Method of Calculating the Compensation for Rectifying the Horizontal Displacement of Existing Tunnels by Grouting

Yongjie Qi,Feifan Feng,Gang Wei,Jiaxuan Zhu

doi:10.3390/app11010040

Yongjie Qi, Feifan Feng + Show 2 more

Open Access

https://doi.org/10.3390/app11010040

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Abstract

Sleeve valve pipe grouting, an effective method for reinforcing soil layers, is often employed to correct the deformation of subway tunnels. In order to study the effect of grouting on rectifying the displacement of existing tunnels, this paper proposes a mechanical model of the volume expansion of sleeve valve pipe grouting taking into consideration the volume expansion of the grouted soil mass. A formula for the additional stress on the soil layer caused by grouting was derived based on the principle of the mirror method. In addition, a formula for the horizontal displacement of a tunnel caused by grouting was developed through a calculation model of shearing dislocation and rigid body rotation. The results of the calculation method proposed herein were in good agreement with actual engineering data. In summary, enlarging the grouting volume within a reasonable range can effectively enhance the grouting corrective effect. Further, with an increase in the grouting distance, the influence of grouting gradually lessens. At a constant grouting length, setting the bottom of the grouting section at the same depth as the lower end of the tunnel can maximize the grouting corrective effect.

Highlights

On the one hand, subway tunnels must be highly safe, but on the other hand, they can experience a horizontal displacement due to the excavation of the side foundation pits
Bai et al [2] studied the influence of sleeve valve pipe grouting on the horizontal displacement of existing tunnels through measured data analysis and numerical simulation
Where N is the number of segment rings on one side of the tunnel affected by the additional stress at the center point, ks represents the shear stiffness between the tunnel segment rings, kt stands for the tensile stiffness between the tunnel segment rings, D is the tunnel diameter, Dt denotes the width of the segment ring, j indicates the proportional coefficient of the rigid body rotation effect of the segment ring, w(y) is the horizontal displacement of the tunnel, and m and m + 1 are the serial numbers of two adjacent segment rings

Summary

Introduction

Subway tunnels must be highly safe, but on the other hand, they can experience a horizontal displacement due to the excavation of the side foundation pits. The random medium theory is generally used to study displacement of the upper soil layer and the ground surface caused by the expansion of slurry bubbles It can only calculate displacement of and additional stress on the soil in the upper part of the shrinkage point or the expansion point but not at the calculation point at a similar or lower depth; the calculation method based on the random medium theory cannot analyze the corrective effect of grouting in the horizontal direction. Based on the mirror image method [9] and combined with the research results of Wang et al [10], formulas for the calculation of additional horizontal stress on surrounding soil caused by slurry injection of sleeve valve pipe were first derived. This model has been employed in many works [17,18] and has been veri-

Calculation of the Horizontal Displacement in an Existing Tunnel

Energy Conversion of Deformation Process of Existing Tunnel

Derivation of Displacement Function of Existing Tunnel

Operating Conditions

Comparison between Uniform Expansion Model and Nonuniform Expansion Model

Conclusions