服役隧道仰拱上抬病害机理分析与整治措施OA

To address the mechanism analysis and treatment of inverted arch uplift and track slab cracking in an in-service tunnel,a combined approach of field structural disease characteristic analysis and laboratory tests was adopted to explore the disease mechanism of inverted arch uplift deformation and track slab cracking in an in-service tunnel of the Shanghai-Kunming Railway.According to the analysis of structural cracking characteristics and disease mechanism,integrated treatment measures of"grouting anchor pipe installation-bedrock grouting and removal-reconstruction of inverted arch structure"was proposed.These measures were adopted to guide the construction of the background project,and the evolution laws of the contact stress between the bedrock and the inverted arch was monitored and analyzed during the construction process.The results indicated that:the expansion deformation of bedrock upon water exposure was the main cause of local uplift of the inverted arch and other supporting structures,leading to increased internal forces,uneven deformation,and cracking;factors such as bedrock bearing capacity reduction,stress concentration induced by local high in-situ stress,and uneven stiffness and stress distribution in the invert arch structure further exacerbated the risk of non-coordinated deformation and cracking in the bedrock-invert arch system;the contact stress between the bedrock and the reconstructed inverted arch showed a phased evolution pattern,initially increasing slowly and then gradually converging to stability.The average contact stresses at three monitoring sections were 167.83,169.51 and 165.82 kPa,respectively,which ensured the stability and safety of the tunnel structure.The treatment measures in combination with the disease mechanism analysis effectively prevented and controlled inverted arch uplift and structural cracking in the in-service tunnel.The research results provide a design scheme and engineering application reference for the treatment and prevention of similar engineering diseases.