Experimental Study on the Strength Characteristics of Loess Reinforced with Calcium-based Mixture, Chitosan and Sisal Fiber

¹ Electric Power Research Institute, State Grid Shaanxi Electric Power Company, Xi’an, China
² State Grid (Xi'an) Environmental Protection Technology Center Co., Xi’an, China
³ State Grid Shaanxi Electric Power Company, Xi’an, China
⁴ Electric Power Research Institute of State Grid Shaanxi Electric Power Company, Xi’an, China
⁵ Institute of Soil and Water Conservation, Northwest A& F University, Yangling, China

^* Corresponding author: 450832762@qq.com

Abstract

Loess has engineering characteristics such as loose structure, strong collapsibility, and rapid decrease in strength when exposed to water, which can easily cause environmental and engineering problems. Calcium-based mixture, chitosan and sisal fiber were introduced to improve soil. Loess samples with different additive contents and sisal fiber contents were prepared, and the liquid limit, plastic limit and unconfined compressive strength test were carried out. The effect and mechanism of each material on improving the liquid limit, plastic limit and unconfined compressive strength of loess were analyzed. The test results showed that: calcium-based mixture chould significantly improve the liquid limit, plastic limit and strength of fiber reinforced loess. The optimum content of mixture wass 9 %, which increased the liquid limit, plastic limit and unconfined compressive strength to 1.35,1.35 and 3.81 times of untreated soil. Chitosan chould significantly change the liquid limit and strength of fiber reinforced loess, but had no significant effect on the plastic limit. The optimum dosage of chitosan was 0.48 %, which increased the liquid limit and unconfined compressive strength to 1.30 and 5.50 times that of untreated soil. The sisal fiber chould significantly improve the unconfined compressive strength of the treated soil, but had no significant effect on the liquid plastic limit. The optimum content of sisal fiber was 0.75 %. The combined use of biological, natural materials and short fibers chould enhance the interaction between soil particles and formed an overall three-dimensional interlocking grid structure, which significantly improved the engineering mechanical properties of loess.