Frozen-wall design is a success prerequisite for the freezing method, few literatures have reported, however, that side-wall displacement convergence affects frozen-wall thickness design. To consider the influence of side-wall displacement convergence, the Column-hole expansion theory was used to derive the complete formal solutions on stress and displacement for plastic frozen wall and elastoplastic unfrozen formations, and a calculation formula of frozen-wall thickness was established. An engineering case was studied by three methods, to verify the correctness of the established formulas. The effects of horizontal ground pressure, cohesion and internal friction angle of frozen soil, elastic modulus and Poisson's ratio, cohesion and internal friction angle of unfrozen soil on side-wall deformation and frozen-wall thickness were analyzed. The results show that the frozen-wall thickness difference is about 8.6% and side-wall deformation is about 0.17 at 800 m depth, considering the influence of well side displacement convergence or not, for the fully plastic frozen wall and elastic formation mechanical model. The new formula has high theoretical significance and practical value in predicting the side-wall deformation for a kilometer topsoil shaft.

Abstract：In view of the problems of the traditional design mode of the main drainage pump room, such as complex layout, many links, long construction period and late equipment maintenance, this paper puts forward the optimization scheme of using the suction pool instead of the distribution well, the distribution lane and the suction well. After the design and optimization, the whole main drainage pump room is only composed of the pump room and the suction pool, and is applied in the second level main drainage pump room in the eastern area of Guqiao Coal Mine. Compared to the traditional scheme, the construction period is shortened by about 30 days and the cost is reduced by 18.9%. Practice has shown that the scheme has the advantages of a simple layout,less links, complete functions, greatly reduced construction period and construction cost, and provides considerable economic benefits and good safety benefits for coal mine production.

In the mining area of Guizhou, the ecological environment is fragile, and the topography is complex, most of them are low and medium mountain monopoly ridges, so the 11071 working face of Panzhihua coal mine in this typical geological condition is used as the background of the study. This method improves the recovery rate of coal resources and reduces the impact of coal mining on the environment and surface of the mine area, which has important application value. Through theoretical analysis and calculation, the width of retained coal pillar a is not less than 20m, and the strip mining width b is 25m~35m, and the surface deformation characteristics of three strip mining solutions are studied by numerical simulation method, and the "mining-retaining" solution is integrated and preferred. The effect of different replacement rates on the movement of the overlying rocks was studied, and the replacement rates were determined reasonably according to the conditions of the overlying rocks to maximize the resource recovery rate. The results of the study show that the solution of "mining 35m and leaving 30m, replacement rate 25%~50%" is the most reasonable, the secondary deformation of the ground surface is not obvious, and the ground surface deformation is in line with the standard of building damage level Ⅰ.

In order to effectively solve the technical problems in the design of large mining height release top coal mining in extra thick coal seam, due to the hard top coal and the working face is above the hollow area, resulting in small mineral pressure, large coal blocks in the process of coal release, poor venting, low recovery rate, etc., we adopt deep and shallow alternating borehole hydraulic fracturing technology to weaken the top coal in the extra thick hard coal seam, and conduct industrial test in Jinshan Coal 13101 working face, through FLAC3D Numerical simulation and field monitoring were used to analyze the effect of hydraulic fracturing. The results show that the hydraulic fracturing technology of alternating deep and shallow boreholes in the extra-thick hard coal seam can effectively destroy the integrity of the hard top coal seam, enable the top coal to fully collapse and recover, and shorten the cycle pressure step, reduce the working resistance of the fracturing range bracket, and the maximum size of the top coal block after fracturing drops from about 800 mm to less than 300 mm. The maximum size of the top coal block after fracturing is reduced from about 800 mm to less than 300 mm, and the recovery rate of the released top coal is increased by 11.3%, which realizes the safe and efficient production of the working face and the full recovery of resources. The technology of hydraulic fracturing to weaken the extra-thick hard top coal provides a technical way and direction for similar engineering design.

