This technology is a steel pipe jacking method that horizontally excavates ground using an auger screw while simultaneously installing a steel pipe casing. During the process, liquid nitrogen is supplied through the hollow rotating shaft of the auger screw to rapidly freeze the ground in front of the excavation face, allowing for continuous excavation and pipe installation through the frozen soil.
Securing rescue and supply passages in urban underground collapse sites requires horizontal excavation; however, this often leads to soil loosening and water leakage, causing hydraulic and mechanical instability. Furthermore, depending on soil conditions and groundwater levels, there is a high risk of face collapse, often necessitating additional ground reinforcement at the jacking and receiving pits.
In this technology, a moving pipe inside the hollow rotating shaft extends through a front discharge hole to spray liquid nitrogen, while a rotating pipe operates a blocking member to open and close the discharge hole and prevents heat transfer between the hollow rotating shaft and the moving pipe. This allows for rapid groundwater blocking during excavation, increases the stiffness of the surrounding ground to reduce collapse risks, and minimizes ground disturbance. It can be applied to creating rescue passages in urban underground collapse sites, trenchless pipe installation near subways and tunnels, and horizontal jacking in soft ground with high groundwater levels, ensuring immediate excavation face stability without the need for separate chemical grouting.
N/A
