Effect of uncertainty of soil parameters on the dynamic response of soil using random field theory

Document Type : Research Article

Authors

1 MSc student, Department of Civil Engineering, Shahrood University of Technology, Shahrood, Iran

2 Assistant professor, Department of Civil Engineering, Shahrood University of Technology

Abstract

Seismic waves caused by earthquakes undergo many changes when passing through different layers of soil. For this reason, the effects of soil parameters on the dynamic response of the ground should be considered. The parameters in a heterogeneous soil layer are affected by a set of uncertainties, which in this research is the inherent variability of the soil shear modulus parameter. In this research, using random field theory and finite difference method in the framework of Monte Carlo simulations, the effect of two-dimensional spatial variability of the soil shear modulus parameter on the magnification factor of the maximum ground acceleration and the surface acceleration response spectrum has been investigated. In the conventional deterministic analysis, only a constant value of the average shear modulus is considered in the dynamic model, but in the stochastic analysis, the parameter of the soil shear modulus is considered as a random variable. The results obtained from the analysis show that with the increase of heterogeneity and changes in the shear modulus of the soil, the values of the magnification factor of the maximum ground acceleration decrease. Also, with the increase in the coefficient of variation of the soil shear modulus and as a result of the increase in the heterogeneity of the soil profile, the acceleration response spectrum of the surface of the soil profile obtained from random analyzes decreases.

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Main Subjects


[1] T.-T. Tran, S.R. Han, D. Kim, Effect of probabilistic variation in soil properties and profile of site response, Soils and Foundations, 58(6) (2018) 1339-1349.
[2] G.W. Rathod, K.S. Rao, K.K. Gupta, Monte Carlo Simulation for modelling uncertainties in ground response analysis, Japanese Geotechnical Society Special Publication, 2(19) (2016) 709-714.
[3] E.E. Haber, C. Cornou, D.Y. Abdelmassih, D. Jongmans, T. Al-Bittar, F. Loppez-Caballero, Effect of the 2D Spatial Variability of Linear Soil Properties on the Variability of Surface Ground Motion Coherency, in:  Geotechnical Earthquake Engineering and Soil Dynamics V: Seismic Hazard Analysis, Earthquake Ground Motions, and Regional-Scale Assessment, American Society of Civil Engineers Reston, VA, 2018, pp. 348-358.
[4] K.-K. Phoon, F.H. Kulhawy, Characterization of geotechnical variability, Can Geotech J, 36(4) (1999) 612-624.
[5] A. Nobahar, Effects of soil spatial variability on soil-structure interaction, Doctoral (PhD) Thesis, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, 2003.
[6] H. Kim, Spatial variability in soils: stiffness and strength, PhD Thesis, Faculty of Civil and Environmental Engineering, Georgia Institute of Technology, 2005.
[7] E.H. Vanmarcke, Probabilistic modeling of soil profiles, Journal of the geotechnical engineering division, 103(11) (1977) 1227-1246.
[8] D.V. Griffiths, G. Fenton, Risk assessment in geotechnical engineering, John wiley&Sons, Inc,  (2008) 381-400.
[9] A. Ahmed, Simplified and advanced approaches for the probabilistic analysis of shallow foundations, PhD thesis, University of Nantes, 2012.
[10] F. Uribe Castillo, Probabilistic analysis of structures using stochastic finite elements, Universidad Nacional de Colombia-Sede Manizales, 2015.
[11] H.S. Lizarraga, C.G. Lai, Effects of spatial variability of soil properties on the seismic response of an embankment dam, Soil Dyn Earthq Eng, 64 (2014) 113-128.
[12] H. El-Ramly, N. Morgenstern, D. Cruden, Probabilistic stability analysis of a tailings dyke on presheared clay shale, Can Geotech J, 40(1) (2003) 192-208.
[13] R. Alaie, Slope Stability Analysis in Heterogeneous and Anisotropic Soils using
Random Field Theory, Master’s thesis, Guilan University, 2012.
[14] R. Popescu, G. Deodatis, A. Nobahar, Effects of random heterogeneity of soil properties on bearing capacity, Probabilistic Engineering Mechanics, 20(4) (2005) 324-341.
[15] B. Sunardi, J. Nugraha, Peak Ground Acceleration at Surface and Spectral Acceleration for Makassar City Based on a Probabilistic Approach, Jurnal Meteorologi dan Geofisika, 17(1) (2016).
[16] A. Tuncel, Ö.C. Özdag, E. Pamuk, M. Akgün, Comparison of the soil dynamic amplification factor and soil amplification by using microtremor and MASW methods respectively, in:  IOP Conference Series: Earth and Environmental Science, IOP Publishing, 2017, pp. 032006.
[17] P. Plengsiri, L.Z. Mase, S. Likitlersuang, Influence of ground variation on site amplification factor of Bangkok subsoils, Master’s thesis, Department of Civil Engineering, Chulalongkorn University, 2018.
[18] K. Bajaj, P. Anbazhagan, Ground motion site amplification factors for deep soil deposits sites in Indo-Gangetic Basin,  (2017).
[19] A.T. Council, Quantification of building seismic performance factors, US Department of Homeland Security, FEMA, 2009.
[20] F. Itasca, FLAC-Fast Lagrangian Analysis of Continua, Version. 8.0, in, Itasca Consulting Group, lnc.Minneapolis, 2016.