Abstract: Combining with the increasing mine production scale，hoisting capacity and hoisting equipment，the paper introduces the design of the structure of the main shaft tower of Hulusu coal mine，summarizes the Loads and combination of loads and special frame calculation of equipment for large diameter and deep vertical shaft．

In order to optimize the relocation parameters of No. 3 raw coal semi fixed crushing station in Shengli West No. 2 open-pit coal mine, the development of stope and waste dump engineering positions in each year is deduced through the preparation of the mining schedule, and then the appropriate relocation time node of No. 3 crushing station is analyzed and determined. Two methods of relocation cost compensation and weighted cost minimization are proposed to determine the economic and reasonable relocation step of No. 3 crushing station. The indexes such as raw coal resources, raw coal truck transportation distance, belt transportation distance and service life of the crushing station in the mining block are calculated and determined when the No. 3 crushing station is moved at different distances, and the reasonable moving distance of the No. 3 crushing station is calculated and determined. The research results show that the relocation time point of No. 3 crushing station is before April 2026, and the relocation path is to retreat along the layout direction of the belt transportation system at the east side of the stope, with a relocation distance of 1200 m. At this time, the relocation cost is compensated, the weighted cost is minimal, and the economic effect is good.

In view of the instability problem of the coal column roadway in Fucun Coal Mine under the complex geological conditions of the secondary mining, theoretical analysis, numerical simulation and field measurement were conducted. The main work and conclusions are as follows. The technical parameters of dense drilling top cutting are rationally configured according to the theory of masonry beam. A numerical model of different coal pillar widths was established. The stress evolution characteristics of the coal column and roadway under the influence of mining was studied. The rationality of the top cutting parameters and the reinforcement and support scheme were verified. A mineral pressure monitoring system including the content of the monitoring of roadway surrounding rock deformation, roof off-layer monitoring, anchor rod (cable) force monitoring and the development monitoring of the internal cracks of the surrounding rock has been established. The results show that the top-cutting pressure relief scheme has successfully prefabricated the noncontinuous artificial weak surface. The stress state of the roadway surrounding rock has been optimized. The disturbance of coal pillar stress caused by rock covering movement is weakened.

The pre-tightening force of bolt plays an important role in maintaining the stability of surrounding rock in coal roadway. However, the instability of roadway caused by the loss of pre-tightening force in field engineering generally occurs. In this paper, the transformation relationship between bolt pre-tightening torque and pre-tightening force is analyzed. The phenomenon of bolt pre-tightening force loss in Wujiagou Coal Mine is studied. The characteristics and causes of bolt pre-tightening force loss behavior are revealed, and the influence of bolt on surrounding rock stress and displacement distribution under different pre-tightening force loss rates is explored. The results show that there is a linear positive correlation between the pre-tightening torque and the pre-tightening force. However, due to the friction between the supporting components and the surrounding rock conditions of the roadway, the average loss rate of the pre-tightening force of the bolt ranges from 20 % to 58 %. The increase of the loss of the pre-tightening force of the bolt can lead to the decrease of the stress of the shallow surrounding rock of the roadway, the increase of the deformation of the surrounding rock and the depth and volume of the plastic zone, and the decrease of the bearing capacity of the surrounding rock. This study can provide guidance for on-site bolt pre-tightening construction and improve the stability of roadway surrounding rock at the initial stage of support.

In order to solve the problem of large deformation of surrounding rock under the conventional support condition of roadway in fully mechanized top coal caving face with extremely soft and easily broken coal seam in Huaibei mining area 8# seam, based on the support surrounding rock synergy mechanism, the "drilling, bolting and leveling" support technology of roadway in fully mechanized top coal caving face with extremely soft and easily broken coal seam is proposed, which is based on roadway bottom breaking and slope lowering + bolt advance support + anchor cable support + advance grouting + flat roof U-shaped steel shed support. It has been applied in Xinhu and Wobei coal 8# seams in Huaibei mining area. The field application shows that the roadway support effect is good after using the "drilling, anchoring and leveling" support technology, which can effectively control the large deformation of the roadway surrounding rock in the extremely soft and easily broken fully mechanized top coal caving face, and the tunneling speed has been greatly improved, which has great guiding significance for the props of the same type of roadway.

