Boundary integral formulation and two-dimensional fundamental solutions for dynamic behavior analysis of unsaturated soils

This paper aims at obtaining an advanced formulation of the time-domain Boundary Element Method (BEM) for two-dimensional dynamic analysis of unsaturated soil. Unlike the usual time-domain BEM the present formulation applies a Convolution Quadrature which requires only the Laplace-domain instead of the time-domain fundamental solutions. The coupled equations governing the dynamic behavior of unsaturated soils ignoring contributions of the inertia effects of the fluids (water and air) are derived based on the poromechanics theory within the framework of the suction-based mathematical model. In this formulation, the solid skeleton displacements, water pressure and air pressure are presumed to be independent variables. As there is no analytical solution for the 2D wave propagation in unsaturated soils in the literature, to verify the accuracy of this implementation, the displacement response obtained by the boundary element formulation is partially verified by comparison with the elastodynamics problem.

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“…In eq. (15), is the adjoint operator to used for the deduction of fundamental solutions (Maghoul et al 2011).…”

Section: Boundary Integral Equationmentioning

confidence: 99%

“…Secondly, the Boundary Integral Equation (BIE) is developed directly from those equations via the use of the weighted residuals method in a way that permits an easy discretization and implementation in a numerical code. The associated fundamental solution obtained by Maghoul et al (2011) is used in the BIE.…”

Section: Introductionmentioning

confidence: 99%

A Boundary Element Formulation for the Wave Propagation in the Unsaturated Soils

et al. 2013

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“…For example, Lu and Jeng [35] investigated the porous soil which governed by the u À P formulation, using the boundary element method. Maghoulaet al [37] applied a boundary integral formulation for dynamic behavior analysis of unsaturated soils. Khoshghalib and Khalili [30] used a meshless radial point interpolation to solve the fully coupled Biot's equations.…”

Section: Introductionmentioning

confidence: 99%

Recovery-based error estimation in the dynamic analysis of offshore wind turbine monopile foundations

Bayat

Ghorashi

Amani

et al. 2015

Computers and Geotechnics

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“…Such a technique was based on an integral equation formulation in terms of solid displacements and fluid stress. The 2D and 3D fundamental solutions of dynamic poroelasticity was further developed by [13][14][15][16] . The solutions were obtained in both time and Laplace transform domain, and can be recovered to elastodynamics and steady-state poroelasticity.…”

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confidence: 99%

Laboratory-scale characterization of saturated soil samples through ultrasonic techniques

Liu

Maghoul

Shalaby

2020

Sci Rep

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the propagation of poroelastic waves in a soil specimen is dependent on the physical and mechanical properties of the soil. in the geotechnical practice, such properties are obtained through in-situ geotechnical testings or element soil testings in the laboratory. these methods require almost advanced equipment and both testing and sample preparation may be expensive and time-consuming. this paper aims to present an algorithm for a laboratory-scale ultrasonic non-destructive testing to determine the physical and mechanical properties of saturated soil samples based on the distribution of stress waves. the ultrasonic setup, in comparison to most conventional soil lab testing equipment, is low-cost and non-invasive such that it reduces the soil disturbance. for this purpose, a poroelastodynamic forward solver and differential evolution global optimization algorithm were applied to characterize the porosity, density, and other mechanical properties for a soil column. the forward solver was developed based on a semi-analytical solution which does not require intensive computational efforts encountered in standard numerical techniques such as the finite element method. It was concluded that the proposed high-frequency ultrasonic technique characterizes effectively the saturated soil samples based on the output stress wave measured by the receiver. this development makes geotechnical investigations time-efficient and cost-effective, and as such more suited to applications in remote areas.Characterizing foundation soils is the first step in design and construction of civil infrastructure. The measurement of physical and mechanical properties of soils (e.g shear wave velocity, compression wave velocity, density and porosity) requires intensive in-situ or laboratory tests, which can be time consuming and costly. Soil samples, especially from projects in remote areas, are required to be transported to a geotechnical laboratory for various tests. This can cause the disturbance of soil samples, and laboratory tests on disturbed samples may lead to erroneous conclusions.The laboratory methods for measuring the shear wave velocity of soil samples include the resonant column test, bender element test among others. However, there is no established standard developed for the interpretation of the dynamic test results 1 . The bender element method was developed in the 1980s and its simplicity is widely recognized: one transducer is placed at one end of a soil specimen for the generation of stress waves; one receiver is placed at the other end to record the induced stress waves. Various interpretation methods have been proposed in the past. The shear wave velocity can be calculated from the time difference between the input and output waves by assuming the absence of reflected or refracted waves 2 . However, it is well known that the identification of the arrival time of the output wave is subjective 1 . Other signal processing techniques such as the cross-correlation of the input and output stress waves 3 and the second arrival of...

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Boundary integral formulation and two-dimensional fundamental solutions for dynamic behavior analysis of unsaturated soils

Cited by 24 publications

References 39 publications

A Boundary Element Formulation for the Wave Propagation in the Unsaturated Soils

A Boundary Element Formulation for the Wave Propagation in the Unsaturated Soils

Recovery-based error estimation in the dynamic analysis of offshore wind turbine monopile foundations

Laboratory-scale characterization of saturated soil samples through ultrasonic techniques

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