Abstract: A shield tunneling method of excavating a tunnel with an optional cross section by rotating a center cutter about an axis extending in the direction of propulsion and revolving a planetary cutter around the axis so as to excavate the region between the profile of excavation by the center cutter and the desired profile of excavation. A machine for practicing the method includes a center cutter supported by the body of the machine so as to be rotatable about an axis extending in the direction of propulsion of the body, a rotary body rotatable about the same axis as the center cutter, a planetary cutter supported by the rotary body so as to be movable radially of the rotary body, and operating device for moving the planetary cutter in the radial direction to permit the planetary cutter to revolve along a locus during the rotation of the rotary body so that the planetary cutter excavates the above-mentioned region.

Abstract: Soil including a setting agent such as fiber-soil-cement or the like is sprayed onto a slope so that corrugations extending substantially in parallel to the horizon are formed. Grooves and ridges of the corrugated surface provide conditions for allowing plants to grow on the protected slope.