考虑非线性渗流特性的软土隧道开挖变形规律研究

Study on Deformation Law of Soft Soil Tunnel Excavation Considering Nonlinear Seepage Characteristics

为揭示掌子面排水、不同渗流系数对地表沉降、隧道拱顶拱底土层变形的影响规律,文中建立复杂地下水环境下隧道有限元模型,采用Drainage-only flow边界模拟开挖掌子面的出水情况,通过建立流固耦合有限元模型模拟隧道开挖掌子面出水量并计算出排水速率与排水量。结果表明,考虑掌子面排水的条件下,地表纵向沉降总体上大于掌子面不排水的情况,对于不同排水条件,沿水平方向地表沉降曲线均近似为高斯分布,并在隧道开挖面达到峰值;不同渗流系数条件下,地表沉降随着渗流系数的增加而逐渐加大。

In order to reveal the influence of drainage and different seepage coefficients on surface settlement and deformation of soil layer at the top and bottom of tunnel arch,a finite element model of tunnel under complex groundwater environment is established,and the Drainage-only flow boundary is used to simulate the water discharge of excavation face.Through the establishment of fluid structure coupling finite element model,the water yield of tunnel excavation face is simulated,and the drainage rate and displacement are calculated.The results show that the longitudinal settlement of the ground surface is larger than that of the undrained tunnel face considering the drainage of tunnel face.For different drainage conditions,the surface settlement curve along the horizontal direction is approximately Gaussian distribution,and reaches the peak value at the tunnel excavation face.Under the condition of different seepage coefficient,the surface settlement increases with the increase of seepage coefficient.