| According to the problem of deep roadway surrounding rock stability monitoring and early-warning, the indoor physical model experiment and numerical simulation were conducted. Based on the similarity theory, with constant resistance and large deformation bolt as the prototype, small constance reistance bolt is developed which suitable for indoor physical model experiment, digital image correlation techniquestudy is used to the surface displacement probe of the physical model. The deformation and failure physical model experiment of the level and the 45 degree angle of rock roadway under loading condition is carried out, the roadway deformation and failure characteristics is summed, the displacement and bolt mechanical monitoring results is analyzed. Based on the physical model, the simulation experiment of stability monitoring and early warning of deep roadway surrounding rock with various strata inclination is carried out, the deformation and failure law of deep layered rock mass and the deformation and failure rule of monitoring and early warning of deep layered roadway based on constant resistance monitoring bolt is got.Firstly, with constant resistance and large deformation bolt as the prototype, reference field bolting parameters, small constant resistance bolt meet geometric and mechanical similarity isdeveloped, the indoor tensile experiments prove that the design is feasible.In Datai mine as engineering background, dimensional analysis method is used to design parameter of the physical model, geometry parameters, physical model of strain parameters were determined, to build the physical model based on the finite element method, and the strain gauge layout of roadway, etc. The physical model of the horizontal and 45 degrees of rock is constructed, pre buried common bolt and constant resistance monitoring bolt, according to the stress measurement and calculation results of construction site roadway, the loading path design of the physical model is carried out to explore the failure and deformation process of deep roadway in the supporting conditions under overload, the deformation of the roadway precursory informationand is captured by monitoring the monitoring anchor.The strain gauge and monitoring bolt are embedded in the physical model experiment, the non contact detection method-digital image technology is used to the test of large size physical model, the displacement fields of model information and extract key displacement information are gained, the displacement information of key points can be extracted at any time, realize the monitoring of the whole process of physics experiment, this has certain advantages compared with the contact type displacement and strain monitoring method.The experimental results of horizontal rock physical model is analysised, deformation and failure characteristic of horizontal rock physical model of roadway is got, the level of stress and the level of rock layers parallel to the bedding surfaces, only the friction between layers to resist horizontal stress, so under the horizontal stress prone to slip and extrusion deformation, loading by the late model effect of high level of roadway roof strata stress occurs along the joint plane slip and plastic deformation, horizontal compression leads to roof separation and the final result of roof cavingg.The evolution characteristics of the horizontal strain field and vertical deformation strain field are obtained though the analysis of 45 degrees of rock physical model experimental results. Physical model of field evolution characteristics, failure stage of model stress loading have been analyzed by the strain and stress of key points of tunnel, from which it can gets the deformation and failure characteristics of roadway. In the 45 degrees obliquity of rock physical model experiment the horizontal displacement and the vertical displacement of the tunnel model are significantly affected by the obliquity of rock. The model of roadway in the process of step loading show a characteristic of friction sliding damage, where the deformation damage of the roadway is also mainly occurred. The constant resistance bolt and common bolt are built in the 0 degree and 45 degree rock physical model, and the axial force of bolt is real-time monitored by the force sensor. The axial force of common thread steel decreases rapidly due to the large deformation of the roadway. while the constant resistance bolt can bear its strength always until to the end of experiment test. From the above studies show that the constant resistance bolt in roadway can withstand the large deformation of roadway damage, and the whole process of deformation and failure of roadway monitoring can be realized, while the traditional bolts are prone to be failed, which is difficult to realize the whole process monitoring and early warning.The monitoring curve of the constant resistance monitoring can be divided into the slow stage, accelerated rise stage of the the physical experiment. The anchor monitoring curve in accelerated phase during the process of large deformation of roadway through the analysis of the constant resistance bolt monitoring point displacement data, when the bolt force rises to a certain value before the roadway failure.it indicates that the monitoring