Polyurethane Anchor Reinforcement Technique

Polyurethane anchor is a new full-length bond type anchor, which polyurethane material is used as anchoring agent. Because of the expansion of the polyurethane, the drill hole wall will get the normal pressure, and the pressure will affect the strengthen of polyurethane anchor. With using ANSYS finite element numerical simulation method and surface-to-surface contact analysis technique, the paper analysis and study the reinforcement of polyurethane anchor.The main conclusions are as follows:(1)The numerical simulation analysis of reinforcement of anchor could get a better result by using surface-to-surface contact analysis technique.(2)With using literature retrieval and laboratory test, the Compression stress-strain relationship of polyurethane anchoring agent is approximate ideal elastoplastic model.(3) The expansion of the polyurethane will generate the normal pressure, and the pressure significantly improves the range of the reinforcement and the deformation control function to surrounding rock of the polyurethane anchor. Also, Stress condition is improved of the nearby surrounding rock of the anchor in a certain range, and the bearing capacity of the surrounding rock is increased, with the maximal tensile stress of the anchor being decreased.(4)The reinforcement of polyurethane anchor is mainly affected by crustal stress, the expansion ratio of polyurethane anchoring agent and the Anchor length, while the alteration of the bolt diameter and the elastic modulus of anchor do not affect the strengthen of polyurethane anchor.(5)It is functional for avoiding the roof caving accidents to use polyurethane anchor to reinforce the upper rock of the roadway with soft roof, soft coal and soft floor in advance.In general, as a new-type anchor, polyurethane anchor has a good promotion value based on the above conclusions, and the work and experience in the paper provides some useful references to promote the use of polyurethane anchor.