| Deep surrounding rock stress is the inevitable atmosphere of the roadway surrounding rock deformation, when rock structure, lithology, rock strength and other self-affecting index factors have effects on the rock deformation amount, as well as joints, cracks, faults control the rock deformation. These structural cutting action make these rocks into continuous rocks but discontinuous rocks, making the rocks carried the forces from multi-field (stress, temperature, seepage) and heterogeneous (gas, liquid, solid) by the influence of the geological structure and engineering structure interaction coupling. Therefore those surrounding rock deformations comprehensively reflect surrounding rock morphological changes after excavation, and it is also the stability of roadway intuitive basis, and support design is the basic means to control the deformation. Surrounding rock displacement can be divided into three parts according to time history;(1) section excavation instant elastic displacement;(2) load releasing elastic or inelastic displacement;(3) timely visco-elastic displacement in case of the release of the maximum load while maintaining constantly. The actual measuring surfaces are later than excavation surfaces, so the convergence measured is just a portion, mainly the third part. Therefore, the analysis of rock deformation causes and mechanism and reasonable support to ensure timely roadway stable is core of this research, and it is also the key to ensure normal production and mine safety. Currently, on-site monitoring, similar material simulation experiment, the computer numerical simulation and theoretical analysis by means of rock deformation research, analysis of surrounding rock deformation mechanism in order to achieve a reasonable support and accurately predict results.Daye Iron Mine Jianlinshan NO.2ore body metamorphic rocks, on the plate diorite contact zone ore crushing, is listed as an unstable region and type IV unstable areas class and V ultimate unstable areas. From-20m level beginning, the roadway on the plate appears ore ground pressure activities, and roadway collapsed make that part of the ore cannot be recycled; form-30m horizontal section also corresponds to a similar situation; in the half of1993, the mining enter-40m level,-40m level corresponding parts of the roadway on the plate apparent cracks and local caving, rock smashed drill rig collapsed, blocking transport roadway; after1996,-50m level,-60m level, including cave mining district-62m level,-74m average varying degrees of water into the road tunnel collapsed, large haulage collapse phenomenon.Daye iron ore deposits are hosted in the fracture zone, while the stability of the contact zone ore is poor and boring and support are difficult, as well as mining engineering and technical personnel and workers of the complex mechanical behavior of rock excavation particular understanding of the laws of deformation and destruction unclear, mining there are significant security risks. In order to ensure mine production safety, to prevent the occurrence of major casualties in underground tunnel, to increase labor productivity, underground geological characteristics of rock, rock stability, surrounding rock deformation and failure mechanism of must be study deeply. Therefore, the paper combined with Daye Iron unstable region underground mining roadway stability control and support methods research project to Daye Iron Mine Roadway mainly used for the study, the use of data collection, site investigation, theoretical analysis, laboratory tests, numerical simulation and field testing and other methods, revealing instability mechanism of roadway surrounding rock stability and influence factors analysis of surrounding rock deformation instability region (cross roadway, roadway ore at the contact zone and fine ore roadway), micro-instability mechanism and control methods, development spray-anchor support design intelligent systems for underground mining Daye iron construction provides a theoretical basis and technical support, research results with a more important theoretical and engineering application value.After reviewing a large number of papers relevant literature, a comprehensive summary of previous studies based on the results, the system launched Daye Iron Mine underground mining tunnel surrounding rock stability and control technology research, and mainly to complete the following work:1. Engineering geological conditions and the physical and mechanical properties of rock study(1) By on-site investigation and geological data on the Daye Iron Mine Based on the analysis, summarized overview mining and engineering geology, hydrogeology, Jianlinshan workshop is identified as major research area for the project.(2) Through Jianlinshan-60level6#,8#, and13#road jointed rock mass survey it shows jointed existence of the following distribution:a.6#jointed approach towards the130°～160°between the distribution of more in the direction of135°jointed largest number; joint set has two advantages, namely S1:76/229, S2:28/255to steeply inclined joints based,70°～80°(50%), with an average spacing of5.7/m;b.8#approach jointed to mainly concentrated in the115°～130°, between approximately normal function of distribution; has a set of advantages joint sets, namely S1:44/011, jointed angle wide distribution, mainly in the tilt, steeply inclined and the average spacing of4.2/m;c.13#into the road joints strike mainly concentrated in25°direction and115°～135°between; has two advantages of joint sets, namely S1:69/043, S2:85/030, with steeply inclined joints as Lord, the average spacing of3.8/m;d. Joints are generally very small aperture, and scalability is poor, but there are several also great. Joints fill rarely, and the survey found jointed filling calcite, chlorite.(3) Achieving rock mechanical parameters by field rock sampling, experiments derived altered diorite average uniaxial compressive strength of98.8MPa, the measured elastic modulus of the average of4.42×104MPa, obtained the metamorphosed diorite strain values and Poisson’s ratio for subsequent research has laid a good foundation.