Study on construction technology of water blocking wall in hydrodynamic pathway of submerged mine

The process of blocking water by pouring aggregate into the water passage involves many mechanical evolution stages,people pay more attention to the water blocking effect than the project cost,which leads to the key technical problems of the construction process rarely involved.Based on the data of previous engineering cases,this paper analyzes the general construction process of water retaining wall,establishes a hydraulic model to describe the process from aggregate accumulation to grouting closure,puts forward the calculation method of relevant parameters,and studies the internal stress distribution and failure mechanism of water retaining wall.The results show that:①The construction of water retaining wall can be divided into four stages of macro hydraulic model:the pipeline flow model in water inrush stage,the pipeline flow and low-speed seepage model in aggregate pouring stage,the high-speed seepage and low-speed seepage model in aggregate topping stage,and the low-speed seepage model in grouting closure stage.②The aggregate grows in horizontal and vertical direction in moving water and has an equilibrium relation with the flow field.③Considering the factors of pressure difference,wall resistance,accumulation section resistance and initial setting time of slurry,the estimation model of accumulation section length is established,and the prediction method of roadway top velocity at different stages and the selection method of aggregate particle size are proposed.④The maximumshear stress in the water blocking wall occurs near the direction of incoming water.Compared with the whole length of the wall,the affected range of stress is only a small part of it.The larger the water pressure is,the larger the shear force and axial force are,but the distribution state,the range of influence and the peak position remain unchanged.The larger the ratio of elastic modulus of surrounding rock to wall,the more concentrated the distribution of shear stress,the closer the peak shear stress is to the direction of incoming water.When the maximum shear stress first reaches the shear strength,the shear stress will flow to the downstream until the equilibrium state is formed,otherwise the instability will be destroyed.