Monitoring At Construction Period And Dynamic Reinforcement Of Underground Power House Group

It is the most difficult problem of underground project reinforcement design to rightly bring wall rock's carrying capacity to play.The dying away of self-supporting capacity and failure of wallrock is developed with the growth of displacement, and such kind of distortion has a given process. If the deformation process can be measured and recorded, then the trend of deformation can be analyzed, the harmful deformation can then be judged and hanested.Based on New-Austeria principle and technique, take the Guandi underground power station for an example, this paper studies monitoring and dynamic reinforcement technique of large underground power-house in construction period, probed for the practical useful technique and method for under-ground engineering.After analysis of in-situ module cave test of right bank underground power house and 2D finite element method and 3D FLAC3D analysis of deployment, excavation, reinforcement, and stability analysis, the cave wall stability and cave forming condition are proposed. For caves with and without reinforcement, the maximum deformation, maximum stress and volume of loosening region are compared. The function and possible effect of the design reinforcement scheme is anticipated. The optimizing and adjustment suggestions are put forward. The idea of dynamic reinforcement design at construction period accompanying monitoring and its appilication condition are discussed.The main results and and advices are as follows:(1) The jet concrete of present anchoring scheme is divided into three stages:1/3 thickness for each time. The first jeting is applied adjacent to the excavation face. The second jeting time is determined based on the convergence condition and wall diaplacement. If or not the third jeting is needed,and the moment of jeting is based on the convergence condition of monitoring results.(2) The anchoring reinforcement is divided into two steps. The first anchoring is adjacent to the excavation face but in a double distance than the design scheme. If the cave needs further...