additional gravel造句

• Additional gravel was put down and a sand runway was laid down.
• In 2006, the tracks of the " Chorweiler " station were raised with additional gravel.
• Since the infrastructure was designed for high-floor Stadtbahn vehicles, the tracks were raised by the insertion of half a metre of additional gravel.
• The airport had already sunk that much by last December, even though its opening was delayed one year so that thousands of tons of additional gravel could be poured in to stabilize the structure after sinkage projections were revised in 1992.