地下水对盾构开挖面上方土拱效应影响的试验研究

发布时间：2018-12-12 09:49

【摘要】：针对地下水对盾构隧道开挖面上方土拱效应的影响,进行了干砂和饱和砂的对比模型试验。首先针对盾构施工过程和试验研究内容,设计了包括玻璃模型槽、隧道装置、数字照相量测装置的试验系统。之后通过试验获得了不同砂土粒径、不同埋深情况下,分别在干砂、饱和砂土层中支护力减小时开挖面上方土拱的形成过程。试验结果显示地下水的存在,减缓了土拱随开挖面位移的形成过程,在相同开挖面位移时,相对于干砂时地下水减小土拱高度的比例为10%~15%。同时,地表沉降的发展过程与开挖面上方土拱的形成过程具有对应关系,地下水的存在通过降低土拱高度从而减小了地面沉降。根据试验结果结合楔形体模型指出,需对上方棱柱体受到的侧土压力系数进行修正,由此体现地下水对开挖面上方土拱效应的影响。
[Abstract]:In view of the influence of groundwater on the soil arch effect above the excavation surface of shield tunnel, a comparative model test of dry sand and saturated sand was carried out. Firstly, a test system including glass model slot, tunnel device and digital camera measuring device is designed for shield construction process and experimental research. After that, the formation process of soil arch above excavated surface was obtained under different sand particle size and different buried depth in dry sand and saturated sand respectively. The experimental results show that the existence of groundwater slows the formation process of soil arch with the displacement of excavated surface. When the same excavating surface displacement, the ratio of soil arch height reduction to ground water in dry sand is 100.15%. At the same time, the development process of surface subsidence has a corresponding relationship with the formation process of soil arch above the excavated surface. The existence of groundwater reduces the ground subsidence by reducing the height of soil arch. Based on the experimental results and the wedge model, it is pointed out that the lateral earth pressure coefficient of the upper prism needs to be corrected, so as to reflect the influence of groundwater on the soil arch effect above the excavated surface.
【作者单位】：河南城建学院;东南大学;上海隧道工程股份有限公司;河海大学;
【基金】：国家自然科学基金(51278099) 国家973项目(2013CB036003)
【分类号】：U455.43

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