The countermeasures using stabilizing piles are proposed to stabilize for cut slopes in soft grounds. The proposed design method is established on the basis of the stability analysis of slope with rows of piles. The basic concept applied in the stability analysis is that the soil across the open space between piles can be retained by the soil arching action, when a row of piles is installed in soil undergoing lateral movement such as landslides. To obtain the whole stability of slope containing piles, two kinds of analyses for the pile-stability and the slope-stability are performed simultaneously. An instrumentation system has been installed at a cut slope in soft ground to confirm the stability of the cut slope. The behavior of both the piles and the soil across the open space between piles is observed precisely. The instrumentation shows that the cut slope has been stabilized by contribution of stabilizing effect of piles on the slope stability in soft ground.
Recently, rapid economic and population growth has led to a need for a more efficient use of land. Sometimes, excavation work in these reclaimed areas has been performed for the construction of apartment, buildings, and infrastructure facilities. The excavation work in the reclaimed lands naturally causes produce the unstable cut slope, because of the limited conditions of the site. In general, the steeper gradient of cut slopes produces the lower slope stability. Therefore, several countermeasures to prevent slope failure are proposed for cut slopes in soft grounds. Stabilizing piles are suggested as one of the most favorable countermeasures to prevent slope failure in soft grounds. To confirm the effects of slope stability using piles, however, the behavior of both piles and slope must be investigated and analyzed in detail.