| 滇中引水工程超深圆形基坑施工变形和内力监测结果分析 |
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| 引用本文： | 徐前卫,龚振宇,孙梓栗,胡如成,胡开富.滇中引水工程超深圆形基坑施工变形和内力监测结果分析[J].土木工程学报,2022,55(6):102-111. |
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| 作者姓名： | 徐前卫 龚振宇 孙梓栗 胡如成 胡开富 |
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| 作者单位： | 1. 同济大学上海市轨道交通结构耐久与系统安全重点实验室，上海201804；
2. 中铁五局电务城通公司，湖南长沙 410205；3. 云南省滇中引水工程建设管理局，云南昆明 655600 |
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| 基金项目： | 国家自然科学基金(41672360)； |
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| 摘 要： | 以滇中引水龙泉倒虹吸盾构接收井77.3m超深圆形基坑工程为例，介绍了超深基坑监测布置方案，并基于监测数据研究圆形基坑受力变形规律。研究结果表明：①基坑开挖引起圆筒状地连墙逐渐变成沿一个方向拉长、而另一方向缩短的椭圆筒形状，朝向基坑内、外侧的变形值较小，远低于目前规范中对一级基坑的变形量要求；②圆形超深基坑开挖过程中，位于地连墙外侧的环向钢筋以受压为主，内侧的环向钢筋局部出现拉应力，而竖向钢筋既有部分受拉，也有部分受压，主要受圆筒结构空间变形影响所致；③墙体所受弯矩较小，最大弯矩仅为-390kN·m，出现在开挖至40m深度时；④地表变形以隆起为主，地连墙与土体之间并未发生有效滑移，土体卸荷作用使得坑底土体带动地连墙以及周边土体发生隆起；⑤基坑周围水位下降幅度很小，说明本工程地连墙采用铣接头能较好地保证圆形围护结构的完整性，具有良好的隔水效果。
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| 关 键 词： | 超深基坑 圆形基坑 地下连续墙 监测分析 |
Analysis on the monitoring results of construction deformation and internal force of ultra-deep circular foundation pit of Dianzhong Water Diversion Project |
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| Xu Qianwei Gong Zhenyu Sun Zili Hu Rucheng Hu Kaifu.Analysis on the monitoring results of construction deformation and internal force of ultra-deep circular foundation pit of Dianzhong Water Diversion Project[J].China Civil Engineering Journal,2022,55(6):102-111. |
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| Authors: | Xu Qianwei Gong Zhenyu Sun Zili Hu Rucheng Hu Kaifu |
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| Affiliation: | 1. Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety, Tongji University, Shanghai 201804, China;
2. The Electricity Engineering Co., Ltd., under CREC No.5 Group, Changsha 410205, China;
3. Central Yunnan Provincial Water Diversion Project Construction Administration Branch, Kunming 655600, China |
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| Abstract: | By taking the 77.3 m deep circular foundation pit project of the Longquan Inverted Siphon Shield Receiving Well in Central Yunnan as an example, the force and deformation laws of the circular foundation pit are studied based on the monitoring data. The research results show that: (1)The excavation of the foundation pit may cause the cylindrical diaphragm wall to gradually become an elliptical tube shape which elongates in one direction but shortens in the other direction, and the deformation values towards the inside and outside of the foundation pit are small and far lower than the requirements in current codes for the deformation of the foundation pit of grade I. (2)During the excavation of ultra-deep circular foundation pit, the circumferential steel bars on the outer side of the diaphragm wall are mainly under compression, the inner circumferential steel bars may be subject to local tensile stress, while the vertical steel bars shall be partially tensioned and partially compressed caused by the spatial deformation of the tubular structure. (3)The bending moment on the wall is relatively small, and the maximum bending moment is only -390 kN·m occurring at the excavation depth of 40 m. (4)The ground surface deformation mainly appears to be upheaval, without effective slippage occurring between the diaphragm wall and the soil. The excavation and unloading effect of the stratum tends to uplift the diaphragm wall and its surrounding soil. (5)The drawdown of groundwater level around the foundation pit is very small, indicating that the use of milling joints for the diaphragm wall in this project may ensure the integrity of the circular structure very well and good water-proof performance. |
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| Keywords: | ultra-deep foundation pit circular foundation pit diaphragm wall monitoring analysis |
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