钢管幕群顶进顺序对地表沉降的影响分析

Analysis of the Influence of Jacking Sequence of Steel Tube Curtain Group on Surface Subsidence

依托合肥市滨湖科学城庐州大道浅埋隧道段实例工程,利用有限差分软件FLAC3D对不同顶进顺序下钢管幕群顶推施工过程进行模拟。结合模型计算结果和监测数据,总结钢管幕群顶进顺序对地表变形影响规律。结果表明:横向管幕顶进宜采用从中间向两端的方案,能有效抑制群管效应的影响;竖向管幕顶进宜采用由上至下的方案,可降低上排钢管施工对土体的扰动;先上排、再两侧、最后下排的方案为最优顶进方案,将钢管幕群分为6组,分组进行顶推施工,可有效保护管幕结构的围护土体,实现“边顶推、边开挖”,大幅提高施工效率。

Based on the example project of shallow buried tunnel section of Luzhou Avenue in Hefei Binhu Science City,finite difference software FLAC3D was used to simulate the jacking construction process of steel tube curtain group under different jacking sequence.Combined with the results of model calculation and monitoring data,the influence of steel tube curtain group jacking sequence on surface deformation was summarized.The results show that:(1)the jacking sequence of the transverse curtain should be from the middle to both ends,which can effectively suppress the effect of group tube effectꎻ(2)the jacking sequence of vertical tube curtain should be adopted from top to bottom,which can avoid the disturbance of the soil caused by the construction of the upper row steel pipeꎻ(3)the scheme of first arranging up,then on both sides and finally arranging down is the optimal jacking scheme.The steel tube curtain group is divided into 6 groups for jacking construction in groups to effectively protect the retaining soil of the tube curtain structure and achieve“pushing while digging”,which greatly improves the construction efficiency.