Abstract
Dynamic shear modulus plays an important role in the seismic assessment of geotechnical systems. Changes in the degree of water saturation influence dynamic soil properties because of the presence of matric suction. This paper describes the modification of a suction-controlled cyclic triaxial apparatus to investigate the strain-dependent shear modulus of unsaturated soils. Several strain- and stress-controlled cyclic triaxial tests were performed on a clean sand with various degrees of saturation. Suction in unsaturated sands increased the shear modulus in comparison with the ones in dry and saturated conditions for different shear strain levels, with a peak modulus in higher suction levels. Also, shear modulus decreased with an increase in the shear strain for specimens with similar matric suction. The normalized shear moduli of the unsaturated sand specimens followed a similar trend to the ones predicted by the available empirical shear modulus reduction functions but showed lower values. The modulus reduction ratios of unsaturated sands shifted up as a result of higher effective stress and suction-induced stiffness. These trends were consistent for both strain- and stress-controlled tests.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors acknowledge partial funding of this project by the National Science Foundation (NSF) through NSF CMMI Grant 1333810.
References
Alramahi, B., Alshibli, K. A., Fratta, D., and Trautwein, S. (2008). “A suction-control apparatus for the measurement of P and S-wave velocity in soils.” Geotech. Test. J., 31(1), 12–23.
Biglari, M., Jafari, M. K., Shafiee, A., Mancuso, C., and d’Onofrio, A. (2011). “Shear modulus and damping ratio of unsaturated kaolin measured by new suction-controlled cyclic triaxial device.” Geotech. Test. J., 34(5), 1–12.
Bishop, A. W. (1959). “The principle of effective stress.” Tek. Ukeblad, 39, 859–863.
Cary, C. E., and Zapata, C. E. (2016). “Pore water pressure response of soil subjected to dynamic loading under saturated and unsaturated conditions.” Int. J. Geomech., 1–9.
Cho, G. C., and Santamarina, J. C. (2001). “Unsaturated particulate materials—Particle-level studies.” J. Geotech. Geoenviron. Eng., 84–96.
Craciun, O., and Lo, S.-C. R. (2010). “Matric suction measurement in stress path cyclic triaxial testing of unbound granular base materials.” Geotech. Test. J., 33(1), 33–44.
Cui, Y. J., Tang, A. M., Marcial, D., Terpereau, J. M., Marchadier, G., and Boulay, X. (2007). “Use of a differential pressure transducer for the monitoring of soil volume change in cyclic triaxial test on unsaturated soils.” Geotech. Test. J., 30(3), 227–233.
Darendeli, M. B. (2001). “Development of a new family of normalized modulus reduction and material damping curves.” Ph.D. thesis, Univ. of Texas at Austin, Austin, TX.
Dashti, S., Bray, J. D., Pestana, J. M., Riemer, M., and Wilson, D. (2010). “Mechanisms of seismically induced settlement of buildings with shallow foundations on liquefiable soil.” J. Geotech. Geoenviron. Eng., 151–164.
Dong, Y., McCartney, J. S., and Lu, N. (2016). “Small-strain shear modulus model for saturated and unsaturated soil.” Proc., Geo-Chicago 2016, ASCE, Reston, VA, 316–325.
El Mohtar, C. S., Drnevich, V. P., Santagata, M., and Bobet, A. (2013). “Combined resonant column and cyclic triaxial tests for measuring undrained shear modulus reduction of sand with plastic fines.” Geotech. Test. J., 36(4), 484–492.
Georgiannou, V. N., Hight, D. W., and Burland, J. B. (1991). “Behavior of clayey sands under undrained cyclic triaxial loading.” Geotechnique, 41, 383–393.
Ghayoomi, M., and McCartney, J. S. (2011). “Measurement of small-strain shear moduli of partially saturated sand during infiltration in a geotechnical centrifuge.” Geotech. Test. J., 34(5), 1–11.
Ghayoomi, M., McCartney, J. S., and Ko, H.-Y. (2011). “Centrifuge test to assess the seismic compression of partially saturated sands.” Geotech. Test. J., 34(4), 321–331.
Ghayoomi, M., McCartney, J. S., and Ko, H.-Y. (2013). “Empirical methodology to estimate seismically induced settlement of partially saturated sand.” J. Geotech. Geoenviron. Eng., 367–376.
Ghayoomi, M., and Mirshekari, M. (2014). “Equivalent linear site response analysis of partially saturated sand layers.” UNSAT2014 Conf., CRC Press, Boca Raton, FL, 1–6.
Hardin, B. O., and Black, W. L. (1969). “Vibration modulus of normally consolidated clay closure.” J. Soil Mech. Found. Div., 95(6), 1531–1537.
Hardin, B. O., and Drnevich, V. P. (1972). “Shear modulus and damping in soils: Design equations and curves.” J. Soil Mech. Found. Div., 98(7), 667–692.
Hilf, J. W. (1956). “An investigation of pore-water pressure in compacted cohesive soils.” Ph.D. thesis, Univ. of Colorado, Boulder, CO.
