The Susceptibility Assessment of Gullies on Rammed Earth Sites Based on Extenics in Hexi Corridor

Abstract

ABSTRACT The formation or development of gullies is one of the most direct manifestations of soil erosion on rammed earth sites. Timely conducting risk assessments related to gully erosion is a primary condition for formulating corresponding protective measures. According to previous research results, through field surveys and statistical analysis of 355 gullies on 15 sites in Hexi Corridor, an index for the comprehensive development degree of gully was proposed, which is based on single gully erosion factors and the classification characteristics of gully development ages. The index quantifies the actual development degree of gullies in various regions and serves as a reference standard to evaluate the applicability of subsequent models for gully susceptibility. Therefore, the paper combines extension theory to construct four types of evaluation models for gully susceptibility. They are, respectively, Extenics+AHP, Extenics+CRITIC, Extenics+Improved CRITIC, and Extenics+AHP+Improved CRITIC. The results indicate that the Extenics+AHP+Improved CRITIC model has higher accuracy and applicability, with an evaluation accuracy rate of 87%. The relative mean square error is as low as 1.87 × 10−3, and the goodness of fit is maximized at 0.9828. Additionally, 53.33% of the 15 sites is classified as having moderate or higher susceptibility levels, indicating an urgent need for protection.