Desiccation and cracking behavior of three compacted landfill liner soils

Abstract

Tests were conducted to investigate desiccation cracking of three compacted liner soils obtained from local landfills in southeast Michigan. The soils had low plasticity with varying fines content. Large-scale samples of the soils were subjected to wetting and drying cycles. Surficial dimensions of cracks and suction in the soils were monitored. Surficial dimensions of cracks were quantified using the crack intensity factor (CIF), which is the ratio of the surface area of cracks to the total surface area of a soil. All of the soils were subjected to a compaction-dry cycle (i.e. soils were allowed to dry after compaction) and a subsequent wet-dry cycle. An additional sample of one of the soils was subjected to a compaction-dry cycle and three wet-dry cycles. The maximum CIF obtained in the tests was 7% and suctions exceeding 6000 kPa were recorded. It was observed that cracking was affected by the fines content of the soils. In general, high suctions, rapid increases in suctions, and high amount of cracking were observed in soils with high fines content, with less cracking observed in soil with low fines content. In addition, it was observed that cracking increased significantly due to addition of moisture to the soils. The CIF for wet-dry cycles were significantly greater than the CIF for compaction-dry cycles. Subsequent to moisture addition to the soils, critical suctions that caused a significant change in CIF during the drying cycles were <1000 kPa for all the soils. In the test with multiple wet-dry cycles, the amount of cracking did not change significantly after the second cycle.

Characterizing Dessication Cracking of a Remolded Clay (&lt;i&gt;Eutric Vertisol&lt;/i&gt;) Using the Fractal Dimension Approach

“…However, upon further drying the rate of CA increase started to decline and gradually reached stabilization on day 7. This observation is consistent with earlier studies on desiccation cracking behavior of polypropylene fiber-reinforced clayey soil [19] [22]. This stabilization in crack area was approximated as the intersection between the log of crack area and soil moisture content lines.…”

“…Our study also showed that, estimating the CIF from thinned binary images through the pixel count as well as the Cover/Brightness generated by the software were adequate and showed similar decomposition over time, although with an order of magnitude of 1 -2 between them. The SMCs that enhanced initiation, rapid propagation and development of cracks during the first 1 - 4 days are herein referred to as critical soil moisture contents analogous to the critical suctions employed by [22]. As aforementioned, the Crack Intensity Factor (CIF) of a digitized binary image was determined and expressed as the ratio of the surface area of the cracks to the total surface area of the binary image of the soil specimen.…”

Salts Removal from Synthetic Solution-Potash Brine by Non-Planted Constructed Wetlands

“…The treatment mechanics and efficiency are less affected by these factors, as are their planted counterparts. However, the alterations of soil particles such as desiccation and creaking are reported to cause failures to the clay liner in landfills [7]. Therefore, the application of a compacted clay layer as the primary pollutant filter bed in non-planted CWs might experience the same issue.…”

Numerical Investagation of the Mechanisms of Desiccation Cracking in Fine-Grained Soils

“…Crack usually initiated and propagate in fine-grained materials including clayey soils [16] , gels [19], fine-grained mining wastes or tailings [18]. Yesiller et al, (2000) proposed that "large amount of cracking were always observed in samples with high fine contents and high suction in soils, and less cracking in soil with low fines content" [23]. It is obvious that porous materials with finer particles have smaller pore size.…”