In order to improve the mine water disaster prevention and control technology, based on the summary of the drilling construction in Chensilou Coal Mine for many years, the deflection mechanism and law of the borehole for underground floor grouting transformation are statistically analyzed. The results show that the error between the vertical inclination of the borehole and the vertical depth of the final hole point is the largest, the azimuth deviates to the right, and the deviation is relatively small, which is easy to form a blank zone and affect the effect of water disaster control. By analyzing the influencing factors of coal seam floor lithology and different BHAS, a complete set of comprehensive drilling deviation correction measures are put forward, such as increasing the guide, giving priority to the use of threaded drill pipe, controlling the drilling speed and feed pressure during lithology change, and strengthening equipment maintenance, which greatly improves the accuracy of drilling construction and reduces the invalid footage, The cost of mine water disaster control is saved, which provides a basis for the next water disaster prevention technology and guides the mine safety production.

In order to further understand the roof movement law of fully mechanized mining face with large mining height in yuheng Mining area. Based on the microseismic monitoring technology, a joint monitoring of surface and underground micro-seismic monitoring network is constructed., the roof movement law under the influence of four influencing factors including initial pressure, periodical pressure, “single side square” and mining speed in the first working face of Dahaize coal mine is studied. The results show that the peak of roof breakage is generally 1 day ahead of the first pressure; Continuous correlation between frequency of roof rupture and periodic weighting; The correlation between roof fracture strength ( energy ) and periodic weighting is weak when weighting strength is less than 17 000 kN; The peak value of roof rupture appeared at 26 m before “single side square”, and the roof activity gradually stabilized after 16 m; When mining speed is less than or equal to 1.6m/d , the roof fracture is always at a low level ; when mining speed is 2.4m/d~6.4m/d, the roof fracture gradually increases, and the upper limit of fracture strength increases obviously. When mining speed is more than or equal to 7.2m/d, the lower limit of roof fracture strength is significantly increased compared with that in the medium-speed mining period.

The 11# coal seam return roadway of Fujiawa coal mine is seriously affected by the mining movement of the adjacent working face, and the roadway is prone to deformation, which affects the safe production of the mine. In order to ensure the safe and smooth recovery of 11207 working face and the smooth excavation of 11205 working face, hydraulic fracturing technology was used to cut the top plate and unload the pressure in 11207 return airway, weaken the hard rock layer on the top plate of 11207 return airway, shorten the overhanging top distance, optimize the stress distribution in the adjacent working face and reduce the impact on the adjacent roadway. Through on-site research and observation by drilling peeper, it was found that there were multiple intact rock layers and composite top slab in the roof of 11207 backwind roadway, so the design used backward segmental fracturing to weaken the intact rock layers in the roof slab, and specific drilling and fracturing parameters were determined. Based on the collapse situation of the working face, drilling peephole situation and adjacent working face roadway formation, the effect of hydraulic fracturing at working face 11207 was comprehensively analyzed. The results show that with the use of hydraulic fracturing section, the collapse step of the retrieved working face is controlled at about 8m, the fracture development of the borehole is obvious, the adjacent roadway is not significantly affected, and the control of the hard roof is achieved.

As the scale of coal mining is gradually shifting to the deep in China, the problems of gas prevention and the exploitation and utilization of coalbed methane (CBM) resources in deep coal mining remain to be resolved urgently.Taking Sihe mine in Jincheng, Shanxi Province as an example, the stress distribution, fracture evolution and permeability change of the underlying strata of No. 3 Sihe Mine Field after mining pressure relief were analyzed. The feasibility of reducing gas content by surface extraction of CBM from the lower coal group has been studied, and research on the deployment method of surface extraction CBM wells from the lower coal group, drilling techniques and drainage key technologies has been carried out.The results showed that the permeability in No. 15 lower coal group has been increased by about 2.20 times, which is beneficial to the surface CBM pre-drainage of No. 15 coal seam. According to the requirements of CBM development project, based on the method of comprehensive analysis of surface wells, the deployment of CBM extraction wells in the horizontal wells of the lower coal group through the coal wedge was optimized, the structure of the three section drilling well body was conceived, the design of borehole trajectory and drilling trajectory control technology was evaluated, and drilling technologies such as drilling fluid system, leak plugging and graded cementing process of fracture development section for different drilling layers was investigated.In order to effectively reduce the wear resistance of the string in the drainage of L-shaped horizontal Wells, the technology of "well buttoning positive + two-way protection rod collar prevention eccentric wear + guider torque reduction" was adopted. The maximum daily gas output of the horizontal well through coal pillar of the lower coal group is 9522 cubic meters, and the cumulative gas output is 2.2 million cubic meters within 14 months. The gas production effect is ideal, which proves the feasibility of the technology and has a certain degree of implications for CBM exploitation of the lower coal group in the research area and the similar areas in China.

