Paper:

# Sensitivity Analysis of Depth-Integrated Numerical Models for Estimating Landslide Movement

## Teuku Faisal Fathani^{†}, Djoko Legono, and Muhammad Ahnaf Alfath

Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Jalan Grafika No. 2, Yogyakarta 55281, Indonesia

^{†}Corresponding author

Landslides are natural phenomena that occur in slopes with thick layers of weathered soil or weak geological formations. High intensity of precipitation, earthquake, and human interference can cause a huge landslide disaster. To mitigate landslide risk, an appropriate investigation to determine the stability and movement mechanisms is important to predict its potential scale. This paper proposes a sensitivity analysis of depth-integrated numerical model of landslide movement by implementing solid friction and fluid friction as the shear resistance in the constitutive systems. The hyperconcentrated solid-liquid mixture flow model and Voellmy-fluid friction model are employed in the solid friction and fluid friction mechanism, whereas the Mohr-Coulomb model is used in the solid friction mechanism. In order to analyze model characteristics and sensitivity to the inputted parameters, the parametric studies on an imaginary slope were examined. The results show that the internal friction angle among input data strongly affects the runout distance and moving velocity. The Voellmy-fluid friction model produces more lateral tendency and wider deposit in transversal directions of landslide compared to other models. The numerical model along with three constitutive equations of shear resistance was applied to the Bishamon Landslide. The hyperconcentrated solid-liquid mixture flow model and Mohr-Coulomb model yield a good agreement with the actual deposition area, whereas the Voellmy-fluid friction model produces more lateral tendency in transversal directions. The calculated runout distance reaches more than 350 m and 10.3 to 13.9 m/s of maximum velocity.

*J. Disaster Res.*, Vol.12, No.3, pp. 607-616, 2017.

