Study On Stability And Control Technology Of Surrounding Rock Of Gob-side Retaining Roadway In Fully Mechanized Caving Face With Gaohe Energy

In order to realize that the gob-side retaining roadway in pillar-free mining is affected twice by the mining disturbance of continuous working face,the original support of retaining roadway is difficult to maintain the stability of roadway and can not meet the requirements of Engineering production.For fully mechanized top coal caving face gob-side entry retaining in service period is in a long-term high pressure state.Strengthening support research during the second use of gob-side entry retaining in fully mechanized top-coal caving face is the key to realize coal pillar-free mining.Based on the engineering background of E1316 working face air intake roadway(E1315 retaining roadway)of Luan Group Gaohe Energy Co.,Ltd.,this paper studies the surrounding rock stability affected by mining in continuous second adjacent working face,and puts forward the measures of grouting reinforcement along gob retaining roadway to ensure the safe production of roadway.The main research results are as follows:(1)The deformation and failure characteristics of the surrounding rock of W1316 air intake roadway in time series are investigated.The deformation and failure characteristics of surrounding rock of E1316 intake roadway during the whole period of retaining roadway and reusing are obtained.(2)The vertical stress,plastic zone,vertical displacement and horizontal displacement of E1316 intake roadway during excavation,primary and secondary mining disturbance are analyzed by numerical simulation.It is concluded that the loosening nature of coal mass leads to the decrease of the bearing capacity of coal pillar wall broken by the primary mining disturbance and the wide plastic zone in the secondary mining disturbance.(3)By using the method of theoretical analysis,the influencing factors of surrounding rock failure of E1316 air intake roadway are studied.Firstly,the causes of the destruction of E1316 air intake roadway by the mining process of E1315 working face are analyzed.The theoretical length of the cantilever above the inlet of E1316 is calculated by theoretical calculation method.Secondly,the causes of mining damage of E1316 intake roadway by E1316 working face are analyzed.Finally,the two-way coupling analysis of Weibull function is used to analyze the damage of E1316 intake Roadway after mining near the working face E1316 and E1315.Finally,it is concluded that the failure of the intake roadway in the end triangle area of the working face E1316,especially the leading support section,is not a single factor,which is the result of the normal mining effect of the working face E1316 and the two-way influence of the goaf of E1315.Because of the two-way stress concentration,the strata pressure of E1316 air intake roadway appears obviously.(4)The bearing capacity of grouted coal before and after grouting is tested by field and laboratory experiments,and then the mechanical properties of grouted coal are analyzed by theoretical analysis.After coal grouting,not only the bearing capacity of coal body itself can be improved,but also the bearing capacity can be improved in structure.Combining with the research results,the grouting reinforcement scheme and reinforcement parameters are put forward according to the current situation of E1316 air intake roadway of Gaohe Energy.The existing reinforcement schemes are simulated in laboratory by means of numerical simulation.(5)According to the above research results,industrial experiments were carried out in the inlet tunnel of E1316.The field monitoring data show that the grouting measures can effectively control the further deformation and destruction of the gob-side entry retained in the E1316 working face of Gaohe Energy.