Effects of calcium concentration and differential settlement on permeability characteristics of bentonite-sand mixtures
Source abstract
Abstract
Abstract Liner systems consisting of clay or bentonite-sand mixtures can be installed on the bottom of landfills to prevent contaminants from seeping into the surroundings. Differential settlement of the foundation and presence of heavy metal or alkali metal ions in the leachate can vastly affect permeability characteristics of the liner system. In this study laboratory model tests were performed to investigate the influence of differential settlement and Ca2 + on permeability characteristics of bentonite-sand mixtures. The results showed that when the thickness of bentonite-sand mixtures was 100 and 200 mm, cracks were formed within the bentonite-sand mixtures with respective deflections of 2.5 and 7.0 mm. When the height of developed cracks exceeded 50% and 70% of the thickness, the permeability characteristics of bentonite-sand mixtures was > 10− 7 cm/s. Ca2 + concentration has great impact on the permeability characteristics of bentonite-sand mixtures. Na-bentonite will be converted to Ca-bentonite when the concentration of Ca2 + is two times greater than that of Na+ in the solution, and the anti-seepage performance of bentonite-sand mixtures will consequently deteriorate.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Landfill Environmental Impact Studies · Grouting, Rheology, and Soil Mechanics · Soil and Unsaturated Flow
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (36)
Show source-provided references
1. Effect of desiccation on compacted natural clays10.1061/(ASCE)1090-0241(2001)127:1(67) ↗
2. Field performance of a compacted clay landfill final cover at a humid site10.1061/(ASCE)1090-0241(2006)132:11(1393) ↗
3. Effect of alkaline solutions on bentonite properties10.1007/s12665-017-6704-8 ↗
4. Experimental and modelling studies on the pH buffering of MX-80 bentonite porewater10.1016/j.apgeochem.2008.12.023 ↗
5. Influence of preferential flow induced by a single crack on anti-seepage performance of clay barrier
6. Landfill clay barrier subjected to cracking: multi-scale analysis of bending tests10.1016/j.clay.2010.01.011 ↗
7. Deformation characteristics and design of geosynthetic liner system subjected to local subsidence
8. Shear behaviour of a geogrid-reinforced coarse-grained soil based on large-scale triaxial tests10.1016/j.geotexmem.2014.05.004 ↗
9. CJ113–2007 · 2007
10. Microstructure of a compacted soil submitted to an alkaline PLUME10.1016/j.clay.2007.07.005 ↗
11. Salinity effects on cracking morphology and dynamics in 3-D desiccating clays10.1002/2013WR014424 ↗
12. Dwyer · 2003
13. Natural bentonites - influence of the ion exchange and partial desiccation on permeability and self-healing capacity of bentonites used in GCLs10.1016/S0266-1144(01)00017-6 ↗
14. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils10.2136/sssaj1980.03615995004400050002x ↗
15. A dual-porosity model for simulating the preferential movement of water and solutes in structured porous media10.1029/92WR02339 ↗
16. Deformation behavior of clay cap barriers of hazardous waste containment systems: full-scale and centrifuge tests10.1016/j.geotexmem.2009.09.014 ↗
17. Geosynthetic clay liner interaction with leachate: correlation between permeability, microstructure, and surface chemistry10.1061/(ASCE)1090-0241(2005)131:6(740) ↗
18. Determination and assessment of the mechanical properties of waste materials
19. Hydraulic conductivity and swelling of nonprehydrated GCLs permeated with single-species salt solutions10.1061/(ASCE)1090-0241(2001)127:7(557) ↗
20. Experimentally determined swelling pressures and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions10.1016/j.pce.2006.01.012 ↗
21. A research on characteristic of incineration residues
22. Experimental study on characteristics of bending cracks of compacted soil beams
23. Results from 18 years of in situ performance testing of landfill cover systems in Germany10.1061/(ASCE)EE.1943-7870.0000200 ↗
24. Flexural behaviour of a clay layer: experimental and numerical study10.1139/t2012-006 ↗
25. Treatment and use of air pollution control residues from MSW incineration: an overview10.1016/j.wasman.2007.08.030 ↗
26. A simple treatment of physical nonequilibrium water flow in soils10.2136/sssaj2000.6461926x ↗
27. Predicted performance of clay-barrier landfill covers in arid and semi-arid environments10.1016/j.wasman.2006.06.008 ↗
28. Effect of ion-type and concentration on water-retention capacity of bentonite used in geosynthetic clay liner
29. Evaluation and prediction of the swelling pressures of GMZ bentonites saturated with saline solution10.1016/j.clay.2014.12.032 ↗
30. US Environmental Protection Agency
31. Centrifuge testing of fiber-reinforced soil liners for waste containment systems10.1061/(ASCE)1090-025X(2009)13:1(45) ↗
32. Accelerated carbonation of high Ca content municipal solid waste incineration fly ash and impact on leaching of heavy metal
33. Influence of solution characteristics on swelling and hydraulic performance of geosynthetic clay liner
34. Effects of pH and temperature on the swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite10.1016/j.clay.2014.08.002 ↗
35. Test research on tensile properties of compacted clay
36. Effect of salt concentration on desiccation cracking behavior of GMZ bentonite10.1007/s12665-017-6872-6 ↗