Evaluating the effect of biological stabilization on landslide control at the edge of forest road

Abstract

Landslide is one of the negative sides of building non-standard roads in forest areas. The aim of the present study was to assess the effect of biological stabilization on landslide at the edge of forest roads in south and north aspects. For this purpose, in Neka forest (Mazandaran province) three treatments including control, sliding and stabilized areas covered by 35-years-old even-aged alder trees were selected. Benchmarking and soil sampling were conducted during three periods including July, November after rainfall events and March after rainfall events. The results showed that the mean movement of landslide in north direction was 9 cm, while this value was 6 cm in south direction. Sliding in north direction was 32% more than that in south direction. Biological stabilization by alder in north and south direction caused a 33 and 66% reduction in landslide movement, respectively. The characteristics of soil mechanics were different between stabilized and sliding areas. Besides, the soil texture in north direction for control and stabilized areas was clay with high liquid limit (CH) and for sliding area it was clay with low liquid limit, while this value in south direction was CH for three treatments of control, stabilized and sliding areas. To plan biological stabilization, the mechanical characteristics of soil, site features, and appropriate plant species should be considered as important factors.

Keywords

• sliding area
• stabilized area
• alder trees
• soil mechanics
• benchmarking