Research On Rock Burst Mechanism And Support Scheme For Deep Excavation Roadway In A Hard Rock Mine

In recent years,with the continuous advancement and development of China’s reform and opening up,the demand for minerals from basic industries has continued to grow.However,due to continuous mining by people,especially the early unreasonable planning and exploitation,the shallow resources of mines are gradually reduced,which makes the mining resources turn to deep mining.Rock bursts are often encountered in deep excavations.It may result in casualties of underground workers,destruction of underground construction equipment and delays in excavation progress,resulting in an increase in excavation costs.As far as the academic community is concerned,there is no mature understanding of rock burst.Therefore,it is necessary to further study the prediction,mechanism and prevention of rock burst in actual projects to prevent the occurrence of rock bursts and ensure the safety of mine personnel.The production goes smoothly.Due to the complex terrain conditions of the metal mine and the deeper roadway for excavation,the detailed information on the mechanism of rock burst,the prediction and prediction methods of rock burst,and how to prevent and control it was carried out in-depth,systematic,and comprehensive.Research.The main findings of the paper are summarized as follows:1.This paper analyzes the rockburst formation mechanism,and puts forward four main theories of rockburst action mechanism:strength theory,stiffness theory,energy theory and tendency theory;and three rockburst discriminant indicators:The first category is based on lithology.The rockburst discriminant index（also known as the rockburst proneness index）,the second class is the rockburst discriminant index based on the site conditions,and the third class is the new rockburst discriminant index based on fracture damage,nonlinear science,intelligent science and so on.The first type of rockburst-based rockburst discriminant index was introduced in detail,and the experiment of energy impact index and elastic strain energy index of rock samples and rock samples around excavation roadway was conducted to determine the excavation roadway.Whether it has a tendency to rock burst.2.Through on-site exploration,rock quality assessment,and in-situ stress tests,it is known that the surrounding rock around the excavation roadway at-850m is well integrated,the ground stress is high,and the rock is a brittle rock.The uniaxial compression and splitting experiments were performed on the rock sample and ore surrounding the excavation roadway to obtain the basic physical parameters:compressive strength,tensile strength,Poisson’s ratio,and elastic modulus.Then,the whole stress-strain experiment and pressurization-unloading experiment are performed on the surrounding rock and ore,and then the energy impact and elastic strain energy indexes of the surrounding rock and ore are calculated based on the images obtained from the experiment and the graphical integration method.,and use these two indicators to predict the extent of rock burst.According to experiments,the energy impact index of rock sample is between 1-2,and the elastic strain energy index is between 3-5.Therefore,it is judged that the excavation roadway has a medium rock burst tendency.3.According to the experiment to measure various mechanical parameters of the rock around the roadway,carry out FLAC3D modeling of the roadway and analyze the force situation of the roadway model.It can be known that the stress in the horizontal direction and vertical direction of the roadway is concentrated in the At the arched end of the excavation roadway,the maximum principal stress is concentrated on the arched end of the excavation roadway and near the top.The minimum principal stress is concentrated on the arched end of the excavation roadway.The determination of the stress concentration area can provide the basis for the support of the next roadway4.Through the modeling of FLAC^3D,the concentrated area of the stress caused by the excavation is determined,and then combined with the research of the existing roadway rock burst support,a three-support method is proposed,namely,strengthening the surrounding rock,weakening the surrounding rock,and drilling the pressure relief..And by calculating the energy generated by the roadway surrounding rock during excavation rock burst,the method of bolting+hanging metal mesh and shotcrete is adopted for the excavation roadway to prevent the occurrence of rock burst and ensure the safe and smooth progress of the mine.produce.