Developments in Modeling Liquefaction of Granular Soils, Caused by Cyclic Loads

Abstract

The aim of this review article is to present historical developments of mechanics of saturated granular soils in relation to the liquefaction phenomenon, as well as to analyze the present state of this subject in connection with practically important problems. The first part is an introduction to mechanics of liquefaction, in order to make this paper self-contained. Then, some basic empirical findings are described. In the third part, the development of theoretical approaches to liquefaction-related problems, such as cyclic loading compaction and pore pressure accumulation, or cyclic loading degradation of shearing resistance, is presented. The fourth part deals with the presentation of the methods applied for solving practically important problems and those that have not been solved satisfactorily. The last part of this paper presents some of the most important conclusions and suggestions regarding further research. There are 152 references cited in this review article, and a supplementary bibliography of 45 publications is also included.

The Mechanical Coupling of Fluid-Filled Granular Material Under Shear

“…Previously, the only mechanism that was suggested to induce liquefaction was compaction of loosely packed grains under undrained conditions [Sawicki and Mierczynski, 2006], leading to an elastic-like pore pressure evolution, (as modeled in our undrained loose simulation, U14). Therefore, the occurrence of liquefaction events with densely packed drained conditions, leading to viscous-like evolution of pore pressure, is a surprising result of our model (that was also obtained in our approximate model [Goren et al, 2010]).…”

“…As for the mechanism of liquefaction, it was attributed to the tendency of loose soil to compact with drained conditions [Sawicki and Mierczynski, 2006], a tendency that was observed in dry and completely drained experiments [e.g. Youd, 1972].…”

“…The classical approach suggests that cyclic loading (such as the passage of shear waves during an earthquake) leads to irreversible collapse of initially under-consolidated pore volume. When drainage is poor, 'the tendency for volume reduction' of the loose granular skeleton may lead to pore fluid pressurization and to liquefaction [Sawicki and Mierczynski, 2006]. This basic understanding guides most engineering practices, yet the classical approach still leaves open questions: What is the role of fluid compressibility in the pressurization process [Garga and Zhang, 1997]?, What are the relevant drainage conditions -can liquefaction occur also when fluid inflow and outflow to and from the system are allowed [Seed et al, 1976, El Shamy andZeghal, 2007]?…”

Some Effects of Intrinsic Cyclic Loading in Saturated Sands

“…The phenomenon of pore-pressure generation should be described by a separate constitutive equation, as the above phenomena cannot be described by classical models that have been developed for centuries in mechanics of materials. The above problems were the subject of extensive research in the past decades, for references see Sawicki and Mierczyński (2006), Lade and Yamamuro (1999) or Jefferies and Been (2006). However, there is also another approach to this problem, represented by marine engineers, who focus on wave-induced pore-pressures in the seabed.…”

“…In order to describe this phenomenon, they use various classical models of porous media, which however lead to different results. A short state-of-the-art is presented in Sawicki and Mierczyński (2006), see also Jeng (2013). The classical standard in marine engineering was established by Yamamoto et al (1978).…”