Detonating cord splitting is a quite common production technique for dimension stone blocks, in granite and gneiss quarries, where the blasts are usually designed based on local experience. The paper relates to a vibrometric test campaign, carried on in a group of gneiss quarries using accelerometric measurements at proximity to the hole’s rows, both in primary splitting and recutting operations. The purpose of the test campaign was to detect (or to exclude) the possibility of impairment of the commercial stone blocks produced by this technique, to check the validity of the blast design criteria adopted, and to obtain experimental data for predicting the friction conditions at the boundaries of the blocks and their expected displacement. The results highlight the limited damage of the commercial blocks obtained, confirming the validity of the detonating cord as a functional technique to split and slightly move the blocks from their original position. The vibrations due to the blast are also very limited even at a short distance, confirming that the technique is precautionary and respects the quality of the exploited blocks.

Anchored mesh systems constitute a widely adopted protective mitigation measure against rockfall, particularly suitable for highly weathered sub-vertical rock face These systems are composed of steel wire mesh panels combined with a regular anchoring pattern. In this work, we investigate by means of discrete element simulations the mechanical behavior of the mesh with the commonly adopted quincunx-like (or diamond) anchoring pattern, comparing with what we have already found for the square pattern. The effects of the loading condition and the mesh system properties on the out-of-plane response of the system are evaluated and ana-lytical relationships for quantifying the mesh punching resistance and maximum deflection are proposed. The results allow quick assessment of the suitability of the design choices and provide an insight on the force transmission paths during the loading of the mesh system.

It is necessary to obtain reliable estimates of the in situ stress state for the design of any underground engineering project in rock, but it is of paramount importance for safety-critical projects such as deep geological repositories for nuclear waste. It is widely considered that in situ stress is a function of depth below ground surface. This often leads to rock masses being partitioned into depth based domains, but there are no universally agreed and statistically robust methods for doing so. In this paper we present a novel method that uses Bayesian linear segmented regression of Cartesian stress components to probabilistically characterize the variability and uncertainty in the depth of non-crisp stress domain boundaries, and the in situ stress state within each domain. We demonstrate the efficacy of the method using synthetically generated stress data, and then apply the method to overcoring stress measurements obtained at the Forsmark site in Sweden.

Analysis of rock slope stability is a key step on the successful design and excavation of open pit mines and quarries. This study shows the rock mass characterization and the different analyses carried out to assess the stability of the final slope of a calcareous quarry. The studied excavation is located on the near-axis flank of a syncline, in such a way that the stratification set varies its dip from some 40º on the nearest zone of the axis to 20º on the farthest zone, creating a slightly complex geometry. This situation requires a set of different approaches to assess the stability of the slopes. For the studied case, a proposed design of the full open pit quarry was received. All the different possible failure mechanisms of the quarry were identified and analysed using limit equilibrium and numerical methods. West slope, which resulted to be parallel in strike to the stratification, featured a planar mechanism stability problem, so it was analysed in detail and a new stable design was proposed. This paper describes the steps carried out to characterize the rock, the discontinuities and the rock mass, as well as the different approaches used to obtain the stable design.