scholarly journals The Capillary Rise in Fine and Coarse-Grained Soils Considering the Matric Suction

2020 ◽  
Vol XII (V) ◽  
Keyword(s):  
Capillary Rise ◽  
Matric Suction ◽  
Coarse Grained

scholarly journals The Capillary Rise in Fine and Coarse-Grained Soils Considering the Matric Suction

2021 ◽  
Author(s):  
Jair Arrieta Baldovino ◽  
Ronaldo Izzo ◽  
Carlos Millan-Paramo
Keyword(s):  
Soil Column ◽  
Capillary Rise ◽  
Experimental Studies ◽  
Matric Suction ◽  
Coarse Grained ◽  
Column Height ◽  
Maximum Height ◽  
Rise Velocity ◽  
Unsaturated Hydraulic Conductivity ◽  
Time Required

Abstract Few pieces of research have been conducted on the phenomenon of capillary rise in the field of soil for agriculture and geotechnical engineering. The rate of capillary rise of water in fine and granular soil is one of the major challenges for rising experiments in vertical open-tubes, as the time required for the water to reach the maximum height of capillary rise (hc) can vary from 50 to 400 days. The control variables during the capillary experiment are mainly: saturated and unsaturated hydraulic conductivity, soil density, water content, soil column height, and velocity of capillary rise. Thus, this paper presents theoretical and experimental studies of capillary rise in several soils based on matric suction models. Results were gathered by comparing the behavior of capillary rise using the analytical solutions developed by Lu (2016), Lu and Likos (2004), and by Terzaghi (1943). On analysis of the results, it was concluded that the equation proposed by Lu and Likos (2004) is the most suitable to predict the capillary rise velocity for the fine-coarse soils and the equation proposed by Lu (2016) is more suitable to predict the matric suction. Other mathematical model developed by Liu et al. (2014) is also suitable to estimate the hc but don’t consider the velocity of the water. The capillary rise method to measure the matric suction must be more applicable in sandy soil than clayey soils.

Preventing surface deposition of chromium with asphalt caps at chromite ore processing residue sites: a case study

2007 ◽  
Vol 44 (7) ◽  
pp. 814-839 ◽  
Author(s):  
Karen S Henry ◽  
John C Petura ◽  
Steven Brooks ◽  
Steven Dentico ◽  
Stephen A Kessel ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Capillary Rise ◽  
Matric Suction ◽  
Upward Movement ◽  
Chromite Ore Processing Residue ◽  
Chromite Ore ◽  
Ore Processing ◽  
Unsaturated Hydraulic Conductivity ◽  
Water Rise

Caps were constructed on chromite ore processing residue (COPR) sites in the Kearny, New Jersey, area between 1989 and 1994 to prevent human exposure to hexavalent chromium (Cr(VI)). The caps comprise geotextile overlain by 100 mm of dense graded aggregate (DGA) and 100 mm of hot mix asphalt (HMA). Prior to constructing these "composite asphalt caps" (CACs), Cr(VI) was sometimes deposited on surface soils as chromate (salts) during evaporative periods. We initially thought the geotextile and DGA acted as a capillary barrier, stopping capillary water rise, but site inspection revealed that the DGA and geotextile were too moist to perform this function. Further study included a literature review, DGA capillary rise estimates, in situ measurement of soil-water content over 7 months at a representative COPR site, and numerical modeling of matric suction gradients induced by evaporation. The collective results reveal that the CACs eliminate upward matric suction gradients from the COPR–soil through the DGA, thereby precluding surface chromate deposition. Even during evaporative periods, the low unsaturated hydraulic conductivity of the HMA restricts upward movement of moisture and soluble chromate from underlying COPR–soil. In contrast, there are almost always upward matric suction gradients in uncapped COPR–soil.Key words: capillary rise, chromite ore processing residue, chromate, hexavalent chromium, composite asphalt cap, evaporation.

A simple air pressure gauge for unsaturated soils

2007 ◽  
Vol 44 (8) ◽  
pp. 1013-1018 ◽  
Author(s):  
Julio  Ángel Infante Sedano ◽  
Sai K. Vanapalli ◽  
Vinod K. Garga
Keyword(s):  
Unsaturated Soils ◽  
Low Cost ◽  
Pressure Gauge ◽  
Matric Suction ◽  
Coarse Grained ◽  
Water Characteristics ◽  
Main Components ◽  
Column Pressure ◽  
Boyle’S Law ◽  
Air Column

