Rock fragmentation mechanism and engineering application by shaped water pressure smooth blasting

Abstract

In recent years, various regions are vigorously promoting road infrastructure construction, and the tunnel is one of the essential ways of road infrastructure in mountainous areas, but the traditional smooth blasting has problems such as large disturbance of surrounding rock, easy to exceed and underdog, high dust concentration, etc., which delays the construction process of tunnel drilling, time-consuming and laborious. To solve these problems, this paper, relying on the newly built Guantian tunnel project of the ZJHZQ-9 section of Zhangjiajie to Jishou-Huaihua railway Project, studied the stress propagation law of rock blasting, vibration and displacement changes generated by seismic waves and analyzed them through theoretical analysis and numerical simulation, and drew the following conclusions: (1) Based on the basic theory of rock blasting, the principle of shaped charge action and forming mechanism of shaped charge jet are introduced. The effect of water medium and mortar on rock breaking in the blasting process and the movement law of mortar in the hole are analyzed; (2) ANSYS/LS-DYNA software was used for numerical simulation, and the blasting stress propagation law and surrounding rock damage were analyzed. The results showed that the stress propagation of the shaped water pressure smooth blasting was outstanding, and there was an obvious stress concentration phenomenon at the water bag, which verified the shaped energy jet effect of the shaped energy tank; (3) ANSYS/LS-DYNA software was used for numerical simulation, and the changes of vibration velocity and displacement of blasting simulation were analyzed respectively. The results showed that the vibration velocity of shaped charge hydraulic smooth blasting was the smallest, indicating that the water medium had certain energy storage and buffering effect, while the displacement change was on the contrary. Under the joint action of water bag and mortar, the water wedge enlarges the surrounding rock fissures so that the displacement variation of the shaped water pressure smooth blasting is the largest; (4) Through the field engineering application, the direction and width of blasting cracks correspond to the simulation results, which verifies the accuracy of the simulation.