Research On Reservoir Dam Structure Stability And Anti-seepage Technology In Mined-out Area

The main cause of mine water disaster accidents is the instability and seepage damage of the goaf reservoir dam.Before the goaf water reservoir is put into use,the stability of the reservoir dam structure is analyzed and predicted,and anti-seepage measures are set in time to reduce The osmotic pressure and the amount of water seepage around the dam are the key to ensure the safe operation of the mine underground water reservoir.The stability of the dam structure of the groundwater reservoir in the mined-out area and the selection of the optimal anti-seepage measures are very important for the orderly operation of the coal mine underground reservoir.Goaf Reservoir is an environmentally friendly water conservancy project in the mining area.It uses the underground space formed after coal mining as the main water storage area.Due to the complex and variable geological environment of the coal mining process and the mining area itself,the service environment is poor.The area is bound to be limited by these environmental conditions,so it is easy to form damage areas after the completion of the mining operation;the safety coal pillars in the damaged area retained by the mining operation are used as the dam structure of the underground water reservoir,and its stability and seepage are difficult to analyze directly;Therefore,in actual operations,the experiment and FLAC 3D numerical simulation should be carried out simultaneously and the data and conclusions should be compared:the experimental process through field sampling on the spot,the mechanical strength test of the rock samples taken and record the data;simulate the actual operation The mechanical properties and seepage conditions of various dam structures under the environment are analyzed using the mechanical changes and seepage effects obtained by the simulation to analyze the stability and seepage conditions of the dam,as well as the stability of the dam body and the main areas of the seepage field According to the damage area and the distribution of the seepage field,the most economical and efficient anti-seepage measures are selected.The research shows that the immersion time of coal rock samples is prolonged,the unidirectional compressive strength gradually decreases from 10.10 MPa to 7.14 MPa,the tensile strength decreases from 1.42 MPa to 1.07 MPa in natural state,and the elastic modulus increases with the immersion time Small fluctuations,basically kept in the range of 0.6 to 1.0 GPa;the compressive strength of the C30 concrete artificial dam specimen is determined to be 33Mpa and the tensile strength is about 3.33Mpa in the case of extreme damage and damage;actual operation The dam body under the environment is subjected to unilateral hydrostatic pressure and mine water softening,and its mechanical strength decreases.As the simulation progresses,the deformation strength reaches the peak,and the mechanical strength no longer decreases.After ensuring the stability of the dam structure,before the implementation of the anti-seepage measures,it is necessary to numerically simulate the specific anti-seepage effects of different anti-seepage materials.The obtained cloud map of the plastic zone shows that with the increase of the permeability coefficient,the seepage flow and seepage speed are accelerated Therefore,the more obvious the seepage movement occurs,after comprehensive consideration of the cost performance,the material with the permeability coefficient of 10~-1212 m~2/Pa can be used as the anti-seepage material in the anti-seepage of the groundwater reservoir dam body of the mine goaf.Therefore,according to the water storage requirements of the underground water reservoir,different anti-seepage techniques can be used.In recent years,coal pillar anti-seepage techniques have mostly used curtain grouting,vertical paving geotextiles,concrete anti-seepage walls and other methods;artificial dam body anti-seepage selection Straight artificial dam,H-shaped artificial dam structure.In addition,the goaf reservoir constructed according to the above scheme not only stabilizes the structure of the dam body and meets safety standards,but also has a good effect on the anti-seepage system.It provides a specific plan for the further development of the anti-seepage technology of the underground coal mine reservoir in the future.