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A deep understanding of the behavior and specifications of grouting materials between soil particles is required to increase the applications of various grouting technologies. Out of the different grouts that can be injected in fine-grained soils, colloidal silica has been selected in this study due to its unknown effects on fine-grained soils. In this study, the effects of colloidal silica on silty sand with different amounts of silt were studied, and the strength parameters (c, ϕ) of stabilized samples under long-term static loading was evaluated. A total of 42 uniaxial compression tests and 75 consolidated-drained triaxial tests were done on the samples. Uniaxial compression tests were conducted to determine the most suitable age of the samples for testing, which was three days. The results of the triaxial tests indicate an increase in the drained cohesion parameter in all samples, while changing the drained internal friction angle in silty sands decreases. [ABSTRACT FROM AUTHOR]

Measurement of tensile strength of soil by direct methods can be challenging due to difficulties in sample preparation and in fixing the specimen while applying uniaxial tension forces. However the tensile strength of soil samples can be measured by indirect tests, such as the Brazilian and double punch tests, assuming that tensile stress is distributed uniformly on the failure plane. In this study, the tensile strength of statically-compacted sand bentonite and cement-enhanced sand bentonite mixtures is measured in varying curing time periods using the “double punch” test. The compressive strengths of samples are also measured using the unconfined compression test, and the correlation between tensile and compressive strength is discussed in relation to curing time. A simple method is also applied to determine the undrained cohesion and internal friction angle of samples through the Mohr-Coulomb circle method, using the double punch tensile strength and unconfined compressive strength. The results show that cohesion increases in both sand bentonite and sand bentonite-cement samples along with curing time. [ABSTRACT FROM AUTHOR]