It is better to align the tunnels along good rock mass having homogenous rock mass with relatively less discontinuity sets, fault, shear, and fracture zones. However, it is not possible to completely avoid but it is possible to align the tunnel in such a way that these geological structures impact less in the stability. It is important that the engineering geological character of faults, shear, and weakness zones should be mapped and assessed so that their behavior is well understood. This article aims to assess a serious tectonic fracture zone that the planned 13 km long Hemja-Patichaur road tunnel crosses. For such assessment, data achieved by extensive field mapping and rock mass quality assessment using both Q and RMR systems of rock mass classification will be used. The characterization of the tectonic fraction zone will be made and engineering geological, and rock mechanical properties will be estimated using both field measurement data. Finally, a comprehensive stability assessment of the road tunnel will be carried out for the rock mass of the tectonic fracture zone using analytical and numerical methods.

In this work, computational techniques are applied via discrete element modelling to describe, understand and analyse the mechanical response of a rock medium under the impact of a rock block, inducing an impact fracture of the system. The system consists of a set of monosized rock layers (impacted system) and a singular rock block (impacting system). An attractive feature of the study is that it involves irregular rock geometries, in order to create more realistic modelling. The numerical modelling focuses on the influence of parameters such as the size ratio and irregular shape of the rocks (both the impacting rock and the impacted one) and the fall height (impact velocity) from an energy perspective, to determine the fracture patterns, the altered area of ​​influence, the post-impact degree of fragmentation and the breakage probability of the system based on the energy it receives. The results show a high influence of the shape and size of the rock that impacts on the impacted granular system, inducing a network of forces within the rock system that alters and weakens the surrounding rocks, leaving them prone to fragmentation even at low energy. The application of these findings allows the optimization of underground design in mining systems (mainly applied to hard rock caving mining), both to obtain the optimal degree of fragmentation and to control geomechanical risks in underground environments, mainly controlled by the continuous dynamism of the rock mass under fragmentation.

The present study aims to investigate the dynamic properties of fine-grained sandstone rock collected from the coal mining region of India under indirect tensile dynamic loading conditions. A three-dimensional numerical model similar to the split Hopkinson pressure bar (SHPB) setup is developed to validate the experimental results employing the strain rate-dependent Drucker-Prager constitutive model in finite element software, ABAQUS. The validated parameters are then used to simulate the specimen response of fine-grained sandstone rock with pre-flaw of varying orientations, i.e., 0°, 30°, 60°, and 90°. The analysis results demonstrate the reduced dynamic tensile strength of fine-grained sandstone rock with pre-flaws and varying crack orientation. The stress-strain responses at the flaw center and flaw tip highlight significant variations in their values showcasing the sensitivity of orientation to loading rates. This research contributes insights into the crack propagation behavior of sandstone rock under indirect tensile dynamic loading conditions. Additionally, this study also offers a valuable understanding of the directional influences of loading rate on the strength behavior of rock specimens.

In underground development and production blasting, the investigation into blast-induced rock mass damage has garnered extensive attention over the past several years. We have seen a log-ical evolution of blast induced damage modelling techniques. Practitioners have pursued prag-matic approaches. Notable among these models are those employing near-field peak particle velocity (PPV) contouring, complemented by site-specific damage thresholds. However, the application of these techniques encounters limitations, particularly in more intricate mining en-vironments. This paper briefly discusses the evolution of blast damage predictive techniques, whilst also introducing and demonstrating the concept of maximum velocity mapping, an approach that bridges the gap between practical, peak particle velocity-based methods and advanced computational modelling. Through a destress blasting application, the concept captures the three-dimensional shape of blast damage envelopes, considering key factors contributing to blast-induced damage such as point of initiation, velocity of detonation, potential interaction between multiple charges and the impact of boundary conditions.

Knowledge of in-situ rock stress is important for underground projects like mining, nuclear repository, hydropower and other utility tunnels and caverns for the assessment of stability condition. Specifically, it is very important to know the minor principal in-situ rock stress for the design of unlined pressure tunnels and shafts. If a rock stress map is available, it provides an approximate knowledge about the magnitude and orientation of in-situ rock stress and helps to plan and design the underground structures. This manuscript presents the methodology for developing in-situ rock stress map for south-western part of Norway where many un-lined pressure tunnels and shafts of hydropower projects are located. The development of such map is believed to be useful for both early-stage planning of underground waterway system of hydropower projects as well as for mining and civil engineering underground projects where in-situ rock stresses information is needed.

Copper mining in Poland is currently carried out entirely in the Lower Silesian Copper Basin. Over the 60 years of mining, mining activities covered an area of almost 600 square kilometres. Taking into account the scale of excavation and the depth of the deposit location already exceeding 1,200 meters below ground level, the mining operator must face a visible intensification of geomechanical threats such as seismic activity, rock bursts and rockfalls. In order to minimize the risk of serious accidents and maximize operational efficiency, geomechanical risk assessment using numerical modelling has been implemented in selected mining panels in recent years. This study presents a comparison of the results obtained using geomechanical hazard monitoring systems with the results obtained on the basis of FEM-based numerical modelling. The methodology for preparing a numerical model and the method of determining the strength parameters of rocks were described. For comparison purposes, the distribution of various parameters obtained as a result of numerical modelling, such as stress, displacements and the Safety Factor are combined with in-situ collected parameters such as convergence, stress distribution and areas of instability occurrence. The comparison results prove the reliability of the obtained simulation outcomes, which can be the basis for further use of numerical modelling, after appropriate validation, for the prediction of geomechanical hazards.