Application Of Basalt Fiber Reinforced Plastics In Foundation Pit Support Pile

Basalt fiber reinforced composites(BFRP)has the advantages of high tensile strength,corrosion resistance and chemical stability,high thermal stability,high insulation,low cost and so on.At the same time,the thermal expansion coefficient of BFRP bars is similar to concrete,which ensures the synchronous deformation of concrete and reinforcement.Support piles are often used in foundation pit support,if the design theories of BFRP bar support piles can be propose through research,to replace some or all of the rebar in it,give full play to its economic and technological advantages,the application prospects of BFRP bar will be very broad.In this thesis Based on the laboratory tests,the bond behavior between BFRP bars and concrete is studied,and the important parameters of the design of concrete component with BFRP bars are obtained.The concrete component design method with BFRP bar is obtained preliminary by compare with the concrete component design method with GFRP bars.In this paper,the indoor experimental study on the flexural behavior of BFRP reinforced concrete flexural members with circular section and BFRP reinforced concrete slab is carried out,the bearing capacity and deformation behavior of the component are tested by using different reinforcement methods and reinforcement ratio,and use the numerical simulation to verify the indoor experimental results.At last,the design method of concrete component with BFRP bars is modified by comprehensive the indoor experimental results data.the reinforcement design of concrete supporting pile with BFRP bars in practical engineering is carried out,in the same time field monitoring of deformation of pile body and main tendon force is carried out,the practicability and effectiveness of BFRP reinforced concrete supporting pile are verified.This paper shows,the bond properties of BFRP bars and concrete are good,the bonding strength range is about 14?29MPa.2 kinds of BFRP bars with different diameters and 3 kinds of reinforcement ratio were used to test the BFRP pile,the results show that the bearing capacity of BFRP pile increases with the increase of reinforcement ratio,and when the reinforcement diameter is the same,the higher the reinforcement ratio is,the higher bearing capacity of the component is,when the reinforcement ratio is the same,the smaller the diameter is,the higher bearing capacity of the component is.4 kinds of BFRP bars with different diameters and 3 kinds of reinforcement spacing were used in BFRP concrete slab,the results show that the bearing capacity of BFRP concrete slab increases with the increase of reinforcement ratio,however the increase of reinforcement ratio does not improve the bearing capacity evident.The numerical simulation results are in good agreement with the experimental results,the stress distribution of the internal reinforcement is consistent with the expectation.Based on the experimental and numerical simulation results,the calculation formula of the bearing capacity of BFRP concrete component is modified,and the adjustment coefficient ? of the formula is 2.5.Comparison the deformation and stress monitoring results of BFRP reinforced concrete and reinforced concrete supporting piles in practical engineering,the deformation of BFRP reinforced concrete pile is slightly larger than that of reinforced concrete pile,and the main force is slightly smaller,but the whole structure is stable,the supporting effect is achieved,the safety and reliability of BFRP bars used in foundation pit supporting piles are confirmed.In this paper,the design method and design parameters of BFRP supporting pile are proposed,the practicability of BFRP supporting pile is verified by engineering example,it shuld be popularized in more geotechnical engineering.