Abstract To investigate the temporal evolution of surrounding rock pressure and its transfer pathways within composite lining systems in high in-situ stress soft rock tunnels, a theoretical analytical framework is proposed that incorporates surrounding rock damage evolution and performance degradation of support structures. Based on the Maoxian Tunnel of the Chengdu-Lanzhou Railway, field monitoring data are integrated to analyze the load evolution under single-layer and double-layer initial support configurations. The coupled mechanisms between rock mass rheological damage and support deterioration are revealed, and the time-dependent load evolution from the surrounding rock to support components is quantitatively characterized. The results show that the combined effects of rock mass rheological damage and time-dependent degradation of support elements drive the gradual transfer of extrusion loads from the initial support to the secondary lining, resulting in an increasing load-sharing ratio of the secondary lining. Theoretical calculations indicate that the load-sharing ratios of the secondary lining reach 69% and 49% for the single-layer and double-layer initial support schemes, respectively, demonstrating the effectiveness of multi-layer initial support in mitigating load evolution to the secondary lining. Enhancing the stiffness of the primary support, reducing the stiffness of the secondary lining, and introducing a reasonable lag in secondary lining installation can effectively reduce the load carried by the secondary lining, thereby suppressing long-term load evolution within composite lining systems of deep-buried soft rock tunnels.
Abstract：
To investigate the temporal evolution of surrounding rock pressure and its transfer pathways within composite lining systems in high in-situ stress soft rock tunnels, a theoretical analytical framework is proposed that incorporates surrounding rock damage evolution and performance degradation of support structures. Based on the Maoxian Tunnel of the Chengdu-Lanzhou Railway, field monitoring data are integrated to analyze the load evolution under single-layer and double-layer initial support configurations. The coupled mechanisms between rock mass rheological damage and support deterioration are revealed, and the time-dependent load evolution from the surrounding rock to support components is quantitatively characterized. The results show that the combined effects of rock mass rheological damage and time-dependent degradation of support elements drive the gradual transfer of extrusion loads from the initial support to the secondary lining, resulting in an increasing load-sharing ratio of the secondary lining. Theoretical calculations indicate that the load-sharing ratios of the secondary lining reach 69% and 49% for the single-layer and double-layer initial support schemes, respectively, demonstrating the effectiveness of multi-layer initial support in mitigating load evolution to the secondary lining. Enhancing the stiffness of the primary support, reducing the stiffness of the secondary lining, and introducing a reasonable lag in secondary lining installation can effectively reduce the load carried by the secondary lining, thereby suppressing long-term load evolution within composite lining systems of deep-buried soft rock tunnels.
ZHAN Hongxiang CHEN Ziquan WANG Bo ZHOU Zihan
.ime-dependent Evolution and Transfer Mechanisms of Loads in Composite Lining Systems of High In-situ Stress Soft Rock Tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(5): 13-24
2025, Vol. 62 