粉质黏土层盾构施工地表沉降规律分析

Analysis of Ground Settlement Pattern in Shield Construction with Silty Clay Layer

粉质粘土层土体的含水量较高、渗透性较弱、粘性强,在盾构施工中土体扰动较大,地面沉降很难控制。鉴于此因,利用数值模拟的方法研究盾构施工时地表的沉降规律,通过计算分析,研究了地面的横向沉降、纵向沉降及水平位移的变形规律及特征。结果表明:隧道正上方的地面处的沉降量最大为15.98mm,地表横向沉降的影响范围主要在3倍的隧道直径范围内,其沉降量大概占最终值的90%;盾构通过后的地表沉降,地表沉降值由9.45mm增大到14.71mm,其沉降值约占地表沉降值的60%~90%;地面最大横向水平位移为5.8mm,发生在离隧道轴线垂直距离7~8m范围内。

The silty clay has high water content, weak permeability and strong viscosity, in shield construction, the soil is disturbed greatly, and ground settlement is difficult to control. In view of this cause, the ground settlement pattern is studied by the method of numerical simulation during shield construction, through calculation and analysis, the deformation pattern and characteristics of lateral settlement, longitudinal settlement and horizontal displacement are studied. The results show that the maximum settlement at the ground above the tunnel is 15.98mm, the effect of lateral settlement is mainly within 3 times the diameter of the tunnel, and it accounts for about 90% of the final value;After the passage of the shield, the surface settlement will increase from 9.45mm to 14.71mm, and it accounts for 60% to 90% of surface subsidence;The maximum horizontal displacement of the ground is 5.8mm, it occurs within a range of 7m to 8m from the axis of the tunnel.