矩形顶管施工引起地表隆起变形因素分析

以全国最长的大截面矩形顶管综合管廊工程为背景,研究矩形顶管施工过程中引起地表隆起变形的因素。采用弹性力学mindlin解为理论分析工具,将影响地表隆起变形的因素分为地层参数、设计参数和施工参数。地层参数包括土体泊松比和压缩模量;设计参数包括顶管断面尺寸、隧道埋深和后续管节的断面尺寸;施工参数包括顶管机顶进速度、正面附加推力、顶管机的摩擦系数和管节的摩擦系数。经过分析得到以下结论:(1)该工程地表隆起最大值达到29 mm,随后回落到15 mm并保持稳定,纵向隆起范围为20 m;(2)地层参数中,土体泊松比与地表隆起变形成正比,泊松比每变化0.1,地表隆起变化10 mm,土体压缩模量与地表隆起变形成反比;(3)设计参数中,顶管断面尺寸与地表隆起变形成正比,顶管机宽度每变化1 m,地表隆起变化3 mm,隧道埋深对地表隆起变形最大值不产生影响;(4)施工参数中,正面附加推力、顶管机的摩擦系数和后续管节的摩擦系数与地表隆起变形成正比,顶进速度只影响隆起值出现的时刻,而对隆起值的大小不产生影响。

Analysis on factors of surface heaving deformation caused by rectangular pipe jacking construction

By taking the project of the longest and largesection comprehensive pipeline gallery constructed by means of rectangular pipe jacking in China as the background， the factors of the surface heaving deformation caused by the rectangular pipe jacking is studied herein. The factors affecting the surface heaving deformation are divided into formation parameters，design parameters and construction parameters by adopting the elastic mechanics Mindlin solution as the theoretical analysis tool. The formation parameters include soil Poisson's ratio and compression modulus. The design parameters include the sectional dimension of the rectangular pipe jacking， the tunnel buried depth and the sectional dimension of the subsequent pipe section. The construction parameters include the jacking speed of pipejacking machine， the positive additional thrust， the friction coefficient of pipejacking machine and the friction coefficient of the subsequent pipe section. Through the relevant analysis，it is concluded that ( 1) the maximum surface heaving value of the project reaches to 29 mm，subsequently falls back to 15 mm and maintains stable，for which the longitudinal heaving range is 20 m; ( 2) within the formation parameters， the soil Poisson's ratio is directly proportional to the surface heaving deformation with the surface heaving deformation of 10 mm per Poisson's ratio of 0. 1，while the compression modulus of soil is inversely proportional to the surface heaving deformation; ( 3) within the design parameters， the sectional dimension of pipejacking machine is directly proportional to the surface heaving deformation with the surface heaving variation of 3 mmper width-variation of pipejacking machine of 1 m，while the buried depth of the tunnel has no influence on the maximum value of the surface heaving deformation; ( 4) the positive additional thrust， the friction coefficient of pipejacking machine and the friction coefficient of the subsequent pipe section are directly proportional to the surface heaving deformation，while the jacking speed only affects the moment when the surface heaving deformation appears，but does not affect the value of surface heaving deformation.