Volumetric behavior of intact and compacted loess under isotropic compression and wetting was investigated through stress- and suction-controlled triaxial tests. To assist in the interpretation of test results, X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimeter (MIP) tests were carried out to determine the mineral composition and the microstructure of the tested loess. Results of compression tests showed that yield stresses of intact loess were larger than that of the compacted loess because of stabilization effects contributed by clay particles and calcite in intact loess, as evidenced by SEM and XRD results. On the other hand, constant water content was observed for intact loess during compression at suctions 50 kPa and 100 kPa, while the water content of compacted loess increased by 4.4% and 7.4% respectively. MIP tests revealed that compression of the intact loess mainly occurred in the extra-large pores, but with minuscule effects on the pores governing water distribution at suctions 50 kPa and 100 kPa. For compacted loess, a number of inter-aggregate pores were compressed below the pore diameters responsible for water flowing in the pores at the applied suctions. In addition, intact loess showed wetting induced swelling at an isotropic stress of 50 kPa, while collapse was observed for compacted loess with the same stress path.

通过应力和吸力控制的三轴试验研究了在各向同性压缩和润湿作用下完整的密实黄土的体积行为。为了帮助解释测试结果，进行了X射线衍射（XRD），扫描电子显微镜（SEM）和水银侵入孔隙率仪（MIP）测试，以确定被测黄土的矿物成分和微观结构。压缩试验的结果表明，完整的黄土的屈服应力要大于压实的黄土，这是由于完整的黄土中粘土颗粒和方解石的稳定作用所致，如SEM和XRD结果所证明的。另一方面，在吸力为50 kPa和100 kPa的压缩过程中，完整黄土的含水量保持恒定，而压实黄土的含水量分别增加了4.4％和7。分别为4％。MIP测试显示完整黄土的压缩主要发生在超大孔隙中，但对控制吸力50 kPa和100 kPa的水分布的孔隙的影响却很小。对于压实的黄土，许多聚集体间的孔被压缩到低于在所施加的吸力下负责水在孔中流动的孔径。此外，完整的黄土在各向同性应力为50 kPa时显示出润湿引起的溶胀，而在相同应力路径下的压实黄土则观察到坍塌。许多聚集体间的孔被压缩到低于在所施加的吸力下导致水在孔中流动的孔径以下。此外，完整的黄土在各向同性应力为50 kPa时显示出润湿引起的溶胀，而在相同应力路径下的压实黄土则观察到坍塌。许多聚集体间的孔被压缩到低于在所施加的吸力下导致水在孔中流动的孔径以下。此外，完整的黄土在各向同性应力为50 kPa时显示出润湿引起的溶胀，而在相同应力路径下的压实黄土则观察到坍塌。