This technology is a steel pipe jacking and excavation method that horizontally excavates ground using an auger screw while pushing in a steel pipe casing. It then injects liquid nitrogen through the hollow rotating shaft of the auger to rapidly freeze the ground in front of the excavation face, allowing for the subsequent excavation of the frozen ground and further casing insertion.
When buildings, subways, or tunnels collapse in urban areas, creating a safe passage for evacuation and supplies is critical. However, horizontal excavation often loosens surrounding soil and causes water leaks, leading to hydraulic and mechanical instability. Furthermore, depending on soil and groundwater conditions, there is a high risk of tunnel face collapse, often requiring additional ground reinforcement at the jacking and receiving pits.
This technology features a movable pipe inside the hollow rotating shaft that carries liquid nitrogen. During the freezing phase, this pipe extends out through a discharge hole to freeze the tunnel face, then retracts back into the shaft before the next excavation cycle. A blocking member inside the front of the shaft rotates with the pipe to selectively seal the discharge hole, while the rotating pipe includes a passage that insulates the hollow shaft from the movable pipe. Applicable for rescue passages in collapse zones, trenchless urban utility installation, and steel pipe jacking in soft or high-groundwater soils, it instantly blocks groundwater and stabilizes the surrounding ground, enabling the creation of rescue passages without further collapse.
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