Finite Element Analysis Of BFRP Expansion Anchor Applied To Basement Anti Floating Engineering

At present,the ordinary metal bolt is widely used in underground engineering,structural anti floating engineering,deep foundation pit engineering and other important projects,because this kind of project is often in the corrosive environment with the same water contact,which is unfavorable to the long-term service of the bolt.In view of the disadvantage of ordinary steel anchor,a BFRP expanding anchor bar is developed by virtue of the good corrosion resistance of BFRP material.The BFRP mortar is poured into the mortar to form the mortar to expand the body to improve the bearing capacity of the bolt system.As the reinforcement is a new type of material,the joint action of the three kinds of reinforcement,mortar and soil leads to the anchorage and bearing performance of the anchor system is not clear.Therefore,the anchorage and bearing performance of the BFRP expansion bolt should be studied.In this paper,the basic physical and mechanical properties of the BFRP anchor bar are tested first,and the ultimate tensile strength,modulus of elasticity and ultimate tensile strain of the BFRP bolt are obtained,and a physical model of the expansion bolt is made by the support model,and the bearing capacity test is carried out for the BFRP expansion bolt arranged in the shallow soil.Then the finite element analysis is used to verify whether the anti floating capacity of the BFRP expansion bolt meets the requirements,and the parameters of the finite element are changed to analyze the factors that affect the anti floating bearing capacity.Through the analysis of experimental phenomena,experimental data and finite element data,the following main results are obtained:(1)the tensile strain of partially anchored BFRP anchor rod is basically unchanged with the anchoring depth,but the tensile strain of BFRP anchor rod decreases rapidly in the range of expansion.(2)the failure mode of the BFRP anchor system is the shear failure of the interface between the mortar and the soil when the pulling force is relatively shallow.The failure of the reinforcement itself is not very likely.(3)when the interface between the mortar and the soil is shear failure,the end bearing capacity of the expansion body accounts for more than 60% of the bearing capacity of the bolt.(4)combining with the engineering example and finite element calculation,the anti floating bearing capacity of BFRP expansion anchor system can meet the requirements of basement anti floating design.(5)in the influence factors of the anti floating bearing capacity of the BFRP expansion bolt,the internal friction angle,the diameter of the expansion and the depth of the expanded body have great influence on the bearing capacity,and the cohesive force and the length of the soil mass have little influence on the bearing capacity.