Discontinued Rock Slope Analysis through a New TFS-KGM Analytical Method

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی معدن و متالورژی، دانشگاه یزد

10.29252/anm.8.17.1

چکیده

Slope stability analysis of jointed rocks has been the focus of many studies. The presence of joints and discontinuities in rock environments intensifies instability along with the development of block movements. Many analytical and numerical methods have been proposed and applied to analyze the stability of jointed rock slopes. Computation complexity, incapability of presenting a reliable safety factor to be used for developing a proper design operation and improper analysis speed are the known challenges of these methods. This paper has developed the well-known analytical Key Group Method (KGM) to Toppling-Free fall-Sliding Key Group (TFS_KGM) version. To this end, toppling and free fall failure are added to the existing method in order to have a better analysis of jointed rock slopes. In this method, unstable key blocks participate in creating groups which may rotate or free fall besides sliding. The new TFS_KGM computes stability conditions and final safety factors based on the most unstable sliding, rotating and free fall movements with consideration of in situ stresses. Results of using this method in jointed rock slopes and the comparison with DEM numerical, KBM and KGM analytical methods show that the method is very effective particularly when the geometrical conditions of the jointed rocks make the toppling and free fall failures potentially possible. The method demonstrates a simple computation method along with a proper analysis speed. It also provides accurate design safety factors and much more optimized critical failure areas than previous methods.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Discontinued Rock Slope Analysis through a New TFS-KGM Analytical Method

نویسندگان [English]

  • Mohsen Mohebbi
  • Alireza Yarahmadi Bafghi
  • Mohammad Fatehi Marji
  • Javad Gholamnejad
Dept. of Mining and Metallurgy, Yazd University
چکیده [English]

Slope stability analysis of jointed rocks has been the focus of many studies. The presence of joints and discontinuities in rock environments intensifies instability along with the development of block movements. Many analytical and numerical methods have been proposed and applied to analyze the stability of jointed rock slopes. Computation complexity, incapability of presenting a reliable safety factor to be used for developing a proper design operation and improper analysis speed are the known challenges of these methods. This paper has developed the well-known analytical Key Group Method (KGM) to Toppling-Free fall-Sliding Key Group (TFS_KGM) version. To this end, toppling and free fall failure are added to the existing method in order to have a better analysis of jointed rock slopes. In this method, unstable key blocks participate in creating groups which may rotate or free fall besides sliding. The new TFS_KGM computes stability conditions and final safety factors based on the most unstable sliding, rotating and free fall movements with consideration of in situ stresses. Results of using this method in jointed rock slopes and the comparison with DEM numerical, KBM and KGM analytical methods show that the method is very effective particularly when the geometrical conditions of the jointed rocks make the toppling and free fall failures potentially possible. The method demonstrates a simple computation method along with a proper analysis speed. It also provides accurate design safety factors and much more optimized critical failure areas than previous methods.

کلیدواژه‌ها [English]

  • Toppling-free fall-shearing key group method
  • Key group method
  • Key block method
  • Rock slope stability analysis
  • discontinuum analysis

مراجع

[1]          Duncan JM. State of the art: limit equilibrium and finite-element analysis of slopes. J Geotech Eng 1996;122:577–96.
[2]          Hungr O, Salgado FM, Byrne PM. Evaluation of a three-dimensional method of slope stability analysis. Can Geotech J 1989;26:679–86.
[3]          Hungr O. An extension of Bishop’s simplified method of slope stability analysis to three dimensions. Geotechnique 1987;37:113–7.
[4]          Chen RH, Chameau JL. Three-dimensional limit equilibrium analysis of slopes. Geotechnique 1983;33:31–40.
[5]          Lam L, Fredlund DG. A general limit equilibrium model for three-dimensional slope stability analysis. Can Geotech J 1993;30:905–19.
[6]          Goodman RE, Shi GH. Block theory and its application to rock engineering. Englewood Cliffs, NJ.: 1985.
[7]          Warburton PM. Vector stability analysis of an arbitrary polyhedral rock block with any number of free faces. Int J Rock Mech Min Sci Geomech Abstr 1981;18:415–27.
[8]          Yarahmadi Bafghi AR, Verdel T. The key group method. Int J Numer Anal Methods Geomech 2003;27:495–511.
[9]          M M, KC C, Y. W. Limit analysis of 2-D tunnel key-blocks. Int J Rock Mech Min Sci 1997;34:193.
[10]        Tonon F. Generalization of Mauldon’s and Goodman's vector analysis of keyblock rotations. J Geotech Geoenvironmental Eng 1998;124:913–22.
[11]        Sagaseta C, Sanchez JM, Canizal J. A general analytical solution for the required anchor force in rock slopes with toppling failure. Int J Rock Mech Min Sci 2001;38:421–35.
[12]        González-Palacio C, Menéndez-Díaz A, Álvarez-Vigil AE, González-Nicieza C. Identification of non-pyramidal key blocks in jointed rock masses for tunnel excavation. Comput Geotech 2005;32:179–200.
[13]        Menéndez-Díaz A, González-Palacio C, Álvarez-Vigil AE, González-Nicieza C, Ramírez-Oyanguren P. Analysis of tetrahedral and pentahedral key blocks in underground excavations. Comput Geotech 2009;36:1009–23.
[14]        Zhang Y, Xiao M, Chen J. A new methodology for block identification and its application in a large scale underground cavern complex. Tunn Undergr Sp Technol 2010;25:168–80.
[15]        Greif V, Vlčko J. Key block theory application for rock slope stability analysis in the foundations of medieval castles in Slovakia. J Cult Herit 2013;14:359–64.
[16]        Wang S, Ni P, Guo M. Spatial characterization of joint planes and stability analysis of tunnel blocks. Tunn Undergr Sp Technol 2013;38:357–67.
[17]        Wibowo JL. Consideration of secondary blocks in key-block analysis. Int J Rock Mech Min Sci 1997;34:333–e1.
[18]        Yarahmadi Bafghi AR, Verdel T. The probabilistic key group method. Int J Numer Anal Methods Geomech 2004;28:899–917.
[19]        Yarahmadi-Bafghi AR, Verdel T. Sarma based key group method for rock slope reliability analyses. Int J Numer Anal Methods Geomech 2005;29:1019–43.
[20]        Noroozi M, Jalali SE, Yarahmadi Bafghi AR. 3D key group method for slope stability analysis. International. J Numer Anal Methods Geomech 2012;36:1780–92.
[21]        Wyllie DC, Mah C. Rock slope engineering. CRC Press, Taylor & Francis Group; 2004.
[22]        Bourke P. Calculating the area and centroid of a polygon 1988.
[23]        Brinkgreve RBJ, Swolfs WM, Engin E. PLAXIS 2D Reference manual. Delft University of Technology, 2011.
[24]        Tzivakos, K. P., M. J. Kavvadas, and D. G. Kaltsas. "Elastic response of laterally loaded rock sockets using 3D finite element analyses." ISRM International Symposium-EUROCK 2013. International Society for Rock Mechanics, 2013.
روش های تحلیلی و عددی در مهندسی معدن
دوره 8، شماره 17
اسفند 1397
صفحه 1-18

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سابقه مقاله

  • تاریخ دریافت: 09 شهریور 1395
  • تاریخ بازنگری: 10 آذر 1395
  • تاریخ پذیرش: 29 آذر 1395

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