Influence of Overburden Rock-soil Ratio on Mining Subsidence in Dabaodang Coal Field

Taking the overburden of 2^-2 coal in Dabaodang Mine Field of Yushen Coal Mining Area as geological prototype, 30 numerical models with different rock-soil ratio are established on the basis of regional geological occurrence conditions and 3 typical drillings. With the method of numerical simulation, the influence law of rock-soil ratio on the mining subsidence is researched under the same geological condition and mining technology. The results show that the subsidence coefficient could decrease with the increase of the rock-soil ratio in the 100 m and 200 m depth level; the overall trend of the subsidence coefficient could decrease when the rock-soil ratio increases (excluding the rock-soil ratio is 2:1) in the 250 m depth level. In different depth level, the impact extent of the rock-soil ratio on subsidence coefficient is different. According to the results of numerical simulation, the super thick soil that is more than 80 m could cut down the subsidence coefficient.