深基坑承压水的风险控制及处理实例

发布时间：2018-03-08 07:35

本文选题：基坑开挖　切入点：承压水　出处：《岩土力学》2014年S1期 　论文类型：期刊论文

【摘要】：存在地下承压水的深基坑,当基坑底部承压水层顶部的残留土层不能与承压含水层水头平衡时,处理不当极易造成管涌及坑壁失稳等问题。对相关承压水处理风险源进行分析,针对勘察、设计、施工各阶段都提出具体要求。实例中的基坑临近江面,基坑下承压水与江水存在贯通通道,河道水位变化时会引起承压水头增减,由于设计水头埋深参考值是针对一年观察期而得到的,未考虑到历年水头变化,成为事故埋下隐患,最终因为施工期间河道涨水导致承压水压力超过预期引起了基坑涌水。事故发生后,现场紧急采取堵漏措施,采用灌浆法加固基坑土体,改善土体性质,增加不透水土层的厚度,最终已解决基坑开挖时出现的涌水等现象,保证了工程的顺利安全完成。灌浆法加固是承压水较大情况下基坑安全开挖的有效方式,研究结论对于承压水的风险控制特别是临近江海的工程的设计施工具有较强的指导意义。
[Abstract]:In deep foundation pit with underground confined water, when the residual soil layer at the top of the bottom confined water layer of the foundation pit can not balance with the water head of the confined aquifer, the improper treatment will easily cause problems such as piping and pit wall instability, etc. The risk sources of relevant confined water treatment are analyzed. The concrete requirements are put forward for each stage of investigation, design and construction. In the case of foundation pit near the river surface, there is a connecting passage between confined water and river water under the foundation pit, which will cause the increase or decrease of the confined water head when the water level of the river changes. Because the reference value of design head burial depth is obtained for one year observation period, it does not take into account the change of water head over the years, so it becomes a hidden danger of accident. In the end, the water gushing of foundation pit is caused by the pressure of confined water exceeding expected due to the rising water in the river during the construction. After the accident, the leakage plugging measures are taken urgently, and the grouting method is adopted to strengthen the soil mass of the foundation pit to improve the soil properties. By increasing the thickness of impermeable soil layer, the phenomenon of water gushing occurred in excavation of foundation pit has finally been solved, which ensures the smooth and safe completion of the project. Grouting reinforcement is an effective method for the safe excavation of foundation pit under the condition of high pressure water. The conclusion is of great significance for the risk control of confined water, especially for the design and construction of projects near rivers and seas.
【作者单位】：浙江大学滨海和城市岩土工程研究中心;浙江大学软土与环境工程教育部重点实验室;上海中益建筑工程有限公司;
【分类号】：TU753

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