Project's information

Project's title Research on the failure mechanisms and impacts of landslides on reservoirs and dams
Project’s code GUST.STS. ĐT2020-KHTĐ01
Research hosting institution Graduate University of Science and Technology
Project leader’s name Dr. Pham Van Tien
Project duration 01/06/2020 - 30/06/2022
Project’s budget 300 million VND
Classify Excellent
Goal and objectives of the project

- To identify the landslides and their characteristics in some dam reservoir areas in Central Vietnam; such as some provinces in Thanh Hoa, Nghe An, Quang Nam and Binh Dinh;
- To understand the sliding mechanisms through laboratory experiment, physical simulation and numerical model;
- To analyze and assess the impacts of landslides on the dam reservoir facilities and their effects to the reservoir operation.


Main results

Theoretical results:
- The project has created a database on landslides and their characteristics; and clarified some affecting factors to landslides on slopes in dam reservoir areas (including slopes in the upstream area) in Central Vietnam. Topography, morphology, geology, tectonics and climate settings are main contributing factors while rainfall with high intensity and long duration is the trigger for the sliding.
- Soil testing is carried to measure some physical parameters of sliding surface samples of the landslides, which is useful for slope stability analysis. It indicates that landslide materials with a high percentage of clayed minerals that is very prone to soil moisture, resulting in shear resistance reduction and structural connection within soil layers and causing the landslides. In additions, landslide materials are mostly soils with a high permeability that are derived from the moderate to strong weathering of bedrock. This condition favors the water permeability deeply into the slopes to build up high pore water pressure for the landslide initiation.
- Ring shear apparatus tests were conducted on sliding surface samples in order to investigate the landslide mechanisms. Test results present that samples failed at a high pore water pressure ratio (ru > 0,50). For the large scale landslide near Song Bung-5 hydropower, this ratio is 0,57.
- The simulation of the initiation and motion processes of a rapid landslide in the dam reservoir area of Rao Trang 4 was successfully conducted in accordance with recorded data and site evidences. The Song Bung-5 landslide is likely to move down at pore pressure ratio of 0,55, which puts a high risk to the hydropower facilities.
- The study has also investigated and evaluated some of the main impacts of landslides in dam reservoir areas in Central Vietnam, including economic losses due to damage to the facilities and effects to the project progress; losses causing by debris flows and flash floods and other threatens to dam safety operation such as reservoir sediments.
Applied results:
Methods using in this project can be applied to other areas with the similar conditions of geology, topograpy and climate. Besides, this study has proposed some countermeasure for landslide risk reduction in reservoir areas.

Novelty and actuality and scientific meaningfulness of the results

- A database on landslides and their characteristics on slopes in dam reservoir areas was created.
- The study has examined the mechanisms of landslides in dam reservoir dam areas through laboratory testing, physical and numerical simulation. The computer simulations of some typical landslides were developed and well validated, which are can be applied for hazard assessment of landslides and its secondary processes in the reservoir areas.
- Some countermeasure for landslide risk reduction in reservoir areas was proposed in Vietnam.
- The project has published 02 paper;

Products of the project - Scientific papers in referred journals (list): 02 Papers
Recommendations Further study on landslides in dam reservoir areas should be conducted in order to propose landslide risk assessment and regulations on safe operation in Vietnam.
Images of project