Experimental Investigation of Freeze-Thaw Processes in Soils and Grouting Materials

2021 ◽  
Author(s):  
Jan Christopher Hesse ◽  
Jan-Henrik Kupfernagel ◽  
Markus Schedel ◽  
Bastian Welsch ◽  
Lutz Müller ◽  
...  
Keyword(s):  
Porous Media ◽  
P Wave ◽  
Ice Formation ◽  
Unfrozen Water ◽  
Pure Liquid ◽  
Detailed Knowledge ◽  
Strong Impact ◽  
Hydraulic Flow ◽  
Freeze Thaw ◽  
Grouting Materials

<p>Freezing and thawing in the subsurface is often related to complex technical handling of possible influences on the engineered structures (e.g. permafrost or geothermal heat pumps). Freeze-thaw processes in the vicinity of borehole heat exchangers can significantly impair the system. However, for groundwater protection and thermal efficiency, the hydraulic and thermal integrity of such systems must be permanently ensured for the complete operation time. Detailed knowledge on freeze-thaw processes in porous media, such as soils or geotechnical grouts, and the driven parameters, is still pending. Freezing in porous media does not occur as a sudden transition from pure liquid water to the ice phase, but rather within a freezing interval strongly depending on various boundary conditions such as soil type or pore water chemistry. As the content of frozen and unfrozen water has a strong impact on material properties, it is essential to have suitable information about the different factors influencing freezing processes as well as the thermo-hydraulic-mechanical (THM) effects on porous media due to phase change. Thus, a THM laboratory experiment was developed and built to gain more knowledge on freeze-thaw processes and their effects on soil and grouting materials. The experiment consists of a modified triaxial test, enabling for controlled temperature and hydraulic flow conditions, that is combined with an ultrasonic measurement device to determine the unfrozen water content.</p><p>In this contribution, results of the THM experiment are presented, whereas the following parameters were investigated: The freezing interval using P-wave velocity, freezing pressure as well as axial and radial volume expansion due to ice formation as well as the influence of hydraulic flow on the ice formation. First, benchmark experiments were conducted on well-characterized solid rock samples to avoid any influence of a variable sample pore structure during the experiments. Further experiments focused on the investigation of soil samples of different texture classes. For upscaling to real scale applications, the experimental findings will be implemented in numerical models.</p>

THM Experiment for the Investigation of Freeze-Thaw Processes in Soils and Grouting Materials

2020 ◽  
Author(s):  
Jan Christopher Hesse ◽  
Markus Schedel ◽  
Bastian Welsch ◽  
Ingo Sass
Keyword(s):  
Boundary Conditions ◽  
Wave Velocity ◽  
Liquid Water ◽  
Confining Pressure ◽  
P Wave ◽  
Displacement Sensor ◽  
Unfrozen Water ◽  
Freeze Thaw ◽  
Rock Materials ◽  
Unconsolidated Rock

<p>Freeze-thaw processes induced in the vicinity of borehole heat exchangers (BHE) as a result of operating temperatures below 0 °C can significantly affect the compound structure consisting of the BHE pipes, the cement-based grouting material as well as the surrounding soil. The hydraulic integrity of such systems is not ensured anymore and its thermal efficiency could be impaired. However, the knowledge on freezing and thawing processes in porous media, such as the grout and unconsolidated rock materials, is still incomplete. The content of unfrozen water has a strong impact on material properties influencing the overall heat and mass transfer processes. Moreover, freezing strongly depends on various boundary conditions such as soil type or pore water chemistry. Accordingly, it is essential to have adequate information about the freezing interval for different boundary conditions, which describe the transition from pure liquid water to the ice phase and vice versa.</p><p>Therefore, a thermo-hydraulic-mechanical (THM) experiment has been developed and is used to gain a more detailed insight into freezing processes in artificial grouts and unconsolidated rock materials. It consists of a modified triaxial test system, which can carry cylindrical samples with a diameter of up to 100 mm and a height of up to 200 mm. A confining pressure of up to 16 bar can be gained by a plunger system. The confining pressure liquid (water-glycol-mixture) can be tempered down to -25 °C and is used to induce freezing conditions on the lateral surface of the sample. Mechanical parameters such as the freeze pressure are recorded by an axial load sensor and a displacement sensor. Besides, the radial deformation can be observed by the volume displacement of the confining liquid. Moreover, the hydraulic conductivity of the sample is determined according to DIN EN ISO 17892 (2019). The fluid temperatures during the flow-through experiment can be varied between 5 °C and 25 °C to represent natural groundwater temperatures. In addition to that, the freeze-thaw experiment is equipped with an ultrasonic measurement device: In the observed temperature range, the wave velocity in solid particles is constant and not affected by temperature changes. However, with descending temperature, the ice content increases, which leads to an improved cross-linking of the solid soil particles. As a consequence, the bulk P-wave velocity increases with decreasing unfrozen water content. Hence, this relationship can be used to determine the content of unfrozen water during a freeze-thaw cycle.</p><p>At this time, the first experiments are conducted with this novel device. Consequently, initial results will be presented at the conference. Moreover, the results of the THM experiments will be implemented in numerical models, which allow for an upscaling of the experimental findings to real scale applications.</p>

Remobilization of Residual Non-Aqueous Phase Liquid in Porous Media by Freeze−Thaw Cycles

2011 ◽  
Vol 45 (8) ◽  
pp. 3473-3478 ◽  
Author(s):  
Kamaljit Singh ◽  
Robert K. Niven ◽  
Timothy J. Senden ◽  
Michael L. Turner ◽  
Adrian P. Sheppard ◽  
...  
Keyword(s):  
Porous Media ◽  
Aqueous Phase ◽  
Freeze Thaw ◽  
Phase Liquid

scholarly journals Degradation of Mechanical Behavior of Sandstone under Freeze-Thaw Conditions with Different Low Temperatures

