Evaluation of Index Properties Affecting Unconfined Compressive Strength of Jet-Grouted Soil Columns for Bangkok Soils-PPT Presentation

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The study evaluates how soil index properties affect the unconfined compressive strength (qu) of jet-grouted soil columns in Bangkok. Samples from the MRTA Blue Line and Orange Line projects were core-drilled and tested, creating a database of strength and soil-property results.<br /><br />An artificial neural network (ANN) was used to predict qu for sandy, silty, and clayey soils. Among the input combinations tested, unit weight and percentage passing the No. 40 sieve gave the best predictions for sandy and silty soils. Their validation R² values were 0.75 and 0.86, respectively. For clayey soils, unit weight and plasticity index performed best, with a validation R² of 0.73. The authors recommend using the resulting prediction charts to estimate qu for Bangkok soils.<br /><br />The study also examined the relationship between qu and the modulus of elasticity, E50. It found correlations of E50 = 69.32qu for sandy soils and E50 = 80.83qu for clayey soils. These relationships are lower than the E50 = 100qu correlation cited in JJGA guidance.

Keywords

jet grouting

unconfined compressive strength

soil index properties

artificial neural network

Bangkok soils

unit weight

plasticity index

sieve analysis

modulus of elasticity

core drilling