| Glass fiber reinforced polymer(GFRP)is a kind of synthetic resin polymer based on glass fiber.It has the characteristics of light weight,high strength and corrosion resistance.These characteristics have significant advantages in underground engineering.The application of GFRP reinforcement in bolt system instead of traditional reinforcement or strand structure has great performance advantages and broad application prospects.At present,there is little research on the support design of GFRP anchor at home and abroad.As a temporary support,the research on the anchorage,design principle and mechanical behavior of GFRP anchor at home and abroad is not enough,and there is a lack of in-depth research on the design and construction parameters.According to the existing research results and relevant specifications,this paper puts forward a GFRP reinforced anchor structure,analyzes the connecting sleeve in the structure,and studies the bearing capacity of GFRP reinforced anchor.According to the characteristics of GFRP reinforcement,the special anchorage is designed and developed.The reliability and applicability of the new anchorage are verified through the combination of numerical simulation and laboratory static load anchorage test.Based on the above research,a section of Beigangzi station of Beijing Metro Line 12 is designed and its construction technology is studied.FLAC3 D is used to analyze the support effect,and the service performance of GFRP bolt support is verified by comparing with the actual monitoring,so as to provide reference for the related research in the future.The main conclusions are as follows:1)A new type of GFRP bolt structure is proposed,including GFRP rod body,connecting sleeve and new anchorage.Based on the existing research,the tensile test of 32 mm GFRP Bars is carried out.The design values of tensile strength of 25 mm,28 mm and 32 mm GFRP Bars are suggested to be 480 MPa,500 MPa and 560 MPa respectively.For the connecting sleeve,the tensile test of 50 cm and 60 cm connecting sleeve verifies that the connecting performance is good.When determining the tensile bearing capacity of GFRP anchor rod,the influence of connecting sleeve is considered,and the average bond strength between reinforcement and grouting body is reduced by 0.9 times.2)According to the characteristics of low shear strength of GFRP reinforcement,a new type of anchorage for GFRP reinforcement anchor structure is developed.Firstly,the finite element software ABAQUS is used to simulate the different thickness of the anchor cup,and the optimal thickness of the anchor cup is 9cm.Secondly,according to the results of numerical simulation,the solid anchorage is prepared for test verification.The test results show that when using the clip anchorage,the GFRP tendon is broken outside the anchorage,and the failure mode is ideal.The anchorage efficiency of the anchorage can reach more than90%,which meets the engineering requirements.3)In this paper,the GFRP reinforcement bolt support design is carried out for a section of Beigangzi station of Beijing line 12,and the construction technology of GFRP reinforcement bolt is studied.FLAC3 D is used for numerical analysis of foundation pit.The simulation results show that GFRP reinforcement bolt support can reduce the horizontal displacement of foundation pit by 53 mm.Through the comparison between the numerical simulation and the actual monitoring,it is found that the change law of the two is similar,the overall stability of the foundation pit is good,and the GFRP reinforcement anchor support has good performance. |
PDF Full Text Request