Strata Deformation Induced By Drainage On One Side Of Shaft And Its Influence On The Shaft In Thick Topsoil

The vertical shaft is the main throat for underground and ground transportation in mines,and its safety status is directly related to mine production and personnel safety.Therefore,it has always been the focus of engineering and scientific researchers.Since1987,there have been nearly 120 cases of vertical compression failure in vertical shaft walls in China’s deep topsoil layer;in recent years,a new form of failure has occurred in vertical shaft shafts of thick topsoil and thin bedrock,namely vertical shaft shafts Deflection occurs at the same time of compression,and the mechanism of deflection of the wellbore is still under study,and it has not been fully studied and understood.Carrying out the study on the influence of one-sided drainage of the wellbore on the wellbore and the surrounding strata under the conditions of deep topsoil will provide a reference for further in-depth disclosure of the shaft deflection mechanism and the development of the prevention and control technology of the wellbore deflection,and therefore has certain theoretical significance And engineering value.Based on the background of the shaft deflection accident of Guotun Coal Mine,this paper mainly uses numerical simulation and model test methods to carry out the following preliminary research.First,a numerical simulation study on the deformation law of the vertical shaft and surrounding formation under the condition of unilateral drainage.Based on the three-dimensional numerical model of drainage in the wellbore and surrounding formations,five factors including drainage distance(distance from drainage area to the centerline of the wellbore),depth,velocity,aquifer thickness and inclination angle were investigated on the deformation of the wellbore and surrounding formations Influence law;Through orthogonal calculation and analysis,the primary and secondary relationship of the influence of 5 factors on horizontal deformation of vertical shaft and surrounding stratum is:Drainage depth H(m)>Drainage distance L(m)>Drainage rate Q(m~3/h)>Aquifer thickness Z(m)>Aquifer inclination angleθ(°);through the comparison analysis of single-sided mining typical calculation and single-sided drainage drainage,it is found that the influence of single-sided drainage drainage on shaft deflection is not tolerated ignore.Secondly,based on the similarity theory,the penetration force was used to simulate the vertical self-weight stress field in the soil layer,and a similar model test was carried out under the condition of one-sided drainage of the soil layer around the shaft shaft in a depth of 30m.In order to use the ramming effect to simulate the self-weight stress,the hydraulic gradients of standard sand and silty sand at different ratios were tested through experiments,and the silty sand quality contents were 0%,5%,10%,15%and 20%,respectively.Head loss of 1m along the penetration.Under the ratio of 5%silty soil mass content,a one-sided drainage drainage-induced formation settlement and horizontal movement centrifugation test of the wellbore topsoil layer with a geometric shrinkage ratio of 1:30 was carried out;the drainage drainage distance and depth were studied and analyzed There are three factors,velocity,which affect the deformation of vertical shaft and surrounding formation.The comparison analysis of indoor similar model test and numerical simulation verifies the influence of the unilateral drainage of the wellbore on the deformation of the wellbore and surrounding strata.Within the range of research values,the drainage rate,drainage depth and aquifer thickness are positively correlated with strata movement deformation and deflection deformation of the vertical shaft;the drainage distance and aquifer inclination have a positive effect on the formation displacement and deflection of the vertical shaft.The influence of deformation is:with the increase of the drainage distance and the aquifer inclination,the deformation of the stratum movement and the deflection of the vertical wellbore increase first and then decrease.The paper has 63 figures,tables 26 and 100 references.