Role of Sliding Block Rotation on Earthquake-induced Permanent Displacement of Embankments and Trenches in Roads

Document Type : Research Paper

Authors

Abstract

Since proper functioning of the transportation system is essential in times of crisis, correct design and accurate prediction of earthquake-induced permanent displacement of embankments and trenches have been considered by many engineers. Different methods are available for estimating earthquake-induced permanent displacement of embankments and trenches in roads, such as pseudo-static, numerical, analytical and semi-analytical. Due to its simplicity, Newmarkian rigid block analogy has received considerable attention from geotechnical researchers and practitioners. Since the conventional Newmarkian analogy has many limitations, conservative and non-conservative estimations of sliding displacement would be possible. Therefore, researchers have proposed many modifications to this method. One of these limitations is the effect of rotation. In fact, it is anticipated that the downward rotational (stabilizing) movement of the soil mass, can significantly affect the yielding acceleration of the presumed slip surface. In this paper, keeping in mind the effect of rotation, the conventional formulation of the Newmark approach is modified numerically. The results are presented and compared for several conditions including the conventional rigid block, decoupled assumption of sliding and slope response, coupled consideration of sliding and slope response, and decoupled assumption with the effect of sliding block rotation. According to the results of this study, the period ratio (ratio of natural period of slope to the mean period of input motion) and the length of slip surface, can significantly affect the permanent displacement of sliding mass.

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جعفریان، ی.، لشگری، ع.، میرایی، م. و محملی ابیانه، ر. 1392. عوامل مؤثر بر پاسخ لرزه‏ای و تغییر مکان­های اسکله کیسونی با استفاده از تحلیل‌های عددی تفاضل محدود. هفتمین کنگره ملی مهندسی عمران، اردیبهشت، زاهدان.
Baziar, M. H., Rezaeipour, H. and Jafarian, Y. 2012. “Decoupled solution for seismic permanent displacement of earth slopes using deformation-dependent yield acceleration”. J. Earthq. Eng. 16: 917-936.
Bray, J. D. and Travasarou, T. 2007. “Simplified procedure for estimating earthquake-induced deviatoric slope displacements”. J. Geotech. Geoenviron. Eng., ASCE, 133(4): 381-392.
Chopra, A. K. and Zhang, L. 1991. “Earthquake–induced base sliding of concrete gravity dams”. J Struct. Eng.,  ASCE 117(12): 3698-3719.
Jibson, R. W. 2010. “Methods for assessing the stability of slopes during earthquakes- A retrospective”. Eng. Geol. 122: 43-50.
Kramer, S. L. and Smith, M. W. 1997. “Modified Newmark model for seismic displacements of compliant slopes”. J. Geotech. Geoenviron. Eng., ASCE 123(7): 635-644.
Lashgari, A. and Jafarian, M. 2013. “Role of sliding block rotation on earthquake induced permanent displacement of earth slopes”. 4th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Kos Island, Greece.
Lin, J. S. and Whitman, R. V. 1983. “Decoupling approximation to the evaluation of earthquake induced plastic slip in earth dams”. Earthq. Eng. Struct. Dynam. 11: 667-678.
Makdisi, F. I. and Seed, H. B. 1987. “Simplified procedure for estimating dam and embankment earthquake induced deformations”. J. Geotech. Eng., ASCE 104(GT7): 849-867.
Newmark, N. M. 1959. “A method for computation for structural dynamics”. ASCE J. Eng. Mech. Div. 85: 67-94.
Newmark, N. M. 1965. “Effects of earthquakes on dams and embankments”. Geotech. 15(2): 139-160.
Norwegian Geotechnical Institute (NGI). 2012. “D3.7- Fragility Functions for Roadway System Elements”. Project, Norwegian Geotechnical Institute.
Pradel, D., Smith, P. M., Stewart, J. P. and Raad, G. 2005. “Case history of landslide movement during the Northridge earthquake”. J. Geotech. Geoenviron. Eng. 131: 1360-1369.
Rathje, E. M., Abrahamson, N. and  Bray, J. D. 1998. “Simplified content estimates of earthquake ground motions”. J. Geotech. Geoenviron. Eng., ASCE 124(2): 150-159.
Rathje, E. M. and Antonakos, G. A. 2011. “Unified model for predicting earthquake-induced sliding displacements of rigid and flexible slopes”. Soil Dynam. Earthq. Eng. 122(12): 51-60.
Rathje, E. M. and Bray, J. D. 1999 An examination of simplified earthquake–induced displacement procedures for earth structures”. Can. Geotech. J. 36(1): 72-87.
Rathje, E. M. and Bray, J. D. 2000. “Nonlinear coupled seismic sliding analysis of earth structures”. J. Geotech. Geoenviron. Eng., ASCE, 126(11): 1002-1014.
Stamatopoulos, C. A. 1996. “Sliding system predicting large permanent co–seismic movements of slope”. Earthq. Eng. Struct. Dynam. 25(10): 1075-1093.
Wilson, R. C. and Keefer, D. K. 1985. “Predicting areal limits of earthquake-induced landsliding”. PP. 317-345. In: Ziony, J. L. (Ed.), Evaluating Earthquake Hazards in the Los Angeles Region, U. S. Geological Survey, Reston, Virginia, Professional Paper 1360.