The Analysis And Research On The Effect To The Freeway Engineering Caused By The Gob Of Daliu Coal Mine

With the rapid growth of the economy in China, a large number of high grade highways are being constructed all over the country. When the freeways were being constructed, the geologic engineering problem of the gob of the coal mine would be fallen across inevitably.Based on the background of the item of"The stability analysis and research of Da Liu mined-out area in the west section of Xu Zhou ring highway of Jing-Fu freeway",the observation data of the ground and pier subsidence passing through the freeway were analyzed, and the method of prediction subsidence were taken to forecast the residual deformation at the center of the freeway by the researching in the character of geological mining and geological engineering. At the same time, FLAC3D were used to simulate the influence on the freeway causing by the gob of the coal mine. It can concluded from the research work as follow:(1)Above the Da Liu mined-out area, the ground deformation is present as the broad and gentle subsidence basin. The observation data of subsidence shows: the subsidence deformation was small in the two edges while large in the center of the freeway. The maximum subsidence of the ground is 42.5mm; the maximum subsidence of the pier of the super large bridge crossing Long Hai railway reach to 35mm. The subsidence prediction method shows: in the center of the freeway, the maximum residual subsidence was 92mm; the maximum residual horizontal displacement was 29mm; the maximum residual incline was 0.25mm/m; the maximum horizontal residual deformation was 0.21mm/m; the maximum residual curvature was 0.016×10-3/m2.(2)The results of FLAC3D numerical simulation show that the stresses were concentrated in the end region of the mined-out area, and the distribution of the stresses was characterized by changing along the direction of strata's inclination. The surface subsidence trend was nearly consistent with the results of prediction methods, and the strata on the raising direction moved upward comparing to the original horizon plane. slight ascending was obtained on the surface toward the uphill,the position of the maximum subsidence was lean to the downhill.(3)After the analysis of the engineering geological conditions and surface observation data on the gob of the coal mine, there still have the possibility of activation for the mined-out area. Considering the results both of prediction and FLAC3D numerical simulation, the mined-out area may have less influence to the highway's roadbed but larger to the super large bridge. Some engineering control measures should be taken according to structural characteristics of super large bridge crossing the Long-hai railway.In this paper, the stresses redistribution, surface movement and deformation characteristics of the overburden rocks in the mined-out area were analyzed deeply, and the evaluation on the influence of the mined-out area was made, and some treating measures and methods were put forward for the Da-liu mined-out area and super large bridge crossing the Long-hai railway. There are certain depth in theoretical research , and the conclusions also have some practical meaning for the coal mining and building protection above the gob.