Study on Shear Strength Experiments Base on the Modified Direct Shear Apparatus for Unsaturated Soils

Abstract:

The unconsolidated-undrained fast shear tests of saturated-unsaturated remolded soil samples under different moisture content which is 1.1%, 10.1%, 14.9%, 19.9%, 24.2%, 29.9%, 37.7% respectively, and normal stress which is 50kPa, 100kPa, 200kPa, 300kPa, 400kPa respectively, were studied by the modified SDJ-1-type strain direct shear apparatus and U.S. Lab VIEW data acquisition system. The shear strength parameters of unsaturated soil samples, i.e. general cohesion and general internal friction angle were obtained based on Mohr-Coulomb strength theory. The test results showed that the general cohesion firstly increased and then reduced with the moisture content increasing, and the general internal friction angle increased with the moisture content decreasing. The function between the general shear strength parameters and the moisture content was studied. The concept of general shear strength parameters was proposed in the paper, and would provide a simple and practical method to obtain the strength parameters for engineering practice.

• Periodical: Applied Mechanics and Materials (Volumes 438-439)
• Pages: 1176-1180
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.438-439.1176
• Online since: October 2013
• Authors: Gao Feng Chen, Ying Fa Lv, Zhi Huai Huang, Yan Chang
• Keywords: Direct Shear Apparatus, Laboratory Testing of Soil, Shear Strength, Unsaturated Soil

References

[1] A. W. Bishop, The principle of effective stress, Lecture delivered in Oslo, Norway: published in Teknisk Ukeblad, 39 (1959) 859-863.

[2] A. W. Bishop, I. Alpan, G. E. Blight, I. B. Donald, Factors controlling the shear strength of partly saturated cohesive soil, ASCE Res. Conf. Shear Strength of Cohesive Soils, Univ. of Colorado, Boulder (1960) 503-532.

[3] N. Khalili, M. H. Khabbaz, A unique relationship for the determination of the shear strength of unsaturated soils, Geotechnique, 5 (1998) 681-687.

DOI: 10.1680/geot.1998.48.5.681

[4] D. G. Fredlund, S. K. Vanapalli, A. Xing, D. E. Pufahl, Predicting the shear strength for unsaturated soils using the soil-water characteristic curve, Proc. 1st Int. Conf. Unsaturated Soils, Paris, (1995) 63-69.

DOI: 10.1201/b10526-31

[5] Z. Lu, H. Zhang, J. Chen, etc. J. Chinese Journal of Geotechnical Engineering, 3 (1992) 1-8.

[6] L. Miao, Z. Yin, J. Rock and Soil Mechanics, Vol. 20 No. 3 (1999) 1-6.

[7] S. A. Rohm, O. M. Vilar, Shear strength of unsaturated sandy soil, Proc. 1st Int. Conf. Unsaturated Soils, Paris, (1995) 189-195.

[8] C. Xiong, B. Liu, J. Zhang, etc. J. China Railway Science, 3 (2003) 17-20.

[9] Y. Cui, Y. Lu, P. Delage, etc. J. Geotechnique, 7 (2005) 557-567.

[10] Y. Lu, G. Chen, X. Luo, etc. J. Chinese Journal of Rock Mechanics and Engineering, 9 (2008) 2481-2486.