Research On Settlement And Slope Stability For Coal Gangue Embankment In Expressway

Coal gangue is the waste of coal mining industry. Now, a growing number of coal gangue was piled up in the mountains and plains around the mining area, which not only occupies a amount of useful land, but also cause environmental pollution and geological disasters. A number of countries and regions in the world have begun to explore the way of comprehensive utilization of coal gangue, and achieved initial results. In this paper, combined with the transportation technology projects of Hunan province (project number:200908) and based on the coal gangue of ShaPing coal mine along the AnShao expressway, the physical and mechanical parameters of coal gangue was obtained through indoor test. Through the way of combining these basics with theoretical research, field test and numerical analysis, coal gangue embankment settlement and slope stability problems was researched and then obtained the following research results:(1) Conducting site surveys on AnShao expressway coal gangue embankment construction section, and collected along the hydrological, geological and meteorological data. Selecting coal gangue of ShaPing coal mine as samples for laboratory tests and then obtained the parameter of natural density, grain composition, natural water content, liquid and plastic limit, shear strength, CBR and chemical constituents.(2) Problems such as mineral composition, classification and nomenclature, spontaneous combustion, chemical activity and environmental pollution is summaried through literature investigation work(3) The coal gangue embankment construction is simulated by using FLAC3D software, which obtained the stress field and displacement field of the coal gangue embankment. Stress and sedimentation changes of coal gangue embankment is analysed upon the parameters of the degree of compaction, the filling height and covering soil thickness. Dynamic response of coal gangue roadbed under traffic loads is researched through the dynamic calculation module of FLAC3D. (4) Based on the measured value of settlement of coal gangue embankment, coal gangue embankment settlement is calculated through the method of curve fitting and grey system theory. Moreover, evaluation results upon fuzzy and random reliability theory shows the results of settlement prediction curve is close to the true value and the fuzzy failure probability is in the reasonable scope.(5) By introducing the concept of seepage force into simplified Bishop theory and unsaturated soil strength theory, the calculation formula of coal gangue embankment slope safety factor under rainfall seepage is deducted. The preliminary check shows that the calculation formula is a pplicable.