Influence that Osmotic Suction and Tree Roots has on the Stability of Coastal Soils

Jayathilaka, Balagalla Ralalage Pubudu Manora; Indraratna, Buddhima; Heitor, Ana

doi:10.1007/978-981-13-6713-7_53

Cited by 1 publication

(1 citation statement)

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“…Fredlund et al (2012) pointed out that osmotic suction would have greater influence at higher values of matric suction, hence a key reason why the authors in the current study have investigated the role of osmotic suction at different levels of matric suction for a coastal saline soil. Elsewhere in relation to plant morphology, Pathirage et al (2017) and Jayathilaka et al (2019) have pointed out that the variations of soil osmotic suction can also be associated with the nutrient uptake by roots; this effect is not considered in this study.…”

Section: Introductionmentioning

confidence: 96%

Influence of Salinity-Based Osmotic Suction on the Shear Strength of a Compacted Clay

2021

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As most previous studies have neglected the positive influence of salinity (osmotic suction) on most coastal soils in Australia, the design of transport infrastructure involving these soils have often been overly conservative. In this study, a laboratory approach based on direct shear testing is explained to determine the stress-strain behaviour of compacted coastal silty clay (CL) at different levels of osmotic suction generated by varying salinity (NaCl) concentrations. A broad data set for a total of 147 direct shear tests conducted on remoulded and re-compacted test specimens at seven different initial matric suction conditions is analysed to develop a semi-empirical model that captures the effect of osmotic suction on the soil shear strength. The results suggest that greater the initial matric suction is the more pronounced will be the role of osmotic suction. The proposed semi-empirical model is governed by an electrical conductivity relationship with the osmotic suction generated by soil salinity. A new parameter is introduced to quantify the role of soil salinityon the apparent soil shear strength corresponding to different levels of osmotic suction. When this novel relationship is coupled with the conventional matric suction theory, the overall unsaturated shear strength of a saline soil can be properly evaluated, as proven by the close proximity of the predictions to the measurements.

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Section: Introductionmentioning

confidence: 96%