In order to solve many problems such as a wide variety of equipment and different equipment operating systems and data protocols caused by different equipment manufacturers in the process of intelligent construction of thin coal seam comprehensive mining face, taking the 12422 comprehensive mining face of Ulanmulun Coal Mine as an example, the characteristics and equipment layout of the comprehensive mining face of thin coal seam were analyzed, and combined with the relevant guidance requirements for the intelligent development of coal mines, an underground 5G communication network was established, the operating system of Kuang Hong was transplanted into the equipment of the comprehensive mining face of thin coal seam. The results show that the system unifies the data interface and data protocol standards between the equipment, realizes the interconnection between the equipment and the intercommunication of information, and the successful application of the Kuang Hong operating system in the comprehensive mining face of the 12422 thin coal seam not only improves the mining rate of the thin coal seam, but also enables operators to control the equipment through the intelligent explosion-proof mobile phone.

The open pit mining plan preparation has defects such as inflexibility and complexity of operation in the parallel advance mining and stripping mode. To solve the problems caused by these defects such as poor preparation results, mining quality fluctuations and long preparation period, an automatic preparation method of open pit mining plan in this model is proposed. The solution idea is determined by the overall architectural design, and then the automatic programming mathematical model is constructed for this model. The results show that the generated schedules are highly automated, less subjective and disturbed by subjective factors, and can obtain the optimal schedule preparation results under current conditions. It can be proved that this open pit mining plan automatic preparation method is applicable to parallel advance mining and stripping mode. The deviation value of each component target is small, and the results are fast and stable. It can bring high economic benefits to the production of mining enterprises.

The problem of roofing at the end face of a large mining height intelligent integrated workface is investigated. Starting from the mechanical system of the support surrounding rock, the pressure in the columns and balance jacks of the brackets under the three different conditions of overhead mining, back mining and horizontal mining are analysed to adjust the distribution of the support resistance between the columns of the brackets, so that the point of combined force of the hydraulic brackets is shifted forward and the support resistance of the front beam is improved to reduce the risk of roofing and improve the continuity of the rock at the end face, which can The purpose of controlling the top of the slab is achieved. Through the analysis of the example, the risk of endface caving is reduced and the production quality of the working face is ensured.

The depth of floor failure zone is a key parameter in the design of mine floor water hazard prevention and water inrush risk assessment. Due to the difficulty of deep exploration work, the measured data of deep floor failure zone depth is extremely scarce, which brings great difficulties to the floor water control work of deep mining. By means of downhole borehole water pressure test and borehole imaging test, the depth of floor failure zone was measured on the complete area and broken area of the floor in the deep working face of Linxi Mine respectively. Numerical simulation method is used to study and analyze the development law of floor failure depth under the condition of faulted and non-faulted floor.. The research results show that: under the condition of no faults in the floor, the development of floor failure depth has experienced the evolution law of "increase-stability" with the advancement of the working face; Under the condition that the floor has faults, the development of the failure depth of the floor has experienced the evolution law of "growth-stable-sudden-increase-stable" with the advancement of the working face; The development of faults in the floor will deepen the depth of floor failure zone; The actual measurement determines that the depth of the failure zone in the complete area of the bottom floor of the deep working face is about 23.58m, and the depth of the failure zone in the fractured area of the fault is about 37.45m. The research results will have important reference value for most mines facing deep mining water hazards.

