Application of High-Pressure Gas Expansion Rock-Cracking Technology in Hard Rock Tunnel near Historic Sites

Abstract

In order to study the applicability of high-pressure gas expansion rock-cracking technology in hard rock tunnel near historic sites, theoretical analysis, field tests as well as vibration monitoring are conducted to obtain suitable rock mass cracking parameters for tunnel excavation. The results show that the ideal effect of rock mass cracking can be achieved with the cutting mode of “central vertical empty hole + double wedge cutting hole” and the auxiliary hole network parameter of “0.8 m × 0.7 m”. The measured vibration velocity is less than 0.1 cm/s at the monitoring point 60 m away from the tunnel face in the field test, which meets the vibration control requirements of the historic sites in the process of tunnel excavation. The research results show that as long as there is a high quality of hole plugging and no punching, the high-pressure gas expansion rock-cracking technology has the advantages of little vibration, low noise and less flying rocks, which provides a technical reference for the excavation of hard rock tunnels near ancient buildings and historic sites.

Study on damage mechanism of mudstone radiated by high energy laser

“…If the traditional mechanical rock breaking technology is continuously used, it is easy to cause serious wear of drill bit, in-crease the cost of drill bit replacement, and low rock breaking efficiency [1]. In recent years, with the continuous development of science and technology, there have been many new technologies in rock breaking, such as hydraulic rock break-ing [2], blasting rock breaking [3], microwave rock breaking [4], laser rock break-ing [5], etc. The emergence of these new technologies has greatly accelerated the speed of rock breaking, and most of these new technologies are caused by non-direct contact with rock rock breaking behavior, perfectly making up for the dis-advantages of traditional rock breaking technology.…”