Assessing sand sedimentation in drilling slurry using particle methods for ground excavation management

Abstract

In the construction of cast-in-place concrete piles, residual sand portions in the drilling slurry that are not completely removed can significantly influence the strength and characteristics of the concrete piles. Understanding the sedimentation behavior of these sand portions during concrete placement is crucial to ensure pile quality. However, directly observing this process in real-time at construction sites is challenging, making it difficult to accurately assess the impact of the sand portions. When predicting the sedimentation of sand particles in drilling slurry, the conventionally used Stokes' equation can only express one-dimensional motion of a single particle size, but to accurately capture the real phenomenon, three-dimensional behavior must be considered. In this study, a numerical simulation method based on the particle method (MPS method) was used to visually evaluate the sedimentation process of sand in the drilling slurry. By modeling the drilling slurry and sand particles using the MPS method, the complex three-dimensional settling behavior of sand particles in the drilling slurry at both laboratory and full scales was successfully represented, demonstrating the effectiveness of this modeling approach. The MPS method allows for the analytical visualization of the three-dimensional sedimentation behavior, enabling real-time observation and quantitative evaluation of the sand sedimentation process. Using this method, the temporal evolution of the settling process of sand components in the drilling slurry can be tracked, providing valuable insights into factors that influence the quality of concrete piles. The results of this study demonstrate the potential of the MPS method for visually evaluating the settling behavior of sand components in drilling slurry. This approach offers a more accurate and reliable method for assessing the impact of residual sand on the strength and characteristics of cast-in-place concrete piles. By enhancing the understanding of this process, more effective foundation techniques can be developed to improve the safety and stability of structures built on soft ground, particularly in earthquake-prone regions where fine particles such as clay and silt pose additional challenges to construction practices.