| Weakly cemented soft rocks have low bearing capacity,poor cementation,low strength and easy softening in water.The deformation and sinking of the roof of the roadway is aggravated by the sprinkling of the roof and anchor holes,which threatens the safety and stability of the roadway.Therefore,the combination of bloting grouting support technology and weakly cemented soft rock roof drenching roadway,research this type of roadway surrounding rock control technology has some practical significance.Taking the roof of 5-1 upper coal seam 1# exploration roadway of Yangjiacun coal mine as the research object,the deformation and failure characteristics and causes of the roof of weakly cemented soft rock roadway are analyzed by means of field investigation,indoor test and borehole peeping.The original innovation puts forward the common anchor cable hole sealing grouting technology to control the deformation of surrounding rock through theoretical analysis Similar simulation test and field test are used to study the hole sealing grouting technology of ordinary anchor cable in the water pouring roadway of weakly cemented soft rock roof.1)Through on-site research and test analysis,it can be seen that the roof of 1#exploratory lane is dominated by sandy mudstone,and the recharge sources of the roof surrounding rock and anchor hole drench water are water accumulation in the upper mining area,fault fracture water and weak water-bearing layer of the roof,resulting in the fragmentation of the roof surrounding rock,sinking deformation of the roof and failure of the supporting elements;meanwhile,the existence of geological borehole test and roof anchor hole aggravates the development of disturbance to the roof water.2)Based on the research and analysis of the deformation and failure characteristics of the roof of weakly cemented soft rock roadway,the common anchor cable hole sealing grouting support technology is proposed.The stress of the hole sealing section of the common anchor cable hole sealing grouting is analyzed,and the theoretical calculation formula of the hole sealing section is deduced.Combined with the numerical simulation results of a single anchor cable,it is verified that the easy damage area of the anchor cable hole sealing section during grouting is at the contact between the hole sealing section and the anchor cable and the anchor cable hole wall,and the hole sealing length of the hole sealing section should be 300 ～ 500 mm,The hole sealing section can bear at least 5MPa grouting pressure.3)The ratio of sealing materials and sealing test show that both organic and inorganic materials can be used as sealing materials to seal the shallow sealing section of anchor hole,and the water-cement ratio of cement anchor fixing agent is 0.7:1～1:1,and the ratio of Malisan NS-AB and E-AB double liquid is 1:2～2:1,and the dense filling effect of Malisan in the sealing section of anchor hole is better than that of cement anchor fixing agent.The grouting pressure was maintained at 3～6.5MPa when the water-cement ratio of cement anchor fixing agent was 0.7:1～1:1 and the sealed hole length was 300～500mm,and reached 6.5MPa when the sealed hole length was 500 mm and the water-cement ratio was 1:1;from the downhole sealed hole grouting test,the grouting pressure of the top plate anchor rope was maintained at 4～5MPa,which verified the correctness of the indoor simulation test and achieved The technical parameters and construction techniques of the downhole anchor slurry were determined.4)The field monitoring results show that after the anchor cable hole sealing and grouting,the approach amount of the top and bottom plate and the maximum separation value of the top plate are reduced by 60% and 74% respectively compared with the original support,the displacement of the deep and shallow base points are reduced by50% and 60% respectively compared with the original support,and the average drenching water per minute of a single anchor cable is reduced by 92% compared with the original support;The numerical simulation results are different from the field monitoring results,but the deformation and failure trend of roadway surrounding rock is the same;The research results prove the practicability of anchor cable hole sealing grouting technology,and provide technical and theoretical guidance for the surrounding rock control of similar roadway.The paper has 53 pictures,7 tables,and 65 references. |
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