Abstract
This paper deals with the problem of the slippage failure of bolts in supporting soft rock, and the anchoring system being pulled out when conventional anchoring methods are used for bolts. This situation seriously threatens the safety of personnel and efficiency of work at the supporting soft rock. The main goal of this paper is to develop methods that will take full advantage of the potentially great supporting force that can be provided by bolts installed in soft rock. The study discusses the resin anchoring technique with reaming bottom and filling and proposes that replacing soft rock with high strength hard rock is an effective method to improve the anchoring force that prevents slip failure. The results of a comparative analysis of the different maximum diameters of reaming and the anchorage performance of the method using laboratory testing, numerical simulation, mechanics analysis, and field test are described. The results show that when the reaming diameter is less than five times that of the borehole, the anchorage force increases significantly. When the reaming diameter is more than five times that of the borehole, the increasing degree of anchoring force decreases obviously and the trend is gentle. The anchoring force of five times resin anchoring with reaming bottom and filling is 2.8 times that of conventional anchorage. The resin anchoring technique with reaming bottom and filling guarantees that bolts installed in soft rock will provide high supporting forces.