Geological influence in the index properties variability and shear strength probability density functions

• Published in: Quarterly journal of engineering geology and hydrogeology 2021-11, Vol.54 (4)
• Main Authors: Viviescas, Juan C, Osorio, Juan P, Pastén, Cesar
• Format: Article
• Language: English
• Subjects: Bayesian analysis; Compressive strength; Debris flow; density; design; dynamic properties; Engineering geology; experimental studies; field studies; fine-grained materials; Fine-grained soils; friction; Geology; Geotechnical engineering; laboratory studies; Mudflows; penetration tests; probability; Probability density functions; Probability theory; reliability; Reliability analysis; Reliability engineering; Residual soils; Shape; Shear strength; Soil analysis; Soil density; Soil dynamics; soil mechanics; Soil properties; statistical analysis; uncertainty; Variability; Weathering
• ISSN: 1470-9236; 2041-4803
• DOI: 10.1144/qjegh2020-093

Soil properties variability in geotechnical engineering is one of the most important tasks in reliability-based designs (RBDs). However, these analyses have been carried without taking into account the influence of the geological origin in the different aspects that alter the soil properties variability. Therefore, two types of geological formations are analysed: residual soils (stationary origin) and mudflows (dynamic origin). First, the index properties variability was evaluated for each geology, where mudflows are less variable in comparison with the residual soils. It was confirmed that the correlations of the effective friction angle should not be used for high plasticity and fine-grained soils; however, the shape characteristics of the Probability Density Functions (PDF) of both effective and total parameters depends on the geological origin. The undrained compressive strength (qu) analyses show that geology influences the shape characteristics of the PDF and is directly proportional to the (N1)60 PDF. From the results, mudflows present a qu PDF with a lognormal tendency, which is inferred to be due to the possible presence of rock fragments and randomness related to the soil's formation. However, the residual soils, under the same state of weathering tend to have a normal qu PDF, possibly due to the stationary origin of these soils. Supplementary material: https://doi.org/10.6084/m9.figshare.c.5420240