Probabilistic Analysis and Design of a Strip Footing on Layered Soil Media

Abstract

In the present paper, the analysis of a strip footing resting on a layered soil system has been carried out considering the elastic moduli of soil layers as random variables. Three layers of soil have been considered and the analysis employs Monte Carlo simulation. The modulus of elasticity has been considered as random variable having lognormal distribution. Factors of safety with respect to settlement of footing and the interfacial stresses have been determined and have been related to the associated risk factor and coefficient of variation of the random variable. A detailed parametric study revealed that for a given risk level, the factors of safety is strongly dependent on the coefficient of variation of elastic modulus and only mildly upon other parameters of the soil-foundation system. This facilitated the development of closed form equations for the upper bounds on factors of safety only in terms of allowable risk of failure and the coefficient of variation of elastic modulus.

Application of probabilistic methods to characterize soil variability and their effects on bearing capacity and settlement of shallow foundations: state of the art

“…Probabilistic settlement predictions were also performed for multi-layered soils (Brzakala and Pula, 1996;Kuo et al, 2004;Maheshwari and Kumar, 2011). The former two studies concluded that COV of foundation settlement for double layered soil profile is smaller than that of the single uniform soil profile.…”

“…In a recent study conducted by Maheshwari and Kumar (2011), the response of strip footing supported by layered soil media was probabilistically analyzed. The modulus of elasticity has been considered as a random variable with lognormal distribution and MC simulations were carried out to determine the factor of safety as a function of COV of elastic modulus of soil and the level of risk.…”

Settlement of shallow footings on layered soil: state-of-the-art

“…The random field Monte Carlo analyses suggested that the vertical correlation length had marginal effect on the mean value but considerable influence on its standard deviation. Maheshwari and Kumar (2011) employed the model, as proposed by Maheshwari and Kashyap (2009), to analyze a strip footing resting on three-layered elastic soil medium. Moduli of elasticity of soil layers were considered to be lognormally distributed random variable with infinite autocorrelation distance.…”

Detailed stochastic finite element simulation in geotechnics

“…Μεγάλος πράγματι αριθμός ερευνητών έχει μελετήσει την επιρροή της χωρικής διακύμανσης διαφόρων εδαφικών ιδιοτήτων όπως το μέτρο ελαστικότητας, η γωνία τριβής και η διαπερατότητα σε σχετικές εφαρμογές. Μελέτες φέρουσας ικανότητας θεμελίων (Al-Bittar and Soubra, 2013;Cho and Park, 2010;Griffiths et al, 2002Griffiths et al, , 2006Simões et al, 2014) και καθίζησης (Fenton and Griffiths, 2005;Maheshwari and Kumar, 2011;Paice et al, 1996), ευστάθειας πρανών (Griffiths and Fenton, 2004;Griffiths et al, 2009), καθώς και διήθησης (Griffiths and Fenton, 1997), αποτελούν μερικές μόνο χαρακτηριστικές περιπτώσεις. Επιπλέον, το φαινόμενο της στερεοποίησης υπό πιθανοτική σκοπιά έχει μελετηθεί από διάφορους ερευνητές.…”

“…A number of researchers have studied the effect of spatial variability of various soil properties such as elasticity modulus, friction angle and permeability on different related applications. Investigations of footing bearing capacity (Al-Bittar and Soubra, 2013;Cho and Park, 2010;Griffiths et al, 2002Griffiths et al, , 2006Simões et al, 2014) and settlements (Fenton and Griffiths, 2005;Maheshwari and Kumar, 2011;Paice et al, 1996), slope stability (Griffiths and Fenton, 2004;Griffiths et al, 2009), as well as seepage (Griffiths and Fenton, 1997), are some characteristic cases. Furthermore, the consolidation phenomenon in a probabilistic setting has been studied by various researchers.…”