V.A. Uvarova, Dr. Sci. (Eng.), Head of Department, v.uvarova@nc-vostnii.ru A.P. Kostrykin, Senior Research Assistant V.A. Kopytin, Cand. Sci. (Eng.), Director on Examination and Certification AO «NTs VostNII», Kemerovo, Russia
To increase stability of the rock massif in coal and mining industry, steel-polymer rock anchors are currently used. The efficiency and safety of the rock anchor particularly grows up if the anchor bars are fastened along the entire length by quick-hardening binding compositions based on polyester resin, which are one of the most important elements of the roof support system and the reinforcement of the rock massif.
Normative requirements regulating physical and mechanical (strength) properties, and accordingly the safety of steel-polymer rock anchors application with the use of ampoules containing binding compound based on polyester resin are practically not available nowadays. Studies were conducted to identify and assess the factors influencing the effective mechanism of load distribution and interaction between anchor, resin and rock when using such a rock anchor. To study the process of curing the ampoule chemical composition and assess the strength parameters of the «ampoule with polymer composition — anchor bar» system the artificial wells had been designed, constructed and fabricated. In laboratory conditions with the use of a horizontal testing machine the strength characteristics of the «ampoule with polymer composition — anchor rod» system in the artificial wells of various diameters were measured and assessed.
The dependence of load-bearing capacity of the steel-polymer anchor and the degree of uniformity of the cured polymer composition weight on the diameter of the well, modifications of the polymer resin, and the agitation time of the composition components were revealed. The optimal diameter of the well for roof-bolt setting and the time interval for agitating the ampoule composition were determined, the efficiency of agitating binding polymeric composition of the ampoule and the degree of uniformity of the cured polymer resin were assessed depending on its modification. It is established that in order to control the efficiency and safety of the use of compositions based on polymeric resin in rock bolting technologies the additional methods are required for assessment of their strength characteristics.
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