不同桩基长度对隧道开挖地层变形影响试验研究

为了研究城市隧道沿线邻近既有桩基的情况下，不同桩基长度对隧道开挖导致地层变形规律，通过一个透明土物理模型试验并采用基于PIV技术的土体内部断层三维变形量测系统监测变形，得到了在不同桩基长度下，隧道施工过程中的地层变形规律。研究结果表明:随着桩基长度的增加，隧道开挖引起的隧道周围土体的变形区域先增大，然后减小，中长桩基的存在对隧道顶部土体竖向变形和水平变形均有遏制作用。

Experimental Study on Effect of Different Length of Piles on Ground Deformation from Tunnel Excavation

In order to study the law of ground deformation resulted from tunnel excavation if there exist piles adjacent to urban tunnel, a physical model test of transparent soil, with PIV-based measuring system for 3D internal fault deformation, were adopted to monitor the deformation, and then the law of ground deformation under the different length of piles during the tunnel construction was found out. The result shows that, as the length of piles increases, the deformed area of soil mass around the tunnel caused by tunnel excavation increases first, and then decreases; the existence of medium length piles may contain the vertical and horizontal deformation of soil mass at the top of the tunnel.