Research On Fracture Cracking Rules Of Jointed Rock Specimens Based On Discontinuous Deformation Analysis

The TBM boring machine has unparalleled advantages in tunnel and water tunnel excavation,and the TBM boring machine can continuously dig the excavation rock by relying on the hob at the front end of the TBM cutter head,including the single-edged hob and the double-edged hob.And multi-blade hobs.Because the rock breaking conditions in the actual tunnel excavation project are very complicated,in order to ensure the normal and efficient excavation of the tunnel project,the mechanism of the hob breaking rock and the force of the hob during the rock breaking process need to be further studied.The related research aims to provide some theoretical references for the actual construction and equipment design and manufacture of TBM tunneling machines.Based on the National Natural Science Foundation of China,“Study on rock mass fracture mechanism and hob rock breaking process optimization in tunnel excavation based on discrete element method”,this paper starts from the mainstream classic hob rock breaking prediction model and related theory at the current stage.The new hob rock breaking prediction model and the discrete element software EDEM are used for related simulation verification work.The main research contents are as follows:(1)Summarize the research conducted by experts and scholars on the rock breaking test and numerical simulation of the hob at this stage,and analyze their respective shortcomings.At the same time,the structural stress of the hob and the failure criterion of the rock are introduced in detail.According to the current mainstream classic hob rock breaking prediction model,a new hob rock breaking model-RCC prediction model suitable for CCS hob is established,including hob vertical force prediction model,rolling force predictionmodel and lateral force prediction model..(2)According to the relevant hob rock breaking test data,the new hob rock breaking prediction model is calculated and analyzed,and compared with the classical forecasting model to verify the accuracy of the RCC prediction model.(3)Using the discrete element software EDEM to carry out the simulation research of single and double hob rock breaking and cutterhead rock breaking,according to the simulation results,the rationality and accuracy of the single hob rock breaking prediction model built in this paper are further verified.The influence of the hob’s force on the double-cutter breaking process and the influence of different knife spacing on the rock breaking are explored,and the optimal knife spacing when the double hob is broken is explored.Finally,the research and analysis of the force of the cutterhead and the rock-breaking effect of the cutterhead during the rock-breaking process of the cutterhead are carried out,which provides a certain theoretical support for the actual construction process and cutterhead design of the TBM excavation and excavation.