With low-cost housing developments and other infrastructure falling squarely on the shoulders of municipal engineers, they need to be aware of the dangers of fine-grained sand.
Most building projects need to achieve a certain density of ground conditions, but the occurrence of a soil horizon with a high percentage of very fine-grained sand can present a serious challenge. This is according to Brent Cock, principal engineering geologist at SRK Consulting.
"It is important that municipal engineers, developers and contractors specifically check for the presence of fine sand as early as possible in a project’s preparation," says Cock, who has witnessed these conditions on various occasions in his career. The grain size that raises the most concern is below 150 microns in diameter — or 0.015 mm.
He explains that the central problem lies in the fact that the particle size falls "very close to the boundary of silt-size particles. This is generally 0.075 mm, though the British Standard marks the boundary at 0.06 mm.
