Study And Application On A New Polypropylene Fiber Concrete Sprays Layer Performance

Anchor spray support can change the rock strength ultimately and it also has the technique and economic results which classical external support can not acquired. So it gets the extensive use. Anchor spray reinforcement mechanics research shows, the reason of anchor spray support inactivation is that it is unmatched of anchor spray support's rigidity and limit deformation with tunnel adjacent rock. For support rigidity oversized, can not make the adjacent rock sufficiency pressure relief. So, pressure force which acting on support structure oversized, which cause the anchor spray support damage and inactivation. Although it has success development different producibility bolt in last few year, concrete spraying research have not the obvious break through in anchor spray support. Concrete spraying in general tunnel, after the construct, it is easily appear slit, even it gradually developed to desquamation. So it loss the latch-up and support action to adjacent rock, particularly after a batch new style producibility bolt appeared, this mismatch problem much more prominent.In this paper, it considers that tunnel support cost is reduced, economic benefits are raised and it has a good extending prospect. In the basis of anchor spray support structure, the form of more rational support structure is sought;spray-up structure is improved, at the same time, safety reliability of support system isn't reduced. According to the features of anchor spray support structure, this structure is either improving the ability of itself bearing ground pressure or preventing effectively support system premature failure when it occurs to big distortion.This paper according to mechanical principle of polypropylene fiber concrete structure, searches and researches mechanical principle of polypropylene fiber concrete spray-up. And the interior test and the industrial test of polypropylene fiber concrete spray-up are done. At the same time, tunnel excavation process is-simulated by Ansys finite-element software. Test indicates polypropylene fiber concrete is tension, highly shearing and has good ductility and impermeability, so that it can effectively barrage crack generating and developing. Shotcrete has a litter rebound, so in concrete spray-up stress distribution is more uniform, stress value is small and concrete spray-up is better yielding and non-deformability. It externalizes polypropylene fiber concrete is big distorted, yielding, and bearing capacity high. It supplies reliable support form that is economy rational, technology prior and safety reliable to tunnel support.