Experimental Study On Seepage And Deformation In Deep Unconsolidated Layer In East China

Deep unconsolidated layer compression caused by groundwater exploitation is the mainreason surface subside, the phenomenon universally exist all over the world. Large number ofcities and regions in our county subsidcd due to groundwater extraction. The bottom aquiferof the wellbore area with water level continued to decline in East China affected by a longtime continuous drainage and discharge of the wellbore in the coal seam and led to groundsettlement, and many Wall Fracture caused by greater compressive deformation ofunconsolidated layer. The main reason is water level of quaternary water-bearing layerdecreased and inadequate supply. Research law of unconsolidated layer seepage deformationand discover water injection of loose layer can improve unconsolidated layer of settlementgovernance means and reduce for loose ground settlement deformation caused by geologicaldisasters, which has very important significance.Based on the geological features of deep unconsolidated layer bottom aquifer, this paperanalyzed bottom aquifer seepage law, established bottom aquifer hydraulic coupling model,researched bottom aquifer effective stress distribution and improved unconsolidated layerdeformation calculation model.Designed deep unconsolidated layer of seepage and deformation simulation test deviceand monitoring system based on the principle of Darcy law and hydraulic similarity theory.Calculated on the size of the model and verified the model intensity. Analyzed unconsolidatedstratar gravel particles by experimental, researched configuration of model material.Measured and calculated seepage parameters applied test device. Experimental study on themodel seepage and deformation law and model effective stress distribution characteristics.Verified deep unconsolidated stratar seepage and deformation theory and test research byengineering test. The paper introduced four water injection tests in Jining No.3Coal Mine.Analyzed bottom aquifer strain changes during water injection tests. Researchedunconsolidated layer stable injection time and injection scope. Established a effective stressdistribution evaluation method for waterflood of unconsolidated layer.Research shows that ratio D20test model material meet the seepage and deformation model test. Increased injection depth in the vertical direction of unconsolidated layer couldincrease water injection sphere. Increased water injection rate could be increased stratumdeformation stability. The evaluation method of stratigraphic effective stress distribution canpredict the stress concentration zone of unconsolidated layer, which provide the basis for deepunconsolidated layer injection outcome evaluation and wellbore deformation prediction.