In order to solve the vibration problem of the rocker arm in the cutting process, taking MG500/1130-WD shearer as the research object, a method of vibration characteristic identification of the rocker arm based on strain mode was proposed.The Block Lanczos method was used to conduct modal analysis on the rocker arm housing, to obtain the first 10 natural frequencies of the rocker arm of the coal miner, and to analyze the 2-order modal resonance characteristics of the rocker arm housing and the transmission system.According to actual working condition of cutting,three - way cutting load and three - way cutting resistance moment of cutting drum are obtained by EDEM simulation, based on the ADAMS - EDEM - ANSYS joint simulation dynamics of the rocker, the rocker arm 2 order strain modal natural frequency is 63.98 Hz,built rocker arm strain data acquisition system,start experiments about the strain response of key section of rocker arm and anaylze the data in time and frequency domain. The results show that the error of the second order natural frequency of the rocker arm obtained by strain modal analysis and co-simulation is 0.52%, and the error of the modal analysis and experiment of the second order natural frequency of the rocker arm is less than 5%.The strain modal analysis method can effectively identify the low natural frequency and low frequency excitation of the shearer rocker arm and provide a new idea for the vibration research of shearer rocker arm.

Mine pressure prediction is the key and difficult point of coal roof disaster prevention. At present, the popularity of hydraulic support electro-hydraulic control system makes the pressure data can completely and quickly reflect the change of roof pressure. However, due to the large amount of data and many interference information, it is difficult to complete it only by manual analysis. In view of this situation, a method that can automatically extract the cycle cycle, predict and divide the pressure area of the support pressure data is designed. Firstly, according to the working characteristics of the hydraulic support, design rules, and extract the pressure data under normal working conditions as the cycle data. Then, through the clustering method, combined with the pressure data of each support, the significant pressure area is divided. Finally, the LSTM algorithm is used to predict and analyze the cycle pressure data. The feasibility of this method is proved by practice, which provides ideas for the study of mine pressure law and safe mining.

In view of the deficiency that the current research on the hole layout parameters of roof directional long drilling is only to determine the drilling layout horizon and horizontal range, taking the 21215 working face of Dongpang mine as the engineering background, the vas pumping model of roof long drilling under five different layout modes is established by using COMSOL numerical simulation software, and the drilling layout mode of "normal spacing of 2 m and horizontal spacing of 3 m" is determined according to the simulation results. According to the height of fracture zone in 21215 working face, the layout parameters of drilling holes are designed, and the feasibility of hole layout parameters is verified by using the formula determined by the horizontal position theory of drilling holes. The field application results show that in the mining process of the working face, there are stable stage and attenuation stage in the roof directional long drilling drainage. In the attenuation stage, the drilling drainage effect decreases and the gas concentration in the upper corner increases. The analysis is due to the reduction of the drilling height and the destruction of the drilling integrity. On the whole, the gas concentration in the upper corner during mining is 0.3% ~ 0.4%, which is at a low level, indicating that the drainage effect of roof directional drilling is good. This arrangement effectively solves the problem of gas concentration overrun in the upper corner.

Aiming at the problem of excessive dust concentration in fully mechanized excavation face, taking the fully mechanized excavation face of Sima Coal Mine in Changzhi, Shanxi Province as the research object, a simulation model of double air curtain ventilation system formed by parallel outlets was established. The standard k-ε turbulence model was used in the air phase, and the DPM model was used in the particle phase to simulate the air flow field and dust field near the fully mechanized excavation face. The research shows that the double air curtain ventilation system generates two independent air curtains in front of the driver under the Conda effect of the air outlet guide plate, and the first air curtain near the dust production point blocks most of the dust generated during the operation in the main control dust area. The second air curtain is located between the first air curtain and the driver to form an auxiliary control dust area to further intercept dust; when the angle α of the upper and lower deflectors is 45 °, the height H of the air outlet is 30 mm, and the distance L of the air outlet from the fully mechanized excavation face is 10 m, the dust concentration in the breathing zone is the smallest. Comparing the dust control and dust removal performance of the double air curtain ventilation system with the traditional long pressure short pumping ventilation system, it can be seen that the dust concentration in the breathing zone is much lower than that of the latter, and the dust removal rate is increased by 84 %. The research results prove that the double air curtain ventilation system can effectively reduce the problem of dust diffusion from the heading face to the roadway, and provide a new ventilation method for dust removal in the fully mechanized heading face．

