原状、扰动非饱和黄土应力—应变—强度特性研究

The Stress—Strain and Strength Characteristics of Unsaturated Prototype and Disturbed Loess

利用我校岩土室25g.t 离心机模拟黄土高路堤的原型特性,试验后从离心模型试验箱内取出高路堤中非饱和黄土原状土,又取与离心模型试验中相同的土料,作成干密度相近的扰动非饱和黄土试样。通过三轴剪切试验表明:二者应力～应变曲线都为应变软化型.在小应变(ε<3%)时,曲线有反弯段。达到峰值时对应的应变ε_1原状土大于扰动土.原状非饱和黄土的强度包线宜分段表示。所得结果与现场取原状样情形相符,对工程实际有重要指导意义.

The unsaturated prototype loess specimen was made from our 25g·t geote- chnical centrifuge test,which was compared with the unsaturated disturbed loess;the soil samples were obtained from the same site in Gansu.The triaxial test shows:The Stress-Strain Curve of these twp kinds of loess specimen under the action of deviatoric stress（σ1—σ3）are strain-softening, and both curves have a reverse part under small strain（ε1<3%）,the strain of the peak shear stress of prototype loess is greater than that of disturbed loess.The Mohr-Columb envelops for prototype loess are different from those for disturbed loess,All the results of unsaturated prototype loess agree with those of field sample tests.So we can quickly get effective results from geotechnical centrifuge model test.On the other hand,we should carefully apply the characteristics of disturbed loess to designing and construction.