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The Effects of Treatment of Collapses in Shallow-Buried Loess Tunnels with Unsymmetrical Loading
(1 Key Laboratory of Ministry of Education for Special Area Highway Engineering, Chang′an University, Xi′an 710064; 2 China State Construction Silkroad Construction Investment Group Co. Ltd., Xi′an 710065; 3 China Railway First Survey and Design Institute Group Co. Ltd., Xi′an 710043; 4 China Railway Eryuan Engineering Group Co., Ltd. Chengdu 610031)
Abstract In order to study the effects of the treatment of collapses in loess tunnels, the main reasons for tunnel collapse are analyzed and such treatment measures as the combination of a large pipe-roof and small pipe grouting, surface treatment and treatment inside a tunnel are put forward based on the collapse event that occurred at the portal of the Ganquan tunnel on the Baotian expressway. Treatment effects are analyzed by numerical simulation and field experiments. The analysis results show that if the tunnel is buried shallowly and unsymmetrical in terms of topography, the original design concept is unsafe and the surrounding rock is soaked with water from rainfall coming in from surface cracks, it would ultimately result in tunnel collapse and surface subsidence; the deformation and force applied on the initial support and secondary lining tend to be stable and no abnormal changes occur 20 days after treat? ment; and the calculation results of the crown settlements and peripheral convergence basically agree with the measured results and the changed values are within the scope of the specification, with the tunnel structure being stable after treatment.
Abstract：
In order to study the effects of the treatment of collapses in loess tunnels, the main reasons for tunnel collapse are analyzed and such treatment measures as the combination of a large pipe-roof and small pipe grouting, surface treatment and treatment inside a tunnel are put forward based on the collapse event that occurred at the portal of the Ganquan tunnel on the Baotian expressway. Treatment effects are analyzed by numerical simulation and field experiments. The analysis results show that if the tunnel is buried shallowly and unsymmetrical in terms of topography, the original design concept is unsafe and the surrounding rock is soaked with water from rainfall coming in from surface cracks, it would ultimately result in tunnel collapse and surface subsidence; the deformation and force applied on the initial support and secondary lining tend to be stable and no abnormal changes occur 20 days after treat? ment; and the calculation results of the crown settlements and peripheral convergence basically agree with the measured results and the changed values are within the scope of the specification, with the tunnel structure being stable after treatment.
.The Effects of Treatment of Collapses in Shallow-Buried Loess Tunnels with Unsymmetrical Loading[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(2): 194-201
2017, Vol. 54 