Study On Support Technology Of Deep Roadway In Broken And Weak Rock Formation

Based on the-1010 main air return roadway of shaft station in east area No.2 level shaft station,the integrated use of theoretical analysis,experimental research,numerical simulation method and engineering practice was studied in Huainan Mining Group Guqiao Coal Mine,in view of the broken soft rock roadway,a new combined support was proposed and was carried on the design.Meanwhile the key technical problems on the construction were carried out with systematic research.The major research contents and results following:(1)Analysis of roadway excavation in deep broken soft rock roadway using advanced pre-grouting reinforcement technology mechanism,through theorical analysis,calculation combined with the actual situation of engineering theory,related technical parameters of pre grouting reinforcement technology scheme was determined,and was applied in engineering practice according to the technical scheme design and technical parameters.Through the practice results show that the pre grouting reinforcement technology in deep soft rock roadway with two properties of water plugging andreinforcement which play the expected effect in the new combined support technology,and solve water inflow in the roadway excation radius.Moreover broken soft rock can be cemented together,which plays the role of surrounding rock reinforcement.The pre grouting technology is suitable for roadway excavation in deep broken soft rock roadway with new combined support.(2)Based on the theoretical analysis of the composite structure of the double-layer steel plate,the composite brackets are designed to determine the main components of the composite double-deck steel high-strength concrete composite stent : the steel plate high-strength concrete composite component,the joint compression Plate cushion and wall post-fill layer.(3)The structure of being sutibale for new combined support technology in deep broken soft rock roadway excavation has developed.Meanwhile assembly type double-layer steel reinforced concret composite bracket was designed with parameter,and preparation experiment of concrete with high strength and performance was conducted.By the combination of theoretical analysis,numerical simulation and model test,the mechanical properties of the new support structure were studied systematically.The results show that:(1)The assembled double-layer steel reinforced concret composite bracket structure not only has a high bearing capacity,but also has a certain degree of flexibility,"Let the side edge" effect can be played in the actual project,which is suitable for deep broken soft rock roadway excavation support and meets the requirement of new combined support technology.(2)The composite effect of assembled double-layer steel high-strength concrete composite bracket is better.Under the load,the internal and external steel plate had little difference in the circumferential stress,while the intermediate concrete layer was in the multi-axial compressive stress state.The compressive performance of concrete under the steel plate restraint fully used.(3)The bearing capacity of the assembled double-layer steel high-strength concret composite bracket is related to the factors such as the strength grade of concrete,the thickness of steel plate,the thickness ratio of arc plate and the load non-uniformity factor.According to the numerical simulation analysis,increasing the strength grade of concrete is the most effective and direct way to improve the ultimate bearing capacity of the bracket support.(4)The new combined support technology has been applied in the filed of-1010 main air return roadway of shaft station in east area No.2 level shaft station in Huainan Mining Group Guqiao Coal Mine.Advanced pre grouting reinforcement technique was used in the early time,and then the compressible U type steel shed was used for temporary support,smoothly through the region after later,the assembly double-layer steel high strength concrete composite bracket supportwas applied for permanent support,the field application results indicated that: the new combined support technology successfully passed the deep section of the broken soft rock,and controlled the deformation of the broken soft rock.The scheme achieves the desired results and meets the requirement for application.