软土地区基坑对周边环境影响空间效应分析
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摘要
软土地区基坑开挖引起的变形具有明显的空间效应,为了进一步研究开挖引起周边地面及建构筑物变形的特性,结合对温州某大型深基坑工程的监测,从垂直于基坑围护墙以及平行于围护墙两个方向,对基坑外地面道路以及建筑物的沉降和裂缝情况进行了监测分析,总结了开挖引起基坑外地表沉降的分布特性,分析发现:基坑边角对围护墙变形以及地表沉降具有明显限制作用;在垂直于基坑方向上,处在沉降主要影响区2H_e范围内,建筑物均具有明显的差异沉降,最大角变量达到1/1300;平行基坑方向距离边角(0.4～1.2)H_e(最大开挖深度)范围观测到纵向裂缝,沉降变化率较大,可能破坏道路或建构筑物;此外,桩基础的建筑物总沉降以及差异沉降均明显小于条形基础建筑。
The deformation due to excavation in soft clay areas has considerable spatial effects. To investigate the deformation characteristics, a large-scale deep excavation project in Wenzhou is monitored, the settlements and cracks of the ground and adjacent buildings are observed and analyzed through two directions: perpendicular to the retaining wall and paralleled to the wall, and the distribution characteristics of the ground settlement are summarized. The field measurements show that the corner has inhibition effect on the wall deflections and ground settlements. In the vertical direction, the buildings in the range of 2 H_e outside the excavation have large differential settlement, and the maximum angular variable reaches 1/1300. The longitudinal cracks are observed from 0.4 H_e to 1.2 H_e(the maximum excavation depth) on the parallel direction, the large rate of settlement change may damage the road or the structures. In addition, the total and differential settlements of the buildings on pile foundation are significantly smaller than those on strip foundation.
The deformation due to excavation in soft clay areas has considerable spatial effects. To investigate the deformation characteristics, a large-scale deep excavation project in Wenzhou is monitored, the settlements and cracks of the ground and adjacent buildings are observed and analyzed through two directions: perpendicular to the retaining wall and paralleled to the wall, and the distribution characteristics of the ground settlement are summarized. The field measurements show that the corner has inhibition effect on the wall deflections and ground settlements. In the vertical direction, the buildings in the range of 2 H_e outside the excavation have large differential settlement, and the maximum angular variable reaches 1/1300. The longitudinal cracks are observed from 0.4 H_e to 1.2 H_e(the maximum excavation depth) on the parallel direction, the large rate of settlement change may damage the road or the structures. In addition, the total and differential settlements of the buildings on pile foundation are significantly smaller than those on strip foundation.
引文
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[9]TAN Y,WEI B.Observed behaviors of a long and deep excavation construction by cut-and-cover technique in Shanghai soft clay[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2012,138(1):69-88.
[10]HSIEH P G,OU C Y.Shape of ground surface settlement profiles caused by excavation[J].Can Geotech,1998,35(6):1004-1017.
[2]赖冠宙,房营光,史宏彦.深基坑排桩支护结构空间共同变形分析[J].岩土力学,2007,28(8):1749-1752.(LAIGuan-zhou,FANG Ying-guang,SHI Hong-yan.Spatial mutual deformation analysis method for row of piles of deep excavation[J].Rock and Soil Mechanics,2007,28(8):1749-1752.(in Chinese))
[3]FINNO R J,BLACKBURN J T,ROBOSKI J F.Threedimensional effects for supported excavations in clay[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(1):30-36.
[4]LEE F H,YONG K Y,QUAN K C N,et al.Effect of corners in strutted excavations:field monitoring and case histories[J].Journal of Geotechnical and Geoenvironmental Engineering,1998,124(4):338-349.
[5]ROBOSKI J F,FINNO R J.Distributions of ground movements parallel to deep excavations in clay[J].Canadian Geotechnical Engineering,2006,43:43-58.
[6]郑刚,李志伟.不同围护结构变形形式的基坑开挖对邻近建筑物的影响对比分析[J].岩土工程学报,2012,34(6):969-977.(ZHEND Gang,LI Zhi-wei.Comparative analysis of responses of buildings adjacent to excavations with different deformation modes of retaining walls[J].Chinese Journal of Geotechnical Engineering,2012,34(6):969-977.(in Chinese))
[7]PECK R B.Deep excavation and tunneling in soft ground[C]//Proceeding of the 7th International Conference on Soil Mechanics and Foundation Engineering State-of-the-art Volume,Mexico City,1969:225-290.
[8]CLOUGH G W,O’ROURKE T D.Construction induced movements of in situ walls[C]//Proceedings,ASCEConference On Design And Performance Of Earth Retaining Structures,Geotechnical Special Publication No.25,ASCE.New York,1990:439-470.
[9]TAN Y,WEI B.Observed behaviors of a long and deep excavation construction by cut-and-cover technique in Shanghai soft clay[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2012,138(1):69-88.
[10]HSIEH P G,OU C Y.Shape of ground surface settlement profiles caused by excavation[J].Can Geotech,1998,35(6):1004-1017.