通过压力板试验,对比分析了荆门原状膨胀土与石灰改良土持水特征的差异性;应用非饱和土三轴仪,开展了原状膨胀土、石灰改良膨胀土与重塑膨胀土的变形及强度特性试验。结果表明:①石灰改良膨胀土与原状膨胀土相比,其进气值有显著降低,残余含水率显著升高,土-水特征曲线两个特征点的斜率较为平缓,说明其水稳定性较好,土体性状更为稳定;②原状膨胀土和石灰改良膨胀土在非饱和与饱和状态的应力-应变关系曲线均呈应变软化型,随净围压的增大,应变软化的程度趋缓;随含水率的减小,峰值应力增大,应力峰值点有所提前,应变软化现象更加显著。饱和重塑膨胀土的应力-应变关系呈应变强化型,非饱和重塑膨胀土则呈现为应变软化型,但其应变软化的程度较前两类土大为趋缓;③经石灰改性后,膨胀土强度参数值有大幅度提高,即使在湿化饱和后,石灰改良膨胀土仍保持了相对稳定的力学性质和较高的抗剪强度参数值。相比之下,无论是重塑膨胀土,还是原状膨胀土,对湿化作用均十分敏感,其强度参数值或波动较大,或整体水平较低。 Through the pressure plate test, the difference between the original water-holding characteristics of the Jingmen original expansive soil and the lime-modified soil was comparatively analyzed. The deformation and strength of the original expansive soil, lime-treated expansive soil and remolded expansive soil were studied using unsaturated soil triaxial apparatus Characteristic test. The results show that: (1) Compared with the original expansive soil, the lime-treated expansive soil has a significantly lower air intake value and a significantly higher residual moisture content. The slope of the two characteristic points of the soil-water characteristic curve is relatively gentle, indicating that the water stability is better And the soil properties are more stable. (2) The stress-strain curves of unsaturated expansive and saturated expansive soils are in the form of strain softening. With the increase of net confining pressure, the degree of strain softening tends to be slow With the decrease of water content, the peak stress increases, the stress peak points ahead, and the strain softening phenomenon becomes more pronounced. The stress-strain relationship of saturated remolded expansive soil is strain-hardening type, while that of unsaturated remolded expansive soil is strain-softening type, but its degree of strain softening is much slower than that of the former two types of soil. ③ After lime modification , The expansive soil strength parameter values ​​have greatly increased, even after wetting saturation, lime-treated expansive soil retains relatively stable mechanical properties and high shear strength parameter values. In contrast, both remolded expansive soils and undisturbed expansive soils are very sensitive to wetting and have a greater or lesser strength parameter value or overall level.