Research and discuss on development of deep tunnel bolt supporting technology

resistance increasing bolt with large deformation has the advantage of both let-pressure bolt and resistance increasing bolt, it makes best use of the advantages and bypass the disadvantages of the two types of bolt, so it can achieve the goal of improving the bearing capacity of surrounding rock and stably bolting the surrounding rock. With more and more retractable anchor are being researched and developed, it is more necessary to research and develop the retractable anchor which can both have the function of let pressure and increasing resistance. Though the way of analysising and summaring the experimental study and application of retractable anchor at home and abroad systematically, the understanding of the retractable bolt is being inhanced, the intact theoretical and practical basis is provided for the extension of this kind of anchor. Finally, the development of retractable anchor in the future is prospected. Resistance increasing bolt with large deformation which both have the function of let pressure and increasing resistance is a kind of retractable anchor, which can apply to deep weak and broken surrounding rock. Therefore, it is worthy of researching and applying.