- [1] O. Hungr, “Dynamics of rapid landslides,” Progress in Landslide Science, Springer Berlin Heidelberg, pp. 47-57, 2007.
- [2] J. Aaron and O. Hungr, “Dynamic simulation of the motion of partially-coherent landslides,” Engineering Geology, Vol.205, pp. 1-11, 2016.
- [3] S. Egashira, “Prospects of debris flow studies from constitutive relations to governing equations,” J. Disaster Res., Vol.6, No.3, pp. 313-320, 2011.
- [4] N. Gerolymos, “Numerical modeling of seismic triggering, evolution, and deposition of rapid landslides: Application to Higashi–Takezawa (2004),” Int. J. Numer. Anal. Meth. Geomech., Vol.34, No.4, pp. 383-407, 2010.
- [5] G. Devoli, F. V. De Blasio, A. Elverhøi, and K. Høeg, “Statistical analysis of landslide events in Central America and their run-out distance,” Geotech. Geol. Eng., Vol.27, pp. 23-42, 2009.
- [6] M. Pastor, B. Haddad, G. Sorbino, S. Cuomo, and V. Drempetic, “A depth-integrated coupled SPH model for flow-like landslides and related phenomena,” Int. J. Numer. Anal. Methods Geomech., Vol.33, pp.143-172, 2009.
- [7] C. G. Johnson, B. P. Kokelaar, R. M. Iverson, M. Logan, R. G. LaHusen, and J. M. N. T. Gray, “Grain-size segregation and levee formation in geophysical mass flows,” J. Geophys. Res., Vol.117, F01032, 2012.
- [8] R. M. Iverson, “Elementary theory of bed-sediment entrainment by debris flows and avalanches,” J. Geophys. Res., Vol.117, F03006, 2012.
- [9] E. B. Pitman and L. Le, “A two-fluid model for avalanche and debris flows,” Philos. Trans. A, Math. Phys. Eng. Sci., Vol.363, pp. 1573-1601, 2005.
- [10] S. P. Pudasaini, “A general two-phase debris flow model,” J. Geophys. Res., Vol.117, F03010, 2012.
- [11] O. Hungr, “Numerical modelling of the motion of rapid, flow-like landslides for hazard assessment,” KSCE J. of Civil Engineering, Vol.13, No.4, pp. 281-287, 2009.
- [12] S. McDougall and O. Hungr, “A model for the analysis of rapid landslide run out motion across three dimensional terrain,” Can. Geotech. J., Vol.41, pp.1084-1097, 2004.
- [13] R. Sosio, G. B. Crosta, and O. Hungr, “Numerical modeling of debris avalanche propagation from collapse of volcanic edifices,” Landslides, Vol.9, pp. 315-334, 2012.
- [14] M. Pastor, T. Blanc, B. Haddad, S. Petrone, M. Sanchez, V. Drempetic, D. Issler, G. Crosta, L. Cascini, G. Sorbino, and S. Coumo, “Application of a SPH depth-integrated model to landslide run-out analysis,” Landslides, Vol.11, No.5, pp. 793-812, 2014.
- [15] W. Wang, G. Chen, Z. Han, S. Zhou, H. Zhang, and P. Jing, “3D numerical simulation of debris-flow motion using SPH method incorporating non-Newtonian fluid behavior,” Natural Hazards, Vol.81, No.3, pp. 1981-1998, 2016.
- [16] H. Nakamura, T. F. Fathani, and A. K. Karna, “Analysis of landslide debris and its hazard area prediction,” Proc. of the Int. Symp. on Landslide Mitigation and Protection of Cultural and Natural Heritage, pp. 173-189, 2002.
- [17] T. F. Fathani, “The analysis of earthquake-induced landslides with a three-dimensional numerical model,” Proc. of Geotechnics Symp., pp. 159-165, 2006.
- [18] O. Hungr and S. G. Evans, “Rock avalanche runout prediction using a dynamic model,“ Proc. of the 7th Int. Symp. on Landslides, pp. 233-238, 1996.
- [19] P. Revellino, O. Hungr, F. M. Guadagno, and S. G. Evans, “Velocity and runout simulation of destructive debris flows and debris avalanches in pyroclastic deposits Campania region, Italy,” Environmental Geology, Vol.45, pp. 295-311, 2004.
- [20] K, Sassa, O. Nagai, R. Solidum, Y. Yamazaki, and H. Ohta, “An integrated model simulating the initiation and motion of earthquake and rain induced rapid landslides and its application to the 2006 Leyte landslide,” Landslides, Vol.7, No.3, pp. 219-236, 2010.
- [21] K. Dang, K. Sassa, H. Fukuoka, N. Sakai, Y. Sato, K. Takara, L. H. Quang, D. H. Loi, P. V. Tien, and N. D. Ha, “Mechanism of two rapid and long-runout landslides in the 16 April 2016 Kumamoto earthquake using a ring-shear apparatus and computer simulation (LS-RAPID),” Landslides, 2016.
- [22] S. Egashira, K. Miyamoto, and T. Itoh, “Constitutive equations of debris flow and their applicability,” Debris-Flow Hazards Mitigation, Water Resources Engineering Division/ASCE, pp. 340-349, 1997.
- [23] S. Egashira, “Mechanism of sediment deposition from debris flow (part 1),” J. of Japan Society of Erosion Control Eng., Vol.46(I), No.186, pp. 45-49, 1993(in Japanese).
- [24] O. Hungr and S. G. Evans, “Entrainment of debris in rock avalanches: an analysis of a long run-out mechanism,” Geol. Soc. Am. Bull., Vol.116, No.9/10, pp. 1240-1252, 2004.
- [25] K. Miyamoto, “Numerical simulation of landslide movement and Unzen-Mayuyama disaster in 1792, Japan,” J. Disaster Res., Vol.5, No.3, pp. 280-287, 2010.
- [26] S. Egashira, N. Honda, and T. Itoh, “Experimental study on the entrainment of bed material into debris flow,” Physics and Chemistry of the Earth Part C, Vol.26, No.9, pp. 645-650, 2001.
- [27] A. Xing, X. Yuan, Q. Xu, Q. Zhao, H. Huang, and Q. Cheng, “Characteristics and numerical runout modelling of a catastrophic rock avalanche triggered by the Wenchuan earthquake in the Wenjia valley, Mianzhu, Sichuan, China,” Landslides, Vol.14, No.1, pp. 83-98, 2017.
- [28] S. McDougall, N. Boultbee, O. Hungr, D. Stead, and J. W. Schwab, “The Zymoetz River landslide, British Columbia, Canada: Description and dynamic analysis of a rock slide-debris flow,” Landslides, Vol.3, No.3, pp. 195-204, 2006.
- [29] T. F. Russell, ”Stability analysis and switching criteria for adaptive implicit methods based on the CFL condition,” SPE Symp. on Reservoir Simulation, pp. 97-107, 1989.
- [30] K. Kim, S. J. Baek, and H. J. Sung, “An implicit velocity decoupling procedures for the incompressible Naver-Stokes equations,” Int. J. for Numerical Methods in Fluid, Vol.38, No.2, pp. 125-138, 2002.
- [31] Japan Landslide Society, “Landslides in Japan (The Fifth Revision),” National Conf. of Landslide Control, 1996.
- [32] Y. H. Lang and H. Nakamura, “Characteristics of slip surface of loess landslides and their hazard area prediction,” J. of Japan Landslide Society, Vol.35, No.1, pp. 9-18, 1998.

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