Scale Effect on the Apparent Anisotropic Hydraulic Conductivity of Geomaterials

ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems Part A Civil Engineering, Journal Year: 2023, Volume and Issue: 9(3)

Published: June 6, 2023

Properties of geomaterials often exhibit stratification and anisotropy due to various influencing factors such as weathering sedimentation. However, the measurement is a difficult task since not only depends on direction but also varies with scale. In current study, hydraulic conductivity considered typical geomaterial property simulated by random field theory. A novel method based two-dimensional three-dimensional analytical expressions proposed estimate apparent (k) in different directions determine corresponding anisotropic ratios. series simulation tests specimens dimensions from one strong site are performed via finite element method. The solutions verified numerical results. Results indicate that ratio shows substantial sensitivity sample decrease scale can result reduction ratio; result, k gradually approaches point level's value, effect decreases. This work sheds light gap between laboratory results field's inherent properties provides guidelines upscaling small-scale (e.g., scale) field-scale applications.

Language: Английский

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Material Constants of Anisotropic Poroelasticity and Its Impacts on Shale Gas Production

Energy & Fuels, Journal Year: 2023, Volume and Issue: 37(23), P. 18722 - 18734

Published: Nov. 17, 2023

While the production of shale gas is always accompanied by stratum deformation, previous studies have commonly assumed isotropy to simplify modeling process despite substantial experimental evidence supporting anisotropy these formations. This work contributes both theoretical and practical aspects anisotropy. For aspect, a novel mixture theory approach used explore poromechanical constants anisotropic poroelasticity. By incorporating new elements in intrinsic solid density unjacketed frame we are able establish complete set parameters considering micro-inhomogeneity micro-anisotropy macroscopically porous medium like shale. The bounds on material established, their relationship with poroelasticity proposed Cheng (2021) discussed. In context, examine impacts 3D reservoir elastic permeability anisotropy, compared isotropic counterpart, identify significant dissimilarities horizontal stress parallel wellbore (σxx here) between assumptions transverse isotropy. an inclined plane isotropy, largely inhibited, could observe distribution reorientation. To conclude, models unable reproduce changes predicted models, this research better understanding reservoirs.

Language: Английский

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Numerical analysis of time-dependent negative skin friction on pile in soft soils

Computers and Geotechnics, Journal Year: 2022, Volume and Issue: 155, P. 105218 - 105218

Published: Dec. 28, 2022

Language: Английский

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Toward temporal evolution of consolidation in fluid-saturated poroelastic media with various permeable conditions

Computers and Geotechnics, Journal Year: 2023, Volume and Issue: 156, P. 105273 - 105273

Published: Jan. 19, 2023

Language: Английский

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Anisotropic continuum framework of coupled gas flow – adsorption – deformation in sedimentary rocks

International Journal for Numerical and Analytical Methods in Geomechanics, Journal Year: 2023, Volume and Issue: 48(4), P. 1018 - 1045

Published: Dec. 27, 2023

Abstract Solid deformation is always a crucial factor of gas transport in sedimentary rocks. While previous studies adopt the assumption isotropic poroelastic deformation, anisotropic poroelastoplastic rarely considered, despite anisotropy being ubiquitous property natural In this work, an poromechanical model established to analyze matrix porosity and apparent permeability evolutions during process migration. Using thermodynamic formulation that treats fluid–solid interface as independent phase, we derive rate form for obtain new dissipation function contains three parts: dissipations from solid adsorption, fluid flow. For justify rationality adopted model; flow, updated can be substituted into sophisticated models full‐scale analysis; recently developed constitutive appropriate rocks exhibiting transverse isotropy both elastic plastic responses work. Through novel stress‐point simulation incorporating two effective stress measures adsorption strain, patterns are obtained, which fit experimental data quite well cannot reproduced poroelasticity. The advantages our include consistency ability employ finite‐element‐based formulation. Finally, initial‐boundary value problem production considering plasticity conducted, effects bedding plane different highlighted.

