Investigation of the Effect of Multiple Wetting and Drying Cycles on the Shrinkage and Cracking of Engineered Clay Soil

Abstract

limate change is predicted to result in warmer and drier summer as well as wetter winter which we are already experiencing. This could result in instability of earth structures hence this study. Durham boulder clay was used to investigate the crack patterns, crack geometric parameters, shear strength and infiltration time of 400 mm x 400 mm x 75 mm samples sieved through 20 mm sieve and compacted to 1.35 g/cm 3 , 1.65 g/cm 3 and 1.70 g/cm 3 densities. Six cycles each were carried out and the samples were air-dried. The photographic images of the sample surface were used for crack analysis. Stability of crack pattern for each cycle was attained after 24 hours of drying. The final shear strengths of all the samples were higher than the control implying increased strength. The final crack depth of the VLC sample was 3.48 times that of the WC sample. The final crack width for the VLC sample was 2.12 times that of the WC sample. The CIF of all the samples reached stability by the 5 th cycle. There was also stabilization in the infiltration of the samples by the third cycle and as such valid predictions could be made from this cycle. In practical scenarios, earth structures undergo more than 6 cyclic wetting and drying hence it can be inferred that they will attain stability by the fifth cycle. From this study, it can be noted that loosely compacted structures are more susceptible to failure than well-compacted structures.

Potential pollution risks of historic landfills in England: Further analysis of climate change impacts

“…Drying of landfill capping materials increases the likelihood of them cracking and opening up new pathways for leachates and gases to escape and surface waters to enter (Bloomfield et al, 2006). It also risks damaging the landfill's structural integrity, increasing the likelihood of it eroding and releasing solid waste materials (Umana et al, 2016). The likelihood of this will vary depending upon the materials used in the construction of the landfills and the hydrological and geomorphic conditions where they are located.…”