Research On Mining Subsidence Laws Of Thick Alluvium Region In Northwest China

The northwest region is very rich in coal resources, many areas cover conditions forthick alluvium layer, overlying strata in mining conditions, the surface subsidence rule has itsparticularity, the law of surface subsidence research, has the vital significance to the northwestcoal mine safety mining.Based on the measured data of a plurality of thick alluvium mining area in NorthwestChina, through the FLAC numerical simulation experiments combined with thecharacteristics of mining under thick soil layer, analysed the influence in Northwest MiningArea under thick loose layer of surface movement and deformation characteristics of miningsubsidence damage.The data mining in thick loose layer analysis thinks, thick loose layer mining surfacemovement and deformation has the characteristics of fast development, quickly stable, activeperiod short, loose layer properties and thickness is an important factor affecting the surfacemovement regularity,and there is a significant correlation between the parameters of surfacemovement. In the thick loose layer of soft rock mining conditions, the loose layer with thebedrock fracture subsidence caused full thickness crack,which was cut into the block structure,forming a step shaped cracks in the surface.Using FLAC software, the different thickness of loess layer and different ratio of widthto depth of surface movement conditions were simulated,analyzed that: in the same bedrockthickness, maximum moving surface and moving range varies with the loose layer thicknesschange, change the subsidence coefficient of bedrock and unconsolidated layers with miningwidth to depth ratio the changes, through the numerical simulation of the quantitative relationship between the loose layer thickness, width depth ratio of mining.