Study On The Control Of Rib Fall Of Coal Wall Basde On The Working State Of Large Mining Hydraulic Support

In large mining height are broken coal mining process of fully mechanized working face,the coal wall height,complex reasons,such as coal seam geology condition,the working face of coal wall piece to help bring mine production safety hidden trouble,this paper Lu'an Wangzhuang coal mine 8101 large mining height are broken during the production of fully mechanized working face the working state of the hydraulic support,using the method of theoretical analysis,numerical simulation and engineering application of different support the working status of coal wall piece to help control effect are studied,the main contents and conclusions are as follows:(1)Through the study of actual observation and geological data on the project site,the engineering information,such as the occurrence of coal seams in no.3 coal 8101 of luan wangzhuang coal mine,the occurrence law of coal pressure,the formation of surrounding rock roof and floor strata,and the characteristics of coal siding in the process of coal face stoping,was acquired.(2)Through theoretical analysis,it is determined that zy15000/33/72 d type two-pillar shield type large mining height hydraulic support is selected for 8101 fully mechanized mining face.The structural characteristics of the two-column shield type hydraulic support,the bearing process of the roof supported by the working face hydraulic support and the coupling relationship between the hydraulic support and the surrounding rock of the working face are analyzed.In this paper,the theory of coal face caving and the characteristics of coal face caving are studied,and it is put forward that the coal face caving can be reduced by controlling the working state of hydraulic support.(3)The numerical simulation calculation is carried out for the support of different initial support forces of the working face hydraulic support,and the conclusion is drawn: the initial support force of the working face hydraulic support shall not be less than 12000 KN.The improvement of the initial support force of the working face hydraulic support directly reduces the vertical pressure of the coal wall on the top of the coal wall,which can effectively control the coal wall sheet.(4)To simulate the hydraulic support different protection help plate work state influence on the coal wall support,research shows that: in all help plates supporting coal wall horizontal displacement on the state of coal wall decreased 2.67 mm,when in the secondary protection for plate and top beam bracket to establish the three-stage hydraulic cylinder to improve supporting force under the condition of horizontal displacement on the coal wall decreased 6.2 mm,the supporting effect is increased by 2.3 times.The support force provided by the support plate of the hydraulic support to the coal wall directly changes the horizontal stress state inside the coal wall,and the coal body changes from the original tensile stress state to the compressive stress state,which improves the stability of the coal wall.(5)Simulate the connection state of the hydraulic support of the entire working face and the shearer,and compare the influence of the hydraulic support on the coal wall support in the original maintenance area,the clapboard recovery area,the support lagging area and the recovery maintenance area.In the support lagging area,the horizontal displacement of the coal wall is up to 53.5mm,and the stability of the coal wall is poor 43.7mm.In the process of engineering production,the support in the front of the shearer should be recovered in advance of 4,and the support in the rear of the shearer should not exceed 2.(6)The above coal wainscot control technology is applied to the support management process of fully mechanized mining face.At the same time,the coal wainscot is monitored and counted.The number,width,depth and height of the coal wainscot are obviously reduced,and the control effect of the coal wainscot is obvious.