Study On Survey Technology Of The Steep Goaf Under Expressway And Its Impact On Stability Of Embankment

In recent years, with the high-speed development of economy, mineral resources were extracted steadily, a large number of steep mined-out area was formed in xinjiang region. With the increasing investment in infrastructure construction, highway construction was developing rapidly and traversing the steep mined-out area inevitably. Therefore, it is very important to study the movement and distortion rules of the steep goaf under expressway. However, the study on interaction of the expressway and the steep goaf underneath was very less, and the theory was not yet mature. To study deeply on the movement and distortion rules of underlying steep goaf’s impact on the expressway and layers. Relying on steep seam goaf of highway-ring around urumqi(eastern) in xinjiang region, by means of the theoretical research, the job-site-survey, the model test and the numerical simulation, steep mined-out area prospecting technology was compared after analysis, and embankment of the steep mined-out area under expressway stability was studied, the main research contents are as follows:(1) Aim at the steep seam goaf of highway-ring around urumqi in xinjiang region, based on the existing technologies of mined-out area prospecting, high density resistivity method and transient electromagnetic method were used to survey in the field, and the geophysical anomaly points were drilled and provided verification, geophysical interpretation results were in good agreement with those obtained in the borehole, it is concluded that high density electrical method and transient electromagnetic method for steep mined-out area prospecting has a good applicability.(2) According to similarity theory and model test, the similarity constant of large scale physical model test is determined. Through the test of physical and mechanical properties similar materials, determine the proportion of similar material of quaternary gravel layer: M: soil sand m = 1:2, ρ = 2.0 g/cm3, ω = 10%, petroleum jelly content of 6%; the proportion of similar material of reasonable weathered sandstone: M: soil sand m = 1:2, ρ = 2.2 g/cm3, ω = 10%.(3) According to the theoretical research and relying on the construction site actual situation, choose the first contract section K23+220 ~ K24+70 small kiln of mined-out area, by changing the influence factors such as mining thickness and coal seam dip Angle, different conditions is simulated. Through the original embedded in soil model test and fixed observation of soil vertical displacement, using the data from tests of subgrade and strata displacement curve, embankment and ground movement deformation regularity are obtained.(4) Establish the FLAC3 D numerical model, monitor displacement of survey point, analysis of the results of numerical simulation, through comparing the model test with the numerical simulation, result in the impact on stability of embankment of layer thickness, dip Angle of coal seam, and the overlying layer thickness, determine the influence rules of steep seam goaf to embankment and strata.