Testing the rocks loosening process by undercutting anchors

Abstract

The method of unconventional solid rock loosening with undercutting anchors and the literature analysis of the problem are presented. The tests and test results of the rocks loosening process with a fixed undercutting anchor are described. The tests were carried out within the RODEST project, OPUS 10 competition No. 2015/19/B/ST10/02817, financed by the National Science Centre. Numerical modeling process as well as a series of laboratory and in situ tests were carried out. The test stand equipment and methodology for the in situ tests are presented. The tests were conducted in four mines, which allowed to obtain and determine the following characteristics: 1. loosening force as a function of anchoring depth (for a given type of rock), 2. the range of rock loosening in a function of anchoring depth (for a given type of rock), and 3. loosened rock volume as a function of anchoring depth (for a given type of rock). The in situ test results are compared with the concrete capacity design (CCD) model used for the calculation of anchor load capacity in concrete.