Mechanical Properties of Continental Clay under Low Confining Pressure.

在2年期间。本文对不同围压下的饱和和非饱和土进行了静、动剪切试验，得到了以下结果。1.低围压下饱和粘土的不排水抗剪强度比高围压下饱和粘土的强度增量大50%。2.无论围压和超固结比如何变化，饱和粘土的强度各向异性基本不变。3.非饱和土的抗剪强度受干密度和含水量的影响。在较高的预压应力比（P<@D2c@>D2/σ M <@D2c@>D2）下，应力-应变关系出现明显的屈服点，屈服应力随P<@D2c @> D2/σ D2和含水量W的变化而变化。4. 45 °平面上的抗剪强度（τ <@D2f @>D2）随正应力（digma<@D2f@>D2）的增大而增大，τ <@D2f@>D2-sigma<@D2f@>D2关系的程度（phi）随预约束应力比（P<@D2c@>D2/sigma<@D2c@>D2）的增大而增大。并且，sin phi随log（P<@D2c@>D2/sigma<@D2c@>D2）线性增加，但在较大的P<@D2c@>D2/sigma<@D2c@>D2.5处逐渐接近1。φ <@D2wn@>D2任意含水量（w）和P<@D2c@>D2/sigma<@D2c@>D2= n，如以下等式所示。D2 = D7-（D7-D2）exp { -D70.434W（D2/sigma D2）（D）（pi/2-D2）cosphi D7 } 6.在较小的重复次数（N <100）下，非饱和粘土在偏应力重复作用（q<@D2d@>D2）下的残余应变与静压缩状态下的轴向应变基本相同。弹性性能随着重复次数的增加而增加。

During 2 Years. We had carried static and dynamics shearing test on saturated and unsaturated continental clay subjected to different confining pressure.On the results of these investigation following results are obtained.; 1. Undrained shearing strengths of saturated clay under low confining pressure are 50% larger than those of saturated clay calculated on the strength increment value under high confining pressure. 2. Strength anisotropy of saturated clay are nearly constant in spite of difference of confining pressure and overconsolidation ratio. 3. Shearing strength of unsaturated continental clay are influenced by the dry density and water content. Yielding point of stress-strain relationship are appeared clearly at higher pre-confined stress ratio ( P<@D2c@>D2/sigmaM<@D2c@>D2 and yield stress are changed on value of P<@D2c@>D2/sigma<@D2c@>D2 and water content W. 4. Shearing strengths (tau<@D2f@>D2) on the 45ﾟ plane increase with normal stress (digma<@D2f@>D2) and the degree(phi) of tau<@D2f@>D2-sigma<@D2f@>D2 relation are increasing with magnitude of pre-con- fined stress ratio ( P<@D2c@>D2/sigma<@D2c@>D2 ). And also , sin phi increases linearly with log( P<@D2c@>D2/sigma<@D2c@>D2 ) but gradually approach to 1 at large P<@D2c@>D2/sigma<@D2c@>D2.5. phi<@D2wn@>D2 any water content (w) and P<@D2c@>D2/sigma<@D2c@>D2= n in shown as following equation . phi<@D2wn@>D2 = <@D7pi(/)2@>D7 - (<@D7pi(/)2@>D7 - phi<@D2w1@>D2) exp { - <@D70.434W(P<@D2c@>D2/sigma<@D2c@>D2)(/)(pi/2-phi<@D2w1@>D2)cosphi<@D2w1@>D2@>D7 } 6. Residual strain of unsaturated clay subjecting to repeated deviator stress ( q<@D2d@>D2 ) is nearly same axial strain under static compression state during smaller repetition (N <100) 7. Elastic properties are increasing with increase of repetition.