鄱阳湖地区级配不良偏细砂砾石料力学特性

Mechanical properties of poorly-graded sandy gravel with high content of fine particles in Poyang Lake area

基于大型三轴试验数据,研究了级配和相对密度D_(r)对鄱阳湖地区级配不良偏细砂砾石料强度和变形特性的影响。结果表明:随着小于5 mm粒径颗粒质量分数的增加,砂砾石料压实性能降低;随着大于5 mm粒径颗粒质量分数P_(5)和D_(r)的增大,强度指标、初始切线弹性模量与体积模量增大;本文研究范围内,随P_(5)和D_(r)的增大,强度指标c、φ、φ_(0)、Δφ线性增大,且P^(5)和D_(r)对强度指标的作用效应几乎不存在相互影响;随P 5和D_(r)的增大,邓肯E-B模型参数K、K_(b)增大,且P_(5)越高D_(r)对K、K_(b)的影响越显著,D_(r)越大时P_(5)对K、K_(b)的影响越强烈,存在相互影响效应;提出了考虑级配与D_(r)双重影响的强度指标和变形参数经验计算公式,该公式能高精度预测鄱阳湖地区级配不良偏细砂砾石覆盖层料的力学指标。

A series of large-scale triaxial tests are conducted on the influence of particle grading and relative density on the strength and deformation characteristics of sandy gravel with high content of particles smaller than 5 mm.It shows that the compaction performance of sandy gravel decreases with the increasing mass fraction of particle less than 5 mm.Strength parameters and deformation parameters increase with the increase of the mass fraction of particles larger than 5 mm P 5 and relative density D_(r).The strength parameters,c,φ,φ0 andΔφ,increase linearly with the growth of P_(5)and D_(r),and there is almost no interaction between influences of P_(5)and D_(r)on strength parameters.The test results also show that the Duncan E-B model parameters K and K_(b)increase with the growth of P_(5)and D_(r),the effects of D_(r)on K and K_(b)are greater for sandy gravel with higher content of particles larger than 5 mm,and the effects of P_(5)on K and K_(b)are more significant for sandy gravel with higher relative density.The empirical formulas,considering the effects of particle grading and D r,are proposed to predict mechanical properties and Duncan E-B model parameters,and the formulas have high precision in prediction of mechanical indexes of poorly-graded sandy gravel with high content of fine particles for overburden in Poyang Lake area.