降水是基坑工程施工中减小地下水危害所采取的一种最常见、最有效的方法之一，施工中需根据地质条件及工程实际确定合理的参数和工艺，以达到较好的降水效果。结合工程实践介绍了地下水对深基坑工程的危害和降水参数计算方法以及环境控制措施。

Dewatering is one of the most common and most effective methods to minimize the adverse impacts of the ground water adopted during the construction of the foundation pit works. During construction, proper parameters and suitable techniques are determined on basis of the geological conditions and actual situations of the works, so as to achieve satisfactory dewatering results. On basis of the engineering practice, the article presents the adverse impacts of the ground water on the deep foundation pit works, the methods of calculation of the dewatering parameters and the environmental control measures.