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[III-112] The cause and mechanism of the Tachikawa district slope failure in Kochi Expressway due to heavy rain in July, 2018

*伊藤 博信¹、平山 浩司²、内田 純二¹ (1. 西日本高速道路エンジニアリング四国株式会社、2. 西日本高速道路株式会社)

Keywords:Slope disaster prevention, Slope failure, Heavy rain disaster, Slope failure mechanism

The earth and sand on the natural slope fell on July 7, 2018 in the upper part of the Tachikawa Tunnel south entrance of the Kochi Expressway. The slope failure caused the bridge superstructure to flow out at Tachikawa Bridge. In this paper, based on the field survey and the survey and construction data at the time of construction, we report the topography and geology of the runoff of the bridge and the cause and the Slope failure mechanism.