Benching is a popular technique used on cut slopes in mining, or where a break in slope is required to retain rockfall in road cuts. It is also useful in breaking up the span of a high rock cut in order to make the slope appearance more natural (Figure 4). Bench heights vary from about 3 to 5 m in highway corridor applications to over 30 m for highwalls in mines.
The purpose of benching a slope is to transform the behavior of one high slope into several lower ones. Benching of slopes is also used to control erosion and establish vegetation. Each bench should have drainage to convey runoff to a suitable discharge outlet. Benches are also used along highway corridors as a means of intercepting rockfall before it reached the roadway.
Figure 4: benching of slope