堰下悬挂式截渗墙基坑控降水优化设计

Optimization Design on Dewatering Control of Foundation Pit of Down-weir Suspended Cutoff Wall

根据水工建筑物所处位置的特点,以基坑控降水费用最小为优化目标,提出了在已知基坑水文地质条件情况下有围堰悬挂式截渗墙的墙体形式及墙体贯入深度的计算公式.在计算方法上,通过常规的计算手段即可完成整个优化设计过程,解决了以往对悬挂式截渗墙基坑进行渗流分析必须借助计算机利用有限元、二维或三维数值分析模型所带来的相关问题.通过对目标函数各参数的综合分析,提出了基坑控降水费用与截渗墙贯入深度、墙体单位造价、基坑开挖工期及含水层水文地质参数之间的函数关系,给出了最不利贯入区、经济贯入区、最不利贯入深度和经济最小贯入深度的计算公式,为合理确定是否需设截渗墙、设何种结构形式的截渗墙及墙体经济贯入深度提出了理论依据,可为该类基坑控降水的优化设计提供有益的参考.

According to the characteristics of the location of hydraulic structures, taking the minimum cost of foundation pit dewatering control for the optimization goal, in the case of the known foundation hydrogeological conditions, the wall type of down-weir suspended cutoff wall and the formula of wall penetration depth are proposed. In the calculation method, the optimization design can be realized by means of conventional calculation; this solves the limitation the pit seepage analysis of suspended cut-off wall of foundation must use finite element method, two-dimensional or three-dimensional numerical analysis model, etc.. Through a comprehensive analysis on each parameter of the objective function, a functional relationship between the cost of foundation pit dewatering control and cutoff wall penetration depth, wall unit costs, pit excavation duration and aquifer hydrogeological parameters is put forward. Furthermore, the formulas of the most unfavorable penetration zone, the economic penetration zone, the most adverse penetration depth and economic smallest penetration depth, etc. , are given. This can provide a theoretical basis for reasonably determining whether the need to set cutoff wall, setting what structure forms and economic penetration depth of the cutoff wall, and also provide a useful reference to optimize the design of the dewatering control of these kinds of foundation pits.