Experimental Study About Influence Of Thickness Of Unconsolidated Sediments And Rock Layers On The Height Of Fracture Region Induced By Coal-mining

In this paper, the influence of thickness of unconsolidated sediments and rock layers on the height of fracture belt induced by coal-mining are studied by means of theoretical analysis, similar material model test and numerical simulation based on the geological and cavating data from Yu-Shen-Fu Coal Mining Area ,so as to rationally utilize coal resources, prevent and control geological disasters, protect groundwater resources,and contribute to the harmonious development of resources, environment and economy.Yu-Shen-Fu Coal Mining Area are divided into five engineering geological subareas according to the spatial distribution patterns of sand, loess and rock layer on the main coal seam. Quaternary Salawusu group and the metamorphic rock by self-igniting are the main aquifers in Yu-Shen-Fu Coal Mining Area, therefore both the subarea of sand- loess -rock and the one covered with the metamorphic rock by self-igniting are the main areas to protect groundwater resources in coal cavating process.Hoek-Brown rule can be applied to describe the rock deformation during coal cavating. For shallow burying thin coal seam, when the ratio of sand and rock is less than 0.6, the maximum height of the fracture region can be forecasted by formula when it is greater than 0.6, there will be all strata-falling down. For other situation, the fracture region can be forecasted by formula The forecasted results of the fracture region in some typical districts by the formula above are consistent with the actual observation and simulation tests.