This paper presents the design details of a simple compressible air column pressure gauge system. The main components of this pressure gauge consist of a Mariotte bottle, plastic tubing, and a graduated scale. This low-cost gauge design is based on applying the principle of Boyle’s law for gases, which makes it particularly well-suited for the measurement of soil–water characteristics of coarse-grained soils, which desaturate at a faster rate, particularly in the low matric suction range of 0–10 kPa. Among its many uses, this precise gauge is best employed in the axis translation technique to measure matric suction in the range of 0–700 kPa.

scholarly journals An experimental investigation into the salt-weathering susceptibility of building limestones

2020 ◽  
Vol 53 (12) ◽  
pp. 5329-5343
Author(s):  
Simona Scrivano ◽  
Laura Gaggero
Keyword(s):  
Morphological Changes ◽  
Capillary Rise ◽  
Coarse Grained ◽  
Relative Mass ◽  
Salt Weathering ◽  
Built Heritage ◽  
Ornamental Stones ◽  
Saline Solutions ◽  
New Buildings ◽  
Selection Of

AbstractDimension and ornamental stones used for built heritage are frequently affected, under all climates, by intense weathering induced by the transport of saline solutions. Accordingly, researchers addressed the weathering mechanisms induced by salts (primarily Na2SO4), the stresses generated in the host material, and the durability of ornamental and dimension stones.This study investigates the behaviour of four sedimentary lithotypes, differing in texture and structure (Breccia Aurora, Rosso Verona, and fine- and coarse-grained Vicenza Stone) exposed to a selection of saline solutions, aiming at evaluating their susceptibility to weathering and the influence of petrographic features on durability. The chosen Na2SO4, MgSO4, Na2CO3, NaCl, and KNO3 solutions include the anions characterizing the major saline sources affecting built heritage: capillary rise, acid rain, atmospheric particulate deposition, bird or other animal scat, and de-icing salt contamination.The petrophysical properties of unweathered and salt-weathered samples were characterized by relative mass variation estimation, capillary rise, and hygroscopic absorption-based porosimetry. Scanning Electron Microscopy coupled with microprobe allowed studying the morphological changes triggered by weathering and analysing the chemical composition of the efflorescence crust.The whole of data, consistently with literature, allowed inferring pore type and distribution as the main intrinsic parameters controlling salt weathering susceptibility. Moreover, Na2SO4 and Na2CO3 proved to be the most harmful, probably due to their ability to crystallize in different hydration stages at room temperature. The comparative analysis of the induced weathering can help to choose suitable dimension stones for new buildings or restoration replacements.

Unsaturated flow in coarse porous media

2005 ◽  
Vol 42 (1) ◽  
pp. 252-262 ◽  
Author(s):  
Jeff R Reinson ◽  
Delwyn G Fredlund ◽  
G Ward Wilson
Keyword(s):  
Porous Media ◽  
Hydraulic Conductivity ◽  
Soil Water ◽  
Unsaturated Soils ◽  
Unsaturated Flow ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Coarse Grained ◽  
Capillary Barrier ◽  
Coarse Porous Media

Design of effective capillary barrier systems requires a thorough understanding of the soil–water interactions that take place in both coarse- and fine-grained unsaturated soils. Experimental observations of water flow through coarse porous media are presented to gain greater understanding of the processes and mechanisms that contribute to the movement and retention of water in coarse-grained unsaturated soils. The use of pendular ring theory to describe how water is held within a porous material with relatively low volumetric water contents is explored. Experimental measurements of seepage velocity and volumetric water content were obtained for columns of 12 mm glass beads using digital videography to capture the movement of a dye tracer front at several infiltration rates. An estimated curve for hydraulic conductivity versus matric suction is shown and compared to a theoretical curve. The method is shown to provide a reasonable predictive tool.Key words: soil-water characteristic curve, hydraulic conductivity curve, water permeability function, capillary barrier, matric suction.

scholarly journals A Numerical Model to Predict Matric Suction Inside Unsaturated Soils

10.14311/588 ◽  
2004 ◽  
Vol 44 (4) ◽  
Author(s):  
A. Farouk ◽  
L. Lamboj ◽  
J. Kos
Keyword(s):  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Coarse Grained ◽  
Soil Parameters ◽  
Measuring Devices ◽  
Proposed Model ◽  
Testing Techniques ◽  
The Relationship ◽  
Water Contents

The objective of this research is to introduce a numerical simulation model to predict approximate values of the matric suction inside unsaturated soils that have low water contents. The proposed model can be used to predict the relationship between the water content and the matric suction of a studied soil to construct the soil-water characteristic curve. In addition, the model can be utilized to combine the predicted matric suction with the soil parameters obtained experimentally, which enables us to explain how matric suction can affect the behaviour of unsaturated soils, without the need to utilize advanced measuring devices or special testing techniques. The model has given good results, especially when studying coarse-grained soils.

