Evolution law of surrounding rock stress field for ultra-deep shaft development blasting.

With the increase of the construction depth for ultra-deep shaft development blasting, it is prone to occur problems such as reduced driving efficiency, frequent dynamic disasters, wellbore instability and fracture under the coupling effect of deep high stress and strong blasting disturbance. In this paper, the dynamic evolution process of surrounding rock stress field and the propagation law of explosion stress wave in the process of ultra-deep shaft development blasting were studied by combining theoretical analysis with physical model test. The theoretical analysis model of ultra-deep shaft blasting excavation was established based on elastic mechanics, and the stress distribution and failure mechanism of surrounding rock under the coupling effect of deep high stress and blasting load were explored.

Experimental Study on the Dynamic Response and Pore Structure Evolution of Coal under High-Pressure Air Blasting.

High-pressure air blasting (HPAB) is one of the main feasible technologies to improve the extraction efficiency of unconventional gases. At present, there are few visual studies on the evolution characteristics of pore structure in coal under HPAB, resulting in an unclear understanding of the mesoscopic damage evolution mechanism of coal under HPAB. To study the dynamic response and mesoporous structure evolution characteristics of coal under HPAB, simulated coal specimens were used in HPAB experiments.