以天津地铁3号线某区段平行隧道施工为背景,结合地层沉降实测资料分析,采用有限元程序ABAQUS进行数值模拟,研究小间距平行隧道施工对地层沉降的影响.分析结果表明:先行隧道单独开挖引起的地表横向沉降与 Peck 公式的地表沉降槽形状类似,先行隧道轴线上方地表沉降最大,远离轴线逐渐减小;后行隧道施工对两平行隧道中间的土体产生二次扰动效应,两隧道中间位置处竖向位移达到最大;不同深度处土层的沉降量及影响范围不同,越靠近隧道轴线位置土体受盾构施工扰动越大;注浆压力越大,沉降槽的深度越小.研究结果对软土地区类似小间距隧道工程施工有一定的借鉴意义.%With the observed data analysis of ground settlement and the numerical simulation of ABAQUS, the influence of the construction of small spacing parallel tunnels on ground settlement in a certain section construction of Tianjin subway line 3 has been studied. The results are as follows: the transverse ground settlement induced by the separate excavationof preceding tunnel is similar to that by the Peck formula and the ground settlement in the axial line of preceding tunnel shows that it is the largest, which is gradually deceasing far from the axial line; the construction of subsequent tunnel produces the secondary disturbance to the soil between the two parallel tunnels, and then the vertical displacement amounts to the maxi-mum value; the settlement and influence scope are both various with the different soil depths; the disturbance of shield con-struction becomes heavier, when the soil is closer to the tunnel axial line; the larger the grouting pressure is, the smaller the depth of settling tank is. The above-mentioned studies can be used as a reference to the construction of small spacing tunnel engineering.
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