ASTM International

Direct and Indirect Permeability of Fissured Tills

- By:

Courtesy of Courtesy of ASTM International

Comparison of direct and indirect measurements of water permeability on relatively large undisturbed and compacted Scottish till specimens in rigid-wall (Rowe cells) and flexible-wall (triaxial cells) permeameters shows the interaction of macro-fabric, test method, evaluation basis, effective stress, and possibly sidewall leakage. At low stresses, the sidewall leakage in a Rowe cell is the most likely cause of the directly measured permeability, kd, and pore-pressure-dissipation-based permeability, kp, becoming higher than settlement-based permeability, ks. Similarly, fissures raise permeability measured in both permeameters. Generally, kp is higher than ks (or volume-change-based kv from triaxial cells) with ka in between but closer to ks (or kv). The differences decrease with increasing stresses; the reduction rate for fissured specimens is dependent on fissure coating thickness and permeability.

Customer comments

No comments were found for Direct and Indirect Permeability of Fissured Tills. Be the first to comment!