Language: Английский

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Triaxial direct shear properties, cohesive damage behavior and shear constitutive model of sandstone under high confining pressure

European Journal of Environmental and Civil engineering, Journal Year: 2023, Volume and Issue: 28(6), P. 1284 - 1299

Published: Aug. 24, 2023

The shear mechanical properties of rock under high confining stresses are required in deep underground construction projects for stability evaluation. This paper tested the sandstone pressures by a novel triaxial direct device with self-balancing structure both low and pressure. experiments on Zigong from tunnel were carried out to evaluate its strength deformability. Our experimental results suggested that stress-displacement curves exhibited two distinct characteristics different pressures. damaging stage occurs initially turns wider curve as pressure exceeds threshold stress. is observed be 10–20 MPa. Meanwhile, statistical damage model based Beta distribution was proposed describe stress (cohesion contribution) during whole shearing process, which demonstrates better prediction performance than previously existing models, especially study provides important insights into high-pressure induced sheds light engineering assessment tunnels.

Language: Английский

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A dynamic SNS-PFEM with generalized-α method for hydro-mechanical coupled geotechnical problems

Computers and Geotechnics, Journal Year: 2023, Volume and Issue: 159, P. 105466 - 105466

Published: April 24, 2023

Language: Английский

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Interior three-dimensional acoustic modeling and modal analysis using wavelet-based finite-element approach

The Journal of the Acoustical Society of America, Journal Year: 2024, Volume and Issue: 156(2), P. 1252 - 1268

Published: Aug. 1, 2024

This paper introduces two-dimensional (2D) and 3D acoustic modeling modal analysis using the wavelet finite-element method (WFEM). Governed by Helmholtz equation, domain is parameterized analyzed scaling functions of B-spline wavelets, which facilitates construction elements with varying numbers nodes via multi-resolution analysis. The wavelet-based shape provide a semi-orthogonal basis that enables rapid searching for approximate solutions in Lebesgue spaces, thereby offering significantly reduced interpolation errors computational burden. Numerical examples are considered WFEM, comprising 2D problem involving tube predicting pressure eigenfrequency investigations, problems cubic room an L-shaped capturing characteristics. results compared those (i) standard FEM same mesh (ii) analytical solutions. Importantly, WFEM demonstrates stability being insensitive to internal size variations, indicating have minimal effects on numerical results. Furthermore, effectively control pollution (dispersion) error methods when imposing Neumann boundary conditions high-frequency range, they reduce caused polynomial low-frequency domain.

Language: Английский

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Micromechanical analysis of upward pipe-soil interaction behaviors in unsaturated granular soil

Tunnelling and Underground Space Technology, Journal Year: 2024, Volume and Issue: 155, P. 106162 - 106162

Published: Nov. 2, 2024

Language: Английский

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Step-changed strain rate effect on the mechanical properties of undisturbed expansive clay

European Journal of Environmental and Civil engineering, Journal Year: 2023, Volume and Issue: 28(1), P. 38 - 52

Published: April 17, 2023

Up to now, most of the research on rate effects has investigated behavior soft soils, much less is known for stiff clays. In particular, method stepwise changing strain rarely been used in studies soil effects, but many have well demonstrated that this beneficial overcome problems variability between samples and time requirements associated with rates. Isotropic consolidated-undrained triaxial tests were conducted specimens same void ratio at step-changed axial rates under four different confining pressures study. We carried out effect from 0.09 300%/hour mechanical properties naturally expansive soils. Experimental results showed higher rate, effective stress a given strain. The shear strength increases 5.9% 11.4% per log cycle saturated undisturbed by introducing strain-rate parameter ρ0.09, which similar excess pore water pressure gradually decreases after reaching peak lower cell increasing ones. addition, failure mode clay both main band multi-fissures band. new findings are helpful better understanding time-dependent

Language: Английский

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