Supportadaptive Research On The Residual Coal Longwall Fully-mechanized Coal Mining

Tian Shenghua Coal Company, which subsidiary belongs to Jin Coal Group,is a separate retaining mine mainly for residual coal resources mining after reorganization and integration. Through on-site mine pressure observation, we found that in the working process of the four shield caving support in Shenghua coal mine, the pressure in the front and the rear of the support is extremely uneven, usually the pressure of the anterior column is bigger; however, the after column doesn’t bear stress and even under tension, which is an extremely common phenomenon, and the phenomenon of support bows even the tensile failure of after column also occurs occasionally. In view of the problem that arise in the working process of hydraulic support, the paper analyzes the working face in the process of a alley stope roof breaking rule through the methods of the similar simulation and numerical simulation. Reasonable ranges of the outside resultant forces of the top beam are suggested through mechanics analysis. The mechanism of action is analyzed and the support working resistance is calculated through the established of the theory model of support-surrounding rock. A kind of reasonable support suit for residual coal mining of Shenghua coal work face is proposed through the selection research of support. The paper analyzes the adaptation of the newly selected supports on Shenghua Coal through numerical simulation.(1) Through the observation of mine pressure in 1301 working face of Shenghua coal mine, we found that the setting load and working resistance frequency distribution of anterior column and posterior column of a four columns shield hydraulic support has the feature of higher in anterior column but lower even tension in posterior column. Due to the offset load phenomenon,the support efficiency of the support is extremely low, which cannot play the supporting role effectively, as a result, the support is hard to adapt to the geological conditions of Shenghua Coal Mine.(2) By using similar simulation and numerical simulation method, we find that when the support passing an empty roadway and the coal pillar between the support and empty roadway reach the limit width, in a certain position of the main roof strata, where advance the empty roadway position, fracture would occur and key "rock block" would form. With the advance of the working surface, the occurrence of "rock block" rotating instability and sliding instability will greatly affects the working state of the support.(3)After the force analysis of support, we found that the sphere of action of external load resultant force of the top beam of four shield type hydraulic support load have certain requirements. For those holding power of the anterior and posterior columns of the hydraulic support are P1 and P2, the sphere of action of support resultant force, only when the external resultant load is in the range, the anterior and posterior columns of the support can be loaded and the support can be in a good working state. On the contrary, when the external resultant load of the support is not in the range, just smaller force will also cause the support to lose the balance.(4) In view of the mechanism of the instability of the support, the theory model of the support and surrounding rock is established, and the mechanism of the support and surrounding rock is analyzed, and the three factors that may lead to the instability of the stent are obtained, which are top coal quality, the process of top coal caving and the "rock block" rotating instability and sliding instability leaded by the advanced fracture.(5) By the establishment of mechanical model of support passing empty roadway, reasonable working resistance of support is determined. Combined with the Shenghua coal mine conditions, the support type and its parameters is determined, and ultimately two shield type caving coal hydraulic support ZFY10200/25/42 which is adapt to Shenghua coal mine is determined.(6) By numerical simulation we find that ZFY10200/25/42 two shield type caving coal hydraulic support can be very good control of roof sinking and bottom support pressure can also satisfy the support demand, the support can adapt to the Shenghua coal mine geological conditions.