An assessment of the mechanical behavior of zeolite tuff used in permeable reactive barriers

Çevikbilen G.

GEOMECHANICS AND ENGINEERING, vol.31, no.3, pp.305-318, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 3
  • Publication Date: 2022
  • Doi Number: 10.12989/gae.2022.31.3.305
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), Compendex
  • Page Numbers: pp.305-318
  • Keywords: clinoptilolite, hydro-compression, permeability, permeable reactive barrier, shear strength, zeolite, LAB-SCALE EXPERIMENTS, HEAVY-METALS, HYDRAULIC CONDUCTIVITY, BENTONITE MIXTURES, GROUNDWATER
  • Istanbul Technical University Affiliated: Yes


Permeable reactive barriers used for groundwater treatment require proper estimation of the reactive material behavior regarding the emplacement method. This study evaluates the dry emplacement of zeolite (clinoptilolite) to be used as a reactive material in the barrier by carrying out several geotechnical laboratory tests. Dry zeolite samples, exhibited higher wetting-induced compression strains at the higher vertical stresses, up to 12% at 400 kN/m2. The swelling potential was observed to be limited with a 3.5 swell index and less than 1% free swelling strain. Direct shear tests revealed that inundation reduces the shear strength of a dry zeolite column by a maximum of 10%. Falling head permeability tests indicate decreasing permeability values with increasing the vertical effective stress. Regarding self-loading and inundation, the porosity along the zeolite column was calculated using a proposed 1D numerical model to predict the permeability with depth considering the laboratory tests. The calculated discharge efficiency was significantly decreased with depth and less than 2% relative to the top for barrier depths deeper than 20 m. Finally, the importance of directional dependence in the permeability of the zeolite medium for calibrating 2D finite element flow analysis was highlighted by bench-scale tests performed under 2D flow conditions.