Research On Water Disaster Prevention And Surrounding Rock Reinforcement Technology Of Roadway Passing Through Fault

During the construction phase of coal mines,there is often a construction problem that roadways pass through fault fracture zones.Due to the poor integrity of the surrounding rocks in the fault fracture zone,it brings great safety hazards to the tunneling construction,especially the water-rich fault,where the fracture zone is directly connected.The upper aquifer leads to the connection of the upper and lower waterways.When a coal mine tunnel passes through a fault,it is easy to cause water inrush and roof fall,causing the mine to be flooded and casualties.Based on the engineering background of the concentrated return airway passing through the F6water-rich fault in the lower 1 coal and fifth mining area of the Ehuobulak Coal Mine,this paper systematically studies the rich water-rich faults through advanced detection,numerical simulation,and engineering practice.Water and water conductivity,and use numerical simulation to analyze the stress changes and deformation characteristics of the water-rich fault zone.The numerical simulation results are used to guide engineering practice,and a reasonable engineering scheme design is proposed for the return air tunnel crossing the F6 fault.The main research content and conclusions obtained in the thesis are as follows:（1）Based on hydrogeological data,conduct advanced detection of fault fracture zone and surrounding rock.The main methods adopted are ground magnetic exploration,transient electromagnetic exploration of underground working face,and advanced drilling exploration of working face.The exploration results show that the F6fault is a high-water-rich fault.The fault zone has connected the upper sandstone aquifer.The aquifer has a relatively large water supply.It is dynamic water with stable water volume and cannot be completely drained in a short time.（2）Using FLAC^3D numerical simulation software to analyze the stress and deformation of the engineering example,the following conclusions are drawn:（1）The fracture zone of the fault is inconsistent with the stress gradient of the surrounding rocks of the two walls,and the stress at the interface between the fault and the two walls is the most concentrated.During tunneling,the stress will continue to increase.The stress inside the fault is smaller than the stress at the interface position.（2）In the process of tunnel excavation,the range of 5-15m behind the tunnel face is the position of maximum deformation.At the interface between the fault and the two disks,the deformation of the bottom plate is greater than that of the top plate,while inside the fault,the deformation of the top plate is greater than that of the bottom plate.This shows that at the interface where the stress is relatively concentrated,the bottom heave of the bottom plate is greater than the sinking amount of the top plate.Inside the fault fracture zone,due to changes in the stress gradient,the fracture zone’s fractured rock mass blocks the internal stress transfer of the surrounding rock,while the fracture zone has poor integrity and poor physical and mechanical properties,resulting in the roof subsidence greater than the bottom heave volume.（3）Comparative analysis in the case of reinforcement shows that after the fault fracture zone is reinforced,the stress gradient decreases,and the maximum stress value increases by about 20%,but the deformation decreases to 60%of the pre-reinforcement.The stress at the interface between the fault and the two disks is slightly reduced,but the amount of deformation is narrowed by about 30%.This shows that the integrity of the fault is better after reinforcement,and the stress transmission effect is increased.（3）Refer to the numerical simulation results to design the scheme design of the centralized return air roadway crossing the F6 fault in the No.1 coal No.5 mining area of the Ehublak Coal Mine.Set up a full-section grouting pipe（also used as a pipe roof）at the fault interface position where stress concentration occurs during the simulation excavation process,and implement double-row grouting pipes for the largest deformation area in the middle of the fault to ensure that the grout diffusion radius meets the requirements of the reinforcement range.Aiming at the problem that the lithology of the two plates is soft and easy to be muddy,easy to fall,and the grout is difficult to spread,the traditional single grouting scheme is broken,and the construction method of one drilling and two grouting is adopted.To give full play to the advantages of different materials,first use a cement-water glass double-liquid slurry with poor permeability to reinforce the surrounding rock,and then use a chemical slurry with a better permeability to plug water in the fissures of the surrounding rock.（4）After the reinforcement construction,the drilling method is adopted to verify the reinforcement quality and water blocking effect.Drilling data shows that grouting has a very good effect on breaking and improving the surrounding rock,and the integrity of the surrounding rock is improved.However,the single-hole water output and total water output of the fault are greatly reduced,and the water pressure is reduced to 1/16 of the expected,which can meet the normal excavation conditions.During the tunnel excavation process,the tunnel deformation monitoring is used to guide the construction,optimize the construction parameters,and ensure the safety of the construction.The smooth implementation of the centralized return air tunnel in the F6fault in the lower 1 coal and 5th mining area of the Ekhobrak Coal Mine also proved that the design scheme is feasible.The paper has 57 pictures,15 tables,and 61 references.