Hoyos, L. R., Suescún-Florez, E. A., and Puppala, A. J. (2015). “Stiffness of intermediate unsaturated soil from simultaneous suction-controlled resonant column and bender element testing.” Eng. Geol., 188, 10–28.
Khalili, N., Geiser, F., and Blight, G. E. (2004). “Effective stress in unsaturated soils: Review with new evidence.” Int. J. Geomech., 115–126.
Khosravi, A., Ghayoomi, M., and McCartney, J. S. (2010). “Impact of effective stress on the dynamic shear modulus of unsaturated sand.” Proc., GeoFlorida 2010, ASCE, Reston, VA.
Khosravi, A., Salam, S., McCartney, J. S., and Dadashi, A. (2016). “Suction-induced hardening effects on the shear modulus of unsaturated silt.” Int. J. Geomech., 1–10.
Kimoto, S., Oka, F., Fukutani, J., Yabuki, T., and Nakashima, K. (2011). “Monotonic and cyclic behavior of unsaturated sandy soil under drained and fully undrained conditions.” Soils Found., 51(4), 663–681.
Kokusho, T. (1980). “Cyclic triaxial test of dynamic soil properties for wide strain range.” Soils Found., 20(2), 45–60.
Kondner, R. L., and Zelasko, J. S. (1963). “Hyperbolic stress-strain formulation for sands.” Proc., 2nd Pan American Conf. on Soil Mechanic and Foundations Engineering, Associação Brasileira de Mecânica dos Solos, São Paulo, Brazil, 289–324.
Kramer, S. L. (1996). Geotechnical earthquake engineering, Prentice Hall, Upper Saddle River, NJ.
Lu, N., Godt, J. W., and Wu, D. T. (2010). “A closed form equation for effective stress in unsaturated soil.” Water Resour. Res., 46(5).
Lu, N., and Likos, W. J. (2006). “Suction stress characteristic curve for unsaturated soil.” J. Geotech. Geoenviron. Eng., 131–142.
Lu, N., Wu, B., and Tan, C. P. (2007). “Tensile strength characteristics of unsaturated sands.” J. Geotech. Geoenviron. Eng., 144–154.
Mancuso, C., Vassallo, R., and d’Onofrio, A. (2002). “Small strain behavior of a silty sand in controlled-suction resonant column-torsional shear tests.” Can. Geotech. J., 39(1), 22–31.
Marinho, F. A. M., Chandler, R. J., and Crilly, M. S. (1995). “Stiffness measurements on an unsaturated high plasticity clay using bender elements.” Proc., 1st Int. Conf. on Unsaturated Soils, Vol. 2, A. A. Balkema, Rotterdam, Netherlands, 535–539.
Mendoza, C. E., Colmenares, J. E., and Merchan, V. E. (2005). “Stiffness of an unsaturated compacted clayey soil at very small strains.” Proc., Conf. on Advanced Experimental Unsaturated Soil Mechanics, CRC Press, Boca Raton, FL, 199–204.
Menq, F.-Y. (2003). “Dynamic properties of sandy and gravelly soils.” Ph.D. thesis, Univ. of Texas at Austin, Austin, TX.
Mirshekari, M., and Ghayoomi, M. (2015). “Simplified equivalent linear and nonlinear site response analysis of partially saturated soil layers.” IFCEE 2015, Geotechnical special publication 256, M. Iskander, M. T. Suleiman, J. B. Anderson, and D. F. Laefer, eds., ASCE, Reston, VA, 2131–2140.
Mirshekari, M., and Ghayoomi, M. (2017). “Centrifuge tests to assess seismic site response of partially saturated sand layers.” Soil Dyn. Earthquake Eng., 94, 254–265.
Ng, C. W. W., Xu, J., and Yung, S. Y. (2009). “Effects of wetting-stress ratio on anisotropic stiffness of an unsaturated soil at very small strains.” Can. Geotech. J., 46(9), 1062–1076.
Oztoprak, S., and Bolton, M. D. (2013). “Stiffness of sands through a laboratory test database.” Géotechnique, 63(1), 54–70.
Qian, X., Gray, D. H., and Woods, R. D. (1991). “Resonant column tests on partially saturated sands.” Geotech. Test. J., 14(3), 266–275.
Seed, R. B., and Duncan, J. M. (1986). “FE analyses: Compaction-induced stresses and deformations.” J. Geotech. Eng., 23–43.
Seed, H. B., and Idriss, I. M. (1970). “Soil moduli and damping factors for dynamic response analyses.” Rep. No. EERC70-10, College of Engineering, Univ. of California, Berkeley, CA.
Van Genuchten, M. (1980). “A closed form equation for predicting the hydraulic conductivity of unsaturated soils.” Soil Sci. Soc. Am. J., 44(5), 892–898.
Wu, S., Gray, D. H., and Richart, F. E., Jr. (1984). “Capillary effects on dynamic modulus of sands and silts.” J. Geotech. Eng., 1188–1203.
Information & Authors
Information
Published In
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Jun 3, 2016
Accepted: Jan 18, 2017
Published online: Apr 11, 2017
Published in print: Sep 1, 2017
Discussion open until: Sep 11, 2017
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.