基于颗粒接触理论的深层砂土剪切波速度

夏唐代^1,2, 刘瑜^1,2, 吴明^1,2, 周新民³

1.浙江大学软弱土与环境土工教育部重点实验室;2.浙江大学岩土工程研究所;3.浙江省地震局



摘要:

为了研究深层砂土剪切波速度,首先假设深层砂土为不规则排列等球体颗粒的集合体,在颗粒接触理论以及细观颗粒弹性力学的研究成果上推导出砂土的等效剪切模量,继而得到宏观剪切波速计算公式;然后分析了孔隙率、饱和度、内摩擦角、土粒密度、应力大小以及砂土颗粒的弹性模量和泊松比等因素对剪切波速的影响,最后将理论方法计算结果与深层砂土实测剪切波速进行了对比验证.结果表明:理论方法计算得到的结果与实测结果吻合较好,剪切波速度主要受孔隙率、应力大小及砂土颗粒弹性模量等因素影响显著;高应力状态下,尤其是当密实度达到100%后,应力增长会导致剪切波速继续增加.

关键词:  颗粒接触理论  实际平均接触点数  等效剪切模量  应力状态

DOI：10.11918/j.issn.0367-6234.2011.04.020

分类号:TU435

基金项目:国家自然科学基金资助项目(5107833)



Shear wave velocity in deep buried sand based on spheres-contact theory

XIA Tang-dai^1,2, LIU Yu^1,2, WU Ming^1,2, ZHOU Xin-min³

1.MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,310058 Hangzhou, China;2.Institute of Geotechnical Engineering,Zhejiang University,310058 Hangzhou, China;3.Seismological Bureau of Zhejiang Province,310013 Hangzhou,China

Abstract:

Assuming deep buried sand is an aggregate of randomly packed uniform spheres,the equivalent shear modulus and the formula of shear wave velocity(V s) in sand media were derived based on the the spheres-contact theory and the research results of microscopic particles elasticity.Seven influencing factors were analyzed,including porosity,saturation,internal friction angle,soil grain density,magnitude of stress,elastic modulus of sand grain and Poisson ratio of sand grain.The results were compared with the measured data,and the calculated value of V s were generally in good agreement with the measured values.This study indicates that the value of V s is mainly influenced by porosity,magnitude of stress and the elastic modulus of sand grain,and the shear wave velocity increases with the increasing of stress in high stress state,especially after the degree of density achieves 100%.

Key words:  spheres-contact theory  actual coordination number  equivalent shear modulus  stress state