https://www.jstage.jst.go.jp/article/sandf1972/14/3/14_3_1/_pdf

Shear modulus and shear strength of cohesive soils

This paper describes the results of an experimental investigation of capillary effects on the low strain shear modulus of sands in a partially saturated condition. It studies: (1) Void ratio; (2) c...

Voids and Granulometry: Effects on Shear Modulus of Unsaturated Sands

Pavements are constructed on compacted soils that are typically unsaturated. The negative pore-water pressure (soil suction) due to the ingress of water in between soil particles has a significant effect on pavement foundation stiffness and strength. The study characterized the effects of soil suction on shear strength and resilient modulus of four soils representing different regions of Minnesota. The deviator stress in shear strength measurements followed a power function relationship with soil suction. Resilient modulus also followed the power function relationship with suction but these relationships fell within a narrow range. The authors present models for incorporating suction effects in shear strength and resilient modulus measurements of highly compacted subgrade soils. They also briefly outline a framework for incorporating these models in the resistance factors of MnPAVE. Since soil water content and the resulting soil suction under the pavement varies with season, adjustments are needed to account for increased strength and stiffness of the material as a result of unsaturated soil conditions. These adjustments will not only reflect the more realistic field conditions but will result in more reliable performance predictions than the current pavement design method.

/pdf/pavement-design-using-unsaturated-soil-technology-2j2bl1ns5c.pdf

Pavement Design Using Unsaturated Soil Technology

The resonant-column test is one of the most common procedures for dynamic characterization of soils (American Society for Testing and Materials standard). The test procedures require the measuremen...

Difference between current and voltage measurements in resonant-column testing

Low-strain wave propagation velocity and attenuation are effective measures of state in particulate media. The standard resonant column test procedure is modified to facilitate the study of wave propagation at low strains. The system uses band-limited random noise excitation in combination with signal averaging to control the signal-to-noise ratio. This procedure is efficiently implemented by replacing typical peripheral devices with a signal analyzer and computer control. The methodology permits testing at very low strains. The effect of non-linear system response on computed transfer functions is addressed. Other results include the analytical treatment of coupling between torsional and transverse modes, the evaluation of local low-strain shear parameters from solid specimens tested in torsion, and the use of multi-mode testing for the evaluation of field parameters.

Stanley D. Wilson

Papers

Effect of Consolidation Pressure on Elastic and Strength Properties of Clay