Research On The Supporting Technique Of Gateway With Limestone Roof Interbedded With Mudstone Interlayers

The hard limestone roof contains uncertain amount of soft mudstone interlayers at different position.“Trapezoidal I-steel shed+Wooden backboard”passive support method is a traditional support method for such roofs.However,lower utilization of the roadway section,high cost,slowly construction speed and intensive labor are seriously restricting the tunneling construction of such roadways.The reliability,economy,and simple construction flow of the bolt technology make this active support technology the first choice for coal mine roadway support.This paper takes 10203 mining roadway of Tongfuxin Coal Industry Co.,Ltd which belongs to Jinneng Group as the engineering background.Through the observation and field sampling of the surrounding rock,according to the development degree of the joint crack and the position of the weak mudstone interlayers among the limestone roof,combined with the requirements of the bolt length for the bolt construction,the surrounding rock of the roadway is classified.Targeted support scheme is adopted to achieve differential support of surrounding rock at different locations in the same roadway.The 10203 mining roadway of Jinneng Group Tongfuxin Coal Industry Co.,Ltd.is the object of the research.Using the sample of field drilling,the physical and mechanical parameters such as uniaxial compressive strength,uniaxial tensile strength,internal friction angle,elastic modulus and Poisson's ratio of the rock were measured experimentally.Using FLAC^3D numerical simulation software,the numerical simulation of different distances of the weak interlayer from the coal seam roof was carried out,and the distance critical value to classify different types of surrounding rock was determined.Using the same numerical simulation method,the deformation laws of roadway surrounding rock when different types of roofs are adopted with different support schemes are analyzed,so as to determine each type of roof support scheme and roof protection method.On this basis,the optimization of support parameters for different support schemes,including the spacing and arrangement of bolts and cables,and the design of roadway support construction drawings for different support schemes are made.Through field test verification,the traditional“Trapezoidal I-steel shed+Wooden backboard”was changed to targeted bolt support,which greatly reduced the cost of roadway support and sped up the roadway construction.And the surrounding rock control is effective.