| Lane 5102 of Yongdingzhuang Mine in Datong Mining Area is affected by the intrusion of igneous rock.The surrounding rock of the roadway is characterized by low strength,fracture development,support structure failure,etc.Especially under the influence of dynamic pressure,the deformation of the roadway will further increase.In this paper,the deformation and failure laws and characteristics of the surrounding rock of the roadway in the igneous rock invasion area are analyzed by means of on-site investigation,drill hole peeping and surrounding rock loose zone testing.Combined with the on-site engineering geological conditions,the ordinary anchor cable grouting support technology is proposed and the reinforcement scheme of the roadway in the igneous rock invasion area is designed.Through numerical simulation and comparative analysis of the roadway displacement,stress and plastic zone distribution,the appropriate roadway reinforcement scheme is selected,And through indoor experiments,suitable grouting reinforcement materials and ratios were selected,and mine pressure monitoring was conducted to compare and analyze the tunnel displacement,roof separation value,and anchor cable stress of the reinforcement anchor cable support scheme and the ordinary anchor cable sealing grouting reinforcement support scheme.The feasibility of the ordinary anchor cable sealing grouting reinforcement support scheme was verified.The main findings of this paper are as follows:(1)Through drilling observation and testing analysis of surrounding rock loosening zones,it was found that the roof of the roadway and the surrounding rock within 0-2.6m of the shallow sides are severely fractured,with a high degree of crack development.Within the range of 2.6-5.2m,the surrounding rock is relatively intact,with a significant decrease in crack development and a decrease in the number of cracks.The size of the loosening zone is between 2.3-2.8m and is a typical large loosening zone;The tunnel simulation analysis shows that as the 8102 working face advances,the vertical stress peaks of the coal pillar and working face sides are 19.5MPa and 21.3MPa,respectively;The maximum displacement of the top and bottom plates,as well as the two sides,is 735.5mm and 852.3mm respectively;Within the range of 0-6.2m,the failure of the surrounding rock of the tunnel is mainly shear failure.(2)According to the theoretical analysis,the reinforcement of broken surrounding rock by grouting with ordinary anchor cable sealing holes can significantly improve the mechanical parameters of surrounding rock,such as cohesion,internal friction angle,and then improve the shear strength,tangential stiffness and normal stiffness,thus enhancing the self bearing capacity and integrity of surrounding rock,and ultimately effectively controlling the destruction of surrounding rock;According to theoretical calculations,the support strength provided by ordinary anchor cable sealing grouting support is 7.9-20.4MP,which is significantly greater than that provided by ordinary support.(3)Through indoor experimental comparison and analysis,it was found that the compressive strength and setting rate of PO42.5 ordinary Portland cement and PO52.5 rapid setting Portland cement reached their maximum values at a water cement ratio of 0.5.Compared with PO42.5 ordinary Portland cement,the compressive strength of PO52.5 rapid setting Portland cement exceeded 23.2% and the setting rate was 4.58% higher;The water precipitation rate and fluidity of PO42.5 ordinary Portland cement and PO52.5 rapid setting silicate reached their maximum at a water cement ratio of 1.0.Compared to PO42.5 ordinary Portland cement,PO52.5rapid setting Portland cement has a 6% higher fluidity and a 24.28% lower water precipitation rate;PO52.5 rapid setting Portland cement has the shortest setting time at a water cement ratio of 0.5,with initial and final setting times of only 17 minutes and 25 minutes,respectively.In engineering practice,it can significantly shorten construction time.(4)Through numerical analysis of the two reinforcement schemes and the original support,it was found that the reinforcement anchor cable support scheme and the ordinary anchor cable sealing hole grouting reinforcement support scheme reduced the maximum roof and floor displacement of the roadway by 62.9% and 87.8% respectively compared to the original support scheme;The maximum displacement of the two groups decreased by 62.5% and 86.9%respectively;Compared with the original support scheme,the plastic area of the surrounding rock in the tunnel is reduced by a maximum of 28.9% in the ordinary anchor cable sealing hole grouting reinforcement support scheme.(5)According to the analysis of mining pressure data during the mining period of Tunnel 5102,as the mining face advances,compared to Scheme 1,the maximum displacement of the top,bottom,and two sides of Tunnel 2 decreases by 66.3% and 65.7% respectively,the maximum displacement of deep and shallow base points decreases by 66.7% and 60% respectively,and the maximum separation value of the roof decreases by 50%;The ordinary anchor cable sealing grouting section did not experience anchor cable detachment,and the force on the anchor cable also tended to normal level,fully exerting the anchoring performance of the anchor cable.It can be seen that the stability of the surrounding rock of the tunnel is well controlled.This paper has 48 images,9 tables,and 75 references. |
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