Research On Mining Deformation Mechanism And Damage Evaluation Index Of Express Highway

With the rapid development of economy in China,the road network is becoming more and more perfect.It is inevitable to encounter traffic safety problems caused by coal mining under highway.In order to scientifically predict the damage degree of highway caused by coal mining under highway,optimize the technical scheme of coal mining subsidence control under highway and ensure the safety of highway transportation,it is necessary to master the law of deformation and destruction of highway under the influence of mining and establish a reliable prediction and early warning system of highway deformation in mining area.By combining theoretical analysis,analogous material simulation,numerical simulation and field investigation with field measurement,this paper systematically studies the deformation and failure mechanism of high-grade highway under the influence of mining,the law of synergistic deformation of foundation,subgrade and pavement,the deformation characteristics and damage index of high-grade highway,and the monitoring and prediction of settlement and deformation of highway,with the aim of revealing the high-grade highway.The mechanism and law of mining deformation,the index of mining deformation and damage and classification index of high-grade highway are formulated.Then the safety monitoring and prediction system of high-grade highway in mining area is established by dynamic monitoring of coal mining area and prediction model of highway subsidence.The main results are as follows:(1)Through similar material model test,the development process,form and deformation characteristics of roadbed deformation and failure during coal mining are simulated and studied.The research shows that mining affects the subsidence deformation of roadbed from bottom to top and gradually develops to pavement.The deformation process has basic continuity in space and lags behind in time.The degree of deformation is partly offset by the strength of highway structural layer,resulting in the gradual reduction of settlement and the gradual increase of horizontal displacement.In the early stage of mining,the layers of roadbed,pavement and foundation subsided continuously and synchronously with the mining of underground coal face,and the moving direction of each layer in roadbed was consistent.With the increase of stratum subsidence,the subsidence of each layer of roadbed also increased significantly,and there was no obvious separation layer development and deformation cracks in roadbed.(2)The increase in pavement thickness is helpful to improve the stability of pavement structure,increase its ability to resist deformation.The results show that with the increase of pavement thickness,there is a stable mathematical relationship between the highway and foundation subsidence and horizontal movement.Firstly,the subsidence value of the road surface will increase to a certain extent,but the range is limited.However,the horizontal movement of pavement decreases with the increase of pavement thickness.The tensile stress decreases with the increase of pavement thickness,and the compressive stress increases with the increase of pavement thickness,which is beneficial to keep pavement structure stable.(1)Pavement stiffness is an important factor affecting the highway deformation characteristics in the mining area,the greater the pavement stiffness,the greater the subsidence difference between the pavement and the subgrade,the more serious the pavement damage is under the action of traffic load;The range and value of the horizontal movement of semi-rigid pavement and rigid pavement are generally larger than the horizontal movement value of foundation.Affected by mining,the distribution law of additional horizontal stress generated in the subgrade and pavement is basically the same.The stress value of the pavement is far greater than that of the subgrade.The extreme value of the pavement tensile stress increases to a certain value with the increase of the extreme value of the foundation deformation and then no longer increases and remains constant.Rigid pavement has strong resistance to deformation,but too much stiffness can easily cause separation between pavement and subgrade.Under the impact of vehicle load,once the maximum tensile strength is exceeded,a small deformation will cause its breakage.(2)The increase in pavement thickness is helpful to improve the stability of pavement structure,increase its ability to resist deformation.The results show that with the increase of pavement thickness,there is a stable mathematical relationship between the highway and foundation subsidence and horizontal movement.Firstly,the subsidence value of the road surface will increase to a certain extent,but the range is limited.However,the horizontal movement of pavement decreases with the increase of pavement thickness.The tensile stress decreases with the increase of pavement thickness,and the compressive stress increases with the increase of pavement thickness,which is beneficial to keep pavement structure stable.(3)The pavement material is different also affects the highway anti-deformation ability,the rigid pavement material horizontal compression stress and compressive stress is obviously greater than the semi-rigid pavement material index value,so the rigid pavement anti-deformation ability is strong.(4)The highway and the goaf relative position is different,the highway main deformation direction and the deformation process has the obvious difference.With the increase of the included Angle between the highway strike and the advancing direction of the working face,the extreme value of the longitudinal deformation of the road surface increases,and the horizontal movement value of the line first increases and then decreases.(3)Combined with similar material simulation and numerical simulation results,the deformation and failure process and development mechanism of foundation,roadbed and pavement caused by mining subsidence are analyzed.Taking the nantun well field section of the zoucheng-jining first-grade highway as the research object,the relationship between the damage degree of the lower semi-rigid base asphalt pavement and the surface(foundation)deformation under the influence of mining is analyzed by using the numerical simulation results and field measured data,and the mining deformation and failure grading index of the high-grade highway is developed.(4)Based on D-InSAR technology,leveling measurement and GPS measurement data coupling,and combined with mining subsidence prediction technology,the mining area highway monitoring,prediction and early warning system is constructed.And through the SBAS time-series analysis has carried on the data processing technology,improved the precision of data utilization and regional monitoring,optimization of the mining subsidence model parameters is expected probability integral method,improves the forecast accuracy of mining damage of highway and for highway transportation department under the state council in coal mining subsidence control and security early warning and provides scientific basis.