Analysis On The Influence Of Prestressed Bolt Support Parameters Of Deep Argillaceous Sandstone On Compression Arch Of Deep Roadway

With the rapid development of society and the increasing demand for energy,coal mining is gradually carried out in the deep.The deeper the roadway is,the greater the stress of the original rock,and the more complex the types and properties of rock layers become,which adds new difficulties to the support of underground roadway and requires a more safe and effective support scheme.In the support of underground coal mine roadway,bolt and cable support is the mainstream support method.Due to the different depth of roadway,different lithology and different size of roadway cross section,no support method is universal.Aiming at the 3238 bottom drainage project of xutuan coal mine in huaibei mining area,this paper studies the additional stress distribution of roadway and the formation and development of composite arch under the condition of argillite sandstone,and analyzes the typical displacement spatial and temporal distribution curve under the condition of composite arch formation.This paper mainly analyzes the influence of bolt support spacing on additional stress of roadway side,and the influence of bolt length on additional stress of roadway side.In order to make the study have practical significance,the muddy sandstone was selected as the research object.The tunnel cross-section was a straight wall semicircular arch,with a height of 1.6 meters at the top,a semicircular arch radius of 2.6 meters,and a length of 5.2 meters at the bottom.Bolt spacing is 800 mm,600mm,400 mm and 300 mm respectively.The stress of the original rock is taken as0 Mpa to analyze the distribution of additional stress.In the case that the additional stress forms a composite arch,the stress of the original rock is taken as 16 Mpa to analyze the spatial and temporal distribution characteristic curve of displacement gradient.The coordinates of the bolt in the numerical model in different schemes,the concrete support spacing,length and preload of the bolt are shown in the text.Using TXT text program,adjust the bolt spacing,the length and the pre-tightening force,using FLAC3 D numerical simulation software for numerical simulation of the view in the FLAC3 D model of additional stress nephogram,FLAC3 D file into Tecplot,using Tecplot software processing data,taking help of additional stress and displacement gradient data,in the end,taking the Origin to the data into the graph,and analysed.In this paper,the stability analysis of surrounding rock is mainly to analyze the distribution of additional stress and the change of horizontal displacement of surrounding rock.The additional stress analysis mainly considers the effect of bolt spacing on the superposition of additional stress,and the displacement analysis mainly considers the change of horizontal displacement of the side part.Finally came to the following conclusion:Bolt spacing is the main factor affecting the superposition of additional stress,followed by bolt length,preload,lithology,buried depth,and cross-sectional area of roadway.The smaller the bolt spacing is,the more obvious the additional stress is,the easier the composite arch is to form,and the more favorable it is to the tunnel stability.To sum up,the roadway with poor lithology and large buried depth needs to be more densely arranged with bolts.On this premise,the bolts should be arranged according to the actual situation of each roadway.This paper can provide a reference for engineering practice.