Accurate prediction of blasting vibration should be achieved in mine blasting production practice. It is also a critical problem in the field of blasting vibration control technology research. In this research paper, on the basis of the previous research results and taking account into the reflection principle of elastic wave at the free interface, the authours proposes the blasting seismic wave propagation model. In addition, the blasting positive elevation effect are theoretically explained in detail, and the vibration velocity prediction formula of the positive elevation effect is derived. Finally, the positive elevation effect mechanism and the step (positive) formula are calibrated based on the on-site monitoring data of blasting vibration of Qipanjing Jinou coal mine. In beirf, a theoretical basis is laid by this paper for similar blasting projects.

In this study, cubic and cylindrical cement mortar specimens were first subjected to high temperatures, then the cubic and cylindrical specimens were taken out and conducted with uniaxial compressive test and splitting tensile test, respectively. The effect of the length to side ratio on the uniaxial compressive properties and the effect of thickness-to-diameter ratio on the splitting tensile properties of cement mortar specimens after high temperature were studied. Test results show that: (1) With temperature increasing from 25°C (room temperature) to 400°C, the compressive strength and elastic modulus of cubic specimens with three kinds of side lengths decrease; the decreasing rates of compressive strength and elastic modulus of cubic specimen with side length of 70.7 mm is higher than those of cubic specimens with side length of 100 mm and 150 mm, and the strain at the peak stress of cubic specimens with three kinds of side lengths increase. (2) After the same temperature, the tensile strength of cylindrical specimen decreases with the thickness-to-diameter ratio increasing from 0.5 to 1.0. The decreasing rate of tensile strength of cylindrical specimen with thickness-to-diameter ratio is highest when the temperature is 25°C (room temperature), followed by that after the temperature of 200°C, and that after the temperature of 400°C is the lowest.