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As mines have expanded due to increased depth, new challenges have appeared for mining engineers. High-stress environments, where there are rockburst events caused by energy release, have become especially interesting in terms of geomechanics and have prompted changes in conventional designs, demanding more research into how underground excavations absorb dynamic impacts.For these underground excavations, the development of new reinforcement elements capable of both resisting dynamic loads and yielding in the process without failing has advanced in the last 30 years due to studies and testing programs carried out by recognised institutions. However, executing these testing programs implies a high cost in time and validation. Hence, a limited number of these have been completed. In this context, numerical modelling to represent the performance of the process and enhance laboratory testing has become increasingly necessary and relevant.In this paper, a numerical modelling methodology based on the finite difference method has been applied in order to predict the behaviour of threadbar, commonly used in Chilean mining as reinforcement in underground excavations, in dynamic load testing. Accordingly, a comparison and calibration of the numerical model with laboratory-scale dynamic tests from previous research is presented.

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Ground support systems must provide safe and effective designs for underground excavations under high stress conditions. These systems must be capable to resist dynamic impacts and yielding during the loading process. In this context dynamic testing of the reinforcement and retaining elements that compose the ground support system are required to study and improve the behaviour of these elements under dynamic load events. During the last years, Geobrugg has been working on the improvement of retaining products by testing them in a large-scale impact test facility located at Walenstadt, Switzerland. The test facility is composed of a double level platform with a square-shaped pyramidal trunk geometry, the upper level houses a loading mass that drops from a height up to 5 m. The loading mass is guided by one central steel pipe, and the impact occurs in the sample to be tested, which is located at the lower level in a slab with an area of 3.6 m × 3.6 m. This is where the ground support system is installed. During the last few years, this innovative facility has been used to test several configurations of ground support systems. The results of these tests have enabled the authors to improve the understating of the behaviour of ground support systems under dynamic loads. In this manuscript, the arrangement, measurement, results, and the preliminary analysis of large-scale dynamic tests of two ground support systems performed in 2019 and 2021, supported by the Advanced Mining Technology Center (AMTC -University of Chile), are presented.