Shear strength characteristics of two saprolitic soils

1996 ◽  
Vol 33 (4) ◽  
pp. 595-609 ◽  
Author(s):  
Julian K-M Gan ◽  
D G Fredlund
Keyword(s):  
Shear Strength ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Direct Shear ◽  
Strength Behavior ◽  
Decomposed Granite ◽  
Insight Into ◽  
Completely Decomposed Granite

The saturated and unsaturated shear strength behavior of an undisturbed, completely decomposed fine ash tuff and an undisturbed, completely decomposed granite from Hong Kong were studied using direct shear and triaxial tests. The completely decomposed fine ash tuff is a fine- to medium-grained saprolite. The completely decomposed granite is a coarse-grained saprolite. Results show that matric suction increases the shear strength of both soils. The extent of the increase is the shear strength with matric suction is related to the soil-water characteristic curve for the soil and to the amount of dilation during shear. The effect of matric suction on the shear strength was more pronounced for the fine- to medium-grained completely decomposed fine ash tuff than for the coarse-grained completely decomposed granite. These studies on the saprolitic soils provide insight into the understanding of the shear strength of unsaturated, coarse-grained soils. Key words: saprolites, shear strength, matric suction, triaxial, direct shear, coarse-grained soils.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

On the Origin of the Microscystalline Structure in Rapidly Solidified IN-100 Powder

1977 ◽  
Vol 35 ◽  
pp. 260-261
Author(s):  
J. M. Walsh ◽  
K. P. Gumz ◽  
J. C. Whittles ◽  
B. H. Kear
Keyword(s):  
The Other ◽  
Coarse Grained ◽  
Microcrystalline Structure ◽  
Routine Examination ◽  
Atomization Process ◽  
Centrifugal Atomization ◽  
Splat Quenching ◽  
Powder Particles ◽  
Dendritic Microstructures ◽  
Rapidly Solidified

During a routine examination of the microstructure of rapidly solidified IN-100 powder, produced by a newly-developed centrifugal atomization process1, essentially two distinct types of microstructure were identified. When a high melt superheat is maintained during atomization, the powder particles are predominantly coarse-grained, equiaxed or columnar, with distinctly dendritic microstructures, Figs, la and 4a. On the other hand, when the melt superheat is reduced by increasing the heat flow to the disc of the rotary atomizer, the powder particles are predominantly microcrystalline in character, with typically one dendrite per grain, Figs, lb and 4b. In what follows, evidence is presented that strongly supports the view that the unusual microcrystalline structure has its origin in dendrite erosion occurring in a 'mushy zone' of dynamic solidification on the disc of the rotary atomizer.The critical observations were made on atomized material that had undergone 'splat-quenching' on previously solidified, chilled substrate particles.

Correlation between dislocation, grain boundary and interface of duplex SS in stress corrosion cracking(SCC)

1990 ◽  
Vol 48 (4) ◽  
pp. 928-929
Author(s):  
Wang Zheng-fang ◽  
Z.F. Wang
Keyword(s):  
Stainless Steel ◽  
Thermal Cycle ◽  
Secondary Phase ◽  
Corrosion Cracking ◽  
Coarse Grained ◽  
Test Environment ◽  
Fine Grained ◽  
Evaluation Test ◽  
Welding Thermal Cycle ◽  
Micro Analysis

The main purpose of this study highlights on the evaluation of chloride SCC resistance of the material,duplex stainless steel,OOCr18Ni5Mo3Si2 (18-5Mo) and its welded coarse grained zone(CGZ).18-5Mo is a dual phases (A+F) stainless steel with yield strength:512N/mm2 .The proportion of secondary Phase(A phase) accounts for 30-35% of the total with fine grained and homogeneously distributed A and F phases(Fig.1).After being welded by a specific welding thermal cycle to the material,i.e. Tmax=1350°C and t8/5=20s,microstructure may change from fine grained morphology to coarse grained morphology and from homogeneously distributed of A phase to a concentration of A phase(Fig.2).Meanwhile,the proportion of A phase reduced from 35% to 5-10°o.For this reason it is known as welded coarse grained zone(CGZ).In association with difference of microstructure between base metal and welded CGZ,so chloride SCC resistance also differ from each other.Test procedures:Constant load tensile test(CLTT) were performed for recording Esce-t curve by which corrosion cracking growth can be described, tf,fractured time,can also be recorded by the test which is taken as a electrochemical behavior and mechanical property for SCC resistance evaluation. Test environment:143°C boiling 42%MgCl2 solution is used.Besides, micro analysis were conducted with light microscopy(LM),SEM,TEM,and Auger energy spectrum(AES) so as to reveal the correlation between the data generated by the CLTT results and micro analysis.

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