侧向卸荷条件下不同含水率原状黄土变形特性分析

为研究原状黄土的侧向卸荷变形特点，选取陕西地区具有代表性的不同含水率Q₃原状黄土，进行不同固结压力下的分级侧向卸荷试验。试验结果表明：原状黄土在侧向卸荷下应力应变曲线为硬化型；初始固结压力较低的试样无明显破坏且轴向应变最终趋于稳定，固结压力较高的试样则发生破坏且轴向应变持续增加，对于低固结压力试样，含水率越高，最终稳定时的轴向应变越大；提出原状黄土的临界轴向应变比值，并通过拟合得出指数函数表达式，以计算各种情况土体卸荷达到塑性破坏时的围压值；根据试验结果拟合得到初始切线模量的经验公式，从而推导出不同含水率原状黄土在卸荷时的变形模量计算公式。

Deformation Characteristics of Undisturbed Loess with Different Moisture Content under Lateral Unloading Conditions

To study the characteristics of lateral unloading deformation of undisturbed loess, the representative Q3 undisturbed loess with different moisture content in Shaanxi Province was selected to carry out graded lateral unloading tests under different consolidation pressures. The results show that the stress-strain curve of undisturbed loess under lateral unloading is hardening. The samples with low initial consolidation pressure had no obvious performance of damage and the axial strain finally tended to be stable, while the samples with high consolidation pressure have damage and the axial strain continued to increase. For the samples with low consolidation pressure, the higher the moisture content, the greater the axial strain at the time of final stability. The critical axial strain ratio of undisturbed loess is put forward, and the exponential function is obtained by fitting, so as to calculate the confining pressure when the critical displacement of soil is reached. According to the experimental results, the empirical formula of the initial tangent modulus is obtained, and the formula of the deformation modulus of the undisturbed loess with different moisture content under unloading is derived.