The formation and development of plastic zone in the surrounding rock is the essence of large deformation damage to the surrounding rock in deep, highly stressed roadway. The −850 m roadway of the Qujiang mine is laid flat longitudinally under the 805 working face and coal pillar, and under the influence of the mining movement of the upper working face and the pre-stressing pressure of the coal pillar, the periphery of the roadway is no longer a pure non-uniform stress field, but a non-uniform stress field with both vertical and horizontal dynamic pressure. Based on the Hoek–Brown strength criterion, the unified strength theory is modified and the nonlinear unified strength theory of rock is established by comprehensively considering the intermediate principal stress, rock properties and rock structure. The boundary line equation of the plastic zone of the surrounding rock with non-uniform stress field under mining is proposed, and the effects of lateral pressure coefficient, Hoek–Brown parameter and intermediate principal stress as well as dynamic pressure coefficient on the morphology of the plastic zone are investigated. The results show that: (1) When the lateral pressure coefficient λ ≠ 1.0, the plastic zone of the surrounding rock expands in the direction of inclination to the corners of the roadway, and the whole is similar to the “butterfly-type”, and the more the value of λ deviates from l.0, the more the shape of the plastic zone is similar to the “butterfly-type”. (2) Regarding the dynamic pressure coefficient and the change curve of the radius of the plastic zone, whether it is the shallow stress field or the deep stress field, the curve is the first smooth growth, and the dynamic pressure coefficient reaches a certain value (about D_i = 2.5), and the radius of the plastic zone starts to show a sharp nonlinear growth, which is a ‘sharp lifting type’. The influence of the dynamic pressure coefficient on the radius of the plastic zone exists D_ξ critical dynamic pressure coefficient. (3) The influence of intermediate principal stresses on the extent of the plastic zone and the magnitude of displacements in the pavement enclosure is inter-zonal in nature. The study on the evolution of the “butterfly-type” plastic zone is of great theoretical and practical significance for the development and utilisation of deep underground resources.

This study employs a drop-hammer blast simulator to conduct eight impact tests on reinforced concrete (RC) slabs. Experimental results demonstrate that the peak pressure and duration exhibit waveform characteristics similar to those of actual blast loads. Numerical simulations further validate strong agreement with experimental data. Through dimensional analysis, a functional expression correlating parameters with impact load is derived. Orthogonal design methodology optimizes parameter combinations, while experimental and numerical results jointly determine unknown coefficients to establish a predictive model for impact load. Key findings indicate that impact velocity exerts the most extensive influence on peak pressure and impulse adjustment. Variations in pyramid rubber height demonstrate more significant effects on impact load than flat-layer thickness. The proposed method offers a safe and cost-effective alternative to conventional explosive testing for simulating blast loads on RC slabs.

To explore efficient pathways for the resource utilization of silicon-rich solid wastes in low-carbon concrete, this study proposes a synergistic regulation strategy centered on the silicon-to-calcium (Si/Ca) ratio. Three types of silicon-rich solid wastes-glass sand, glass powder, and rice husk ash-were incorporated to produce waste glass and rice husk concrete (WGRC). The effects of varying Si/Ca ratios on the workability, mechanical properties, and durability of WGRC were systematically investigated. Furthermore, the underlying mechanisms were elucidated through microstructural analysis. The results indicate that WGRC exhibits optimal overall strength within a Si/Ca ratio range of 0.46 ~ 0.58. When the Si/Ca ratio ranged from 0.52 ~ 0.58, WGRC demonstrated superior resistance to water penetration and sulfate attack, with the lowest mass loss rate (0.54% after 180 drying-wetting cycles) and the smallest ultrasonic velocity reduction (only 2.6%). At a Si/Ca ratio of 0.58, the carbonation resistance was maximized, yielding the lowest carbonation rate. In addition, the Si/Ca ratio within the C-S-H gel increased progressively with curing age, though the rate of increase slowed after 90 days. A shear damage constitutive model was developed to accurately describe the nonlinear response characteristics under varying Si/Ca ratios and shear angles, validating the coupling relationship among composition, structure, and performance. These findings provide new theoretical insights and design strategies for the synergistic utilization of multiple solid wastes in low-carbon concrete. They also offer a scientific basis for enhancing the mechanical and durability performance of WGRC, thereby contributing significantly to the advancement of sustainable construction materials.

The key blocks are the core factors affecting jointed rock high slopes. How to quickly identify key blocks in complex rock high-steep slopes and obtain block information is one of the key issues to be solved in engineering. Due to the numerous joint fissures in jointed rock slopes, which bring complexity and variability to the search for key blocks, this paper proposes a targeted and flexible key block search method based on the finiteness theorem and movability theory of block theory. Non-contact photogrammetry technology is used to collect the structural plane information of the slope rock mass in the study area, and the data is imported into Trimble RealWorks software to establish a 3D model of the rock high-steep slope. Through the processing of point cloud data, parameters such as the sliding direction, structural plane intersection points, area, and volume of key blocks in the slope are obtained, and key blocks are searched from a geometric perspective. Finally, according to the full-space stereographic projection theory, movable fissure blocks are identified, and the residual sliding force calculation theory of movable fissure blocks is used to determine the key blocks in the slope free face, and the sliding instability mode of jointed rock slopes is studied. The application of this theory in the Fujian Yongtai high-steep slope project has verified that the method has the advantages of strong pertinence, simple operation, and good adaptation to the judgment conditions specified in relevant codes. The research results provide a scientific basis for further revealing the key blocks of jointed rock slopes.