Pham Thi Chien (Vietnam)

Email: s139314 @matsu.shimane-u.ac.jp

Thesis title:  Evaluating the impact of heavy rainfall to initiation and motion of landslide on slopes at Haivan station, Vietnam.

Supervisor:  Prof. Fawu Wang and Assoc. Prof. Toshihide Shibi (2013-2015).

Landslides are natural hazards that are common worldwide. Landslides affect utilities, transportation networks, and all other forms of infrastructure, whether public or private. Landslides cause property damages, can take lives, and adversely affect a variety of resources. Moreover, landslides negatively affect the economy, with impacts such as the cost to repair structures, consequent loss of property value, disruption of transportation routes, medical costs in the event of injury, and indirect costs such as loss of timber resources and lost fish stocks. Because of the natural conditions and regional weather, landsliding is one of the most serious natural disasters in Vietnam. Many landslides occur at the mountainous areas each year, threatening people’s lives and livelihoods, and affect seriously road transport systems.

Many factors may combine to induce landslides. These include geological structure, natural conditions and climate, and events such as earthquakes, groundwater level changes and heavy rain. However, heavy rain events have the strongest impact on landslides in Vietnam. Especially in the rainy season, rainfall penetrates into the potential landslide, increasing the soil bulk density, and softening the soils, thus reducing the stabilizing force. In addition, pore water pressure rises rapidly, and this decreases the effective stress and shear strength in the potential sliding surface. After high excess pore water pressure is generated, the soil mass suddenly loses a large proportion of its shear resistance and flows in a manner resembling a liquid, creating a landslide. My aim of my work is to focus on the topic: "Evaluating the impact of heavy rainfall to initiation and motion of landslide on slope at Haivan station in Vietnam".

Research in landslides:

• To understand basic slope processes and the causes of slope failure, especially the impact of heavy rainfall
• Evaluating the impact of natural conditions in the initiation and motion of landslides on slopes

Purposes:

The slope at Haivan station has complex geological features and structure. Landslides may occur at any time of the year, and this hazard to the road network in the area is ever present. However, evaluation of the impact of heavy rainfall on the landslide hazard on slopes is not well advanced in Vietnam, so I will focus on studying this problem using data from Haivan station.

Research method

• Collection of rainfall data and geological information at Haivan station.
• Analysis of initiation and motion of landslides that are affected by heavy rainfall, using FEM (model of various geotechnical problems by the Finite Element Method).

Expected results

• Overview research of change in soil parameters impacted by heavy rainfall
• Evaluate impact of heavy rainfall on landslide hazard on slopes.