| With the construction and development of China’s transportation industry,the proportion of tunnels in the entire transportation system has gradually increased,and it is more obvious in the southwest region.The geological conditions also pose more problems for tunnel construction,accompanied by gas,coal seams and highlands.A series of complicated problems such as stress.Gas outburst accidents in tunnels in coal strata usually cause casualties and economic losses.Outburst accidents in gas tunnels are random and segmental.How to ensure safety is what we have to consider.Due to the actual situation,sometimes it is necessary to build a coal-penetrating tunnel.Therefore,the gas problem greatly affects the safety of the tunnel construction and later operations.Among them,coal and gas outburst are particularly strong in tunnel accidents.At present,the tunnels in our country mainly reserve a certain safety rock pillar during the coal uncovering process to ensure the safety of the construction.After the outburst of the coal-bearing stratum section is eliminated,the safety rock pillar is excavated,and then Through the use of reasonable excavation methods to uncover coal,so as to achieve the purpose of safe construction.Therefore,the study of the stability of rock pillars based on catastrophe theory is of positive significance for the safe passage of coal measures strata section,and has a guiding help for theory and engineering.In this paper,combined with the Yang Jiaoao Tunnel of Zheng Xi Expressway,the construction was simulated using MIDAD / GTS simulation numerical simulation software,and a reasonable value of rock pillar thickness and coal seam uncovering method was obtained.Based on the analysis of related researches at home and abroad,this paper proposes a method suitable for Yang Jiaonao Tunnel’s uncovering coal through numerical simulation.Based on the Yang Jiaonao Tunnel of Zheng Xi Expressway in Guizhou Province,this paper has carried out the methods of combining literature review and field investigation,theoretical analysis,on-site monitoring,numerical simulation and other methods to develop the technology of uncovering coal outburst of Yang Jiaonao Tunnel of Zheng Xi Expressway the study.The main research contents are as follows:Based on the Yang Jiaonao tunnel,an analysis and study was carried out based on the catastrophe theory on the stability of the rock column.The method of numerical simulation was used to analyze the reserved safety rock column in the tunnel under the conditions of different coal seam inclination and gas pressure,and the coal bed The relationship between the minimum value of the rock column and the gas pressure under different spatial positions is fitted with a two-dimensional expression.The reserved thickness of rock pillars for gas outburst tunnels under other similar strata conditions will be promoted and applied.The method of numerical simulation is used to analyze the full-section method,the step method and the CD method.From the perspective of displacement comparison,a reasonable method for uncovering the coal seam is obtained.Based on the settlement results of numerical simulation,actual site conditions and economic considerations,it is considered reasonable to use the step method for the construction of the Yang Jiaonao tunnel.Reasonable design was made for coal uncovering and anti-burst in Yang Jiaonao tunnel.Including coal and gas outburst prediction,anti-outburst measures,effect inspection and coal uncovering methods. |
PDF Full Text Request