Exploring the effects of temperature on intrinsic permeability and void ratio alteration through temperature-controlled experiments

doi:10.1016/j.enggeo.2021.106299

Engineering Geology

Volume 293, November 2021, 106299

https://doi.org/10.1016/j.enggeo.2021.106299 Get rights and content

Highlights

•
Hydraulic conductivity of both fine and coarse-grained soils increases with temperature.
•
The intrinsic permeability of Ottawa sand reduces by 50% from 20 °C to 80 °C.
•
The intrinsic permeability of Kaolin clay shows almost no changes with temperature.
•
The void ratio of both Ottawa sand and Kaolin clay reduces with an increase in temperature.
•
Void ratio, tortuosity, shape factor, and the specific area are expected to change with temperature.

Abstract

An increase in temperature changes the groundwater density and viscosity, therefore, it is expected that the soil hydraulic conductivity varies with temperature. Beyond this point, thermal loading induces volumetric changes for both sand and clay and may alter soil fabric. These variations might increase or decrease the intrinsic permeability of the soil. A modified temperature-controlled triaxial permeameter cell was used in this study to elevate soil temperature from 20 °C to 80 °C. Moreover, the setup was designed to control the temperature and pressure of the permeant water injected into the specimen. The hydraulic conductivity of both Ottawa sand and Kaolin clay under different confinement stresses (69 kPa to 690 kPa) was measured. Then, intrinsic permeability was calculated considering water properties variation with temperature. The results determined that, although hydraulic conductivity increases with temperature for both Ottawa sand and Kaolin clay, the intrinsic permeability of Ottawa sand reduces by 50%, while in Kaolin clay it slightly reduces when the temperature rises from 20 °C to 80 °C. Nonetheless, analyzing volumetric changes and void ratio variations for both selected soil types show a reduction in void ratio with temperature. Reduction in the void ratio can explain the lower intrinsic permeability in Ottawa sand at the elevated temperature, however in Kaolin clay despite the higher void ratio reduction, another mechanism which is the degeneration of a part of the immobile water within the structure into the mobile water plays an important role.

Introduction

Permeability is one of the most important soil properties which controls the seepage and water movement in the ground and directly, or indirectly underpins many geotechnical problems such as slope stability analysis and landfill designs (Damiano et al., 2017; Dou et al., 2014; Jefferson and Rogers, 1998; Ng and Leung, 2012; Sadeghi and AliPanahi, 2020). Accurate prediction of soil permeability and its variation with temperature is necessary to accurately model energy geo-structures, waste disposals, and landfill covers subjected to daily temperature variations (Campanella and Mitchell, 1968; Garakani et al., 2015; Ghasemi-Fare and Basu, 2018; Joshaghani and Ghasemi-Fare, 2019). Thermal loading alters soil and fluid properties (Cherati and Ghasemi-Fare, 2019; Monfared et al., 2014; Tamizdoust and Ghasemi-Fare, 2020a). Therefore, to properly understand the thermo-hydro-mechanical (THM) response of the geotechnical infrastructures, the variations of the soil properties (e.g., permeability) with temperature must be investigated (Chen et al., 2017; François et al., 2009; Ghasemi-Fare and Basu, 2019; Tamizdoust and Ghasemi-Fare, 2020b). In most of the previous research changes in hydraulic properties (e.g., hydraulic conductivity) of both coarse and fine-grained soils with temperature were mainly considered due to the fluid properties (density, and viscosity of the water) alteration (Cho et al., 1999; Delage et al., 2000; Ghasemi-Fare and Basu, 2015; Gobran et al., 1987; Sageev, 1980). Nevertheless, recently there have been studies that showed the measured hydraulic conductivity (H·C.) values at elevated temperatures are different from the calculated values by only considering the updated viscosity and density of the water at the selected temperatures (Gao and Shao, 2015; Ye et al., 2012; Ye et al., 2013). Therefore, both hydraulic conductivity and intrinsic permeability are expected to change with temperature alterations.

