Experimental Study On Deformational Behaviour And Support Performance Of Reinforcing Polymeric Thin Spray-on Liner

With the proposal of intelligent mine construction in China,it is of great significance to develop new technologies for safe,efficient and fast roadway surface protection suitable for China’s geological and production conditions.Thin spray on liners(TSL)technology is a surface spraying film protection technology,which is widely used in mine sealing engineering.Reinforcing Thin Spray-on Liners is a new technology that can replace metal mesh,so as to achieve the goal of fast tunneling,high degree of automation and suitable for unmanned.In this paper,the research on Reinforcing Polymeric Thin Spray-on Liners,RPTSL materials and supporting spraying equipment is carried out,and RPTSLl with independent intellectual property rights and related mechanical behavior and support performance test methods are developed.Compared with cement-based TSL,it has the advantages of "instant spraying and use" and various mechanical properties of materials.It is suitable for complex and changeable industrial and mining conditions in China.It aiso has great application prospects in the intelligent construction of underground coal mine roadway rapid support and anchor support.In this study,a variety of research methods such as theoretical analysis,laboratory experiment,numerical calculation and field industrial test are comprehensively used to systematically study the bearing deformation law of RPTSL material modified by temperature limit,the surface protection mechanism and support performance of roadway surrounding rock.Based on the deformation law of TSL surface support,the bearing mechanism in the process of TSL support is determined.Through theoretical analysis,the bearing characteristics of each stage of TSL surface support and the corresponding relationship with the mechanical properties of materials are established.It is determined that the bonding,tensile,shear and compressive properties of TSL materials are the key parameters for the stability of TSL support composite bearing structure.Using the rock mechanics experimental method,the bearing performance of the developed RPTSL material is comprehensively tested,and the material properties are compared with the TSL materials developed at home and abroad in recent years.The results show that the mechanical properties of the new material are significantly better than the cement based TSL,close to the international leading level,and suitable for the geological environment of deep resource mining in China.In the study of RPTSL support performance,the TSL thin shell structure supporting effect is first analyzed and experimentally studied.By comparing with the diamond mesh support method,the yield strength and peak strength of the specimens increase by 20-45% after the shell structure is formed by RPTSL,and the energy absorption effect is significantly enhanced.The influence of RPTSL on the stability of coal pillar is studied by using large briquette sample according to the deployment of isolated coal pillar in shaft coal mine in China.The results show that the peak load of RPTSL after support is increased by 30%,and the deformation is increased obviously.The deformation process of thin spray layer and surrounding rock composite structure is analyzed by numerical calculation methods.It is found that RPTSL changes the stress state of the composite structure through its own bearing capacity,reduces the tensile failure of coal and rock mass,and plays a supporting role.A special thin spray machine is designed for the developed RPTSL materials.Through laboratory orthogonal spraying test,multiple spraying molding process is determined.The spraying capacity is 1.1 ～6.6 L/min,and the utilization rate of material and liquid is 95%.The experimental results show that the mechanical properties of atomized materials are slightly reduced,but the supporting properties are not affected.Finally,the industrial test of the large deformation roadway in Hengda coal mine of Fuxin mining(Group)Co.,Ltd.is carried out in the typical deep coal mine.The feasibility of RPTSL support is verified by RPTSL field test for the first time.The bonding performance and support effect of RPTSL on large and small scale loose rock mass are observed and analyzed.The spraying operation is simple,safe and efficient.RPTSL support can greatly improve the tunneling speed.The effect of RPTSL support and spraying machine is in line with expectations.The RPTSL material and equipment developed in this study have independent intellectual rights and excellent mechanical properties.The deformation process,failure mode and bearing characteristics of its support structure are verified by RPTSL support experiment and numerical calculation.The feasibility of RPTSL operation is verified through field test.This study provides basic theoretical and technical support for RPTSL engineering practice and provides new materials,technologies and processes for the intelligent construction of deep mine bolting in China.In this dissertation,there are 156 figures,19 tables and 127 references,respectively.