砂砾石地层中防渗墙开挖槽壁稳定性特征及影响因素研究

Study on the Stability Characteristics and Influencing Factors of Trench Wall Stability of Seepage Control Wall Excavation in Gravel Formation

摘要: 以砂砾石地层防渗墙成槽施工为研究背景，通过数值模拟方法研究砂砾石地层防渗墙成槽泥浆槽壁稳定性特征及其影响因素。研究结果表明：泥浆液面波动与地下水位变化是诱发砂砾石地层防渗墙槽壁发生失稳的重要原因，其失稳区域为导墙顶面下1.20~6.80 m范围的人工填土层、20.3~39 m范围的中砂与卵石层；槽壁水平变形沿深度呈非对称的“鼓肚”形态，最大值约5.79 mm，出现在导墙顶以下约30.0 m处。地表沉降在横向上呈V形分布，沉降槽宽度大致为(1.0~1.5) he，最大沉降量约5.75 mm，位于距槽壁约(0.10~0.15) he的位置。研究同时指出，合理提升泥浆液面高度并抑制地下水位下降有助于控制变形。研究成果可为同类工程防渗墙槽壁稳定性控制和施工参数优化提供参考。

Abstract: Based on the construction of a cutoff wall trenching in a gravel stratum, this study investigates the stability characteristics of the slurry trench wall and its influencing factors using numerical simulation. The results indicate that fluctuations in the slurry level and changes in the groundwater level are significant factors leading to the instability of the trench wall in gravel strata. The instability zones are identified as the artificial fill layer at depths of 1.20~6.80 m below the guide wall top, and the medium sand and cobble layers at depths of 20.3~39 m. The horizontal deformation of the trench wall exhibits an asymmetric “bulging” shape along the depth, with a maximum value of approximately 5.79 mm occurring at about 30.0 m below the guide wall top. The surface settlement displays a V-shaped distribution laterally, with a settlement trough width of about (1.0~1.5) he and a maximum settlement of approximately 5.75 mm, located at a horizontal distance of about (0.10~0.15) he from the trench wall. The study also suggests that appropriately raising the slurry level and suppressing groundwater level decline can help control deformation. The findings provide a reference for stability control and construction parameter optimization of cutoff wall trenching in similar projects.