Browsing by Author "Lo, Chia-Ming"

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Evaluating failure mechanisms of dip slope using a multiscale investigation and discrete element modelling
(2019-12-20)
Weng, Meng-Chia
;
Lin, Ming-Lang
;
Lo, Chia-Ming
;
Lin, Hsi-Hung
;
Lin, Cheng-Han
This study proposed an in-depth multiscale analysis procedure to identify the dip slope area and assess dip slope stability and influencing area. The proposed analysis procedure comprised five stages: (1) identifying the potential area of a dip slope, (2) analyzing the possible failure types of the dip slope, (3) evaluating slope activity, (4) analyzing dip slope stability under the influence of possible triggering factors, and (5) assessment of the deformation and deposition area. To validate the proposed procedure, the Chaochouhu region of Taiwan was analyzed as a dip slope case. In stages (1) to (3), the scale of the utilized map and the precision of associated data were evaluated to identify the potential area of a dip slope, the possible failure types, and the activity of each slope unit. In stages (4) and (5), the processes of deformation and sliding in a high-activity slope unit were simulated using the discrete element method. The numerical model was first verified using in-situ monitoring data obtained from inclinometers. Subsequently, the model was used to predict the slope behavior under conditions of wetting deterioration of geomaterial. The multiscale analysis revealed comprehensive information regarding the dip slope. The application of the proposed approach would be useful to civil engineers for evaluating dip slope stability as well as to relevant authorities for planning hazard mitigation strategies.
Landscape evolution characteristics of large-scale erosion and landslides at the Putanpunas Stream, Taiwan
(2018-01-01)
Lo, Chia-Ming
;
Weng, Meng-Chia
;
Lin, Ming-Lang
;
Lee, Shun-Min
;
Lee, Kuo-Chen
This study used multi-temporal terrain and remote sensing images to investigate the geomorphological evolution of the Putanpunas stream caused by large-scale erosion and landslides over the last decade. Discrete element method was then performed to gain the physical insight of the slope failure mechanisms and landslide movement. Our results show topographical changes in the alluvial fan downstream and the deposits in the midstream and downstream segments of the Putanpunas Stream between 2005 and 2009. In 2009, torrential rainfall induced large-scale landslides (the volume was about 8.4x 10(7) m(3)) that greatly altered the terrain of the Putanpunas Stream valley and the alluvial fan. A thick, unstable layer of colluvium (the thick of colluvium more than 150 m) was also deposited in the valley. In 2012, further large-scale landslides turned the colluvial layer into debris flows that cut across the Ryukyu Terraces downstream to the downstream segment of the Laonong Stream to the south-west. The change of debris flow direction from southeast to south-west eventually posed a considerable threat to the safety of protected targets and the access road downstream.