黄土的三轴剪切吸力变化特性与结构性的分析

Analysis on structure and suction property of loess under tri-axial compression

黄土的结构性与其骨架中存在的吸力作用有密切关系,吸力作用提高了土骨架的结构稳定性.黄土表现出的结构性不仅仅与其内在吸力作用有关,而且与土骨架中存在的胶结作用相关.本文通过原状黄土、重塑土的非饱和三轴试验,揭示了它们的基质吸力随着剪切变形的发展规律,以及原状黄土应力结构性参数随剪切变形的变化规律.表明原状黄土较重塑土的基质吸力小,但其抗剪切能力较大,它的结构性在较低应变条件即发挥到了峰值.随着剪切变形发展,黄土的结构性逐渐衰减,而其基质吸力却不断增长.非饱和黄土的基质吸力对其抗剪强度有增强作用,但不能反映黄土的结构性.结构性参数及其变化能明确地反映黄土的结构性演变.

The structural property of loess is related to the suction of its fabric, which improves the stability of soil structure. The shear strength of loess increases with suction and cementation of particles of loess, which can’t be reflected by suction of unsaturated soils. The changing laws of suction and stress structural parameter with shear strain are analyzed by the triaxial tests of unsaturated intact and remolded loess. The structural property of loess reveals the peak value in the low strain condition, and after that, along with the development of the shearing deformation, the loess structural property weakens gradually. The suction is growing unceasingly with the development of the shearing deformation. The suction of intact loess is smaller than the remolded loess. Comparing structural parameter with the suction of loess, the structure effect weakens with shearing deformation and the suction growing unceasingly. Furthermore, the structural property of loess is one of the important mechanical properties. The suction of unsaturated soil reinforces the shear strength of soil particles structure, but it can’t reflect the loess＆#39;s structural property. The structural parameters can reflect the change of loess structure.