The Law Of Ground Pressure Behavior And Support Selection In Shallow Shallow Thinner Coal Seam

For a long time,the characteristics of shallow thinner coal seam are small working space and special equipment,which lead to many problems such as poor safety and low efficiency.In order to reveal the law of roof movement and select the reasonable type of hydraulic support selection in shallow shallow thinner coal seam,based on the geological conditions of N1112 fully mechanized working face in Ningtiaota Coal Mine,a combination of field research,theoretical analysis and numerical simulation was carried out to analyze the movement law of the overlying strata and the support type.The results can provide technical guarantee for the shallow thinner coal seam mining and ensure the safe and efficient production of working face.The main achievements are as follows:(1)The results show that the resistance value of the support in the shallow thinner coal seam increases with the increase of the depth and mining height,and the peak value of the front abutment pressure increase first and then decreases with the increase of the depth and mining height.(2)The key technical parameters and characteristics of the support in the shallow thinner coal seam were determined.The design scheme of the hydraulic support was put forward and the electro-hydraulic control system was optimized.The strength of the support in the shallow thinner coal seam should be greater than 0.8711MPa,the support height of the support shall be 1.3-2.6,and the center distance of the support shall be 1.75m.(3)The structure of the double expansion column without liquid return of the movable column of the hydraulic support in the shallow thinner coal seam was optimized.The reasonable structural strength of the column was determined.The reasonable strength of the bottom of the middle cylinder and the reasonable position of the through-hole of the middle cylinder wall was obtained.The overall bearing capacity of the column was improved.(4)The immediate roof caving interval,first weighting interval,periodic weighting interval and strength of roof weighting are predicted accurately.