软土超深大基坑工程施工监测分析
摘要：以上海国际金融中心超深大基坑工程为背景，分析了软土层中顺逆作分区交叉实施的坑外土体变形特性及立柱变形和支撑轴力变化等情况。实测结果表明，地下连续墙后的土体侧向位移随施工工况逐步发展，变形形态为“纺锤形”;墙后土体侧斜与墙体侧斜相协调，且土体侧斜随距坑边距离增加而减小；此外逆作区受顺作区开挖卸荷及时间效应影响的变形增量及影响范围均较大。墙后土体应变主要发生在基坑开挖面附近，且剪应变值基本处于小应变范围内。立柱的位移表现为隆起，且隆起量随开挖工况逐步发展，随底板浇筑后趋于稳定。支撑轴力增量主要发生在邻近下两皮土方开挖工况下。地下水位监测表明，采用新型TRD工法构建的等厚度水泥土搅拌墙作为悬挂止水帷幕起到了较好的隔水和遮拦作用。围护墙两侧的侧压力分布形态类似三角形分布，侧压力均随着施工工况而逐步减小，且实测侧压力值较理论值偏小。
关键词：高层建筑深基坑顺作逆作结合法变形软土监测
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参考文献[1] 戴斌.基坑工程顺逆结合设计方法[J].地下空间与工程学报，2009,5(S2):1686-1690.
[2] 吕少伟.上海地铁车站施工周围土体位移场预测及控制技术研究[D].上海：同济大学，2001.
[3] 应宏伟，杨永文.杭州深厚软黏土中某深大基坑的性状研究[J].岩土工程学报，2011,33(12):1838-1846.
[4] 王卫东，徐中华，宗露丹，等.上海国际金融中心超深大基坑工程变形性状实测分析[J].建筑结构，2020,50(18):126-135.
[5] 徐中华.上海地区支护结构与主体地下结构相结合的深基坑变形性状研究[D].上海：上海交通大学，2007.
[6] WANG J H,XU Z H,WANG W D.Wall and ground movements due to deep excavations in Shanghai soft soils[J].Journal of geotechnical and geoenvironmental engineering,2010,136(7):985-994.
[7] FINNO R J,ATMATZIDIS D K,PERKINS S B.Observed performance of a deep excavation in clay[J].Journal of geotechnical engineering,1989,115(8):1045-1064.
[8] OU C Y,LIAO J T,CHENG W L.Building response and ground movements induced by a deep excavation.[J].Geotechnique,2000,50(3):209-220.
[9] 华东建筑设计研究院有限公司，上海建工集团股份有限公司.基坑工程技术标准：DG/TJ 08—61—2018 [S].上海：同济大学出版社，2018.
[10] BURLAND J B.“Small is beautiful” - the stiffness of soils at small strains[J].Canadian geotechnical journal,1989,26(4):499-516.
[11] ATKINSON J H,SALLFORS G.Experimental determination of stress-strain-time characteristics in laboratory and in situ tests[J].Proceedings of the international conference on soil mechanics and foundation engineering,1991,3:915-956.
[12] JARDINE R J,POTTS D M,FOURIE A B,et al.Studies of the influence of non-linear stress-strain characteristics in soil-structure interaction[J].Géotechnique,1986,36(3):377-396.
[13] MAIR R J.Developments in geotechnical engineering research:application to tunnels and deep excavations[J].Journal of periodontology,1993,93(1):759-762.
[2] 吕少伟.上海地铁车站施工周围土体位移场预测及控制技术研究[D].上海：同济大学，2001.
[3] 应宏伟，杨永文.杭州深厚软黏土中某深大基坑的性状研究[J].岩土工程学报，2011,33(12):1838-1846.
[4] 王卫东，徐中华，宗露丹，等.上海国际金融中心超深大基坑工程变形性状实测分析[J].建筑结构，2020,50(18):126-135.
[5] 徐中华.上海地区支护结构与主体地下结构相结合的深基坑变形性状研究[D].上海：上海交通大学，2007.
[6] WANG J H,XU Z H,WANG W D.Wall and ground movements due to deep excavations in Shanghai soft soils[J].Journal of geotechnical and geoenvironmental engineering,2010,136(7):985-994.
[7] FINNO R J,ATMATZIDIS D K,PERKINS S B.Observed performance of a deep excavation in clay[J].Journal of geotechnical engineering,1989,115(8):1045-1064.
[8] OU C Y,LIAO J T,CHENG W L.Building response and ground movements induced by a deep excavation.[J].Geotechnique,2000,50(3):209-220.
[9] 华东建筑设计研究院有限公司，上海建工集团股份有限公司.基坑工程技术标准：DG/TJ 08—61—2018 [S].上海：同济大学出版社，2018.
[10] BURLAND J B.“Small is beautiful” - the stiffness of soils at small strains[J].Canadian geotechnical journal,1989,26(4):499-516.
[11] ATKINSON J H,SALLFORS G.Experimental determination of stress-strain-time characteristics in laboratory and in situ tests[J].Proceedings of the international conference on soil mechanics and foundation engineering,1991,3:915-956.
[12] JARDINE R J,POTTS D M,FOURIE A B,et al.Studies of the influence of non-linear stress-strain characteristics in soil-structure interaction[J].Géotechnique,1986,36(3):377-396.
[13] MAIR R J.Developments in geotechnical engineering research:application to tunnels and deep excavations[J].Journal of periodontology,1993,93(1):759-762.
Monitoring Analysis of a Super Large and Deep Foundation Excavation in Soft Deposits
Abstract: Based on the monitored data of the super large and deep excavation of Shanghai International Finance Center which was constructed by the combination of top-down method and bottom-up method, this paper analyzed the characteristics of deformation of soil behind the retaining wall, vertical deformation of central columns, and variation of axial force of struts. The results show that the lateral displacement of the soil behind the diaphragm wall developed gradually with construction conditions and the final shape of wall deformation was spindle-shaped. Deformation behavior of soil was quite similar to that of diaphragm walls. Soil deformation decreased with the increase of distance to the diaphragm wall. Deformation of soil behind the top-down area was obviously affected by excavation conducted in the bottom-up area. Soil strain behind the wall mainly occurred near the excavation surface, and the shear strain value was basically in the small strain range. Due to rebound of soil excavation, the columns were all uplifted, and the uplift value gradually increased with the increase of excavation depth. Axial forces of struts obviously increased when the two layer soils bellow the struts were excavated. The waterproof curtain constructed by TRD technique played a good role in water stop. The lateral pressure distribution on both sides of the retaining wall was similar to triangular distribution. The value of lateral pressure gradually reduced with the excavation proceeded, and the measured lateral pressure value was smaller than the theoretical value.
Keywords: tall buildings; deep foundation excavation; bottom-up and top-down method; deformation; soft soil; monitoring
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