Is it true that the larger the grain size, the less stable the material?

The statement that larger grain size corresponds to less stable material is accurate. In the context of soil mechanics and geotechnical engineering, grain size plays a crucial role in determining the stability of a soil mass. Generally, materials with larger grain sizes, such as gravel and coarse sand, tend to have lower cohesion and may not interlock as effectively as finer materials, like clay or silt.

Coarse-grained soils often have larger void spaces between the particles, leading to decreased friction and less effective weight-bearing capacity. This can make them less stable under certain conditions, especially when subjected to loads or changes in moisture content. Smaller grain sizes typically enhance particle interlocking and increase cohesion, providing greater stability.

In contrast, moisture content can impact the stability of both coarse and fine materials, as it affects the soil's behavior and strength. While it’s true that the stability can vary with moisture, the overarching principle remains that larger grains tend to be less stable than smaller ones when examined in isolation, aligning with fundamental soil mechanics principles.

Limited to sandy soil alone ignores the broader implications of grain size on the stability of various types of soils, which applies more generally across different materials. Therefore, the assertion that larger grain size correlates with less stability