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Geohazards

Our geohazards research spans a broad range of computational and experimental analyses of geotechnics and geohazards such as slope failure, terrestrial and submarine landslides, debris flows, and rock avalanches and their impacts on the resilience and sustainable development of cities. The research theme is led by Dr Tao Zhao and Dr Mei Yin.

The group has been dedicated to understanding the underlying physics of these geohazards and establish predictive models. To date, the public awareness of these risks is high, but our fundamental understanding of the failure mechanism and countermeasures are still limited. This is mainly due to the difficulties in analysing the multiscale responses and characterize the spatial inhomogeneity of material properties of slopes. Not completely addressing these two aspects in slope stability analysis may lead to underestimation or overestimation of slope failure risks for engineering designs, resulting in potential hazards to infrastructures and residential areas.

To obtain the insight of these hazards, physical and numerical modelling are the key ways forward, both for understanding the landslide mechanisms and for the prediction of landslide-induced secondary hazards. Some challenging issues need to be considered, including:

  • How to develop reliable mathematical models with multiscale modelling capability to analyse the progressive failure of slopes?

  • How to address the spatial variabilities and uncertainties of real slopes, e.g. material property, fractures, fluid permeability?

  • How to accurately estimate the spreading of landslide and its impact on infrastructures?

To address these issues, the research group has developed novel multiscale numerical modelling tools using discrete element method (DEM), finite element method (FEM), computational fluid dynamics (CFD) and random field theory (RFT), with special focuses on slope dynamic fragmentation, the spatial variabilities of material properties and pore fluids at the meso- and microscales. The numerical modelling enables the investigation of the microscopic origins of some complex geotechnical phenomena and potentially reveal the physic-mechanical mechanisms ruling the failure of slopes and the subsequent landslide dynamics. The research is essential for further development and mitigation of the hazards in onshore and offshore areas.geohazards - Fig. 1

Figure 1. Illustration of multiscale models of slope failure process

Plan view schematic of a slide on a gentle slope in physical modelling 

 geohazards - Fig. 2a

 geohazards - Fig. 2b

Collaborative partners

Dr Zhao has also built a strong network of international research collaborations with Prof. Stefano Utili from Newcastle University, Prof. Jidong Zhao from the Hong Kong University of Science and Technology, Prof. Giovanni Crosta from Università degli Studi di Milano Bicocca, Italy, Prof. Gordon Zhou from Chinese Academy of Sciences and Prof. Yong Liu from Wuhan University (China) on developing integrate numerical models to study the mobilization mechanism of landslides and the impacts on infrastructures. Dr Yin is currently collaborating across academia and industry to develop successful proposals and conduct research, including with Dr. Robert Hird (ESCC), Dr Echo Ouyang (Mott MacDonald), Dr Stuart Haigh (University of Cambridge).

Relevant publications

1) Zhao, T., Liu, Y. A novel random discrete element analysis of rock fragmentation. International Journal for Numerical and Analytical Methods in Geomechanics, 2020, 44: 1386-1395. (DOI: 10.1002/nag.3067)

2) Zhao T. *, Crosta G. B. On the dynamic fragmentation and lubrication of coseismic landslides. Journal of Geophysical Research: Solid Earth, 2018, 123, 11, 9914-9932.

3) Zhao, T.*, Crosta, G. B., Utili, S. & Dattola, G. Dynamic fragmentation of jointed rock blocks during rockslide-avalanches: insights from discrete element analyses. Journal of Geophysical Research: Solid Earth, 2018,123, 4, 3250–3269 (doi: 10.1002/2017JB015210)

4) Zhao, T.*, Crosta, G. B., Utili, S. & De Blasio, F. V. Investigation of rock fragmentation during rockfalls and rock avalanches via 3-D discrete element analyses. Journal of Geophysical Research: Earth Surface, 2017, 122(3), 678-695.

5) Zhao, T., F. Dai, N.W. Xu. Coupled DEM-CFD investigation of the formation of landslide dams in narrow rivers. Landslides, 2017, 14(1), 189-201 (doi: 10.1007/s10346-015-0675-1)

6) Zhao, T.*, S. Utili, G. B. Crosta. Rockslide and impulse wave modelling in the Vajont reservoir by DEM-CFD analyses. Rock Mechanics and Rock Engineering, 2016, 49(6), 2437-2456

7) Zhao, T., F. Dai, N. W. Xu, Y. Liu, Y. Xu. A composite particle model for non-spherical particles in DEM simulations. Granular Matter, 2015, 17(6): 763-774 (doi:10.1007/s10035-015-0596-7)

8) Zhao, T.*, S. Utili, G. T. Houlsby. Investigation of granular batch sedimentation via DEM-CFD coupling. Granular Matter, 2014, 16(6):921-932. (doi:10.1007/s10035-014-0534-0)

9) Yin M, Measurement of shear strength for marine clay. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 2020, 173(1): 30-39.

10) Yin M. Laboratory study on submarine debris flow. Marine Georesources & Geotechnology, 2018, 36(8): 950-958.

11) Rui Y, Yin M. An Analytical Solution for the Run-Out of Submarine Debris Flows. Marine Geodesy, 2019, 42(3): 246-262.