Research On The Technology Of Uncovering Coal And Preventing Outburst From Tunneling Through Coal Measures Strata

In the process of tunnel construction,when the stratum in the tunnel site area is relatively simple,the excavation and support of the tunnel is relatively simple.Mechanical excavation and drilling and blasting can be used for excavation.The support of the tunnel body is also easy to construct.However,in the west of China,there are abundant underground mineral resources and complex geological conditions.When excavating tunnels,coal seams are often encountered.Ground treatment can easily lead to related disasters such as cave deformation,coal and gas outbursts,and collapse of strata tunnels,causing double losses to the economy and employees.Therefore,this paper studies on the technology of uncovering coal and preventing outburst across the coal stratum tunnel.The two tunnels on the Zhengxi Expressway in Guizhou passed through coal-measure strata and faced problems such as coal and gas outburst and deformation of surrounding rocks.For these two typical coal-crossing tunnels,this paper collected relevant reference materials,then conducted on-site field investigations,and finally combined the theory and numerical simulation analysis to study the technology of uncovering and preventing outburst of coal through the coal stratum tunnel and the stability of surrounding rock.The main research contents are as follows.(1)Analyze the construction difficulties across the coal stratum.Through the collection of common construction accidents through the coal-based stratum tunnel,combined with the engineering profiles and geological conditions of the two tunnels on the Zhengxi Expressway,the safety hazards and influencing factors faced by the coal-based stratum tunnel are analyzed to provide basic data for subsequent research(2)Propose a design plan for the gas control work of high gas tunnel.With reference to the relevant regulations of highway tunnel construction,a gas treatment plan for the tunnel is proposed,and specific parameters and equipment models are determined through calculation to avoid the phenomenon of gas accumulation in the vault of the high gas tunnel and excessive gas concentration in the tunnel.(3)Study on the construction technology of uncovering coal and preventing outburst through coal tunnel.Combined with the actual situation,a coal uncovering plan is proposed,and regional outburst prevention measures and local outburst prevention measures are formulated.Regional outburst prevention measures include hydraulic fracturing to improve coal permeability and coal gas extraction to reduce the possibility of coal and gas outburst.(4)Study the stability of rocks surrounding tunnels passing through coal strata.Use MIDAS/GTS NX geotechnical numerical simulation software to establish a tunnel model,calculate and analyze the deformation and stress of surrounding rock and supporting structure during tunnel crossing inclined coal seam,determine the weak parts of the tunnel structure,and propose adjustment measures for the initial supporting structure of the tunnel.Figure 34 table 10 reference 84...