Study On The Strategy And Technology Of Highway's Construction In Mined-out Region

The existence of mined-out region bring great impact to the highway's construction and operation. The deformation of mined-out region is non-uniform ,large and dynamic development.Therefore, the research of structural design methods and the road construction technique adjust to the deformation of mined-out region has great significance.When the residual subsidence of mined-out region develops slowly, this paper proposes four kinds of pavement structures of classified highway in mined-out region and two kinds of pavement structures of freeway. This paper studies on the impact of structure layer thickness on the maximum tensile stress in structure layers and choose the best pavement structures of classified highway and freeway.This paper calculates and analyzes the subgrade reinforcement technology using inorganic binder and geogrid with FLAC 3D software. The research indicates that inorganic binder used in the lower part of subgrade is better and the thicker the better. Geogrid in the subgrade can greatly reduce the lateral displacement, but hardly reduce the vertical displacement. The location of Geogrid layers and the layer numbers have significant impact on reducing the lateral displacement of the subgrade. When the geogrid is in the middle of the subgrade, the impact is better than other locations. It is better when the layer numbers are large.Study on the effect of foundation treatment with Anti-pressure berm and dynamic consolidation, the results with FLAC 3D show that, when the thickness of Anti-pressure berm is certain,the maximum transverse displacement of subgrade top surface will reduce gradually with increase of anti-pressure berm's width, in other word, the greater width of anti-pressure berm the more effective for the lateral displacement; when the width of Anti-pressure berm is certain, the maximum transverse displacement of subgrade top surface will increase gradually with increase of anti-pressure berm's thickness, that is the lower of anti-pressure the more effective. Foundation treatment with dynamic consolidation could reduce both the horizontal displacement and vertical displacement effectively.The research has a considerable social significance to improve the road traffic safety and reduce road maintenance costs in mined-out region. It provides guidance for the road planning and design in mined-out region.