Abstract
Taking the Hulinjia Tunnel as a case study, the deformation characteristics of tunnel surrounding rock were thoroughly investigated through field monitoring methods, and corresponding support measures were proposed to ensure safe, stable, and normal tunnel operation. The research results indicate that: in terms of time-dependent characteristics, crown settlement exhibits three stages—rapid settlement, slow settlement, and stabilization. The crown settlement during the rapid settlement stage is 23 mm, accounting for 82.1% of the total settlement. Analysis of monitoring data from three different cross-sections reveals that surrounding rock crown settlement increases with cross-sectional size. The time-dependent variation trend of peripheral convergence is similar to that of crown settlement, with peripheral convergence values following the order Cross-section 1 > Cross-section 2 > Cross-section 3. No obvious correlation exists between burial depth and deformation, which is attributed to the influence of in-situ stress, rendering the effect of burial depth on deformation insufficiently pronounced. After implementing combined initial support and advance support measures, crown settlement and peripheral convergence at the three cross-sections were reduced by more than half compared with pre-support conditions, achieving significant control of surrounding rock deformation.
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Title: Analysis of Deformation Characteristics of Surrounding Rock Based on On-site Monitoring and Research on Support Measures
Author: TAN Yazhou
China Railway 16th Bureau Group Fourth Engineering Co., Ltd., Beijing 101400, China
Abstract
This study investigates the deformation characteristics of tunnel surrounding rock through on-site monitoring of the Hulinjia Tunnel case, proposing corresponding support measures to ensure safe, stable, and normal operation. The results demonstrate that crown settlement exhibits three distinct temporal stages: rapid settlement, slow settlement, and stabilization. During the rapid settlement stage, crown settlement reaches 23 mm, accounting for 82.1% of the total settlement. Analysis of monitoring data from three different cross-sections reveals that crown settlement increases with cross-sectional size. Peripheral convergence follows a similar temporal trend, with values decreasing sequentially from Section 1 to Section 2 to Section 3. No significant correlation exists between burial depth and deformation, as geostress effects diminish the apparent influence of burial depth. Following implementation of combined initial and advanced support measures, crown settlement and peripheral convergence in all three sections were reduced by more than half compared to pre-support conditions, achieving significant control of surrounding rock deformation.
Keywords: on-site monitoring; crown settlement; peripheral convergence; deformation characteristics of surrounding rock; support measures