A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Analysis of capillary water imbibition in sandstone via a combination of nuclear magnetic resonance imaging and numerical DEM modeling
Abstract The physics of water imbibition into initially unsaturated sandstone is critical to the understanding of displacement processes and fluid transport in the vadose zone. The distribution of water within rock is important due to its significant influence on rock mechanical behavior. Here, therefore, we used nuclear magnetic resonance (NMR) technology to visualize and quantify the dynamics of water infiltration and distribution in initially unsaturated sandstone. The progression of water imbibition in sandstone specimens under the following two conditions were analyzed: (1) specimens soaked in water for different durations and (2) specimens soaked in water for the same duration and then held in this state for different durations. An analytic function was developed to estimate the sandstone moisture profile and to determine the unsaturated flow within the sandstone when the water distribution matched laboratory observations. Finally, a three-dimensional discrete element grain-based model was formulated that incorporates the local parallel-plate method, the unsaturated flow function, and the generalized effective stress principle. We used this model to effectively reproduce the process of water imbibition in the laboratory sandstone specimens. The effect of water imbibition on the mechanical properties of the studied sandstone was also evaluated. These results show that the strength of the core of the sample was reduced as water migrated from its surface to its center, resulting in a decrease in bulk sample strength as standing duration (i.e. water distribution uniformity) increased. The results of this study aid in our understanding of the influence of water imbibition on the mechanical behavior of sandstone, which is important for rock slope stability assessments following rainfall.
Highlights Nuclear magnetic resonance used to monitor water imbibition in sandstone. Linear relationship found between wetting front migration and square root of time. Strength and Young's modulus decrease as a function of increasing water saturation. 3D numerical DEM simulations are in agreement with experimental data. Water saturation is an important consideration in slope stability assessments.
Analysis of capillary water imbibition in sandstone via a combination of nuclear magnetic resonance imaging and numerical DEM modeling
Abstract The physics of water imbibition into initially unsaturated sandstone is critical to the understanding of displacement processes and fluid transport in the vadose zone. The distribution of water within rock is important due to its significant influence on rock mechanical behavior. Here, therefore, we used nuclear magnetic resonance (NMR) technology to visualize and quantify the dynamics of water infiltration and distribution in initially unsaturated sandstone. The progression of water imbibition in sandstone specimens under the following two conditions were analyzed: (1) specimens soaked in water for different durations and (2) specimens soaked in water for the same duration and then held in this state for different durations. An analytic function was developed to estimate the sandstone moisture profile and to determine the unsaturated flow within the sandstone when the water distribution matched laboratory observations. Finally, a three-dimensional discrete element grain-based model was formulated that incorporates the local parallel-plate method, the unsaturated flow function, and the generalized effective stress principle. We used this model to effectively reproduce the process of water imbibition in the laboratory sandstone specimens. The effect of water imbibition on the mechanical properties of the studied sandstone was also evaluated. These results show that the strength of the core of the sample was reduced as water migrated from its surface to its center, resulting in a decrease in bulk sample strength as standing duration (i.e. water distribution uniformity) increased. The results of this study aid in our understanding of the influence of water imbibition on the mechanical behavior of sandstone, which is important for rock slope stability assessments following rainfall.
Highlights Nuclear magnetic resonance used to monitor water imbibition in sandstone. Linear relationship found between wetting front migration and square root of time. Strength and Young's modulus decrease as a function of increasing water saturation. 3D numerical DEM simulations are in agreement with experimental data. Water saturation is an important consideration in slope stability assessments.
Analysis of capillary water imbibition in sandstone via a combination of nuclear magnetic resonance imaging and numerical DEM modeling
Fu, Teng-Fei (author) / Xu, Tao (author) / Heap, Michael J. (author) / Meredith, Philip G. (author) / Yang, Tian-hong (author) / Mitchell, Thomas M. (author) / Nara, Yoshitaka (author)
Engineering Geology ; 285
2021-02-21
Article (Journal)
Electronic Resource
English
Capillary imbibition of water in discrete planar cracks
| Online Contents | 2017
Capillary imbibition of water in discrete planar cracks
| British Library Online Contents | 2017
Capillary imbibition of water in discrete planar cracks
| British Library Online Contents | 2017