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Uniaxial Compressive Strength ◽  
Dynamic Strength ◽  
Freezing Temperature ◽  
P Wave ◽  
Freeze Thaw ◽  
P Wave Velocity

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.

scholarly journals Low Salinity and High-Level UV-B Radiation Reduce Single-Cell Activity in Antarctic Sea Ice Bacteria

2009 ◽  
Vol 75 (23) ◽  
pp. 7570-7573 ◽  
Author(s):  
Andrew Martin ◽  
Julie Hall ◽  
Ken Ryan
Keyword(s):  
Sea Ice ◽  
Metabolic Activity ◽  
Cell Activity ◽  
Ice Formation ◽  
Freeze Thaw ◽  
Low Salinity ◽  
Antarctic Sea Ice ◽  
Single Cell Activity ◽  
Fast Ice ◽  
High Level

ABSTRACT Experiments simulating the sea ice cycle were conducted by exposing microbes from Antarctic fast ice to saline and irradiance regimens associated with the freeze-thaw process. In contrast to hypersaline conditions (ice formation), the simulated release of bacteria into hyposaline seawater combined with rapid exposure to increased UV-B radiation significantly reduced metabolic activity.

The influence of mesoscopic flow on the P-wave attenuation and dispersion in a porous media permeated by aligned fractures

2013 ◽  
Vol 57 (3) ◽  
pp. 482-506 ◽  
Author(s):  
Jixin Deng ◽  
Shangxu Wang ◽  
Gengyang Tang ◽  
Jianguo Zhao ◽  
Xiangyang Li
Keyword(s):  
Porous Media ◽  
Wave Attenuation ◽  
P Wave ◽  
Attenuation And Dispersion

Amount of unfrozen water in frozen porous media saturated with solution

2002 ◽  
Vol 34 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Kunio Watanabe ◽  
Masaru Mizoguchi
Keyword(s):  
Porous Media ◽  
Unfrozen Water

Acoustically Induced Mass Flow in Partially Saturated Porous Media: Applications to Fuel Cells

2005 ◽  
Author(s):  
Alexander Staroselsky ◽  
Igor I. Fedchenia ◽  
Wenlong Li
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Fuel Cells ◽  
Transport Processes ◽  
Strong Impact ◽  
Wave Dynamics ◽  
Phase Saturation ◽  
Flows Through Porous Media ◽  
Partially Saturated Porous Media ◽  
Media Applications

In this work we aim to develop a theoretical framework for evaluating the feasibility of attaining significant improvement of fuel cells performance and stability by enhancing the transport processes in porous partially-fluid-filled cathode compartments through applying acoustic and structural excitations. A generic unified model has been derived of the structural/acoustic wave propagation in the porous media with consideration of its coupling with mass transfer. It has been demonstrated that the phase saturation has a strong impact on the wave dynamics in porous media. Explicit expressions have been obtained for the generalized multiphase Biot-type coefficients. A generalized filtration equation has been derived that takes into account the effects on mass transfer of dynamic loading, varying saturation, and solid structure distortion in this complex system. For model calibration a series of tests has been conducted to measure water flows through porous media with and without acoustic excitations. It has been demonstrated that the excitations may result in a net change of the saturation inside the porous medium and the applied structural/acoustic loading can intensify the transportation process. Based on the numerical and experimental results, certain recommendations have been made in regards to the selection of materials and the optimization of performance regime.

Assessment of biofilm destabilisation and consequent facilitated zinc transport

2005 ◽  
Vol 51 (2) ◽  
pp. 21-28 ◽  
Author(s):  
M. Muris ◽  
C. Delolme ◽  
J.-P. Gaudet ◽  
L. Spadini
Keyword(s):  
Porous Media ◽  
Pseudomonas Putida ◽  
Facilitated Transport ◽  
Small Extent ◽  
Zinc Transport ◽  
Batch Experiments ◽  
Hydraulic Flow ◽  
Great Affinity ◽  
Pollutants Transport ◽  
The Moment

In infiltration basins, such as in any kind of porous media, bacteria may form biofilms. When conditions induce destabilization of this biofilm, resulting colloids are transported by the hydraulic flow. Some studies have focused on the role played by these bacterial colloids in pollutants transport in soil. This study deals with the ability of Pseudomonas putida to retain zinc and investigates the facilitated transport of this metal. Batch and columns experiments have been carried out. Bacteria display a great affinity for zinc in batch experiments and facilitated transport have been highlighted in a small extent, for the moment. A scenario of stabilization/destabilization of the biofilm has been designed and may be employed for further investigations.

Effect of freeze/thaw on aggregation and transport of nano-TiO2 in saturated porous media

2020 ◽  
Vol 7 (6) ◽  
pp. 1781-1793 ◽  
Author(s):  
Jeffrey M. Farner ◽  
Jacopo De Tommaso ◽  
Heather Mantel ◽  
Rachel S. Cheong ◽  
Nathalie Tufenkji
Keyword(s):  
Porous Media ◽  
Temperature Variability ◽  
Saturated Porous Media ◽  
Nano Tio2 ◽  
Freeze Thaw ◽  
Transport Behavior ◽  
Winter Conditions ◽  
Granular Porous Media

Research has focused on nanoparticle (NP) aggregation and transport behavior in saturated granular porous media, but few studies have looked at the effect that temperature variability associated with winter conditions will have on engineered NPs.

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