Section snippets

Review of existing models

There have been several attempts in the literature to predict the soil hydraulic conductivity and intrinsic permeability variations with temperature using indirect (Habibagahi, 1977; Morin and Silva, 1984; Towhata et al., 1993) or direct measurements (Cho et al., 1999; Derjaguin et al., 1986; Gobran et al., 1987; Joshaghani and Ghasemi-Fare, 2019; Joshaghani et al., 2018). The indirect method is referred to as the back-calculation of hydraulic conductivity from consolidation tests at different

Test setup

To prepare the setup and perform hydraulic conductivity tests at different temperatures, a spiral cooper coil was embedded inside the permeameter cell to circulate a heat carrier fluid from the cooling/heating circulating bath. A type-T thermocouple was placed inside the cell and the second thermocouple was used to measure room temperature. Both thermocouples were connected to a six-channel handheld temperature data logger from Omega Co. Fig. 1 shows different parts of the modified permeameter

Effect of temperature on H.C. of Ottawa sand

The results obtained from the hydraulic conductivity test on Ottawa sand at each thermal step are presented in Fig. 6. Fig. 6 presents the hydraulic conductivity variations for Ottawa sand with temperature for different confinement stresses. Please note, as mentioned earlier the hydraulic conductivity that is reported in Fig. 6 at each temperature is the average of the three different tests. The results confirm the repeatability of the experiment under thermal loading using the modified

Volumetric change

Changes in void ratio with temperature were also studied in this research. Volumetric and void ratio variations with temperature were calculated by monitoring and measuring the amount of expelled water during thermal loading. Campanella and Mitchell (1968) proposed a relation (Eq. 1) between drained (or absorbed) water (∆V_dr) and thermal expansion of the water and solid parts to predict the thermal volume change of the specimen (∆V_m). Thermal volume change or consequently the changes in void

Conclusion

In this research, a temperature-controlled triaxial permeameter cell was modified to analyze the variations of intrinsic permeability and the volumetric changes of sandy and clayey soils with temperature under different confinement stresses. Several calibration tests were conducted to prepare the final setup. Results confirmed that changes in the temperature alter not only the soil hydraulic conductivity but also the intrinsic permeability. This happens because thermal loading changes the soil

Data availability

All data, models, and code generated or used during the study appear in the submitted article.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors would also like to gratefully acknowledge the financial support of the National Science Foundation under Grant No. CMMI-1804822.

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Exploring the effects of temperature on intrinsic permeability and void ratio alteration through temperature-controlled experiments

Highlights

Abstract

Introduction

Section snippets

Review of existing models

Test setup

Effect of temperature on H.C. of Ottawa sand

Volumetric change

Conclusion

Data availability

Declaration of Competing Interest

Acknowledgements

J. Rock Mech. Geotech. Eng.

Comput. Geotech.

Appl. Clay Sci.

Eng. Geol.

Comput. Geotech.

Soil Tillage Res.

Eng. Geol.

Energy and Buildings

Comput. Geotech.

Eng. Geol.

Eng. Geol.

Engineering Geology

Comput. Geotech.

Soils Found.

Eng. Geol.

Effect of Cyclic and In Situ Heating on the Absolute Permeabilities, Elastic Constants, and Electrical Resistivities of Rocks. Fall Meeting of the Society of Petroleum Engineers of AIME

A study of non-isothermal single and two-phase flow through consolidated sandstones

The Effects of Temperature and Pressure on Absolute Permeability of Sandstones. American Nuclear Society Topical Meeting Golden

Influence of temperature variations on soil behavior

Journal of Soil Mechanics & Foundations Div

Investigation on rainwater infiltration into layered shallow covers in pyroclastic soils and its effect on slope stability

Engineering Geology

Heating–freezing effects on the pore size distribution of a kaolinite clay

Environ. Earth Sci.

On the thermal consolidation of Boom clay

Can. Geotech. J.

Permeability changes in Boom clay with temperature

International Conference and Workshop “Impact of Thermo-Hydro-Mechanical-Chemical (THMC) processes on the safety of underground radioactive waste repositories”, European Union