University Team Studies Interaction Between Clay and Geotextile Interfaces

2025-11-25 08:34:03

University Team Studies Interaction Between Clay and Geotextile Interfaces

Abstract

Geosynthetics, particularly geotextiles, are widely used in geotechnical engineering to enhance soil stability, filtration, drainage, and reinforcement. The interaction between clay soils and geotextiles plays a critical role in the performance of infrastructure such as embankments, landfills, and retaining walls. A university research team has conducted an extensive study to investigate the shear behavior, interface friction, and long-term performance of clay-geotextile systems. This paper presents the experimental methodology, key findings, and implications for engineering design.

1. Introduction

Geotextiles are permeable fabrics used in conjunction with soil to improve mechanical properties. When paired with clay—a cohesive, low-permeability soil—geotextiles must effectively manage shear stress, filtration, and drainage while minimizing clogging. Understanding the interaction between these materials is essential for optimizing geotechnical applications.

Previous studies have examined granular soil-geotextile interfaces, but cohesive soils like clay present unique challenges due to their plasticity, swelling potential, and low permeability. This research aims to fill the gap by analyzing:

- The shear strength characteristics of clay-geotextile interfaces.

- The influence of moisture content and compaction on interface behavior.

- Long-term performance under cyclic loading and environmental conditions.

2. Materials and Methods

2.1 Materials

- Clay Soil: A high-plasticity clay (CH) with a liquid limit of 55% and plasticity index of 30 was selected.

- Geotextile: A nonwoven polypropylene geotextile with a mass per unit area of 300 g/m² and tensile strength of 20 kN/m was used.

2.2 Experimental Setup

The study employed:

- Direct Shear Tests: To evaluate interface friction at varying normal stresses (50 kPa, 100 kPa, 150 kPa).

- Permeability Tests: To assess filtration compatibility and clogging potential.

- Cyclic Loading Tests: To simulate long-term traffic or seismic loads.

2.3 Testing Conditions

- Samples were prepared at optimum moisture content (OMC) and ±5% variations.

- Tests were conducted under both drained and undrained conditions.

3. Results and Discussion

3.1 Shear Behavior

The direct shear tests revealed:

- Peak shear strength increased with normal stress but was lower than clay-clay or geotextile-geotextile interfaces.

- At high moisture content, strength reduction occurred due to clay softening.

- The geotextile’s fibrous structure provided interlocking with clay particles, enhancing friction.

3.2 Permeability and Clogging

- Under low hydraulic gradients, the geotextile effectively filtered clay without significant clogging.

- Prolonged exposure to saturated conditions reduced permeability by 15–20%, indicating potential long-term clogging risks.

3.3 Cyclic Loading Effects

- Under repeated loading, the interface exhibited stiffness degradation, with shear modulus decreasing by 30% after 1,000 cycles.

- Post-cyclic shear tests showed a 10–15% reduction in peak strength, highlighting the need for conservative design in dynamic environments.

4. Engineering Implications

1. Design Recommendations:

- Use higher-strength geotextiles in high-stress applications.

- Account for moisture variations in clay to prevent strength loss.

2. Construction Practices:

- Ensure proper compaction to enhance interface friction.

- Consider drainage layers to mitigate clogging.

3. Future Research:

- Investigate alternative geotextile coatings to reduce adhesion loss.

- Study bio-clogging effects in organic-rich clays.

5. Conclusion

This study provides critical insights into clay-geotextile interactions, emphasizing the importance of moisture control, stress conditions, and long-term performance. The findings support improved design practices for sustainable geotechnical infrastructure.

References

(Include relevant academic papers, ASTM standards, and geotechnical manuals.)

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