The residual void ratio of the goaf is an important technique parameter for stability evaluation of foundations above the goaf and the design of the backfill grouting scheme. In order to determine the reasonable value of the residual void ratio in the underground knife pillar goaf below the new substation, the discrete element software of UDEC was used to simulate the collapse characteristics of the overburden for the 2# coal knife pillar goaf, and the simulated caving height was 9.0m. Considering the bulking effect of caved gangue, the residual volume of the block within the caving range of the gob is obtained by using a self-defined fish function, and the average residual void ratio was 0.233 in the caving zone of the 2# coal knife pillar gob. Based on the simulated residual void ratio, the backfilling grouting volume of the goaf under the substation was predicted to be 25267m3, and the deviation between the predicted result and the actual injection volume was only 5.4%. Finally, it can be concluded that the simulated residual void ratio can represent residual void degree in the caving area of the goaf left by knife pillar method, and this method can provide technical reference for goaf treatment by backfill grouting.

As a chain drive system, the scraper conveyor is the main transportation equipment for coal production. The safety and reliability of the chain link will affect the entire fully mechanized mining work. To study the wear resistance and contact effect of the chain links, the ML-100C abrasive particle wear testing machine was used to conduct the counter-grinding test for different chain links materials under different heat treatment processes to study the wear resistance of different samples. Based on the wear information of the chain links in a ten-million-ton coal mine in Shendong, the models of the chain links with different wear levels were established, and the equivalent stress and deformation of the links were analyzed by the finite element method. The results show that the content of C, Cr, Ni, Mn and Mo in the alloy material is relatively increased, and the selection of a reasonable heat treatment process can effectively increase the wear resistance of the chain links by 10%-25%. The stress of the flat link is mainly concentrated on the shoulder, the outside of the curved arm and the inside of the straight arm, and the stress of the vertical link is mainly concentrated on the outside of the curved arm and the transition section between the straight arm and the curved arm. The deformation of the flat link and the vertical link is reflected in the contact part, and the deformation of the flat link is about 1.9 times that of the vertical link.

With the wide application of hydraulic technology in underground coal mines, sand charging and pressurization hydraulic technology has become a new demand for the application in many fields in underground coal mines, but the lack of applicable sand fracturing pump seriously restricts the development of technology. In order to provide scientific and reliable technical parameters for the design and development of underground sand fracturing pump group in coal mine, through the research and analysis of the characteristics of underground working space in coal mine, the design idea of underground sand fracturing pump group with split module and string arrangement is proposed, and the shape control parameters of split module sand fracturing pump group are given; Through the systematic analysis of the water and power supply conditions in the coal mine, the upper limit of the hydropower capacity of the sand fracturing pump group in the coal mine is defined; The fracture pressure of coal seams in mining areas of many provinces in China is statistically studied. Based on the analysis of the rock breaking principle of water injection fracturing and the work principle of fracturing pump, the preset values of the output pressure and displacement of sanding fracturing pump are proposed, and the preset values are verified and verified by simulation test through the calculation of fracturing pump power, physical test of pipeline sand carrying flow and numerical simulation test of fracture sand spreading. Finally, the control dimension of the split module of the sand fracturing pump applicable to the underground coal mine is finally obtained, the height should not exceed 2.0m, the width should not exceed 1.4m, the power supply voltage should be 1140V or 3300v, the operating pressure of the pump unit should not be less than 30MPa, and the reasonable range of output displacement should be 1~1.5m3/min, which provides a design basis for the design and development of the sand fracturing pump in the underground coal mine, It also provides a reference for further research on the technology of adding sand and boosting hydraulic pressure in underground coal mine.

