Numerical Laplace-Fourier transform inversion technique for layered soil consolidation problems; II, Gibson soil layer. Short communication

1987 ◽  
Vol 24 (4) ◽  
pp. 137
Keyword(s):  
Fourier Transform ◽  
Short Communication ◽  
Soil Layer ◽  
Layered Soil ◽  
Soil Consolidation ◽  
Inversion Technique

scholarly journals Infiltration-runoff model for layered soils considering air resistance and unsteady rainfall

2018 ◽  
Vol 50 (2) ◽  
pp. 431-458
Author(s):  
Yongde Gan ◽  
Huan Liu ◽  
Yangwen Jia ◽  
Siyuan Zhao ◽  
Jiahua Wei ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Layer ◽  
Layered Soil ◽  
One Dimensional ◽  
Moisture Deficit ◽  
Cumulative Infiltration ◽  
Air Resistance ◽  
Runoff Rate ◽  
Entrapped Air ◽  
Runoff Model

Abstract A modified Green–Ampt model (MGAM) was proposed to simulate infiltrations into layered soil profiles with the entrapped air under unsteady rainfall conditions. To account for the effects of the air resistance, the saturation coefficient, actual water content, air bubbling pressure, and water bubbling pressure were introduced in the model. One-dimensional infiltration-runoff experiments were then conducted in multi-layered soil columns, under unsteady rainfall conditions, to evaluate the performance of the MGAM model. The cumulative infiltration, runoff rate, and water content of the soil, calculated by MGAM, were compared with the observed data and the results, calculated by the traditional Green–Ampt model (TGAM), the Bouwer Green–Ampt model (BGAM), and the Mein–Larson model (MLGAM), respectively. The results indicated that the cumulative infiltration, runoff rate, and soil water content, calculated by MGAM, were in better agreement with the observed results than previous models. A parameter sensitivity of MGAM was also analyzed. It was found that the sensitivity of the saturated coefficient was high in the first soil layer, and those of the air bubbling pressure and initial moisture deficit were high or medium in the first and second layers, while those of the other parameters were relatively low.

scholarly journals Application of attenuated total reflection infrared spectroscopy in the study ofPeruphasma schulteidefensive secretion

2007 ◽  
Vol 21 (3) ◽  
pp. 169-176 ◽  
Author(s):  
Michael P. Mcleod ◽  
Aaron T. Dossey ◽  
M. Khalique Ahmed
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Natural Product ◽  
Short Communication ◽  
Defensive Secretion ◽  
Structural Characteristics ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Ft Ir ◽  
Ir Study

In this short communication, we present the first Fourier Transform Infrared Absorbance (FT-IR) study of peruphasmal; a defensive secretion fromPeruphasma schultei. The spectral data collected are representative of the natural product structure proposed by Dossey et al. This study demonstrates the viability of FT-IR as another tool in the physical and biological chemist's repertoire for use in determining important structural characteristics from minute amounts of available sample.

Degradation of permafrost beneath a road embankment enhanced by heat advected in groundwater1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.

2012 ◽  
Vol 49 (8) ◽  
pp. 953-962 ◽  
Author(s):  
Isabelle de Grandpré ◽  
Daniel Fortier ◽  
Eva Stephani
Keyword(s):  
Groundwater Flow ◽  
Soil Layer ◽  
Permafrost Degradation ◽  
Soil Consolidation ◽  
Monitoring Wells ◽  
The Road ◽  
Road Pavement ◽  
Advective Heat Transfer ◽  
Road Data ◽  
Northwestern North America

For the past few decades, northwestern North America has been affected by climate warming, leading to permafrost degradation and instability of the ground. This is problematic for all infrastructure built on permafrost, especially roads and runways. Thaw settlement and soil consolidation promote embankment subsidence and the development of cracks, potholes, and depressions in road pavement. In this study, we investigate highway stability in permafrost terrain at an experimentally built road embankment near Beaver Creek, Yukon. A network of 25 groundwater monitoring wells was installed along the sides of the road to estimate groundwater flow and its thermal impact on the permafrost beneath the road. Data on topography, water-table elevation, ground temperature, and stratigraphy of the soil were collected at the site. The geotechnical properties of each soil layer were determined by laboratory analysis and used to calibrate a two-dimensional groundwater flow model. Field observations showed that water was progressively losing heat as it flowed under the road embankment. Our results suggest that advective heat transfer related to groundwater flow accelerated permafrost degradation under the road embankment.

Radial consolidation modelling incorporating the effect of a smear zone for a multilayer soil with downdrag caused by mandrel action

2010 ◽  
Vol 47 (9) ◽  
pp. 1024-1035 ◽  
Author(s):  
Cholachat Rujikiatkamjorn ◽  
Buddhima Indraratna
Keyword(s):  
Lower Layer ◽  
Soil Layer ◽  
Soil Consolidation ◽  
Soil Permeability ◽  
Soil System ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Design Procedures ◽  
Surcharge Preloading ◽  
Time Required

A system of prefabricated vertical drains with surcharge preloading is an effective method for promoting radial drainage and accelerated soil consolidation. A piecewise technique is employed to analyse the radial consolidation in a multilayer soil system to include (i) the effect of soil downdrag and (ii) a smear zone having linearly varying soil permeability. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of the time required for consolidation. It can be seen that the consolidation of the multilayer soil depends on smear zone characteristics, the permeability ratio between upper and lower soil layers, penetration depth, and drain spacing. Design procedures are described with the help of an example.

Stiffness matrix method for analysis of torsionally loaded piles in multi-layered soil

2021 ◽  
pp. 1-19
Author(s):  
Carlos A. Vega-Posada
Keyword(s):  
Stiffness Matrix ◽  
Soil Layer ◽  
Quadratic Function ◽  
Practical Method ◽  
Transformation Method ◽  
Layered Soil ◽  
Structural Element ◽  
The Matrix ◽  
Governing Differential Equation ◽  
Air Interfaces

A new, simple, and practical method to investigate the response of torsionally loaded piles on homogeneous or non-homogeneous multi-layered elastic soil is developed. The soil non-homogeneity is accounted for by assuming for each layer a shear modulus distribution that fits a quadratic function. The analysis of piles in multi-layered soil is carried out by subdividing the pile, at the soil-soil layer and soil-air interfaces, into multiple elements, and then using conventional matrix methods -such as those commonly implemented in structural analysis- to connect them. The governing differential equation (GDE) of an individual structural element is solved using the Differential Transformation Method (DTM). Next, the stiffness matrix is derived by applying compatibility conditions at the ends of the element. Piles partially or fully embedded in multiple layers and subjected to torsion can be analyzed in a simple manner with the proposed formulation -a tedious endeavor with other available solutions. Finally, explicit expressions for the coefficients of the matrix are provided. Four examples are presented to show the simplicity, accuracy, and capabilities of the proposed formulation.

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