Crack Development and Healing in Guar Gum Polymer-Modified Silty Clay Under Natural Wetting-Drying Cycles

Area of Science:

• Geotechnical Engineering
• Soil Science
• Materials Science

Background:

• Cohesive soils are prone to fissure network development under cyclic wetting-drying conditions.
• Understanding crack evolution is crucial for soil stability and slope protection.
• Guar gum is explored as a potential soil stabilizer.

Purpose of the Study:

• To investigate the evolution of fissure networks in cohesive soils subjected to wetting-drying cycles.
• To analyze the effect of varying guar gum content on soil crack characteristics.
• To elucidate the microstructural mechanisms behind guar gum's soil stabilization properties.

Main Methods:

• Outdoor natural wetting-drying cycles (four cycles) were performed.
• Real-time monitoring of surface crack networks.
• Quantitative analysis of geometric parameters (density, width, connectivity, shape, depth ratio) using digital image processing.
• Microstructural analysis using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD).

Main Results:

• Wetting-drying cycles led to simplified fracture networks, decreased fracture density and fractal dimension, and increased fracture width.
• Guar gum incorporation reduced the crack depth ratio and average crack width.
• Guar gum addition stabilized crack connectivity and shape coefficients.
• SEM revealed guar gum promoted 'bonded bridging' structures, enhancing soil particle cohesion.

Conclusions:

• Guar gum significantly enhances the crack resistance and stability of cohesive soils.
• The microstructural improvements induced by guar gum provide a mechanism for soil stabilization.
• Findings offer theoretical support for using guar gum in ecological slope protection of clayey soils.