典型城市承压含水层区域性特性

为了避免基坑工程设计和施工中因没有处理好承压水影响而产生的基坑工程事故,研究承压含水层特性.以调查研究杭州钱塘江承压含水层特性为主,参考上海、武汉、北京、天津4个城市有关水文地质方面的研究材料,研究这5个城市的承压含水层特性.比较分析这5个城市的承压含水层埋深、厚度、水位、顶板厚度等特性,介绍各城市典型的工程实例、承压水处理方法及抽降承压水对地面沉降的影响.研究表明:杭州、上海两地潜水与承压水的越流效果不明显,可视条件选择全降水或隔渗帷幕结合减压降水;武汉地区承压含水层埋藏浅,上层承压水可以采用疏干的方法;北京、天津两地单层含水层和隔水层厚度较小,可以尝试自渗降水.

Regional property of confined aquifer in typical cities

It is common to have a foundation pit accident when failing to deal with the effect of confined water. The confined aquifer property was investigated in order to avoid such accidents. The confined aquifer property of Qiantang River in Hangzhou was studied. The research material about hydro geological of Shanghai, Wuhan, Beijing and Tianjin were consulted to analyze the confined aquifer property. The depth, thickness, water level, and roof thickness in the five cities were analyzed. Typical projects, confined water treatments and the settlement caused by dewatering of confined water were introduced. Results showed that: firstly, the leakage recharge between phreatic aquifer and confined aquifer in Hangzhou and Shanghai is not obvious, and the dewatering or seepage proof wall can be chosen to deal with confined water; secondly, the confined aquifer in Wuhan is not deep, and the upper confined water can be drained; finally, the aquifer and the aquifuge in Beijing and Tianjin are thin, and the confined water can be treated with seepage.