Abstract

Carbon dioxide phase change fracturing technology is a brand-new and efficient cracking and tunneling technology. Because the method utilizes the change of carbon dioxide state, it belongs to a pure physical process. By adjusting the release rate of gaseous substances, it can effectively control the pressure of the gas, and achieve micro vibration, zero flying stone, zero toxic gas emission, and no micro harmful effect of shock wave, but the application of carbon dioxide phase change cracking technology in urban foundation pit excavation is less. In this paper, through the analysis of three different cracking parameters of urban foundation pit excavation process, it is found that when the diameter of the cracked pipe is 85 mm, the construction safety can be guaranteed. In addition, according to the on-site cracking effect, the carbon dioxide phase change cracking technology is a safe, reliable, relatively economical and efficient excavation technology under urban complex environmental conditions, and will not affect the surrounding environment during use, but Its cracking efficiency has a great relationship with the air surface.

Highlights

  • IntroductionIn urban underground space projects (such as subway tunnels, subway stations and underground space civil air defense projects, etc.), the above regulations on safety, vibration and environmental hazards are very strict

  • In urban underground space projects, the above regulations on safety, vibration and environmental hazards are very strict

  • The hydraulic splitting machine captures the brittle nature of rock and concrete, and uses the wedge principle to design - hydraulic cracking of the rock, cracking and rock without vibration and sound [14, 15]

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Summary

Introduction

In urban underground space projects (such as subway tunnels, subway stations and underground space civil air defense projects, etc.), the above regulations on safety, vibration and environmental hazards are very strict. Until the 1980s, Singh [7] pointed out in the PCF (Penetrating Cone Fracture) concept that the liquid CO2 phase change rock breaking technology has no explosive blasting restrictions, and can be operated with high efficiency and is suitable for rock excavation. The mechanism of CO2 cracking is a physical change, and there is no open flame or spark during use, which improves the safety of the technology in all aspects It is not restricted by the control of explosives, and the scope of use is limited. FEASIBILITY STUDY ON THE APPLICATION OF CARBON DIOXIDE PHASE CHANGE FRACTURING TECHNOLOGY IN A FOUNDATION PIT OF AN OPEN CUT TUNNEL. Carbon dioxide phase change cracking technology is less used in urban foundation pit excavation. The feasibility of the vibration response, safety and economy of the excavation process of carbon dioxide cracking technology in a city excavation foundation pit is studied

Application background
Controlled blasting
Hydraulic splitting
Carbon dioxide phase change fracturing technology
Fracture parameter design
Results analysis
Environmental impact and economic comparison analysis
Conclusions
Full Text
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