Effects of frame beam on structural characteristics of artificial soil on railway cut‐slopes in southwestern China

Abstract

AbstractCut‐slope restoration technologies commonly used in southwest China mainly include using simple outside soil spray seeding (OSSS) techniques, or OSSS combined with an anchor frame beam. Artificial soil used in OSSS can establish a soil layer suitable for revegetation; the addition of an anchor frame beam not only fixes soil and shallow rock, it also acts to strengthen deep rock. However, there have been few studies on the effects of frame beams on artificial soil structural characteristics on railway cut‐slopes. In order to evaluate the effects of different frame beams on artificial soil structure, soil samples from a natural slope (NS) and three cut‐slopes restored using OSSS with various frame beams (AS, arched slope; DS, diamond slope; and RS, rimless slope) were analyzed. Soil structural characteristics analyzed include particle‐size percentage and cumulative distribution curve of dry‐sieving and wet‐sieving aggregates, structural failure rate, water stability factor, soil particle size distribution (PSD), bias and peak convex coefficients, fractal dimension of PSD (Dm), and fundamental properties. Our results indicate that structural failure rate, water stability factor, fractal dimension of PSD, soil bulk density, total porosity, moisture content, and organic matter are significantly affected by the use of different frame beams. In addition, a difference in wet‐sieving soil aggregates content, PSD, clay and sand particle contents, Dm, and the area difference ΔS of cumulative distribution between AS and DS was evident. Overall, soil structure in cut‐slopes using a diamond frame anchor beam recorded the best levels of recovery after 8 years of ecological restoration.