南水北调中线典型渠段施工期降水措施研究

Dewatering Measures for Construction Period of the Typical Canal Stretch of Middle Route Project of SNWT

针对南水北调中线工程陶岔—沙河南段施工期地下水问题,选取典型断面建立渗流数值模型,计算分析有、无降水措施及不同计算条件下基坑的渗流场分布特征.研究结果表明,对于存在承压水的基坑工程,当基坑开挖深入地下水位以下且随着含水层顶板减薄,基坑底部易出现安全问题,应采取渗流调控措施;施工期补给边界、含水层厚度及其渗透性、降水井布置等因素对基坑降水效果的影响显著.

The groundwater is an important factor for the safety of foundation pit. In order to analyse the distri- bution of seepage field under different calculating conditions with seepage control measures, a typical canal stretch was modeled for construction period of Middle Route Project of SNWT. The numerical simulation re- sults show that the pit safety would decrease with the less permeable layer being excavated step by step and aq- uifer confined beneath it, so measures should be taken to control and regulate the seepage field. The efficiency of foundation pit dewatering would be affected by the water recharge boundary, the thickness and permeability of the aquifer, the arrangement of dewatering wells, and so on.