摘要

The capacity of the Wuku-Yangmei freeway is insufficient for developing the Taoyuan Aerotropolis. To provide more traffic lanes to the existing freeway, a series of pier foundations at the freeway embankment have been constructed for the Wuku-Yangmei Overpass, meant to ease peak-hour congestion between Taipei and Taoyuan. The H-section with a horizontal wale strip has been widely adopted as an effective shoring measure in Taiwan. However, this may not be applicable as the presence of cobble in the lateritic soil formation may cause difficulties in installing H-sections for excavation. Soil nailing and an alternative shoring method with ring beams at the slope and a composite shoring system at the shaft were applied to Piers B7 and C15, respectively, to compare their slopes' lateral displacement, lateral displacement-time curve, and surface tension cracking. Field measurements indicate that the rectangular shaft with a soil nail shoring system is not effective at limiting the lateral displacement, leading to the slope sliding incident. Three-dimensional finite-element analyses using the input parameters that are back-calculated by comparing the lateral displacement-depth curves to the inclinometer data have been conducted. The modeling results are found to be in reasonable agreement with the inclinometer data and the shear strain increment profile may give a better understanding of the sliding surface position.