A Study On Load-carrying Performance Of Pressing Members In Tunnel Retractable Support System

With the continuous development of Chinese railway construction,the scale of the project is getting larger and larger.The tunnel project with weak surrounding rock is inevitable.Large deformation will occur in the tunnel construction,which will result in damage to the support system,and even landslides and other serious conditions will occur.The safety and progress in the construction of tunnels has increase construction costs,especially in the case of large deformations in tunnels in high-stress areas.In most cases,scientific and technical personnel still have no way to deal with them.In view of the poor joint shrinkage effect in the current shrinkable steel brackets of weak surrounding rock tunnels,the bearing performance of the steel brackets is not fully realized,and a certain tunnel construction in the new Jianlan Railway is taken as the research object,and the shrinkability is theoretically analyzed.The feasibility of the joints proposes a scalable design,and tests verify the load-bearing capacity of the press material formulation and the compression member.The retractable component model was made to carry out the different mixing ratios of the press materials and the different opening sizes of the press components.The influence of the amount of refractory mud and damping material and the size of the opening of the component on the bearing performance of the component was analyzed.Through the above study,the following conclusions are drawn:(1)The compressibility of U-shaped steel collapsible metal stent mainly depends on the force of the overlapping part of the bracket and the force of the cable,and its bearing performance is also different due to the different brackets.At present,there are various types of anchors on the market,divided into Resistance increase type and constant resistance type two types.One is to let the pressure by stretching the material,and the other is to let the pressure by stretching the structure.Its working resistance is mainly provided by friction.(2)Invented a pressure-support system for a pressure-support system and a new type of hydraulic pressure-increasing tunnel pressure relief device,and applied for invention patents and utility model patents.The foundation of the pressure-increasing device for hydraulic pressure-increasing tunnels On the improvement of the processing of the circular cylinder pressure member.(3)Through the use of different mix ratios of fire-resistant mud and damping material,the effect of refractory mud size,amount of mica powder,fly ash,talcum powder,asbestos powder and pore size on the compressive strength of the component was analyzed.It can be concluded that under the same pore size,the mixing capacity of fire-resistant mud and fly ash is the highest.Only the bearing capacity of fire-resistant mud is the lowest,and the bearing capacity of the two is nearly three times larger.(4)In the case of the same pore size,because the particle size and water absorption of the added damping material are different,the compressive material formed after mixing the damping material with the refractory mud will cause the pressure to be different: The pressure of mud and talc is maximized,so that the compressive mud and mica powder have the minimum pressure.