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工程实践中动剪切模量是砂土关键的动力学参数之一。结合压电陶瓷弯曲元波速测试技术开展K0条件下砂土的原生各向异性对动剪切模量的影响试验研究。通过自行研制的试验装置,对沉积角度分别为0°,±45°和90°的丰浦砂在加卸荷条件下剪切模量的变化进行研究。结果表明:90°的砂样在单向荷载作用下,水平方向和垂直方向的剪切模量最大,并且还发现在卸载条件下,不同沉积角度的砂样对应力历史反应不一,沉积角度为90°的砂样应力历史的影响最明显,验证不同的沉积方向对砂土小应变剪切刚度的影响十分显著。基于试验结果,对现有的微观本构模型进行验证,发现该本构模型能较好地反映原生各向异性、应力状态和颗粒接触特征对土的动剪切模量的影响。
The dynamic shear modulus in engineering practice is one of the key dynamic parameters of sand. Experimental study on dynamic shear modulus of sand subjected to K0 under the conditions of K0 piezoelectric wave bending test. The changes of shear modulus of Toyoura sand deposited and unloaded at angles of deposition of 0 °, ± 45 ° and 90 °, respectively, were studied by a self-developed test device. The results show that the 90 ° sand sample has the largest shear modulus in the horizontal direction and the vertical direction under the unidirectional load. It is also found that the sand samples with different deposition angles react differently under different unloading conditions. The deposition angle The effect of sandstone sample stress history of 90 ° is the most obvious. It is verified that the different depositional directions have a significant impact on the small-strain shear stiffness of sand. Based on the experimental results, the existing microscopic constitutive models are validated and found that the constitutive model can better reflect the influence of the primary anisotropy, the stress state and the particle contact characteristics on the dynamic shear modulus of the soil.