天然土尤其是地表浅层土常处于非饱和状态，其小应变剪切模量是预测地基变形及土工结构物动力反应的一个重要参数。通过对非饱和压实粉土三轴样进行弯曲元试验，研究了吸力和干湿路径对其小应变剪切模量的影响。试验结果表明，非饱和压实粉土样的小应变剪切模量各向异性忽略不计；小应变剪切模量G0(vh)、G0(hh)和G0(hv)均随吸力增大而非线性增大；同一吸力下不同干湿路径上的土样，饱和度不同，其小应变剪切模量随饱和度升高而减小，主要原因是土的平均骨架应力和土中毛细水的作用。根据试验结果对非饱和土小应变剪切模量的半经验公式进行了改进，同时考虑了吸力与饱和度的作用。

Natural soils are usually under unsaturated state, especially soils at shallow depths below ground. The small-strain shear modulus of unsaturated soil is an important parameter for predicting ground deformation and dynamic responses of earth structures. Bender element tests were carried out on unsaturated compacted silt triaxial specimens to investigate the effects of suction and wetting-drying on small-strain shear modulus. Test results show that the small-strain shear modulus anisotropy of unsaturated compacted silt is negligible. The small-strain shear moduli G0(vh), G0(hh) and G0(hv) all increase with suction nonlinearly. For specimens under same suction but along different wetting-drying paths, their saturation degrees are different. Small-strain shear moduli decrease with increase of saturation degree. These observations are mainly due to the changes of average skeleton stress and meniscus water effect. Semi-empirical equation for describing small-strain shear modulus of unsaturated soil is modified based on test results; the effects of suction and saturation degree are both considered.