The underground environment of Shendong mining area is humid, the mine water is weakly alkaline and the composition is complex, so the corrosion of underground anchor cable is very serious, which directly affects the service life and support safety of anchor cable. In order to study the influence of the main ions in the mine water of Shendong mining area on the accelerated corrosion of the underground anchor cable, and clarify the main factors and corrosion mechanism of the accelerated corrosion of the anchor cable in the underground environment, this paper takes the Bultai mine of Shendong mining area as the engineering background, and obtains the characteristics of the underground environment and the content of six main ions in the mine water through field survey, water quality sampling and chemical inspection, and carry out accelerated corrosion salt spray experiment to study the main ion composition and corrosion mechanism of the anchor cable in the Shendong mining area mine water, and evaluate the influence of the main ions in the mine water on the accelerated corrosion of the anchor cable by using four indicators: corrosion morphology, mass loss rate, sectional area loss rate and mechanical property attenuation. The experimental results show that the corrosion reaction of the underground anchor cable in Shendong mining area is oxygen absorption corrosion, and Cl- has the greatest promoting effect on the accelerated corrosion of the anchor cable. The corrosion degree of the six main ions in the mine water from large to small is Cl->SO42->CO32->F->Mg2+>Ca2+, revealing the mechanism of the accelerated corrosion of the underground anchor cable, which is of great significance to the support design of the underground roadway and the study of the service life of the anchor cable.

Aggregate betting is over under high-velocity and dynamic water conditions, and the timing of the start of grouting has always been a difficult problem for the on-site staff. The determination of the initial deposition position of the grout under different dynamic water flow rates is to design the aggregate betting scheme and inspect the grouting seal. The key to blocking effect. In this paper, a theoretical model of slurry sedimentation and migration is established by considering the interaction between discrete particles and moving water; a dynamic water grouting test is carried out based on a self-designed laboratory test system, and the initial diffusion and transport form of the slurry in the pipeline is discussed. The relationship between the initial deposition position of the slurry and the flow rate of water, the water-cement ratio and the inner diameter of the pipeline is discussed, and the laboratory test results are compared with the theoretical results. The research results show that: the initial deposition position of the slurry is positively correlated with the dynamic water flow rate, water-cement ratio and the inner diameter of the pipeline; the impact of the dynamic water flow rate and the inner diameter of the pipeline on the initial deposition position of the slurry is greater than that of the water-cement ratio; experimental and theoretical model calculation results Basically the same.

ZDY20000LK large diameter pressure relief drilling rig is developed to solve the problem that the large diameter pressure relief drilling hole of coal bump can only meet the expected pressure relief requirements through the construction technology of one drilling hole and multiple reaming. The drill has the function of automatic loading and unloading drill pipe and 800m remote control. It can improve the safety and reduce the labor intensity of workers during construction. The project also studied the drilling rig with φ 260mm large spiral insert drill pipe and φ 300mm tower PDC bit, which can meet the requirements of coal side pressure relief drilling with a diameter of 300mm. The industrial test shows that the average drilling efficiency of the drill reaches 10min/m and the maximum hole depth is 81m, which fully verifies the reliability and stability of the rig structure, hydraulic system and remote control system. Electromagnetic CT detection shows that the large diameter pressure relief boreholes weaken the coal body, so that the impact risk of coal body in the abutment pressure area of the roadway is significantly reduced, and the smaller the spacing of pressure relief boreholes, the better the pressure relief effect. The research results can be used as reference for the development of large diameter pressure relief drilling equipment and the construction of rock burst pressure relief drilling.

In order to test the life of drilling equipment, a drilling / torsional loading test system is designed, and the hydraulic system is analyzed and the structure is optimized. Firstly, according to the working conditions of the equipment, the test bench model and hydraulic principle are designed for the most important thrust and torque. Then, the sudden change of thrust and torque in the process of use are simulated by using random signals to control solenoid proportional relief valve. The performance analysis and thermodynamic analysis of the hydraulic system are carried out to verify the reliability of the system, and the heat dissipation performance of the system is ensured by adding fans. Finally, the static analysis and fatigue analysis of the system test bench are carried out, and the maximum stress and deformation of the test bench are obtained. According to the calculation results, the test bench is reasonably optimized. The analysis results show that the system can well simulate the working conditions of drilling equipment, and the improved hydraulic system and test bench can meet the design requirements.