Residual deformation characteristics of partially saturated sandy soils subjected to seismic excitation

2006 ◽  
Vol 26 (2-4) ◽  
pp. 175-182 ◽  
Author(s):  
Shunichi Sawada ◽  
Yoshimichi Tsukamoto ◽  
Kenji Ishihara
Keyword(s):  
Residual Deformation ◽  
Sandy Soils ◽  
Seismic Excitation ◽  
Deformation Characteristics ◽  
Partially Saturated

Mechanical model for partially saturated sandy soils

2010 ◽  
pp. 763-769
Author(s):  
H Bian ◽  
T Nishimura ◽  
I Shahrour
Keyword(s):  
Mechanical Model ◽  
Sandy Soils ◽  
Partially Saturated

scholarly journals Laboratory testing on compacted, partially saturated silty and sandy soils

2017 ◽  
Vol 1 (2) ◽  
pp. 13-27
Author(s):  
G. E. Scarcella ◽  
◽  
I. Giusti ◽  
S. Giusti ◽  
D. Lo Presti ◽  
...  
Keyword(s):  
Laboratory Testing ◽  
Sandy Soils ◽  
Partially Saturated

scholarly journals Enhancement of the thermal conductivity of sands via microbially-induced calcite precipitation

2020 ◽  
Vol 205 ◽  
pp. 09011
Author(s):  
Alejandro Martinez ◽  
Lin Huang ◽  
Michael G. Gomez
Keyword(s):  
Thermal Conductivity ◽  
Ground Improvement ◽  
Soil Column ◽  
Sandy Soils ◽  
Shear Stiffness ◽  
Degree Of Saturation ◽  
Engineering Properties ◽  
Calcite Precipitation ◽  
Microbially Induced Calcite Precipitation ◽  
Partially Saturated

Energy piles and ground source heat pump systems have been shown to provide sustainable alternatives for temperature regulation in buildings and other applications such as road de-icing. However, their efficiency can be undermined in partially-saturated and dry sandy soils due to the relatively low thermal conductivity (kt) of these materials. Microbially-Induced Calcite Precipitation (MICP) has been demonstrated to be an environmentally-conscious ground improvement technology capable of modifying the engineering properties of sandy soils including increases in shear stiffness and strength and decreases in hydraulic conductivity. These improvements result from the precipitation of calcium carbonate crystals at inter-particle contacts and on particle surfaces. This paper presents results from a soil column study aimed at investigating changes in soil kt during MICP treatments and subsequent desaturation using a poorly- graded sand. The results indicate that while bio-cementation can increase soil kt, the level of enhancement depends on the degree of saturation. For instance, increases of up to 330% were measured under dry conditions while only modest increases of about 15% were measured under saturated conditions. MICP treatment may therefore be most effective at enhancing the kt of partially-saturated and dry sands. In addition, the similarity between the evolution of kt and shear wave velocity (Vs) during MICP treatment suggests that kt may provide a new method to assess cementation level and contact quality.

Influence of the Particle Size on the Flow Potential and Friction Index of Partially Saturated Sandy Soils

2021 ◽  
Author(s):  
Khayreddine Doumi ◽  
Youcef Mahmoudi ◽  
Abdellah Cherif Taiba ◽  
Wiebke Baille ◽  
Mostefa Belkhatir
Keyword(s):  
Particle Size ◽  
Sandy Soils ◽  
Partially Saturated ◽  
Flow Potential

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

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