Study On Properties Of Recoverable Steel Pipe Anchor

With the development of the country,there are more and more deep foundation pits in engineering projects,and more and more attention has been paid to supporting technology.Steel pipe bolt is a type of bolt in the supporting structure,which is used in the slope support of construction engineering,the support of road and tunnel engineering,and the support of coal mine tunnels.The steel pipe anchor has good supporting performance and can be applied to the support of various soil slopes and surrounding rock.However,because the steel pipe anchor is grouted and anchored in the support,it is difficult to recover after the support is completed.In recent years,in the foundation pit support of construction engineering,more attention has been paid to the requirements of green and sustainable development of land use red lines and urban underground spaces.The development and application of recyclable anchor rods are particularly important.As a thermoplastic resin,bisphenol A epoxy resin E20 has the characteristics of low volatility,high mechanical strength,corrosion resistance,and high bonding strength with metals.Its melting temperature is 64-76°C.Using bisphenol A epoxy resin E20 as a mold reducing agent in combination with steel pipe bolts,a new type of recyclable steel pipe bolt is proposed.During recycling,the steel pipe is pulled out by melting the mold reducing agent to achieve the purpose of recycling,which can not only achieve the green development of underground space,but also realize the recycling of materials.In this paper,the bonding performance and recyclability of steel pipe bolts before and after application of mold reducing agent are studied through laboratory experiments.By comparing the bonding strength of steel pipes coated with mold reducing agent with mortar under pressure test,it is concluded that the bonding strength of steel pipes coated with mold reducing agent is higher than that of steel pipes without mold reducing agent.Strength,further analysis puts forward the relationship between bond strength and displacement.A heating pullout test was performed on the steel pipe coated with the mold reducing agent.The results showed that the bonding strength was greatly reduced in the molten state of the mold reducing agent,and the steel pipe could be recycled.By analyzing the test results and phenomena,the design calculation method of the recoverable steel pipe bolt support structure and recovery is proposed.Combined with engineering practice,numerical analysis method is used to analyze the horizontal displacement of the surrounding structure under the support of the recyclable steel pipe bolt and the vertical displacement of the foundation pit.The research shows that the recyclable steel pipe bolt has good supporting performance.According to the actual project,the recovery analysis of the recyclable steel pipe anchor rod is carried out,and it is concluded that its recovery can better meet the requirements of foundation pit stability.Through the research in this article,a new type of recyclable steel pipe anchor is proposed that uses mold reducing agent to coat steel pipe anchors,and the steel pipe is recovered by heating the mold reducing agent during recovery.The recyclable steel pipe anchors are proved through experiments and actual engineering analysis.The reliability of pole support and the feasibility of recovery.It has better promoted the green development of urban underground space and has guiding significance for practical engineering applications.