This paper investigates the influence of five hole shapes (ellipse, circle, trapezoid, inverted-U, and square) on the mechanical behavior and crack process of rock-like materials under compressive-shear loading. The study employs both laboratory experiments and discrete element method modeling. The results show that the presence and shape of holes significantly reduce load-bearing capacity of rock samples, particularly square holes with sharp corners, which can lead to crack propagation due to stress concentration. The progression of surface deformation, as captured by digital image correlation technology, provides additional insights into the nucleation and propagation of cracks. The numerical simulations show that elliptical hole samples exhibit the highest crack initiation load, while square hole samples exhibit the lowest. The ratio of crack initiation load to peak load remains constant for different hole shapes, ranging from 0.5 to 0.6. The findings of this study provide theoretical insight and practical evidence for rock engineering design and construction in compressive-shear environments.

Based on the pressure of environmental protection, more and more scientific researchers are trying to reuse aluminum–silicon-rich industrial wastes. In this study, activated lithium-slag and lead–zinc tailings were used as raw materials to prepare geopolymers at ratios of 3:7, 1:1, and 7:3. These geopolymers were initially cured for 12 h at 25 °C, 50 °C, 75 °C, and 100 °C and were then cured at room temperature to the specified ages. The compressive strength of each group of geopolymers was tested at the ages of 3 days, 7 days, and 28 days. The optimal group of samples was selected, that is, those with a ratio of lithium-slag to lead–zinc tailings of 7:3 and an initial curing temperature of 75 °C. After that, the heavy metal leaching test and porosity analysis test were carried out on the optimal group of samples, and the curing effect was considered to meet the requirements of the Chinese specifications. In addition, in order to reveal the mechanism of the chemical reaction, scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure and hydration products of the C3 group cured samples. This study provides a new concept for the reuse of industrial wastes such as lithium-slag and fine-tailings.

Tailings dams play a critical role in ensuring the safety of mining operations. However, earthquakes can cause breaches in these dams, resulting in significant casualties and property damage. This study investigates the dynamic response characteristics of uranium tailings dams subjected to seismic loading, employing the discrete element method. It specifically analyzes how seismic wave amplitude, frequency, and the friction angle of tailings sand affect the dams’ dynamic response. The results reveal that the peak ground acceleration ratio (PGAR) exhibits an increasing–decreasing–increasing pattern with elevation. When the friction angle of the tailings sand exceeds 35°, the overall stability of the dam improves. Conversely, a friction angle below 25° significantly increases the risk of dam failure. Additionally, the dam shows a reduced dynamic response to seismic waves with frequencies exceeding 15 Hz. At lower frequencies, deformation and damage are primarily concentrated on the slope face, while at higher frequencies, damage is predominantly located at the bottom of the model. These findings provide a theoretical foundation and reference for the safe operation of tailings dams, highlighting their practical significance.

To further elucidate the relationship between the growth stress and cracking of KDP (KH₂PO₄, potassium dihydrogen phosphate) crystals of different sizes, a three-dimensional finite element calculation was conducted to analyze the growth stress of KDP single crystals grown from Z-plate seeds with varying cooling rates. The mismatch in the coefficient of thermal expansion (CTE), between the cap region and its close vicinity, and among the transparent region, was taken into account. The results indicate that when the cap region is a solid region (when the seed was regenerated with a cooling rate of 0.1 °C/day), the difference in material properties between the cap region and its close vicinity, especially the CTE mismatch along the a-axis, is the main reason of the high stresses. When the cap region is a box-like structure filled with solution (when the seed was regenerated with a cooling rate of 0.3 °C/day), the calculated stress is in proportion to the CTE gradient of the transparent region. Under both models, the stresses induced from an incremental CTE value (from the cap region to the growth front) are greater than those calculated from a diminishing CTE value, implying that the impurities reduce the CTE of KDP crystals, causing the crystals to crack more easily. Despite the maximum stresses inside the crystals changing slightly with an increase in crystal size, the decreased fracture stress of large brittle crystals leads to a higher cracking risk in a large-sized crystal.