基于正交试验的单侧止水帷幕设计参数优化研究

Study on Optimization of Design Parameters of One-sided Water Stopping Curtain Based on the Orthogonal Test

单侧止水帷幕广泛应用于临水施工中,但其设计缺乏系统研究和规范参考。文章依托实际工程,采用Modflow数值模拟软件建立了单侧止水帷幕下抽水降深模型,分别针对影响单侧止水帷幕隔水效果的桩长、桩径、渗透系数以及与工程边界的距离4个因素,开展了正交试验和设计参数优化研究。结果表明:桩长是影响止水帷幕隔水效果最显著的因素,其次为止水帷幕与地下工程的距离;综合考虑工程造价和生态环境影响,建议实际设计过程中桩长取0.7~0.8倍的潜水层厚度,与地下工程的距离应小于0.1倍的大型水体与地下工程距离,且在满足设计施工可行性的前提下,选用单排多头小直径深层搅拌桩较为经济合理。

The one-sided water stopping curtain has been applied in construction near the water body,but there is lack of systematic research and specification references in the design of relevant parameters.Based on the actual project,Modflow numerical simulation software is used to establish the pumping drawdown model under the one-sid⁃ed water stopping curtain.The orthogonal test and design parameter optimization research are carried out in terms of the four factors affecting the water isolation effect of the one-sided water stopping curtain,including the pile length,pile diameter,permeability coefficient and engineering boundary distance.The results show that the pile length is the most significant factor affecting the water isolation effect of the water stopping curtain,followed by the distance between the water stopping curtain and the underground works;comprehensively considering the project cost and ecological environment,it is suggested that the length of the pile should be 0.7~0.8 times as much as the thickness of the phreatic aquifer,and the distance from the underground works should be less than 0.1 times of the distance between the large-scale water body and the underground works.Moreover,on the premise of meeting the design and construction feasibility requirements,it is more economical and reasonable to choose the single-row multi-head small-diameter deep mixing pile.