How does sand behave in excavations?

Sand has a distinct characteristic of low cohesion, which significantly influences its behavior in excavations. When excavated, sand tends to shift and move more freely compared to cohesive soils like clay, which can hold together due to intermolecular forces. The lack of cohesion in sandy soils means that when they are disturbed, they do not have the structural integrity to support vertical loads, leading to potential cave-ins or collapses in excavated areas.

In addition, sand is typically granular and can easily flow under the influence of gravity, especially when it is disturbed by excavation activities. This behavior poses challenges for maintaining safe excavation sites, as workers need to implement proper shoring and bracing techniques to prevent the sand from collapsing into the excavation. Therefore, the assertion that sand behaves poorly in excavations due to its lack of cohesion accurately reflects its properties and the risks associated with working in sandy soils.

While moisture can affect sand's behavior, such as increasing its adhesion slightly when damp, the predominant factor influencing its performance in excavations remains its inherent lack of cohesion.