抄録
There is a ground anchor technique as one of the earth reinforcements to sustain the stability of the slope, which has been widely used for stabilizing cut slopes in Japan for the last thirty years. As ground anchors are anticipated to be deteriorated by geological environments such as ground water and natural disasters such as earthquake and typhoon, it is recommended to evaluate its performance by regular survey and tests. Moreover, it is believed that old-type anchors have a low protection performance against the corrosion on the surface of old-type anchors. Consequently, it is necessary to evaluate appropriately the damage of anchors as well as the stability of slope reinforced by deteriorated ground anchors. The performance of ground anchors is generally checked by soundness diagnosis, which is the visual check of anchor head, and lift-off tests, which is the loading test to measure a residual stress in anchor. The soundness diagnosis and lift-off test are effective for evaluating the performance of single anchor itself, however, the reliability of the safety assessment between the entire reinforced slope and the performance evaluation for single ground anchor has been questioned. This paper analyzed the reliability of soundness diagnosis based on the past regular surveys and lift-off tests statistically, proposed a deterioration model for single ground anchor using the Weibull distribution and finally assess the stability of reinforced slope with the proposed model.
