Abstract In order to study the reinforcement effect of surface pre-grouting in fractured soft rock tunnels with shal? low depth and asymmetrical loading, this paper establishes a 3D finite element model based on the Hongshihe tunnel project which adopts sleeve valve pipe grouting for reinforcement, and conducts a comparative analysis on the grouting reinforcement effect through field tests, monitoring and measurement. Comprehensive analysis shows that after the surface grouting, the strength and integrity of the surrounding rocks are significantly improved, the water permeability of the rock mass is reduced, the arching capacity of the ground is enhanced, and the overall stress characteristics of the tunnel support structure are greatly improved. The maximum axial compressive force of the initial support is reduced by nearly 20%, while the maximum axial tensile force is 43% of the original value; the maximum positive bending moment of the initial support is reduced by 58% while the maximum negative bending moment is reduced by 29%; the changing trends of tunnel vault settlement and surrounding rock convergence are basically the same, with about 70% of the total deformation completed in the first 10-15 days, and the whole deformation basically completed in 20-25 days. And the numerical calculation is consistent with the field measurement results, with a very significant grouting effect.
Abstract：
In order to study the reinforcement effect of surface pre-grouting in fractured soft rock tunnels with shal? low depth and asymmetrical loading, this paper establishes a 3D finite element model based on the Hongshihe tunnel project which adopts sleeve valve pipe grouting for reinforcement, and conducts a comparative analysis on the grouting reinforcement effect through field tests, monitoring and measurement. Comprehensive analysis shows that after the surface grouting, the strength and integrity of the surrounding rocks are significantly improved, the water permeability of the rock mass is reduced, the arching capacity of the ground is enhanced, and the overall stress characteristics of the tunnel support structure are greatly improved. The maximum axial compressive force of the initial support is reduced by nearly 20%, while the maximum axial tensile force is 43% of the original value; the maximum positive bending moment of the initial support is reduced by 58% while the maximum negative bending moment is reduced by 29%; the changing trends of tunnel vault settlement and surrounding rock convergence are basically the same, with about 70% of the total deformation completed in the first 10-15 days, and the whole deformation basically completed in 20-25 days. And the numerical calculation is consistent with the field measurement results, with a very significant grouting effect.
YE Xinxin1 MIAO Miao2 ZHONG Yujian2 XU Shuoshuo2 DU Ke2
.Analysis on Reinforcement Effect of Surface Grouting in Shallow-Buried Tunnels with Asymmetrical Loading and Abundant Underground Water[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 229-236
2021, Vol. 58 