# Characteristics of Vibration Velocity Signal Using Liquid Carbon Dioxide Rock-Breaking Technology
## 1 Introduction
The deformation characteristics, failure strength, and fracture characteristics of rocks at high strain rates are all affected by rate effects. According to different loading rates, rock strain rate characteristics can be classified from low to high into creep, quasi-static loading, medium strain rate, high strain rate, and ultra-high strain rate [19]. Under impact and explosion loads, rocks are subjected to large impact loads in a short period of time, and their stress characteristics fall within the range of ultra-high strain rates and high strain rates. Carbon dioxide phase change blasting has a much smaller loading stress peak and pressure boosting time than explosive blasting. According to current research, three commonly used rock-breaking techniques can be used: explosive blasting, L-CDRB, and HF. The pressure-loading characteristics of different rock-breaking methods are listed in Table 1.  
The rock-breaking process of L-CDRB technology is divided into two parts. The first part is the impact of high-pressure carbon dioxide on the rock mass, and the second part is the quasi-static carbon dioxide driving the further development of cracks. [PERSON] [20] obtained a formula for calculating the radius of the fracture zone by analyzing the process of rock cracking caused by carbon dioxide phase transformation and pointed out that the effect of rock breaking can be improved by increasing the initial pressure of liquid carbon dioxide in the fracturing tube. Through model tests, [PERSON] [21] found that carbon dioxide does not produce a fracture zone in rock breaking, and stress waves are the main cause of damage to concrete model specimens. The structure of the cracking tube has an important impact on the rock-breaking effect. As this technology has been applied in various engineering projects, some scholars have studied a new type of fracturing tube, which changes the way pressure is released from the tube's end to its lateral side. Thus, the pressure acts more evenly on the blast hole, minimizing accidents resulting from the first-generation fracturing tube being stuck or blown off in practical applications. [PERSON] [22] and [PERSON] [23] studied the equivalent energy and characteristics of the blasting vibration signals of the new type of fracturing tube and noted its greater safety and efficiency. At present, no reports directly monitor the internal \begin{table}
\begin{tabular}{c c c c} \hline
**Technology** & **Peak Pressure (MPa)** & **Time of Pressure Rise (s)** & **Pressure Duration (s)** \\ \hline Explosive & \textgreater{}10\({}^{4}\) & \(10^{-7}\) & \(10^{-6}\) \\ L-CDRB & \(10^{2}\) & \(10^{-3}\) & \(10^{-2}\) \\ HF & \(10\) & \(10^{2}\) & \(10^{4}\) \\ \hline \end{tabular}
\end{table} 
Table 1: Loading parameters of different rock-breaking techniques. pressure of the new type of fracturing tube, and few comparative test studies have been made on L-CDRB and explosive blasting in the same field. In this study, the vibration propagation law of the CO\({}_{2}\) rock-breaking technology was investigated by carrying out field tests in an open pit mine, and the main innovations are as follows. (1) Large-scale field trials were carried out using 1378 kg of liquid CO\({}_{2}\). (2) The new fracturing tube was used, and the pressure relief method was changed from the tube's end to its lateral side. (3) At the same site, a monitoring comparison was conducted on the vibration velocities between explosive blasting and L-CDRB, and the characteristics of the low vibration velocities produced by L-CDRB are described here in detail. (4) A wide range of vibration monitoring tests were conducted with many pieces of vibration velocity monitoring equipment arranged at different distances (9.7-260.5 m) from the explosion zone's center, so the vibration velocity attenuation law obtained here is more reliable.