Slope Engineering

Summary of Activities

Extensive research in slope engineering has been or being carried out by the Geotechnical Group of the Centre. 2-D and 3-D computer programs based on the conventional limit equilibrium methods have been developed.  Various innovative computational methods for slope stability analysis are developed, and some important fundamental problems in slope stability analysis are solved. GIS pre-processor has been developed to these techniques are now widely used in Hong Kong, China, Europe and many other countries, and the commercial programs  arising from these works are approved by Hong Kong Building Department and widely accepted by many engineers. Some examples of consultancy works include the stability analysis of clay slopes at Macau, difficult foundation problems to national projects in China and others. A book “Soil slope stability analysis and stabilization – new methods and insights” by Taylor and Francis which is basically a collection of papers and aim at postgraduate students has been published. Limit analysis methods based on the upper bound theorem in plasticity using rigid wedges or rigid elements have been developed for both 2-D and 3-D slope stabilization analysis. Computer, small-scale physical modelling and field trials have been carried on the rock falls, debris flows and glass fibre reinforced slopes.  A study on soil nails including field and laboratory pullout testing and modelling has been carried out in order to investigate the interface resistance between nail cement grout and soils.  Recently, special optical fiber sensors based the Fiber Bragg Grating (FBG) and Brillouin Optical Time-Domain Analysis (BOTDA) have been developed and applied for monitoring soil nails, piles, ground settlement, slope movement, tunnels, etc,

Representative Projects

  • Debris flow dynamics: experimental and numerical simulations
  • Theoretical, experimental and field studies on rockfall dynamics
  • Three-dimensional discontinuous deformation and manifold analysis
  • Formulation of asymmetrical three dimensional slope stability limit equilibrium method
  • Lower bound analysis of slope stability problem
  • Field tests of innovative glass fibre tube soil nail
  • Study on the shear strength at the interface between soil and concrete element
  • Development and application of a three-dimensional limit method for stability analysis of slopes in Hong Kong
  • Development and application of FBG-based sensors for monitoring compression and bending of piles without or with FRP
  • Study on the pullout resistance of pressure-grouted soil nails in a completely decomposed granite soil
  • Study on the field pullout resistance of soil nails with comprehensive instrumentation in a soil slope
  • Study on the fundamental behavior of the interface between cement grout and a completely decomposed granite soil in Hong Kong
  • Experimental study on the interface shear strength behavior of a cement grouted nail in completely decomposed granite soils
  • Development of an innovative FBG sensor based technology for monitoring movements of slopes
  • Development of an innovative FBG sensor based technology for measuring the deformation and quality of piles

Major Facilities

  • MTS large size direct shear box for rock mass testing
  • MTS compression machine for rock testing
  • GDS computerized static and cyclic (2Hz) triaxial apparatus with stress-path control for soil testing
  • Static and cyclic (20Hz) Hollow Cylinder Apparatus (HCA) for soil testing
  • Truly traixial apparatus for soil testing
  • Large size direct shear box (304mm(wide) x 450mm(long) and 220(high)) for soil testing
  • Soil nail pullout testing box (800mm(wide) x 1000mm(long) x 800mm(high)).

An MTS large-size rock direct shear device

A two-directional compression machine for rock or rock-like material testing

Computer-controlled triaxial testing system with shear wave measurement using bender elements - 2Hz cyclic loading, stress-path testing, ko-consolidation, extension shear testing and measurement of Gma

Large-size direct shear box (305mm by 405mm by 204mm) for measuring interface properties between soil and geosynthetics and strength parameters of coarse granular soils 

A new Hollow Cylinder Apparatus and a new Truly Triaxial System (the far right) for soil testing (static and cyclic loading up to 20Hz) 

 

A close-up view of the inside of Truly Triaxial System for soil testing

 

SLOPE 2000 – BD approved computer program, widely used by engineers in many countries, available in English and Simplified Chinese.

SLOPE3D – The first asymmetric 3D slope stability analysis program with arbitrary shape of failure surface and automatic search

Select Publications

1.          Chau, K.T., Wong, R.H.C. and Wu, J.J. (2002) “Coefficient of restitution and rotational motions of rockfall impacts”, International Journal of Rock Mechanics and Mining Science, 39: 69-77.

2.          Cheng, Y.M. (2003) “Locations of Critical Failure Surface and some Further Studies on Slope Stability Analysis”, Computers and Geotechnics, 30: 255-267.

3.          Cheng, Y.M. and Zhang, Y.H. (2002) “Coupling of FEM and DDA Methods”, International Journal of Geomechanics, ASCE, 2(4): 503-517.

