不同加荷方向下横观各向同性饱和粗砂的真三轴试验研究

A True Triaxial Test of Saturated Coarse Sand Under Different Loading Directions

各向异性是岩土材料普遍具有的性质,而横观各向同性是岩土各向异性最通常的表现形式,因此在真三轴试验中,不同加荷方向下的大主应力方向与颗粒沉积方向之间形成的不同夹角(α角)对其本构特性影响的研究是具有意义的。在有效围压为200 k Pa,中主应力系数为0,0.5,1的条件下,采用不同的制样方法,分别进行α角为0°,60°,90°的饱和粗砂进行排水剪切试验,并结合试验数据探究其应力应变及剪胀特性。最后,通过分析似临界状态下有效球应力p′–偏应力q曲线和lnp′–孔隙比e曲线,得出不论α角取何值,其临界状态都是存在的。

Anisotropy is a general property of geomaterials, and transverse isotropy is the most common form of geotechnical anisotropy. Therefore, in the true triaxial test, the direction of the principal stress is different under different loading directions. The study of the constitutive properties of the different angles formed between the particle deposition directions is significant. Under the conditions of effective confining pressure of 200 k Pa and medium principal stress coefficient of 0, 0.5 and 1, different sampling methods were used to conduct the drainage shear test of saturated coarse sand with α angles of 0°, 60° and 90° respectively, combined with experimental data to explore its stress strain and dilatancy characteristics. Finally, the criticality states under different alpha angles are analyzed.