Studying the effect of additives on reducing the dispersive potential of dispersive soils

Rashidian, Sahar; Akhtarpour, Ali; Tabatabaie Shourijeh, Piltan

doi:10.22034/jiraeg.2026.530000.1359

Studying the effect of additives on reducing the dispersive potential of dispersive soils

Articles in Press

Document Type : Original Article

Authors

sahar Rashidian ¹

Ali Akhtarpour ²

Piltan Tabatabaie Shourijeh ³

¹ Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad

² Civil Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad

³ Associate Professor, Shiraz University of Technology, Faculty of Civil and Environmental Engineering

10.22034/jiraeg.2026.530000.1359

Abstract

Dispersive soils, characterized by the presence of sodium ions, are highly susceptible to erosion and easily washed away by water flow, leading to phenomena such as piping and the formation of sinkholes in earthen dams. In this study, soil samples were taken from the borrow area of the Bar Dam located in one of the counties of Razavi Khorasan Province. The effects of various additives, including lime, calcium bentonite, gypsum, and fly ash, on the stabilization of this dispersive soil were investigated using the hole erosion test. Additives were applied at different percentages (1.5%, 2.5%, 3.5%, 5%, and 7.5%) to reduce soil dispersivity. The results of the hole erosion test indicated that adding 3.5% lime-calcium bentonite, 2.5% gypsum, and 5% fly ash reduced the soil erosion index from a relatively rapid dispersive category to a very low category. These percentages also increased the threshold stress, indicating the stabilization of dispersive soil and they are introduced as optimal percentages of additives.

Keywords

Dispersive soil

stabilization

internal erosion

hole erosion test

piping

Subjects