non-linear elastic soil mechanics and the numerical method of analysis,to process in its contrast and research of the soil stress variation together with the consideration of surcharged loads added or ignored;investigating at the same the influence on the whole process of excavation due to the surcharges concerned.After studying a practical engineering case of deep pit excavation with surcharged loads introduced by adjacent constructions,it is mainly concluded that:under the action of surcharged loads,a "weak zone" with obviously reduced value of modulus of deformation appears in the area next to the loads,as the excavation is carried on,any small variation of loadings can bring substantial settlement of that zone,and a broad comprehension of such matter of its origin of stress variation and mechanism is reaching.
This paper is using both the Duncan-Chang hyperbolic model of non-linear elastic soil mechanics and the numerical method of analysis,to process in its contrast and research of the soil stress variation together with the consideration of surcharged loads added or ignored;investigating at the same the influence on the whole process of excavation due to the surcharges concerned.After studying a practical engineering case of deep pit excavation with surcharged loads introduced by adjacent constructions,it is mainly concluded that:under the action of surcharged loads,a "weak zone" with obviously reduced value of modulus of deformation appears in the area next to the loads,as the excavation is carried on,any small variation of loadings can bring substantial settlement of that zone,and a broad comprehension of such matter of its origin of stress variation and mechanism is reaching.
引文
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[10]何昌荣,杨桂芳.邓肯-张模型参数变化对计算结果的影响[J].岩土工程学报,2002,24(2):170-174.(HEChang-rong,YANG Gui-fang.Effects of parametersof Duncan-Chang model on calculated results[J].Chinese Journal of Geotechnical Engineering,2002,24(2):170-174.(in Chinese))
[2]Wang G G,Xiao Z R,Du M F,et al.Geometric Non-linear Analysis in Excavation[A].The Second Inter-national Symposium on Structures and Foundations inCivil Engineering[C].Hong Kong,1997,694-698.
[3]李广信.高等土力学[M].北京:清华大学出版社,2004.(LI Guang-xin.Advanced Soil Mechanics[M].Beijing:Tsinghua University Press,2004.(in Chi-nese))
[4]欧章煜.深开挖工程分析设计理论与实务[M].台北:科技图书股份有限公司,2002.(OU Zhang-yu.De-sign Theory of Deep Pit Engineering and its Appli-cation[M].Taibei:Scientific&Technical PublishingCo.,Ltd.,2002.(in Chinese))
[5]朱伯芳.有限單元法原理與應用(第2版)[M].北京:中國水利水電出版社,1998.(ZHU Bo-fang.The Fi-nite Element Method Theory and Applications(2ndEdition)[M].Beijing:China WaterPower Press,1998.(in Chinese))
[6]陈明祥.弹塑性力学[M].北京:科学出版社,2007.(CHEN Ming-xiang.Elasticity and Plasticity[M].Beijing:Science Press,2007.(in Chinese))
[7]赵锡宏,陈志明,胡中雄,等.高层建筑深基坑围护工程实践与分析[M].上海:同济大学出版社,1996.(ZHAO Xi-hong,CHEN Zhi-ming,HU Zhong-xiong,et al.Engineerin Practice and Analysis ofDeep Pit Surround Engineering for Tall Buildings[M].Shanghai:Tongji University Press,1996.(inChinese))
[8]屈智炯.土的塑性力学[M].成都:成都科技大学出版社,1987.(QU Zhi-jiong.Soil Plasticity Mechanics[M].Chengdu:Chengdu Science and Technology UniversityPress,1987.(in Chinese))
[9]梅传书,严驰,陆红,徐海东.高层建筑基坑开挖的数值分析研究及工程应用分析[J].建筑结构学报,2001,22(3):81-87.(MEI Chuan-shu,YAN Chi,LUHong,XU Hai-dong.Study on the foundation pit ex-cavation of highrise building by finite element methodand its application analysis[J].Journal of BuildingStructures,2001,22(3):81-87.(in Chinese))
[10]何昌荣,杨桂芳.邓肯-张模型参数变化对计算结果的影响[J].岩土工程学报,2002,24(2):170-174.(HEChang-rong,YANG Gui-fang.Effects of parametersof Duncan-Chang model on calculated results[J].Chinese Journal of Geotechnical Engineering,2002,24(2):170-174.(in Chinese))
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