粘性土层基坑开挖降水方案设计与施工

Scheme Design and Construction Foundation pit Dewatering in Cohesive Soil

某电厂 (A)一期装机容量 2× 60 0MW ,规划容量 6× 60 0MW ,按设计要求 ,一期主厂房需要进行基础开挖。本文根据工程设计要求和工程特点 ,对粘性土层的管井降水方式进行了论证 ,确定降水井的结构设计 ,并进行降水方案设计 ,确定井数、井距和井群干扰水量等 ;计算基坑中心地下水埋深是否达到降水工程设计 ;并采用非稳定流公式 ,计算基坑中心地下水埋深随间的变化关系。根据计算成果 ,选择合适的施工方案 ,成功地将地下水位在规定的工期时间内降到设计水平 ,保证了基础开挖如期进行。

According to engineering characteristics of the foundation pit construction of the main building in a Power Plant (A),the patterns of the large*.scale siltyclay formation dewatering are discussed in this paper.The structural design of tube well is determined.First,by using the stable flow equation,the depth of groundwater level to the ground in the center of the foundation pit is computed to determine whether to reach the requirements.The number of tube wells and the distance between tube wells,the discharge of the interferent wells,and so on,are determined.Secondly,by using the unstable flow equation,the depth in the center varied with the time is determined.Hence,considering the computation above,the appropriate patterns of dewatering are determined to make the groundwater level lower to the design level in the stipulated time limit.