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由于长期氯离子侵蚀及干湿交替环境作用,海底隧道锚固支护结构易于加筋锈蚀,造成支护结构强度的降低.结合某海底隧道Ⅲ级和Ⅳ级围岩锚固支护结构设计,基于前人研究理论及试验成果,采用数值分析软件FLAC3D及有限元强度折减思想,探讨加筋锈蚀对锚固支护结构体系承载作用的劣化影响.研究表明,(1)锚杆锈蚀削弱了锚固支护结构的支护强度;随着加筋锈蚀的增加,隧道加锚围岩的变形逐渐增大;锈蚀对隧道加锚围岩起拱线处的收敛变形影响最明显,Ⅲ级围岩位移锈蚀影响度最大可达56.7%,Ⅳ级围岩位移锈蚀影响度最大可达62.98%.(2)锚杆锈蚀降低了锚固支护结构的锚固作用,锈蚀对锚固注浆体的黏结作用的损失影响比对锚杆应力作用的损失影响大;Ⅲ级围岩锚杆最大应力锈蚀影响度最大为11.6%,锚固注浆体最大剪应力锈蚀影响度最大达18.6%;Ⅳ级围岩锚杆最大应力锈蚀影响度最大为12.3%,锚固注浆体最大剪应力锈蚀影响度最大达20.1%;说明锈蚀对Ⅳ级围岩锚固支护结构影响比Ⅲ级围岩略大.研究结果可为海底隧道锚固支护结构运营风险评估提供一定的数据依据.
Due to the long-term chloride ion erosion and alternating dry-wet environment, the anchoring and supporting structure of the submarine tunnel is easy to be reinforced and corroded, resulting in the decrease of the strength of the supporting structure. Combined with the design of the anchoring and retaining structures for Grade III and IV surrounding rock of a subsea tunnel, People's research theory and experimental results, numerical analysis software FLAC3D and strength reduction theory of finite element method are used to investigate the effect of reinforcement rust on the bearing capacity of anchoring and supporting system.The results show that: (1) The strength of supporting structure of the tunnel increases; the deformation of surrounding rock mass increases gradually with the increase of reinforcement corrosion; the corrosion has the most obvious effect on the convergence and deformation at the camber line of the surrounding rock mass reinforced by tunnel, The maximum degree of corrosion can reach 56.7%, and the influence degree of grade Ⅳ surrounding rock can reach up to 62.98%. (2) The corrosion of anchoring bolt reduces the anchoring effect of anchorage and support structure, and the effect of corrosion on the loss of anchorage grouting Which has a great influence on the loss of anchor stress. The maximum influence of maximum stress corrosion on rock bolts of grade Ⅲ rock is 11.6%, and the maximum influence of corrosion on anchor grouting body is up to 18.6% The influence is maximum 12.3%, and the influence of the maximum shear stress of anchor grouting is up to 20.1%. It indicates that the corrosion affects the anchoring structure of Grade IV surrounding rock a little more than that of Grade III. The research results may be the anchoring branch of subsea tunnel Provide a certain data basis for the risk assessment of operation and maintenance structure.