The reliability level of a support or its component is determined by the numerical value of one or more reliability criteria, for example, the duration of the average time of failure-free operation, or the probability of failure-free operation for a certain period of time.

Among the many types of fasteners used in mining, rod fasteners on the principle of action, simplicity of design, cost-effectiveness and versatility takes a special place and every year is gaining more and more recognition in world mining practice.Department of Construction of Mining Enterprises Leningrad Mining Institute studied rod fasteners as a means of combating swelling of the bottom of mine workings in the mines of Donbass, Moscow region and other basins. It is established that the rod support can often prevent frost heave or significantly reduce its intensity. Widely used constructions of rod supports for strong and medium strength rocks are not suitable for strengthening weak rocks, as they do not provide good fixation of locks and have low load-bearing capacity. Foreign mining literature recommends widely used and cheap reinforced concrete rods for strengthening weak rocks. During experimental testing of these recommendations it turned out that not all designs of reinforced concrete rods are effective in weak rocks, especially in rocks that lose mechanical strength when moistened. As a result of studying the principal features of known designs of reinforced concrete rods and analyzing the schemes of their operation in specific mining and geological conditions, fundamentally new designs were developed.