Soil Physical Properties as Predictors of Soil Strength Indices: Trinidad Case Study

Abstract

Characterizing soil engineering properties and analyzing their spatial pattern has a key role in managing soils for dif- ferent land uses. A study was conducted to generate two soil engineering properties; shear strength (SS) and friction angle (FA) both related to slope stability from the database of soil agricultural indices. A total of 30 soils were analyzed in two batches of 15 for physicochemical and engineering properties. The first batch was subjected to correlation and regression analysis among properties, whilst the second was used to validate model predictions. Soil friction angle showed strong significant correlations with clay and sand percent. Further stepwise regression resulted in these two properties being the only predictors of peak and residual friction angle. None of the tested properties explained shear strength distribution among the soils. The validated model predicted friction angles for the larger database, which showed non-significant temporal differences from the present dataset used in this study. Spatially distribution of both peak and residual friction angles varied across Trinidad, higher friction angles being associated with higher slopes. Combination of this data with other spatial land attributes would greatly improve land management and slope stability prediction.