Australian Research Council Centre of Excellence Geotechnical Science and Engineering

Thesis

Dynamic simulation of submarine landslides and their impacts on offshore infrastructure using material point method

Summary

The primary research objectives includes two parts: to develop the MPM code, and to establish models to simulate submarine landslides and their impacts on pipelines. The thesis will be focused on 2D simulations. The 3-dimension code Uintah will be modified into 2-dimension by removing calculation related to Z direction.

A COFS copy-righted MPM code will be developed on platform of Windows in the sake of convenience and portability. The COFS MPM code is totally 2D, saving running time for submarine landslides, which is a plain strain problem. To further promote efficiency of the COFS code, CPU and GPU parallelisation will be developed. Softening and rate effects are considered in the on-going simulation. Modelling accounting for interaction between sliding soil and pipe would be established.

Why my research is important

Submarine landslides are common on submarine slopes, especially where there are weak layers. In recent decades, many cases of submarine landslides were, among which the largest ones spanned several thousand km2. Although some national and international projects were directly related to them, unfortunately, submarine landslides remain to be an open issue.

The probability of occurrence of submarine landslides along the routes raises the running risk of pipeline systems in their life span. Once submarine landslides occur, the moving masses in the areas exert extremely significant impact forces on the downstream pipelines, arousing severe damage or even failure of the pipelines. Therefore, estimation and control of impact forces from submarine landslides are necessary for pipeline design and routing.

Submarine landslide is also a principal cause of tsunami, in addition to submarine earthquake. The reason of tsunami induced by submarine landslides is often attributed to the energy of sliding masses transferred to water motion. Since the consequences of tsunami are dramatic, it should be seen as highly risky geohazard. However, the importance of tsunami generated by submarine landslides is only recognised in recent 15 years. Therefore, the mechanism of tsunami generation by submarine landslides is far from well understood.

Funding

  • SIRF
  • UIS