Technology for Efficient Excavating

High-performance Shields

  • Double Cutters

    These use a double cutter system in which the cutter blades in the front of the shield (excavation face) are separately rotated within the inner periphery and the outer periphery. This achieves an approximately 25% improvement in the excavation progress speed over conventional methods in which all cutter heads are rotated together. It is also an extremely efficient excavation method that reduces energy consumption by approximately 30%.

  • Cutting of Obstacles

    This is a technology where special bits are installed in the shield machine for directly cutting obstacles underground (type III , IV, and V steel sheet piles, and H-section steel). It does not require humans to be in the front of the face.

  • SENS Method

    “SENS method” stands for “Shield-ECL-NATM-System” method. In this method, the stability of the face is preserved during excavation using the Shield method. This method does not require segment assembly and the tunneling work can be completed by aiming for a quick closure with initial timbering using the cast-in-place lining method (ECL), and placing concrete for the second lining following displacement and convergence on the ground, in the same manner as NATM sprayed concrete. The φ11 m class is used for Shinkansen and railway tunnels. We have also released machines with special equipment that allows you to switch between the Shield and SENS method.

    SENS is gaining its place as a cost-efficient construction method of boundary regions of NATM and SHELD method, according to the characteristics of the subsoil. It is expected to have major contributions in the future to the fields of large bore diameters and long distances, in particular.

Special Section Shields (Non-Circular)

  • DPLEX (Eccentric) Shields

    The cutter frame is operated through parallel linking, which makes it possible to excavate any section, such as squares, ovals, horseshoes, and circles.

  • Expansion Shields

    Following soil stabilization around the circumference where the shield tunnel work was performed, the ground is excavated in a circumferential shape along the tunnel circumference in order to expand the tunnel in the prescribed section and concentric circular shape.