基于透明土试验技术的盾构侧穿桩基影响机制研究

Research on Influence Mechanism of Tunnel Crossing Pile Foundation Based on Transparent Soil Test Technology

为深入研究盾构侧穿既有桩基引起的地层与桩基的变形演化机理,引入了透明土试验技术和数字图像处理技术,研制了一套无损观测土体行为的室内物理模型装置,开展盾构隧道施工的模型试验。试验结合透明土可视化非侵入优势对不同隧道埋深、桩基位置、桩基长度等因素的影响规律展开研究。利用理论解析和数值模拟方法验证透明土方法的可行性及准确性。试验结果表明:理论解析、数值模拟及透明土试验具有较好的一致性。双线隧道施工会对地表沉降产生叠加效应,但后行隧道引起的地表沉降不足总沉降的10%;隧道沉降区域及极值都随着埋深比的减小而逐渐增大;当桩基入土深度大于隧道埋深时,桩基易在隧道埋深所在深度发生转动。文章为盾构侧穿桩基影响机制研究提供了一种新方法,丰富了盾构机制探索体系。

In order to deeply study the deformation evolution mechanism of formation and pile foundation caused by the side penetration of existing pile foundations in shield tunnels,transparent soil test technology and digital image processing technology were introduced,a set of indoor physical model devices for non-destructive observation of soil behavior was developed,and model tests for shield tunnel construction were carried out.Combined with the visual non-intrusion advantages of transparent soil,the influence of different tunnel burial depths,pile foundation positions,pile foundation length and other factors was studied.Theoretical analysis and numerical simulation methods verify the feasibility and accuracy of the transparent soil method.The test results show that Theoretical analysis,numerical simulation and transparent soil test have good consistency.the construction of the double-line tunnel will have a superimposed effect on the surface settlement,but the surface settlement caused by the backward tunnel is less than 10% of the total settlement;The tunnel settlement area and the extreme value gradually increase with the decrease of the burial depth ratio;When the depth of the pile foundation is greater than the depth of the tunnel burial,the pile foundation is prone to rotation at the depth of the tunnel burial.This paper provides a new method for the study of the influence mechanism of shield side piercing pile foundation,and enriches the exploration system of shield mechanism.