Operational and physical characteristics of self-drilling rock bolt

Abstract

The key factor in the operation safety for the shaft mining is stabilization of the working surface [1]. The time required to install support element is crucial [2, 3]. Surface stabilization can be done three ways: using frame support or rock bolt or their combination [4]. The rock stabilizing method is realized using significant number of design options of rock stabilizer systems [5, 6]. Friction rock bolts with tubular profile have become widespread recently [7 -9]. Its fixation in borehole is based on generation of friction force at contact surface. There are two methods realized: Swellex and Split Set. According to the first method the closed tubular profile (after being freely inserted into borehole) that has working liquid inside forced under the high pressure is used. Under the pressure outside dimension of profile is increased and its forcing against the borehole surface is provided [10]. The second method is based on use of spindle with unclosed tubular profile and outside diameter that exceeds the spindle diameter [11]. When spindle is inserted into borehole it elastically deforms at cross section. By means of that the distributed pressure is provided on contact surface. This operating principle of spindle and borehole interaction determined name of the support as self-installing rock bolt (SARB). Usage of SARB is preferable for building temporary support because of smaller time expenditure on installation.