Analysis On Filling Effect Of Goaf Under Expressway Subgrade

Since entering the new century, especially after the12th Five-Year Plan Period of China, the highway construction is picking up. By the influence of such factors as the terrain and the energy consumption structure in China, more and more highways have to be constructed through coal mine goaf. According to the surface subsidence rule of goaf, the road would be influenced by goaf roadway more or less, in order to reduce these impacts, when a highway is being built, goaf must be disposed. But to choose what kind of filling, filling rate and filling amount of goaf roadway, to make sure of the dispose result in a acceptable range, is still a subject to be studied.In this paper, on the basis of consulting a large number of relevant literature, combined with the engineering practice of the first contract section K2+535-K2+650of a highway, the main results are as follows:(1)Related literature was reviewed by time sequence and evaluation field respectively, the advantages and disadvantages of each method were analyzed and the existing problems at present were studied; The subsidence moving rule and deformation influencing factors of goaf surface and mechanism were analyzed, the factors were divided into6categories;(2)Physical and mechanical model of goaf roadway under highway was established, four cases of pavement subsidence rule were studied by FLAC3D simulation respectively in whether there is water seepage in surrounding rock or vehicles on surface of the highway road, as a result, the most unfavorable situation was determined;(3)Orthogonal experiment scheme was determined on nine experiments, from three factors, which are filling, filling rate, filling quantity and each factor with three levels, on the basis of experimental results, the significant influence sequence of factors was identified using range and variance analysis, what’s more, optimum filling scheme was determined;(4)Further four joint control measures were disposed by analyzing optimization scheme, and numerical simulation analysis were conducted after adopting the control measures, to verify the validity of the control measures from maximum subsidence and subsidence trend of the pavement respectively.