针对四渡河特大桥宜昌岸隧道锚承载特性问题,采用基于岩石力学的综合研究方法,从围岩地质与力学特性、隧道锚1:12实体模型试验及隧道锚承载特性数值分析等方面,对隧道锚与围岩岩体变形机制、时效特征及超载安全性等方面开展系统研究。结果表明,通过岩石力学试验及基于实体模型试验获得的隧道锚围岩弹塑性及流变参数符合实际;在设计水平下,隧道锚锭围岩变形在mm级水平;隧道锚极限抗拉拔力≥7.6倍设计载荷,满足锚固安全系数〉4.0的设计要求;实桥隧道锚碇的长期安全系数≥2.6。通过工程实际施工过程中的监测实施,对研究成果和结论的合理性进行验证。研究抟术路续及成果可供山区类似桥梁律设借鉴。
According to bearing capacity problem of a tunnel anchorage at Yichang side for Siduhe super-span suspension bridge, to study systematically the deformation and failure mechanism, the rheological characteristics and overloading capacities of the tunnel anchorage and its surrounding rock mass by a comprehensive rock mechanics research method are proposed. The approach included in the research consists of in-situ geological investigation, rock mechanical tests in laboratory and in the field, the 1 : 12 anchorage physical model test with the same rock mass at site of the actual schemed tunnel anchorage, and the numerical simulations related to physical model test and the engineering analysis of bearing capacity evaluations of the actual tunnel anchorage. Several conclusions have been drawn. Firstly, the mechanical properties and the relevant parameters of the surrounding rock mass are obtained comprehensively by rock mechanical tests; and the physical model tests are quite reasonable compared to the actual monitoring results. Secondly, the total deformation of the actual tunnel anchorage is in the grade ofmm with the designing load which will be supplied by the suspension bridge. Thirdly, the design requirement for the safety factor of the tunnel anchorage, which is greater than 4.0, is evaluated to be satisfied by the 1 : 12 in-situ physical model test where the maximum anti-pulling force is carried out in the physical test, and ultimate tensile bearing capacity is permanent safety factor of bridge anchorage is not less greater than 7.6 times of the design load. At last, the than 2.6 according to the rheological observations in the physical test. The rock mass deformation and some relevant results have been verified through monitoring in process of the bridge construction. In addition, the technological line is an example for bridge construction in some other similar mountain areas.