curve can be used as the information of the roadway surrounding rock stability monitoring and early warning stage.The deformation and failure characteristics of surrounding rock of roadway are different in the different strata dip angle of physical model experiment through horizontal strata and 45 degrees of rock at different positions in the physical model. Analysis of constant resistance curve found that monitoring and strata dip angle has a good relation. Constant resistance monitoring result is good at the horizontal roadway roof. The anchors which close to the low side part in 45 degree roadway roof strata and the low side part anchor monitoring effect are good. Deep layered rock mass deformation and failure are influenced by the strata dip obviously, and the effect of the constant resistance monitoring anchor is also different, so it is necessary to analyze the monitoring results in a variety of strata dip angle. Discrete element numerical simulation research has been carried out under the same geometry, geotechnical strength parameters and the condition of the loading paths, which is based on the physical model experiment. The mechanical changes of the monitoring anchor of the different dip strata in the loading deformation and failure process is studied, and the numerical simulation explored the characteristics of the stress monitoring under the the different dip strata in the loading deformation and failure process.The constant resistance bolt is simulated with "Global Reinforcement" anchor in the numerical model. The conditions of the model is similar to the physical model experiment simulation model, then calculation parameters are optimized based on the physical simulation results. Based on which a variety angle of rock roadway characteristic of mechanical damage monitor has been studied by numerical simulationThe numerical simulation experiments of different strata inclinations such as 0 degrees,15 degrees,30 degrees,45 degrees,60 degrees,75 degrees and 90 degrees have been developed in this paper. Constant resistant monitoring bolts are also set in the numerical model.The anchor monitoring data shows that when the strata inclination is 0 degrees, the two sides of roadway slippage to the roadway under the horizontal stress, causing the floor heave and roof caving, and the roof bolt monitoring is better than that of the two sides. In the 15 degrees model, large deformation and outstanding destruction of rock along the slip level firstly happened in the roof near the low side and the floor near the high side. besides, the roof bolt monitoring of the roof near the lower side is better. In 30 degrees numerical model, large deformation and outstanding destruction of rock along the slip level firstly happens in the roof near the low side and the low side of the roadway. While the roof bolt monitoring of the roof near the low side and the low side of roadway is better. In the 45 degrees numerical simulation model large deformation and outstanding destruction of rock firstly happen in the roof near the low side and the high side of the roadway, and the roof bolt monitoring of the roof near the low side and the high side is better. In the 60 degrees model large deformation and outstanding destruction of rock firstly happen in the roof near the low side and the high side near the floor of the roadway, beside, the roof bolt monitoring of the roof near the low side and the high side is better. In the 75 degrees model, large deformation and outstanding destruction of rock firstly happen in the roof near the low side of the roadway, and the roof bolt monitoring of the roof near the low side is better.In this paper, based on the constant resistance monitoring anchor the resistance and large deformation bolt which suitable for indoor physical model experiment is designed, it is successfully applied to the the physical model experiment of stability monitoring and early warning of the stability of surrounding rock in deep layer roadwaythe axial force time curve monitoring. Digital image displacement technology is applied to large scale physical model experiment, the whole process deformation of displacement and strain field is obtained. The failure and deformation physical model experiment of deep roadway surrounding rock proves that the mechanical monitoring of constant resistanceis more suitable for the stability of surrounding rock in deep roadway than ordinary anchor bolt, the accelerating precursory information monitoring and early warning of cross resistance bolt mechanical monitoring is the rising of the monitoring curve. Through the numerical simulation experiment of different inclination of rock roadway, further reveals the deformation characteristics of deep layered roadway, reasonable layout of anchor mechanics monitoring arrangement under different inclination conditions in layered.Through the experiment of physical model experiment and numerical simulation research, the small anchor monitoring is used to the stability monitoring and early warning of the surrounding rock in deep layered roadway. the conclusions provide reference and basis for the research and application of the constant resistance monitoring based on bolt in roadway surrounding rock. |
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