Work

Hydrophobic sand erodibility remediation with biopolymers under long-term environmental conditions

Year: 2025

Type: article

Abstract: ABSTRACT This paper investigates the advantages and limitations of hydrophobic sand surficial improvement using biotreatments. Xantham gum (X.G.) at different concentrations in sand represents the biopolymer class of materials. The study aims to simulate wildfire-burned sands through highly hydrophobic sands at various high and low-rain-intensity slopes in controlled experimental conditions. In addition, a 6-month exposure to environmental conditions like wind, rain, tree debris, and animal interactions assesses the effectiveness of long-term treatment. Results show that sand type is a governing parameter, and fine sands require the highest X.G. percentage. During prolonged rain, surface morphology evolves with ridges that can fail. Results show that, at a 50 mm/hr rain, when left uncured, the XG-soil mix provides catastrophic erosion, more so than untreated hydrophobic sand, while those with 1-3% X.G. concentrations in the mixed layer cured for 24 hours yielded significantly less erosion. Therefore, the study proposes covering hydrophobic slopes with X.G. and hydrophilic sand mix sprayed with 16.5% water per X.G. and sand mix mass and cured for 24 hours. During environmental studies, initial treatments of uncured 0.5% X.G.)mixed with sand provided little erosion reduction compared to the unmitigated hydrophobic slopes but mostly observed even more erosion. With fully formed channels in the slopes, the top layer, re-covered with a 3% XG-sand mix and cured, shows the effects of the mitigation technique on previously eroded slopes. At a higher intensity than the previous storms, this method performs better than the 0.5% X.G. uncured mix, but overwetted sections that were not dry before the next storm led to enhanced erosion. Cumulative erosion between rain events reveals similar erosion trends between the three sand types, with fine sand slopes eroding slightly more.

Source: Biogeotechnics

DOI: 10.1016/j.bgtech.2025.100180

Authors: Jonathon Chavez De Rosas, Ingrid Tomac

Institution: University of California San Diego

Language: English

Topic: Geotechnical Engineering and Soil Stabilization

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Life on land, Clean water and sanitation, Climate action

Open Access status: diamond

Funder: University of California Institute of Transportation Studies