K_0条件下砂土原生各向异性的动剪切模量试验研究  

EFFECT OF FABRIC ANISOTROPY ON DYNAMIC SHEAR MODULUS IN K_0 CONDITION

作　　者：李博[1,2] 余闯[1] 曾向武[3] 

机构地区：[1]温州大学防灾减灾工程研究所,浙江温州325035 [2]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004 [3]凯斯西储大学土木工程系,美国克利夫兰44106

出　　处：《岩石力学与工程学报》2013年第S2期4048-4055,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41202186,41372264);浙江省自然科学基金项目(LQ12E08007)

摘　　要：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。Dynamic shear modulus is a critical factor for sand in engineering practice. In order to evaluate the effects of fabric anisotropy on dynamic shear modulus,the measurement of wave velocity by bender element technique is conducted. The special container is manufactured to prepare the model with deposition angles of 0°, ±45°and 90°. The Toyoura sand specimens with specified deposition angles are tested in loading and unloading conditions. The results show that the sand sample prepare in the deposition angle of 90° has the largest shear modulus in horizontal and vertical directions. It is found that in unloading condition,specimens with different deposition angles show different responses for stress history,and response of sand sample with deposition angle of 90° is most obvious,which verify that influence of deposition angle on small strain shear stiffness of sand is very significant. Based on the results,a micromechanical stress-strain model is validated,which could show the influences of fabric anisotropy,stress condition and particle contact characteristics on dynamic shear modulus reasonably.

关 键 词：土力学 各向异性 K0条件 剪切模量 弯曲元 

分 类 号：TU411[建筑科学—岩土工程]