Prevention of Landslides with Rows of Pressed-In Pipe Piles on Steep Slope-Paper

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The paper describes a landslide-prevention project for a high-speed rail bridge in a steep, geologically unstable area of Kyushu, Japan. The slope had a history of landslides and consisted of colluvial soil and weathered mudstone over layers of mudstone, tuff, and breccia, with several potential landslide planes.<br /><br />To protect the bridge piers, three groups of steel pipe piles were installed in two parallel, slightly staggered rows. The piles were 1,200 mm in diameter, spaced 3 m apart, and ranged from 31 to 43.5 m long, with 13.2–15.2 m embedded in stable bedrock. The spacing and staggered arrangement allowed groundwater to flow between the piles.<br /><br />Installation used the Gyropress method, which rotates and presses piles into the ground using a sacrificial cutting shoe at each pile toe. The shoe reduces installation resistance and enables penetration into hard rock. The GRB System allowed equipment and materials to move along the completed pile rows, minimizing the need for access roads or heavy equipment on the steep, unstable slope. Skip Lock attachments enabled installation at the required pile spacing, while portable platforms provided work areas and equipment access.<br /><br />The project demonstrates that long, large-diameter pipe piles can be installed efficiently and safely into bedrock on steep terrain. The authors conclude that Gyropress piling, combined with the GRB System, provides a practical means of constructing robust landslide-prevention barriers while limiting disturbance to difficult sites.

Keywords

landslide prevention

high-speed rail bridge

Kyushu Japan

steel pipe piles

Gyropress method

GRB System

slope stabilization

colluvial soil

weathered mudstone

bedrock penetration