大尺寸裂隙性黄土的直剪试验

介绍了一种改装的便携式直剪仪,并用该仪器测试了不同形成时期、不同加载方式作用下大尺寸裂隙性黄土样的抗剪强度。结果显示在不同正应力作用下的剪应力-剪切位移曲线具有弱硬化型特点;近期形成的裂隙性黄土抗剪强度指标c和φ值比形成时间相对较早的裂隙性土样小;分级加载方式测得的内聚力比连续加载方式大,而内摩擦角比连续加载时小,但变幅不大;分级加载方式测得的内聚力比剪切带的分级加载方式大,但这两种方式对内摩擦角的影响不大。

Direct Shear Tests of Large-size Fissured Loess

A refitted portable direct shear apparatus is introduced. Using this apparatus shear strength of large-size fissured loess samples formed in different timeare tested with different loading methods. The results show that curves of r-u under different normal stress are little harden. The values of cohesion and friction angle of newly formed fissured loess samples are smaller than those of older samples. The values of cohesion under stepped loading are larger than those under continuously loading, while values of friction angle under stepped loading are smaller with a little variation. And values of cohesion under stepped loading are larger than those under stepped loading with shear zone, but the two methods have little influence on values of friction angle.