Analysis Of The Subgrade Settlement Above The Goaf Under Traffic Loading

In areas where mineral resources are abundant,more and more highways have to be built around the mined-out area or through the mined-out area.Mined-out area affects the properties of overlying strata.The gravity and traffic load will result in settlement,tilt,horizontal movement and other surface deformation,which lead to road surface cracking,even a large area of collapse and other damages.At the same time affecting the normal operation of the road causesadverse social impact.In order to ensure the normal operation of the highways in mined-out area and reduce the losses caused by the disaster,before the construction of the highways in mined-out area the settlement law of the subgrade above the mined-out area which provides a reference for the preliminary design and construction of the actual project is analyzed taking the construction and reconstruction of the 323 line in mined-out area of Henan province as the backgroundwith the help of numerical simulation software,considering the influence of traffic load and the relative position of mined-out area and subgrade and traffic overload.The main contents and main conclusions of this paper are as follows:(1)The distribution of rock formation is carried out on the site of the project area and the drilling and sampling are carried out.The theoretical analysis is carried out by using the formula and the stratification method to lay the foundation for the numerical simulation.(2)Based on field survey to carry out software simulation,Comparing analysis of whether the mined-out area of two states,overlying rock settlement changes in the law.In the dynamic loading cycle time,the existence of mined-out area will speed up the time of overlying rock into the plastic deformation,and the shorter time to enter the plastic deformation of the goaf.The settlement of the overlying strata presents a process from decreasing to steady and then decreasing again,which is in accordance with the division.(3)Changing the mined and subgrade different locations in vertical depth and lateral spacing,and analyzing the Subgrade Settlement in Different Relative Position.When the depth of the mined-out area is 20 ~ 60m(the subgrade level is 0m),the settlement of the roadbedchanges greatly,and the change is less obvious at 60 ~ 80 m.The lateral settlement of the goaf is in the range of-18 ~ 10m(the right foot of the road is right).The trend is weakening,which determines the application of the project under the dynamic load under the critical safety zone.(4)Through the survey of traffic volume,the heavy load on the highway section is determined,and the roadbed settlement deformation of the roadway under the action of heavy load and standard axle load is studied,the mined-out area road is more likely to be damaged than the normal road.The longer the heavy load is,the shorter the time of destruction and the larger the settlement is.At the same time,through the actual survey to determine the heavy load simulation,the results can be got: the time reloaded by the mined-out area roadbed is shorter than that of the standard axle to achieve damage,and the uneven settlement value is greater.So in the mined-out area Restrictions on heavy vehicles.(5)According to the observation of the field test section and the simulation data,it is found that the field data and the simulation data are consistent with the curve,which proves that the simulation results are resonable.The simulation data is applied to repair and maintain the road during the operation,which has certain reference significance to the actual project.In this paper,the study of roadbed settlement in goaf can be used in the planning of road route of goaf in the early stage,which is of great reference significance for the maintenance and maintenance of roadway in goaf.