# Characteristics of Vibration Velocity Signal Using Liquid Carbon Dioxide Rock-Breaking Technology
## 1 Introduction  
Dynamic loads can be generated during blasting, causing the rock mass to crack quickly [1]. Therefore, this technique is widely utilized in some engineering construction fields, such as mining, tunneling, and nuclear power plant construction. However, blasting construction can also cause secondary hazards--including blasting dust, polluted gas, flying rock, noise, shock waves, and vibrations--the last of which is the primary hazard and an important factor in blasting design. blasting vibration velocities are strictly regulated [2], especially when the blasting area is close to buildings, installations, and other specially protected objects. Traditional non-explosive methods, such as demolition agents and rock-breaking machines, are generally time-consuming. In addition, hydraulic fracturing (HF) is also an increasingly popular method [3], which can better control the direction of crack development. However, it is worth noting that HF technology is commonly used in the development of oil and gas wells and is relatively expensive. Liquid carbon dioxide rock-breaking (L-CDRB) technology considering both rock-breaking efficiency and economic cost [4, 5], at the same time, produces a much smaller vibration velocity and has a wide range of applications in special situations in which vibration velocities are severely limited. CO\({}_{2}\) phase transition blasting technology was first introduced by the British company Cardox and was called the Cardox tube system. In the early 1960s, this nontraditional physical blasting technology began to be used in Europe and the United States [3, 4]. [PERSON] introduced the structure and use of the device earlier, noting that the Cardox device could be used for large-scale quarry excavations and demolition blasting for concrete structures [5]. Earlier, Turkey applied L-CDRB to coal mining to increase the lump coal output [6]. The current research on this technology is focused on the fracturing mechanism, engineering applications, and equipment improvements. [PERSON] [7] studied the process of L-CDRB and noted that the technology could be used to blast brittle, porous materials, and the single-release power is influenced by the peak pressure and the liquid CO\({}_{2}\) volume. [PERSON] and [PERSON] [8; 9] developed a high-pressure gas-blasting simulation testing system to research the mechanism of L-CDRB. [PERSON] [10] established a finite difference constitutive model based on the theory of damage mechanics and aerodynamics to calculate the effective influence radius of liquid CO\({}_{2}\) single-hole blasting. [PERSON] [11] carried out multiple groups of tests by changing the liquid CO\({}_{2}\) filling amount, the rated pressure of the constant pressure rupture disc, and the combustion agent amounts. The author also measured the pressure change law in the fracturing tube and concluded that the tube's energy was mainly related to the rated pressure of the constant pressure rupture disc and that the energy utilization rate could be improved by increasing the disc's rated pressure. In engineering applications, [PERSON] [12] and [PERSON] [13] found that CO\({}_{2}\) anti-permeability technology was superior to hydraulic fracturing through testing and numerical simulation, respectively. [PERSON] [14] noted the difference between this technology's applications in the fields of coal seam permeability enhancement and rock-breaking. [PERSON] [15] carried out four L-CDRB tests under different geological conditions in an open-air site and noted that the L-CDRB capacity was closely related to the site's geological conditions, hole arrangement, and other design parameters. [PERSON] [16] noted that the technology has a good blasting vibration reduction effect by field testing L-CDRB in the excavation site of the foundation pit of a nuclear power plant. Rock-like brittle materials exhibit different mechanical characteristics under static and dynamic loading conditions [17; 18].