南水北调中线潮河段Ⅴ标降排水方案优化设计

Optimization Design of Drainage Program in the Fifth Bid Section in Chaohe Tunnel on South-to-North Water Transfer Project

为使南水北调中线潮河段Ⅴ标渠段地下水降至最低渠底开挖高程1 m以下,满足干地施工要求,运用VisualModflow对3种渠道降排水设计方案进行模拟比较。通过确定模拟范围、概化边界性质等要素,建立了水文地质概念模型及数学模型,在方案三的基础上调整相关要素参数,对两个换填段及3个倒虹吸水平管身段的降排水方案进行优化改进。模拟结果表明,优化后的方案可使30 d后的观测水位降至控制水位以下,满足降水要求。适当增大井深、井间距、抽水量等要素,以及增加防渗墙的降排水方案,可在要求时间内保证降水效果,满足施工要求。

For making underground water level of the canal drop one meter lower than the minimum bottom excavation elevation and meetingthe requirements of dry construction, it analyzed and compared the simulation results of the three design schemes by using Visual Modflow.By determining simulation range and generalizing boundary properties and other factors, hydro geological conceptual model and mathematicalmodel were established. The parameters were adjusted on the basis of No.3 scheme and the two replacement segments＇ and three invertedsiphons horizontal tube body＇ design of drainage program was improved. The simulation results show that the water level drops below thecontrol water level after 30 days, meeting the requirements of dewatering. Through increasing well depth, spacing of wells, pumping flow, etcand adding the cut？off wall, it can guarantee dewatering effect and meet the construction requirements in the required time.