The test data of metals, brittle materials and polymers in high, medium and low strain-rate range were summarized. It was found that the dynamic strength or yield stress of these materials was not sensitive to strain-rate in the low and high strain-rate range (corresponding to weak sensitivity area and saturated zone). But in the medium strain-rate range (strong sensitivity area), the dynamic strength or yield stress of these materials was extremely sensitive to strain-rate. The strain-rate effect function in classic Johnson-Cook constitutive model could not describe these phenomena in the range of low to high strain-rate. Therefore, the strain-rate effect function in classic Johnson-Cook constitutive model has been modified to a strain-rate effect expression which is suitable for different materials. This new model can better describe the phenomena of the weak sensitivity area, strong sensitivity area and saturated zone. With this model, the fitted curves are in good agreement with the test data, and the parameters are different for different materials. Finally, the fitting parameters are given.

In mining engineering, the in situ stress changes with the stress induced by the surrounding mining activities. It positively or negatively affects the propagation of ultrasonic guided waves in rockbolts. Therefore, the effect of in situ stress in rockbolt support was determined by applying confining pressure and pull-out load in a laboratory test and using ultrasonic guided waves to test the rockbolt. Furthermore, the propagation law of ultrasonic guided waves and bond quality of the rockbolt under the interaction of the pull-out load and confining pressure were studied. Numerical simulations were performed to deduce the guided wave propagation process in grouted systems, and the influencing mechanism of the pull-out load and confining pressure on the guided wave propagation was discussed. The laboratory test and numerical simulation results show that the confining pressure weakens the guided wave propagation without pull-out load. Under the same pull-out load, the guided wave propagation gradually strengthens with increasing confining pressure. A larger confining pressure weakens the weakening effect of the pull-out load and suppresses the discreteness of the guided wave propagation. Under the same confining pressure, the guided waves did not diffract well into the cement mortar and concrete with increasing pull-out load, the confining pressure restricted the radial vibration of the guided waves, and the guided wave propagation law weakened. Thus, the pull-out load plays a weakening role in the propagation law of ultrasonic guided waves.

In grouted rock bolt systems, bond defects often occur, which seriously affects the safety of rock mass structures. Therefore, in this study, based on the existence of bond defects, laboratory tests were conducted to detect the location and length of bond defects and study the guided wave propagation in grouted rock bolt systems under different pullout loads. The guided wave signal was analysed in the time domain and frequency domain. In addition to the laboratory test, a numerical simulation of the effect of different bond defect locations on ultrasonic guided wave propagation in rock bolts was conducted using a damage-based model. The influence mechanism of bond defects on guided wave propagation under different pullout loads was explored. The study confirmed that there existed a stress platform in the rock bolt at the bond defect under a pullout load. The location and length of the bond defect could be detected by the stress platform and guided wave. The debonding length increased exponentially with the amplitude ratio (Q) of low frequency to high frequency, and the Q value could be used as the quantitative index of debonding length. As the pullout load increased, the impedance mismatch between the rock bolt and cement mortar (defect) increased, and the guided wave propagation in grouted rock bolt systems was irregular. The pullout load weakened the guided wave propagation law. The larger the pullout load is, the greater the weakening effect is.

In order to save natural resources and protect the natural environment, the relevant performance of waste glass powder as a building material must be enhanced. In general, volcanic ash activity is enhanced through grinding the glass powder particles to a specific degree of fineness, thereby improving the overall strength of cementitious sand. Our current need is to study the effects of replacing standard sand with glass powder of varying particle size and dosage range on its resistance to sulfate erosion as well as the corresponding mechanisms. To further examine the durability properties of glass powder cementitious sand, this study uses glass powder of 100–200 mesh and 200–500 mesh to create cementitious sand samples, replacing 10% and 15% of standard sand with equal volume. After curing for 28 days in a standard curing room, the samples are submerged in tap water and a 5% concentration of sodium sulfate solution for 30, 60, 90, 120, and 150 days. Subsequently, the mass loss rate, flexural strength, and compressive strength are measured to reflect the sulfate erosion resistance of the cementitious sand samples containing glass powder. The findings indicate that the flexural and compressive strengths of cementitious sand with waste glass powder experience a swift decline in strength during the pre-erosion stage and a slow decline or even an increase in strength during the post-erosion stage as erosion age progresses. As the glass powder dosage increases, there is a noticeable decrease in the flexural and compressive strengths, in which the doping of 200–500 mesh doped with 15% of glass powder has the worst effect on the resistance to sulfate erosion. As the particle size increases, both flexural and compressive strengths significantly improve, suggesting that sulfate erosion properties are gradually enhanced. The primary reason for this phenomenon is that when glass powder substitutes fine aggregate, the activity develops more slowly in the initial stage, primarily filling the pores and cracks. However, the activity increases rapidly later, more fully integrating with the cement mortar in sodium hydroxide’s hydration product to create dense hydrated calcium silicate crystals. This enhances the overall strength of the sample, filling the pore structure within the system, and is more conducive to resisting the erosion effect of sulfate ions on the sample.