Remedial Measures for Existing Anchored Slopes in Taiwan

Abstract

This paper presents the results obtained from an island-wide investigation program for anchored slopes alongside freeways, highways, and railways in Taiwan. The investigation procedures include the visual inspection of anchor protection caps and anchorage head components, borescope inspection of strands under anchorage heads, and lift-off test to determine residual anchor loads. It was found that groundwater and corrosion were the common problems associated with ground anchors. Immediate measures were taken to backfill cavities under anchorage heads to prevent further corrosion on existing anchors. The upper and lower bounds of the remaining capacity of existing anchors was assessed using a t-distribution statistical method; also, if necessary, extra anchors with better corrosion protection were installed to restore the degraded stability of slope due to anchor corrosion. A low-cost smart anchor capable of self-detecting load changes is also proposed. Use of such smart anchors will allow the anchor load changes on a slope to be monitored on a large scale over an extended period of time and provide needed anchor information for assessing the future stability of anchored slopes.