Study On The Application Of GFRP In Fender Piles In Shield Shaft

Glass fiber reinforced polymer (GFRP) materials have emerged as a practical alternative material for producing reinforcing bars for concrete structures, which can solve the problems such as difficultly incising traditional steel reinforced concrete supporting piles, complicated techniques and bad security when shield passed by the portal in shield shafts. GFRP reinforcing bars offer advantages over steel reinforcement in that GFRP bars are high tensile strength, nonmagnetic, non-corrosive, lightweight, low thermal and electric and easy incision. Due to other differences in the physical and mechanical behavior of GFRP materials versus steel, unique guidance on the engineering and construction of concrete structures reinforced with GFRP bars is needed, because GFRP bars are crisp materials with low elastic modulus, characterized by a linearly elastic stress-strain relationship until failure. Now there are only some experimental researches on concrete members reinforced with GFRP bars.In this paper, on the basis of research of "GFRP reinforced concrete components Experimental on mechanical properties", the stress formula of bending circular components are analyzed by envelope pile indoor model tests and the finite element method, and in the end,by the two pilot sites researches and analysis of south station and houzimen station, the application security of GFRP bars envelope pile is verified. the paper's major content and the results are as follows:1. Bend strength and the shear strength of circular component and fracture width of the calculation formula are proposed on the basis of the existing concrete structure design norms. stress formula and the section moment formula of Circular components are derived by GFRP bar converted into GFRP ring, and the accuracy of the formula is verified through model test of the experimental results.2. Using the research of GFRP reinforced concrete components experimental on mechanical properties, confirm GFRP bars envelope pile is press destruct, and in the process of destruction put up stated extend characteristic.Through the GFRP bars envelope pile structural model tests ,by the analysis of bearing capacity of the envelope components, and observe cracks conformation,by the analysis of the bearing capacity and the deformation of the piles, compare the difference between GFRP bars and reinforcing steel bars.3. By the ADINA finite element software,the nonlinear finite element analysis of GFRP bars piles and reinforced piles are performed. the results of the finite element calculation and the model tests are compared and verified each other. by changing the reinforcement forms, optimization of reinforcement is simulated, elicit the claim of best space between.4. The use of GFRP bars at the two pilot sites, south station and houzimen station, are introduced. through the analysis of the strain measurement, lateral pressure measurement and displacement measurement ,the security , reliability, comprehensive evaluation and economy of GFRP bars envelope piles are concluded.Finally, the full text are summarized , and suggested that further study should be performed.