Research On Anchorage Parameter Optimization And Nondestructive Testing Technology Of Tunnel Fully Grouted Bolt

Because of the factors such as the complexity of geological environmental conditions, the lack of thorough study and appropriate calculation models and the inaccuracy of anchoring parameter estimation, the anchor support design has certain limitations; On the other hand, the anchor structure possesses the characteristic of concealment and relatively complex construction progress, in addition the operating level of constructors is always uneven, which may effect the quality and long-term stability of the entire geotechnical structure. And there are some difficulties in controlling anchor construction quality. Based on this point, the anchor mechanism, parameter optimization and quality testing level of anchoring are still required further research and test.Combined with previous research results on xiaobeishan 1 # tunnel engineering of Guangdong Nanyue Transportation Jie(yang)-Hui(lai) highway construction projects and based on analysis of tunnel surrounding rock stability and full-length grouted mortar anchor support mechanism, a uniform design method was introduced and a finite difference numerical model of the tunnel lining anchor supporting was established in this study.First of all, anchor length L, diameter D, layout distance Sx and layout row distance Sr were set as the Influencing factors, and 6 levels was selected according to the specification reference. In addition four factors-vault displacement, peripheral convergence value, the maximum principal stress in surrounding rocks and the maximum axial force of anchor were chosen as the dependent variables. After that backward stepwise regression method was used for regression analysis on numerical simulation results and then concluded the effect of different parameters on anchoring. At the end, a preferably best anchoring supporting scheme was decided to provide meaningful reference for tunnel anchor design.Meanwhile on the basis of the stress wave theory, anchoring quality testing method was used to calculate the stress wave equation in one-dimensional anchor and to explore the propagation of stress wave in anchor. Based on the nondestructive testing contents, judgment method and basis for stress wave method were proposed. Finally according to practical field application, a stress wave method was used to evaluate the quality of anchor construction, and then can be used to guide practical engineering.