What structure type provides interlocking of particles with smaller grains filling voids between larger particles?

The structure type that describes interlocking of particles with smaller grains filling voids between larger particles is indeed a dense structure. In geotechnical and materials engineering, a dense structure is characterized by the close packing of particles, which enhances stability and load-bearing capacity. The interlocking of larger particles with smaller ones allows for an efficient use of space, as the smaller grains fill the gaps and voids between the larger ones. This arrangement leads to higher density and stronger overall material performance.

A loose structure would imply a more open arrangement of particles where voids are present without being effectively filled, which provides less stability. Poorly graded materials lack the appropriate range of particle sizes to fill voids effectively, thus not achieving the dense packing that leads to interlocking. Granular structure refers to materials made up of discrete particles but does not inherently describe the packing efficiency or the interlocking phenomenon. Therefore, the characteristics of a dense structure make it the most suitable choice for the description provided.