为弄清原状黄土在不同剪切方向角下的强度变形规律，利用平面应变仪，并考虑原状黄土各向异性，对取自陕西泾阳的原状黄土进行了不同剪切方向角、固结围压、含水率条件下的平面应变试验。试验结果表明：平面应变条件下，土体应力应变曲线为硬化型；随着围压增大及含水率减小，原状黄土强度显著升高；随着主应力角增加，应力应变曲线更低缓，呈现弱硬化型，而且土体初始剪切模量也有所降低；土体凝聚力与内摩擦角随主应力角的增大而显著减小，不同主应力角下，含水率对凝聚力的影响比对内摩擦角的影响要大；破坏主应力差随主应力角、含水率的增大而减小。%For understanding the variation laws of strength and strain of original loess under different shear direction angles, by using a plane strain apparatus and in consideration of the anisotropy characteristics, a plane strain test was carried out for the o-riginal loess samples collected at Jingyang area, Shannxi, under different experimental conditions, including shear direction an-gle, consolidation confined pressure and water content. It shows that the loess stress-strain curve is a hardening type under plane strain condition;with the increase of confined pressure and decrease of water content, the strength of original loess goes up-ward obviously;with the increase of principal stress angle, the stress-strain curve is gentle, presenting a weak hardening type and the initial shear modulus decreases as well, also the cohesion and internal friction angle decrease significantly;in case of dif-ferent principal stress angles, the water content imposes a larger influence on the cohesion than it does on the internal friction an-gle;the difference of failure principal stress goes downward with the increase of principal stress angle and water content.
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