隧道施工地层扰动特性分析

研究目的:地铁修建过程中面临大量穿越或临近建(构)筑物的情况,为确保施工安全,应把握施工引起的地层变形规律。本文利用三维非线性有限元模型和相关解析理论,展开对隧道施工后在不同埋深和不同施工控制水平下地层变形规律的研究。研究结论:(1)隧道施工影响半径受埋深和施工控制水平的双重影响;(2)施工影响范围随拱顶沉降的增大而增大,当拱顶沉降增大到一定值后,影响半径达到最大值,此时地层发生剪切破坏;(3)在粉土和粉砂土为代表的典型复合地层中,地表沉降与拱顶沉降的关系、影响半径和拱顶沉降的关系、影响半径与地表沉降的关系分别可用考虑埋深影响的线性函数、二次函数、幂指数函数公式表示;(4)地表沉降斜率与地表最大沉降量的关系可用幂指数函数形式表示,埋深越大,地表沉降斜率越小;(5)本研究成果可应用于地铁穿越工程。

Analysis of Disturbance Characteristics of Tunnel Construction Stratum

Research purposes: During the construction of the subway,there are a large number of traversing or adjacent structures. In order to ensure the safety of construction,the formation deformation law caused by construction should be analysed firstly. In this paper,the three-dimensional nonlinear finite element model and related analytical theories were used,and the formation deformation law was studied with different buried depths and construction control levels.Research conclusions:( 1) The influence radius of tunnel construction is affected by both burial depth and construction control level.( 2) The construction influence range increases with the increase of the vault settlement. When the vault settlement increases to a certain value,the influence radius reaches the maximum value,and the formation shear damage occurs.( 3) In typical composite strata represented by silt and sand,the relationships between surface settlement and vault settlement,influence radius and vault settlement,and influence radius and surface settlement can be expressed by linear function,quadratic function and power exponential function formulas considering the influence of burial depth,respectively.( 4) The relationship between the slope of the ground settlement and the maximum settlement of the surface can be expressed in the form of a power exponential function,and the larger the buried depth,the smaller the settlement slope.( 5) The research results can be applied to the subway crossing engineering.