超载作用下地表沉降偏态分布模式研究
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摘要
地表沉降计算中,如何考虑周边环境影响及确定地表沉降曲线型态是重点问题。现有计算公式大多是在假设坑外没有超载或超载型式单一的前提下得出的,应用范围有限。因此,对不同的超载作用进行等效推导,采用地层损失法原理,建立考虑基坑周边不同超载型式作用下的地表沉降偏态分布曲线预测计算模型,并推导计算公式,以期对地表沉降量得到合理、可靠、更加符合实际的预测计算结果。并结合实际工程,将文中方法与数值分析软件Plaxis-2D模拟计算结果及实测沉降值对比分析。结果表明:超载作用既使地表沉降量有较大的增加,又使最大沉降点位置朝基坑明显移动,计算中正确考虑坑外超载的影响是必要的;另外,文中方法所得结果与实测沉降值吻合较好,计算结果精度较高,对深基坑地表沉降理论计算方法进行了相应的完善,可供类似土质地区及支护结构的工程借鉴参考。
How to consider the influences of surrounding environment and determine the patterns of surface settlement curve is the primary problem in the calculation of surface settlement. The existing formulas are mostly obtained under the assumption that the pit is under the premise of no overload or single overload, and their application is limited. Therefore, different effects of the equivalent overloads are derived, and then the prediction model for skewness distribution curve of surface settlement is established considering the surface settlement under different overloading types based on the principles of formation damage method. The relevant formula is derived in order to get reasonable, reliable and satisfactory forecast results of surface settlement. For a practical project, a comparison is made among results by the proposed method, the simulated results of numerical analysis software Plaxis-2 D and the measured settlement values. The results show that the effect of overloading is necessary to be considered for the reason that it has induced a greater increase in the surface settlement and also made the maximum settlement point moves significantly toward the foundation pit. In addition, the obtained results are in good agreement with the measured settlement values, and the computational accuracy is higher. The proposed method for surface settlement of deep foundation pits is improved, and it can be helpful for other similar projects.
How to consider the influences of surrounding environment and determine the patterns of surface settlement curve is the primary problem in the calculation of surface settlement. The existing formulas are mostly obtained under the assumption that the pit is under the premise of no overload or single overload, and their application is limited. Therefore, different effects of the equivalent overloads are derived, and then the prediction model for skewness distribution curve of surface settlement is established considering the surface settlement under different overloading types based on the principles of formation damage method. The relevant formula is derived in order to get reasonable, reliable and satisfactory forecast results of surface settlement. For a practical project, a comparison is made among results by the proposed method, the simulated results of numerical analysis software Plaxis-2 D and the measured settlement values. The results show that the effect of overloading is necessary to be considered for the reason that it has induced a greater increase in the surface settlement and also made the maximum settlement point moves significantly toward the foundation pit. In addition, the obtained results are in good agreement with the measured settlement values, and the computational accuracy is higher. The proposed method for surface settlement of deep foundation pits is improved, and it can be helpful for other similar projects.
引文
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[8]张尚根,袁正如.软土深基坑开挖地表沉降分析[J].地下空间与工程学报,2013,9(增刊1):1753-1757.(ZHANGShang-gen,YUAN Zheng-ru.Analysis of ground settlement induced by excavation of deep foundation pit in soft soil[J].Chinese Journal of Underground Space and Engineering,2013,9(S1):1753-1757.(in Chinese))
