北京地铁10号线国贸—双井区间土压平衡 盾构施工数值模拟研究

 以北京地铁10号线国贸—双井区间盾构施工为背景，运用FLAC3D软件对盾构过程进行动态模拟，在模拟盾构隧道周围设置应力及位移监测点，计算得出隧道周围土体垂直和水平方向位移及相应的应力变化规律。研究结果表明：盾构推进过程中，盾构开挖面前方土体受到挤压作用，不仅表现在竖向位移，水平位移也有同样现象发生，水平位移绝对值不如竖向位移显著；在盾构开挖面附近边界，土体垂直和水平应力下降明显，释放率在50%左右；盾构推进对周围土体的剧烈扰动主要集中在开挖面处至开挖面后方20 m土体范围内。数值模拟结果跟实测结果吻合较好。

NUMERICAL ANALYSIS OF EARTH PRESSURE BALANCE SHIELD TUNNELING AT GUOMAO-SHUANGJING INTERZONE OF BEIJING SUBWAY LINE NO.10

Shield tunneling process is simulated with FLAD3D combined with engineering situation of Guomao— Shuangjing interzone of Beijing subway line No.10. Stress and displacement monitoring points are distributed around the model shield tunnel. Regularities of displacement and stress in surrounding soil are studied. The main results are as follows：(1) not only vertical but also horizontal displacements show that soil is extruded ahead of excavation；(2) vertical displacement is more prominent that horizontal displacement；(3) vertical and horizontal stresses decrease speedily near the tunneling excavation face with half stress being released；and (4) a mass of disturbance mainly occurs in 20 m between excavation face and its behind. It is found that the simulated results are in good agreement with in-situ values.