Long-term weathering of cut slope consisting of mudstone

摘要

Weathering of geomaterials causes degradation of the material,resulting in a surficial collapse in cut slopes.Thus,slope protection methods such as vegetation and shotcrete are empirically applied to retard the weathering.The weathering mechanism has not been fully understood,and the prediction of the progress of the weathering is still challenging.Therefore,we selected 96 cut slopes on Japanese highway routes and have tried to grasp the progress of weathering of the slopes through field surveys such as elastic wave exploration tests.In this study,a cut slope consisting of mudstone on Tomei Expressway in Yoshida,which exhibited a localized collapse in 2016,was studied to investigate the weathering state of the ground.This slope was constructed in 1968 and has experienced more than 50 years after construction.The objectives are to investigate the spatial distribution of the weathering magnitude of the cut slope and to grasp the weathering effect on mechanical properties of rock such as strength and stiffness.