(4) The acoustic properties of ore/rock field test show that the peak forest mining area-60m stoping in two surrounding rock loose circle range in roughly1.80m or so, the ore body of the average speed of longitudinal wave is roughly4035.50m/s. Longdong mining area-62m level of roadway surrounding rock loose circle two range around2.40m, the marble rock set of p-wave average speed of3625.90m/s; According to the research area of roadway loose loose circle range of1.80～2.40m, the study area can be roughly calculated length of roadway bolt support can be reference design is2.10～2.80m.2. The instability mechanism of roadway surrounding rock analysis(1) The main form of instability of roadway surrounding rock:tensile failure, local rock fall failure, shear failure and composite failure and shear failure, deliquescence expansive destruction, destruction of rock burst.(2) The factors affecting the stability of the dominant, ground stress, groundwater and the integrity of the rock mass surrounding rock roadway cross section, the quality of the surrounding rock materials, as well as the comprehensive factors.(3) The main indicators which influence the stability of surrounding rock of roadway, composition and structure of surrounding rock are the basic factors affecting the stability of surrounding rock; Development characteristic tectonic structural planes are the dominant factors affecting the stability of surrounding rock; Control factors of the stability of surrounding rock influenced by rock weathering degree and alteration degree; To determine the stability of the roadway surrounding rock tunnel buried depth is one of fundamental factors; The groundwater is also have certain influence to the stability of surrounding rock; Span affect the stress state of roadway surrounding rock of roadway, have an effect on roadway support design index selection; Easy cause of adjacent tunnel surrounding rock loose blasting disturbance, crack or failure.3. The unstable area roadway instability of numerical simulation(1) Unreasonable excavation and supporting sequence is one of the important factors affect cross drift instability, based on the numerical simulation of different types of cross tunnel excavation process study the following pattern: a. To cross, cross Y numerical simulation analysis of roadway excavation:cross tunnel choose different excavation sequence, roadway surrounding rock mass of stress and strain of different roadway. Cross tunnel after excavation roadway excavation should choose the small deformation and stress concentration for optimal excavation order less order. After digging a tunnel to the support, and then the excavation and roadway intersection.b. Deformation characteristics of roadway surrounding rock significantly related to the construction process. Therefore, in the design and construction of crossing roadway must analyze each addition, unloading process, when comparing different addition, unloading order due to the scope of the plastic zone of roadway, the results of the stress distribution and displacement of surrounding rock deformation of roadway, choosing the best unloading of excavation sequence, so as to optimize the construction method and the optimization of supporting measures, to ensure the roadway intersection in construction period and operation period of security and stability.(2) The contact zone in ore characteristics and mechanism of roadway surrounding rock instabilitya. In the study area of the current level of mining section roadway section size and shape, the most and can keep the stability of surrounding rock of roadway, although after the excavation will produce secondary stress field, but for iron ore, marble, diorite and other hard rock of mining roadway, for these hard rock itself strong enough to resist cause additional stress after excavation.b. In the ore-bearing rock contact zone, and other general location of weak lithology structure damage to shear failure along the contact zone horizon, relative roadway centerline asymmetry; Local mild piece for two gang, stress, high with the further transfer of appeared from the wall of plastic zone, if the strength of the stress concentration exceeds the yield strength of surrounding rock, this time will produce new plastic zone, plastic zone will appear as the new plastic zone and the further development of continuously.(3) Because of loose powder ore structure, physical and mechanical properties is poor, low intensity, so detrimental to the stability of surrounding rock of roadway.(4) Peak forest mining roadway stability numerical simulation shows that the roadway crossing and ore-bearing rock contact zone is the main area of roadway stress concentration, the results of numerical calculation and field investigation discovers the identified unstable regions in the study area. Unstable area roadway instability mechanism of in-depth analysis can provide reliable basis for the stability of roadway supporting.4. The underground mining roadway surrounding rock stability control technology(1) Unstable area of roadway surrounding rock stability control technologya. In the actual engineering practice, can be used in a numerical simulation analysis method, to determine the optimal excavation sequence of cross tunnel, to ensure the stability of the tunnel after excavation, and carries on the supporting design, avoid the production of instability of roadway collapse, carry out the production safety, to improve mine economic benefit and social benefit. b. Anchor reinforcement to reduce the effect of the shear and tensile damage is obvious. Sprayed concrete to reduce the tensile failure is better than that of bolt support, but in terms of resistance to shear failure is more efficient than bolt. Under the joint support by rockbolt and shotcrete in complementary advantages, shear and tensile damage zone and the plastic zone of surrounding rock has decreased to a certain extent.c. The forepole