4.          Cheng, Y.M. and Zhang, Y.H. (2002) “Wilson non-conforming Element in Numerical Manifold Method”, International Journal for Numerical Methods in Engineering, 18: 877-884.

5.          Cheng, Y.M. and Zhu, L.J. (2004) “Unified Formulation for Two Dimensional Slope Stability Analysis and Limitations in Factor of Safety Determination”, Soils and Foundations, 44(6): 121-128.

6.          Cheng, Y.M., Liu, H.T. and Au, S.K. (2005) “Location of critical three-dimensional non-spherical failure surface with applications to highway slopes”, Computers and Geotechnics, 32: 387-399.

7.          Cheng, Y.M. and Yip, C.J. (2007) “Three-dimensional Asymmetrical Slope Stability Analysis -Extension of Bishop’s and Janbu’s Techniques”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 133(12):1544-1555.

8.          Cheng, Y.M. (2007) “Global optimization analysis of slope stability by simulated annealing with dynamic bounds and Dirac function”, Engineering Optimization, 39(1):17-32.

9.          Cheng, Y.M., Li, L. and Chi, S.C. (2007) “Studies on six heuristic global optimization methods in the location of critical slip surface for soil slopes”, Computers and Geotechnics, 34: 462-484.

10.       Cheng, Y.M. and Zhang, Y.H. (2008) “Three-dimensional Numerical Manifold Method - Tetrahedron and Hexahedron Mesh”, International for Rock Mechanics and Rock Engineering, 41(4): 601-628.

11.       Cheng, Y.M., Lansivaara, T. and Siu, J. (2008) “Impact of Convergence on Slope Stability Analysis and Design”, Computers and Geotechnics, 35(1): 105-115.

12.       Cheng, Y.M., Li, L. and Chi, S.C. and Wei, W.B. (2008) “Determination of critical slip surface using artificial fish swarms algorithm”, Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 134(2): 244-251.

13.       Cheng, Y.M., Albert, Y., Tham, L.G. and Au, S.K. (2008) “New soil nail material-pilot study of grouted GFRP pipe nails in Korea and Hong Kong”, Journal of Civil Engineering Materials, ASCE (accepted).

14.       Cheng, Y.M., Li, L., Lansivaara, T., Chi, S.C. and Sun, Y.J. (2008) “Minimization of factor of safety using different slip surface generation methods and an improved harmony search minimization algorithm”, Engineering Optimization, 40: 95-115.

15.       Cheng, Y.M. and Lau, C.K. (2008) “Soil Slope stability analysis and stabilization – new methods and insights”, Taylor and Francis.

16.       Chu, L.M. and Yin, J.H. (2006) “Study on Soil-Cement Grout Interface Shear Strength of Soil Nailing by Direct Shear Box Testing Method”, GeoMechanics and GeoEngineering, 1(4): 259-273.

17.       Chu, L.M. and Yin, J.H. (2005) “Comparison of Interface Shear Strength of Soil Nails Measured by both Direct Shear Box Tests and Pull-out Tests”, ASCE J of Geotechnical and Geo-environmental Engineering, 131(9): 1097-1107.

18.       SU, L.J., Chan, Terence C.F., Shiu, Y.K., Cheung, T. and Yin, J.H. (2007) “Influence of Degree of Saturation on Soil Nail Pull-out Resistance in Compacted Completely Decomposed Granite Fill”, Canadian Geotechnical Journal, 44(11): 1314-1328.

19.       Wang, Y.J. and Yin, J.H. (2002) “Wedge stability analysis considering dilatancy of discontinuities”, Rock Mechanics and Rock Engineering, 35(2): 127-137.

20.       Wang, Y.J., Yin, J.H. and Lee, C.F. (2001) “The Influence of a Non-Associated Flow Rule on the Calculation of the Factor of Safety of Soil Slopes”, International Journal for Numerical and Analytical Methods in Geomechanics, 25: 1351-1359.

21.       Yin, J.H. and Su, L.J. (2006) “An Innovative Laboratory Box for Testing Nail Pull-out Resistance in Soil”, ASTM Geotechnical Testing Journal, 29(6): 1-11.

22.       Zhou, W.H. and Yin, J.H. (2008) “A Simple Mathematical Model for Soil Nail and Soil Interaction Analysis”, Computers and Geotechnics, 35: 479-488.

Contact Information of the contact person

Prof. Jian-Hua Yin
Department of Civil & Structural Engineering
The Hong Kong Polytechnic University
Kowloon, Hong Kong

Fax:     + 852 - 2334 6389
Phone:   + 852 - 2766 6065
E-mail:  cejhyin@polyu.edu.hk

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