小曲率半径盾构隧道壁后注浆荷载计算分析

Calculation and Analysis on Grouting Loads behind Wall of Shield Tunnel with Small Curvature Radius

摘要:

为有效计算分析小曲率半径盾构隧道壁后注浆时的荷载及分布情况，以减少注浆荷载对管片造成不利影响。依托南昌市轨道交通1号线东延工程中的麻丘站隧道工程，通过浆液渗流分析，以水灰比介于0.5~0.7的水泥浆为研究对象，基于柱面扩散原理，建立了考虑稠度时空效应的管片壁后注浆渗透扩散模型，推导了管片壁后注浆产生的渗透扩散荷载的计算公式，并给出了最大渗透扩散半径与注浆压力的关系式。研究结果表明：水灰比为0.7的水泥浆可注性较好，当注浆压力达到0.25 MPa及以上时，扩散半径能够满足工程需求；注浆对管片产生的荷载随浆液渗透扩散半径的增大而增大，当浆液可注性较好时，应控制注浆压力不宜过大。

Abstract:

In order to effectively calculate and analyze the load and distribution of grouting behind the wall of shield tunnel with small curvature radius, the adverse impact of grouting load on segments is expounded. Relying on the Machu Station Tunnel Project in the East Extension Project of Nanchang Metro Line 1, through the analysis of slurry seepage, taking the cement slurry with a water-cement ratio of 0.5 to 0.7 as the research object, and based on the the principle of cylindrical diffusion, the permeation diffusion model of grouting behind the segment wall considering the time-space effect of consistency is established, and the calculation formula of permeation diffusion load caused by grouting behind the segment wall is derived. And the relationship between the maximum permeation and diffusion radius and the grouting pressure is given. The results show that the grouting performance of cement slurry with a water-cement ratio of 0.7 is good. When the grouting pressure reaches 0.25 MPa or above, the diffusion radius can meet the engineering requirements. The load exerted by grouting on the segments increases with the increase of the radius of grout permeation and diffusion. When the grouting performance is good, the grouting pressure should be controlled and should not be too large.