Debris slope stability analysis using three-dimensional finite element method based on maximum shear stress theory

How to evaluate debris slope stability reasonably is yet an urgent problem. The paper presents an applied method evaluating debris slope stability, using three-dimensional (3D) finite element contact algorithm based on the maximum shear stress theory. The Guanjia debris slope is located between K9 + 940 and K10 + 200 of Longli First-class Highway in Zhejiang, China. On its left slope, some cracks appeared at the end of 2002 and these were immediately backfilled, overlying a plastic membrane. However, many new cracks appeared on the slope during the rainfall in April 2003. Meanwhile, some small collapses and springs occurred in the front of the slope, and many cracks appeared on the middle part. The stability of the Guanjia debris slope was analyzed using the method proposed in the paper, the strength reduction finite element method, the imbalance thrust force method, Fellenius method, Janbu simplified method, Spencer’s method, Morgenstern–Price method and generalized limit equilibrium (GLE) method. The results show that: (1) the safety factors of the debris slope obtained using the imbalance thrust force method is the minimum in all limit equilibrium methods; (2) 1.07 and 1.06 are the safety factors of Section CC′ and DD′ (the middle part of this slope) of the Guanjia debris slope obtained using the method proposed (FEM with shear strength reduction technique based on the maximum shear stress theory) in this study, respectively, which reflect the slope actual condition in critical failure status; (3) the method proposed in this study may take into account the spatial effect of the debris slope, which makes the results of slope stability analysis more reasonable and reliable than other methods that can be used as a reference for the evaluation of stability of the same type of debris slope; and (3) further study should be done to confirm whether the proposed method in this study is suitable for other types of slopes.

[1]  A. Drescher,et al.  Slope stability analysis by strength reduction , 1999 .

[2]  D. Fredlund,et al.  Comparison of slope stability methods of analysis , 1977 .

[3]  Jian-Hua Yin,et al.  A three-dimensional slope stability analysis method using the upper bound theorem: Part I: theory and methods , 2001 .

[4]  Y. M. Cheng,et al.  Two-dimensional slope stability analysis by limit equilibrium and strength reduction methods , 2007 .

[5]  G.-L. Jiang,et al.  Stability analysis of embankments: comparison of limit analysis with methods of slices , 1997 .

[6]  Zhao Shang,et al.  Analysis on safety factor of slope by strength reduction FEM , 2002 .

[7]  Alexander G. Razdolsky Slope stability analysis based on the direct comparison of driving forces and resisting forces , 2009 .

[8]  Maosong Huang,et al.  Strength reduction FEM in stability analysis of soil slopes subjected to transient unsaturated seepage , 2009 .

[9]  N. Morgenstern,et al.  The analysis of the stability of general slip surfaces , 1965 .

[10]  Keizo Ugai,et al.  Reinforcing mechanism of anchors in slopes: a numerical comparison of results of LEM and FEM , 2003 .

[11]  Tamotsu Matsui,et al.  Finite element slope stability analysis by shear strength reduction technique , 1992 .

[12]  R. Lewis,et al.  Associated and non-associated visco-plasticity and plasticity in soil mechanics , 1975 .

[13]  Zuyu Chen,et al.  Slope stability analysis by the upper bound approach: fundamentals and methods , 1997 .

[14]  Mei Songhua 3D stability analysis of landslides based on strength reduction (II): evaluation of reinforcing factor of safety , 2004 .