The permeability of composite soils

Al-Moadhen, Muataz M; Clarke, Barry; Chen, Xiaohui

doi:10.1680/jenge.18.00030

Cited by 8 publications

(4 citation statements)

References 41 publications

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“…The hydraulic conductivity under saturated condition ( k ) can be related to the porosity, according to the studies by Clarke (2018) and Al‐Moadhen et al (2020), which refer to an equation form proposed by Chapuis and Aubertin (2003), for very fine glacio‐lacustrine deposits:

k goodbreak= 1 goodbreak\times 10^{- 10} {[\frac{1}{{LL}^{2}} \cdot \frac{e^{3}}{1 + e}]}^{1.58},

where LL is the liquid limit, and e is the void ratio = n /(1 − n ).…”

Section: Methodsmentioning

confidence: 99%

Geophysical–geotechnical methodology for assessing the spatial distribution of glacio‐lacustrine sediments: The case history of Lake Seracchi

Vergnano

Oggeri

Godio

2023

Earth Surf Processes Landf

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Proglacial lakes are distinctive features of deglaciated landscapes and often act as sediment sinks, collecting solid material from subglacial erosion or washout of deglaciated areas. The solid transport flow, strongly linked to the glaciers and periglacial landforms, may rise due to the rapid changes driven by climate warming, causing deep transformations in the basin hydrology, and even the appearance or disappearance of lakes at a decadal timescale.The goal of this study was to present a geophysical-geotechnical approach that integrates several techniques, to quantify the sediment distribution in a proglacial lake. A geophysical survey is performed with ground-penetrating radar (GPR) installed on a boat, whereas a time-domain reflectometer (TDR) measures the electrical conductivity and permittivity of the lakebed sediments. Unperturbed samples are collected and analyzed to measure the main geotechnical properties of the sediment: grain-size distribution, plastic limit, and liquid limit. Such properties support the interpretation of the GPR data and the detection of spatial variations of the sediment facies.To validate the proposed methodology, field tests were carried out at Lake Seracchi, the largest lake of the Rutor glacier, Italian Alps. It formed around 1880 because of the recent glacier shrinkage, as chronicled by valuable historical documents. Its greyish waters carry a significant amount of suspended sediment recognized as glacial flour, which gradually accumulates on the bottom of the lake.The obtained bathymetry and sediment thickness maps of Lake Seracchi show the strength of the approach: from only a few manual samples, it is possible to extrapolate the geotechnical properties of interest, such as friction angle or hydraulic conductivity, to wider areas, surveyed by the geophysical techniques. This is achieved by investigating the spatial distribution of key geophysical properties linked to the geotechnical properties of interest.

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k goodbreak= 1 goodbreak\times 10^{- 10} {[\frac{1}{{LL}^{2}} \cdot \frac{e^{3}}{1 + e}]}^{1.58},

where LL is the liquid limit, and e is the void ratio = n /(1 − n ).…”

Section: Methodsmentioning

confidence: 99%

Geophysical–geotechnical methodology for assessing the spatial distribution of glacio‐lacustrine sediments: The case history of Lake Seracchi

Vergnano

Oggeri

Godio

2023

Earth Surf Processes Landf

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“…Thus, if the volume of coarse grains is ignored, the matrix void ratio becomes 𝑒 𝑚 = 𝑒 (𝐹𝐶/100) ⁄ (Thevanayagam, 1998). This concept was recently explored for composite soils (Al-Moadhen et al, 2020;Clarke, 2018).…”

Section: Main Differences Between Till Depositsmentioning

confidence: 99%

Clustering and Characterization of Toronto Soils Using Pressuremeter Tests

Siscate Bohrer

2024

Preprint

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<p>This research aims to cluster and characterize Toronto soils based on pressuremeter tests (PMT) by applying machine learning algorithms. More than 400 PMT results were collected from a transit project in Toronto, Canada. Gaussian Mixture clustering was applied to cluster Toronto soils into four main groups with distinct mechanical behaviour: glacial tills I and II, cohesive, and cohesionless deposits. A material index based on the shape of the PMT curve was proposed to enhance the separation between cohesive and cohesionless soils, and PMT soil behaviour charts of material index (M IDvs. Menard modulus (E ) Mere proposed. The isocurves of the coefficient Œ± can be used to estimate soil's elastic moduli by correcting the pre-boring PMT disturbance. Predictive equations for EMandM weID proposed enabling the application of the PMT charts in practice. The application of French PMT charts was investigated, and comparisons between Toronto and UK tills were performed.</p>

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“…Accordingly, many scholars at home and abroad have carried out a vast amount of research from different perspectives. In pore media permeability research, the variation of permeability with stress levels has always been of concern [11,12]. Research on different samples shows that the confining pressure (σ r ) has an obvious influence on the k v of the medium.…”

Section: Introductionmentioning

confidence: 99%

Study on the Nonlinear Permeability Mechanism and Pore Structure Characteristics of Deep Confined Aquifers

Peng,

Li,

et al. 2023

Applied Sciences

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The study of deep soil mechanics is the basis of deep shaft construction. Exploring the nonlinear permeability mechanism of deep confined aquifers in depth is the prerequisite and foundation for carrying out calculations of the hydrophobic consolidation settlement of thick alluviums and preventing and controlling deep-well-damage disasters. Against the background of shaft damage caused by hydrophobic consolidation settlement of the bottom aquifer of thick alluviums, a joint HPLTC-HPPNP (high-pressure long-term consolidation and high-pore-pressure nonlinear permeability) test was carried out on the bottom aquifer of thick alluviums based on the ETAS test system. This paper studied the evolution law of the permeability coefficient (kv) of bottom aquifers under different heads of confined water, confining pressures (σr), permeability hydraulic gradients (i) and loading–unloading methods. The internal pore structure characteristics of clayey sand were obtained by using low-field nuclear magnetic resonance (NMR) technology to explore the clayey sand’s nonlinear permeability micro-mechanism. The research results showed that the bottom aquifer seepage volume (ΔQi) under high stress is affected by the head pressure difference and pore water dissipation, and kv decreases with an increasing σr according to the power function relationship. The influence of the hydraulic gradient (i) on kv is significantly influenced by σr. When σr < 4 MPa, kv decreased with an increasing i, and when σr > 4 MPa, kv increased with an increasing i first, then decreased, before then tending to be stable. Under different stress states, the T2 spectrum of clayey sand showed a bispectrum peak type, and the adsorbed water content decreased linearly with an increasing σr, while the capillary water decreased according to the power function. The content of capillary water in the permeable pores plays a key role in the permeability of clayey sand, and it has a power function relationship with σr. The research results of this paper provide a good experimental method for the study of deep soil permeability characteristics and parameter determination, provide a theoretical basis for deep alluvial hydrophobic consolidation and settlement, and further make up for the shortcomings of existing deep soil mechanics in permeability characteristics.

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The permeability of composite soils

Cited by 8 publications

References 41 publications

Geophysical–geotechnical methodology for assessing the spatial distribution of glacio‐lacustrine sediments: The case history of Lake Seracchi

Geophysical–geotechnical methodology for assessing the spatial distribution of glacio‐lacustrine sediments: The case history of Lake Seracchi

Clustering and Characterization of Toronto Soils Using Pressuremeter Tests

Study on the Nonlinear Permeability Mechanism and Pore Structure Characteristics of Deep Confined Aquifers

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