结构性对原状黄土强度影响规律的真三轴试验研究

True triaxial tests on structural effects on strength of intact loess

岩土材料的强度问题一直是岩土力学研究的热点。在对多种不同结构性原状黄土的真三轴试验基础上,分析了不同结构性原状黄土的强度变化规律。结果表明,当含水率较低时,干密度变化对结构性原状黄土的强度影响较大于含水率的变化,反之,含水率变化对结构性原状黄土的影响大于干密度的变化;当结构性黄土的强度越大时,其在π平面上的破坏线越接近于抹圆曲边三角形;反之,当结构性黄土的强度越小时,其在π平面上的破坏线越接近于抹圆角三角形;结构性黄土随着结构性的增大,在π平面上的强度破坏线从抹圆角三角形逐渐向抹圆曲边三角形发展,最终趋近于Mises圆。各种原状黄土的摩擦角φ13随中主应力比b值的增大而微弱减小,而内凝聚力c随着中主应力比b值的增大呈现先增大后减小的变化。

The strength of geomaterials has been a hot research of the rock and soil mechanics. Based on the true triaxial on variety of different structural intact loesses, the influence of structural change on the strength of the intact loess is anal＇ The results show that the influence of changes of dry density on the structural strength of intact loess is greater than th change of moisture content under low moisture content; on the contrary, the influence of change of the moisture conteJ structural strength of intact loess is greater than that of change of the dry density. When the strength of structural loess is gr the failure line in the zc -plane of structural loess is closer to the rounded crooked triangle. Conversely, when the stren structural loess is smaller, the destruction line of the structural loess in the PI plane is more close to the rounded triangle. the increase of structural effects, the structural loess failure line in the π-plane of structural loess changes from the rou triangle to the rounded crooked triangle gradually, and it eventually tends to Mises circle. With the increase of the prin stress ratio b, the friction angle φ13 of various intact loesses decreases weakly, and the internal cohesion c first increase, then decreases.