The propagation process of blasting vibration has always been a difficult problem affecting the stability of high slopes in open-pit mines. Taking the Jianshan Phosphorus Mine as the research background, combined with engineering geological investigation, field blasting test, blasting vibration monitoring, numerical simulation technology, and theoretical analysis, the three-dimensional dynamic stability of the adjacent high slope after blasting vibration was systematically studied. In our study, a small-diameter buffer shock-absorbing blasting technology near the slope was proposed, which greatly improved the production efficiency. Through regression analysis of a large amount of vibration test data, the law of blasting vibration propagation in Jianshan stope and Haifeng stope was obtained. In addition, by establishing four three-dimensional geomechanical numerical models, the slope’s own frequency, damping characteristics, and dynamic response acceleration distribution after detonation were studied, respectively. On the other hand, under the action of Ei Centro wave with 8-degree seismic intensity, the maximum total acceleration and maximum total displacement of the slope were calculated and analyzed. Both the explosion unloading of the 8-degree earthquake and the Ei Centro wave simulation results showed that the high slope near the Jianshan Phosphorus Mine was generally in a stable state. Thus, this study can provide technical support and theoretical guidance for mine blasting.
Geopolymer is a new type of synthesized aluminosilicate material. Compared with ordinary Portland cement, it has better fire resistance and durability, and is more environmentally friendly. In this paper, a high-strength metakaolin-based geopolymer composite (HMGC) has been developed by utilizing quartz powder and steel fibers. The optimization compositions and effect of curing temperatures (from ambient temperature to 90 °C) on the strength performance of the HMGC is studied. The optimized 1-day compressive strength of the HMGC can reach 80 MPa, and the 3-day compressive strength is close to 100 MPa (97.49 MPa). Combined with XRD, FTIR, SEM and MIP characterization, the mechanisms behind the strength development under different curing temperatures are analyzed. The results show that heat curing can significantly speed up the process of geopolymerization and increase the early strength of the HMGC. However, long-term heat curing under high temperature (such as 90 °C, 7 days) would reduce the mechanical strength of the HMGC. Prolonged high-temperature curing increases the pores and micro-defects in the gel phase of the HMGC, which may be attributed to chemical shrinkage. Thus, the curing temperature should be carefully controlled to make a HMGC with better performance.