[9]杨国伟,刘建航.邻近建筑物或地面超载作用下围护结构水平位移与坑周地表沉降关系研究[J].地下工程与隧道,2002(3):11-14.(YANG Guo-wei,LIU Jian-hang.Study on relationship between horizontal displacement of retaining wall and surround ground settlement of deep excavations under the action of adjacent buildings or ground overload[J].Underground Engineering and Tunnels,2002(3):11-14.(in Chinese))
[10]童建军,王明年,于丽,等.成都地铁车站深基坑周围地表沉降规律研究[J].水文地质工程地质,2015,42(3):97-101.(TONG Jian-jun,WANG Min-nian,YU Li,et al.Astudy of the land subsidence around the deep foundation pit of the Chengdu subway station[J].Hydrogeology&Engineering Geology,2015,42(3):97-101.(in Chinese))
[11]JGJ120-2012建筑基坑支护技术规程[S].2012.(JGJ120-2012 Technical specification for retaining and protection of building foundation excavations[S].2012.(in Chinese))
[12]刘国彬,王卫东.基坑工程手册[M].北京:中国建筑工业出版社,2009.(LIU Guo-bin,WANG Wei-dong.Excavation engineering manual[M].Beijing:China Architecture and Building Press,2009.(in Chinese))
[2]张尚根,陈志龙,曹继勇.深基坑周围地表沉降分析[J].岩土工程技术,1999(4):7-9.(ZHANG Shang-gen,CHENZhi-long,CAO Ji-yong.Analysis of ground settlement around deep foundation-pit[J].Geotechnical Engineering Technique,1999(4):7-9.(in Chinese))
[3]刘长文,陈怿凡,李旭东.考虑空间效应的深基坑周围地表沉降分析[J].辽宁工程技术大学学报(自然科学版),2000,19(2):145-147.(LIU Chang-wen,CHEN Yi-fan,LIXu-dong.Analysis of ground settlement about deep pit considering spatial effect[J].Journal of Liaoning Technical University(Natural Science),2000,19(2):145-147.(in Chinese))
[4]聂宗泉,张尚根,孟少平.软土深基坑开挖地表沉降评估方法研究[J].岩土工程学报,2008,30(8):1218-1223.(NIE Zong-quan,ZHANG Shang-gen,MENG Shao-ping.Surface settlement of deep foundation pits by excavation[J].Chinese Journal of Geotechnical Engineering,2008,30(8):1218-1223.(in Chinese))
[5]刘小丽,周贺,张占民.软土深基坑开挖地表沉降估算方法的分析[J].岩土力学,2011,32(增刊1):90-94.(LIUXiao-li,ZHOU He,ZHANG Zhan-min.Analysis of surface settlement estimation of deep foundation pit excavation in soft soil[J].Rock and Soil Mechanics,2011,32(S1):90-94.(in Chinese))
[6]程琪,刘国彬,张伟立.上海地区地铁超深基坑及深基坑变形有限元分析[J].地下空间与工程学报,2009,5(增刊2):1497-1502.(CHENG Qi,LIU Guo-bin,ZHANG Wei-li.Deformation analysis of subway ultra-deep and deep excavation in Shanghai by FEM[J].Chinese Journal of Underground Space and Engineering,2009,5(S2):1497-1502.(in Chinese))
[7]尹胜斌,丁红岩.软土基坑开挖引起的坑外地表沉降预测数值分析[J].岩土力学,2012,33(4):1210-1216.(YINSheng-bin,DING Hong-yan.Numerical analysis of estimation of ground surface settlement outside pit induced by soft-soil excavation[J].Rock and Soil Mechanics,2012,33(4):1210-1216.(in Chinese))
[8]张尚根,袁正如.软土深基坑开挖地表沉降分析[J].地下空间与工程学报,2013,9(增刊1):1753-1757.(ZHANGShang-gen,YUAN Zheng-ru.Analysis of ground settlement induced by excavation of deep foundation pit in soft soil[J].Chinese Journal of Underground Space and Engineering,2013,9(S1):1753-1757.(in Chinese))
[9]杨国伟,刘建航.邻近建筑物或地面超载作用下围护结构水平位移与坑周地表沉降关系研究[J].地下工程与隧道,2002(3):11-14.(YANG Guo-wei,LIU Jian-hang.Study on relationship between horizontal displacement of retaining wall and surround ground settlement of deep excavations under the action of adjacent buildings or ground overload[J].Underground Engineering and Tunnels,2002(3):11-14.(in Chinese))
[10]童建军,王明年,于丽,等.成都地铁车站深基坑周围地表沉降规律研究[J].水文地质工程地质,2015,42(3):97-101.(TONG Jian-jun,WANG Min-nian,YU Li,et al.Astudy of the land subsidence around the deep foundation pit of the Chengdu subway station[J].Hydrogeology&Engineering Geology,2015,42(3):97-101.(in Chinese))
[11]JGJ120-2012建筑基坑支护技术规程[S].2012.(JGJ120-2012 Technical specification for retaining and protection of building foundation excavations[S].2012.(in Chinese))
[12]刘国彬,王卫东.基坑工程手册[M].北京:中国建筑工业出版社,2009.(LIU Guo-bin,WANG Wei-dong.Excavation engineering manual[M].Beijing:China Architecture and Building Press,2009.(in Chinese))