Characterization of Cementation Factor of Unconsolidated Granular Materials Through Time Domain Reflectometry with Variable Saturated Conditions.

Yong-Hoon Byun,Hyung-Koo Yoon,Won-Taek Hong

doi:10.3390/ma12081340

Yong-Hoon Byun, Hyung-Koo Yoon + Show 1 more

Open Access

https://doi.org/10.3390/ma12081340

Copy DOI

Abstract

The cementation factor is necessary to determine porosity via the Archie equation, and its range of values has been suggested in many previous studies. However, the cementation factors in the literature are limited to fully saturated conditions, and it may thus be inaccurate to use the same value in other saturation conditions. The objective of this study is to characterize how the cementation factor varies depending on the saturation percentage. In this study, glass beads and soil are selected as the specimens, and two relative density values, 40% and 80%, are selected. Time domain reflectometry (TDR) is used to obtain both the saturation and electrical resistivity of the specimens. TDR is installed in the cell, and fluid is continuously circulated from the bottom to the top of the porous material for 30 min. The estimated saturation increases with time and the electrical resistivity is reduced during the circulation. Finally, the cementation factor at every saturated stage is determined, and the error ratio based on the porosity is calculated to show the importance of the cementation factor. The results show that there is a high error ratio when an unsuitable cementation factor that does not consider the saturation condition is used. This study demonstrates that the method for determining the actual cementation factor using TDR and the Archie equation can be applied in various saturation conditions.

Highlights

Pore structure plays an important role when considering the characteristics of porous material because it is affected by various physical properties, including density, strength, friction, and water flow [1,2]
The distribution of cementation factor values at every saturation stage was determined for unconsolidated granular materials, and the importance of selecting the appropriate cementation factor was shown using the error ratio based on the porosity
Time domain reflectometry is selected to measure the dielectric constant, and the value is converted into the saturation and electrical resistivity of each specimen

Summary

Introduction

Pore structure plays an important role when considering the characteristics of porous material because it is affected by various physical properties, including density, strength, friction, and water flow [1,2]. Electrical resistivity, which is an inherent property of a material, is the physical quantity measuring the impedance to the current flow, and it is the reciprocal of electrical conductivity. It is mathematically composed of functions involving the particles and electrolyte of the porous material and the specific surface area [23]: γP = (1 − n) · +n· + (1 − n) ·. Where ρPM (Ω·m) denotes the electrical resistivity of porous material, and ρP (Ω·m) and ρEL (Ω·m) denote the electrical resistivities of the particle and electrolyte, respectively.

Objectives

Results

Conclusion