Slope Stability of Wulu Lidao and Motain Area in Southern Cross Highway

Abstract

This research has two principal parts First using nail networks and single-frequency GPS observe the potential large-scale landslide activity from kilometer markers 164K+82 to 164K+133 of the Motain area Southern Cross Highway to realize the potential large-scale landslide activity as well as the relationship between rainfall and slope sliding Secondly the study makes use of unmanned aerial vehicles to survey exposed rock formations not easily accessible by humans along two sections of the Highway: kilometer markers 174K+155 to 174K+405 and 179K+355 to 179K+425 Coltop3D software performs structural analysis of topography using point cloud The stereographic projection method was used to analyze the slope failure type and describe possible slide direction The displacement observation results of a potential large-scale landslide in the Motain area show that all crack tends to expand in the horizontal direction and downward in the vertical direction according to nail network analysis on the slope Some cracks cause one side of the wall to move outward According to the GPS observative results the maximum horizontal displacement of the slope sliding was 320 39 mm to the southeast The amount of vertical displacement was 161 51 mm Combined with the rainfall data when the cumulative rainfall of the rainfall event exceeds 300 mm or the rainfall of the day exceeds 200 mm during the event the potential large-scale landslide in the Motain area has caused obvious activities Obvious activities intensify the degree of fissure expansion of the artificial structure and cause obvious displacement in the GPS observation station Regarding the analysis of the discontinuities of the disaster-causing slope Coltop3D analysis of the discontinuous surface in the area of exposed rock mass well presents discontinuities and distribution positions consistent with the field measurement results Two possible types of slope failure were identified in the analysis of the discontinuous of the disaster-causing slope between kilometer markers 174K+155 to 174K+405 1 Planar-type failure is expected along with the release joint with an anticipated sliding direction of 177 degrees; 2 Wedge-shaped failure is expected intersecting the release joint and joint J1 with an anticipated sliding direction of 230 degrees with the additional risk of Wedge-shaped failure from release joint and cleavage intersections at an anticipated sliding direction of 105 degrees In the analysis of disaster-causing slope between kilometer markers 179K+355 to 179K+425 of the Southern Cross Highway Overturning failure is expected governed by the influence of the Joint with an anticipated sliding direction of 44 degrees

Date of Award	2020
Original language	English
Supervisor	Ching-Wee Lin (Supervisor)