Studies on soil-water characteristics and shear strength of unsaturated loess have a great significance to prevent and reduce natural disasters of the Loess Plateau.Considering the diversity of soil-water models
several theoretical models were used to fit and evaluate the measurement data of triaxial test apparatus.On this basis
the boundary soil water characteristic curve
hydraulic conductivity function and suction stress characteristic curve were inversed and analyzed under drying and wetting conditions with the latest theory of unsaturated soil.Furthermore
in view of the constitutive relationship
strength characteristics were studied based on suction stress using triaxial shear testing results under different matrix suctions.The results show that the data points measured by the triaxial test apparatus and three corresponding model fitting curves fall within the range of the hydraulic boundary curves(SWCC
HCF and SSCC)
which indicated that the test results are correct and reasonable.The results also indicated that the relationship between the energy and the quantity of moisture in unsaturated soils is variable due to path differences
that is
matrix suction is no longer a single-valued function of water content
but a range system.Meanwhile
it is reasonable and generally effective to use the uniform effective stress principle of the suction stress characteristic curve to describe the shear strength properties of unsaturated soil.It is also verified that the suction stress is unequal to zero when the soil is saturated or without matrix suction;the suction stress at this time corresponds to the apparent cohesion of soil at shear failure.
Residual shear strength of unsaturated soils via suction-controlled ring shear testing [J] . Laureano R. Hoyos,Claudia L. Velosa,Anand J. Puppala. Engineering Geology . 2014
Suction stress and its application on unsaturated direct shear test under constant volume condition [J] . B.S. Kim,S. Shibuya,S.W. Park,S. Kato. Engineering Geology . 2013
Field testing of irrigation effects on the stability of a cliff edge in loess, North-west China [J] . L. Xu,F.C. Dai,L.G. Tham,X.B. Tu,H. Min,Y.F. Zhou,C.X. Wu,K. Xu. Engineering Geology . 2011 (1)
Suction Stress Characteristic Curve for Unsaturated Soil [J] . Ning Lu,William J. Likos. Journal of Geotechnical and Geoenvironmental Engi . 2006 (2)