软土盾构隧道施工阶段上浮量预测综述

随着我国各大城市地铁和江河海底盾构隧道的兴建,施工过程中管片上浮问题已成为当前亟待解决的关键技术问题。首先,从上浮作用机理、横纵向刚度联系、上浮力分布规律以及上浮计算模型方面综述国内外研究现状及存在的问题。其次,在已有研究成果基础上,提出可进一步研究的思路和方向。主要包括:(1)将浆液充填、渗透视为连续过程,探求浆液黏度时变性下管片上浮力分布规律和计算公式;(2)摒弃了传统等效刚度模型和"梁-弹簧"模型,提出横、纵向折中的"局部刚度修正梁-梁"模型;(3)指出弹性地基圆梁法和修正惯用法不适用于分析盾构隧道施工阶段上浮问题,提出抗力反转局部上浮计算模型;(4)考虑浆液时变性、地应力、上浮力以及上覆地层反向压缩特性等因素,创建基于等效刚度或"局部刚度修正梁-梁"思想的盾构隧道整体上浮计算模型。最后,对如何实现给出相应建议。

Review on Prediction of Upward Movement of Shield Tunnel in Soft Soil during Construction

With the development of shield tunnels for urban subway or passages underwater,the upward moving of tunnel segment has become a challenge during the construction. Firstly,the current researches and problems are reviewed in terms of floating mechanism,relationship between lateral and vertical rigidity,distribution law of the buoyancy and floating calculation model. Secondly,based on the existing research results,new ideas and research directions are proposed,including( 1) probing distribution rule and calculation formula when backfill grouting filling and penetration are taken as a continuous process;( 2) putting forward local modified lateral and vertical stiffness( BBM) model in stead of the traditional rigidity model and beam-spring model;( 3) defining the inapplicability of the round elastic foundation beam method and modified routine method in the analysis of upward movement during construction and addressing the applicability of the resistance inversion model;( 4) considering the factors of time-varying grouting,earth stress,buoyancy and compression of the overburden soil,and setting up the model of static buoyancy and dynamic buoyancy based on the equivalent rigidity and BBM. Finally,some practical suggestions are offered.