method. Powder ore in the roadway drivage program is commonly:consider directly in a stability better location for temporary support after excavation, in powder ore district, it must adopt advanced support, which is the first insert some mine i-steel constraints along the roadway to the top, then dug out ore, setting temporary support followed by.d. To optimize roadway support type and structure of powder ore size. According to characteristics of powder ore roadway surrounding rock stress, increase the stability of roadway can be used in a curved wall instead of straight wall, increase the wall thickness, increase the bottom arch and improve the reinforcement of these methods. In powder ore roadway bolt on top of the arch reinforcement effect is limited, if the reasonable design of anchor parameters, is has certain effect on side wall reinforcement.e. Increase powder ore roadway stability is the key to improve construction method. Adopting the following measures can effectively avoid the generation of initial caving and the big gap in between surrounding rock and supporting structure:between the supporting structure and surrounding rock grouting and concrete backfill compacted; Improving the structure of the block like powder ore blasting parameters, and reduce the disturbance, finally jet sprayed concrete; Advance small duct grouting and pipe roof support measures available in powder ore structure and mixed structure powder mine.(2) Based on the analysis of the factors affecting the stability of surrounding rock of roadway, and studies the purpose and principles of classification index selection from the uniaxial compressive strength of Re, gap wall condition of structure surface, the measured RQD value of three indicators of daye iron mine roadway surrounding rock classification is made on the stability of the selection of the research region, determines the characteristics of surrounding rock of daye iron mine as learning samples of neural network. By using neural network nonlinear and with learning and memory function, using the training sample training network structure, the stability of roadway surrounding rock was established neural network identification model. Using the neural network has carried on the classification on the stability of surrounding rock of roadway.(3) Based on engineering analogy and indirect integral reinforcement design and calculation of spray anchor supporting design of drift intelligent system research, and making use of the Visual Basic6.0development and design of the system.(4) Describes the roadway surrounding rock grouting and rock anchor injection reinforcement effect, and according to the actual situation of the unstable region of daye iron mine stope, the grouting material and the anchor note equipment choice, the roadway anchor note construction method are introduced.Integrated use of rock mechanics papers, plastic mechanics, non-continuum mechanics, underground engineering, engineering geology and modern mathematics, computer programming and other disciplines related theories focus on analysis of Daye Iron Mine underground mining roadway stability, development and design spray-anchor support intelligent systems. Thesis topics are multidisciplinary, involving a wide range of features, but the research needed for the construction of China’s national economy, for the construction of underground mining Daye Iron provide a theoretical basis and technical support, research results with a more important theoretical and engineering applications value.Comprehensive analysis of existing research results, the paper in the following two aspects innovative:(1) Integrated use of analytical methods and numerical methods studied Daye Iron Mine Roadway destroy underground mining laws and instability mechanism. Based on numerical simulation method to determine the optimal cross the roadway excavation sequence analysis of ore at the contact zone of roadway surrounding rock with lithological weak structure characteristics and mechanism of instability.(2) Application of Visual Basic6.0development and design of the tunnel spray-anchor support intelligent systems. Knowledge-based artificial intelligence program, follow the analogy support design engineering design methods and analytical thinking, the use of non-linear neural network learning and memory functions, the use of the network structure of training samples to determine the NN model; using neural networks roadway stability was graded based on indirect engineering analogies and overall reinforcement design calculations, using Visual Basic6.0development and design of roadway spray anchor intelligent systems. Thesis research in underground mining roadway damage law, instability mechanism and control technology has made some progress, but in practical engineering, geological environment in which the rock mass and its own internal structure is very complex, if to better understand the law underground mining roadway damage and failure mechanism, the following aspects of the issues to be further studied:(1) in the use of numerical simulation method roadway ore at the contact zone Instability Mechanism, it neglected the impact of the surrounding roadway, and ore at the contact zone will be the stability of surrounding rock roadway surrounding the impact of relief, so during simulation, resulting in unevenness of the boundary conditions.(2) underground mining on mine roadway failure regularity and geological formations, rock pressure, the relationship between space exploration needs further study to examine the common mechanism of action.(3) In this paper, the use of three-layer neural network model MBP roadway surrounding rock stability classification, using three indicators, namely rock RQD value, compressive strength and jointed wall-gap state. However, the factors affecting the stability of surrounding rock far more than three, therefore, in future studies, the choice of classification index to be further optimized. |
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