荆江大堤下伏饱和粉细砂最大动剪模量经验估算

EMPIRICAL ESTIMATES OF MAXIMUM DYNAMIC SHEAR MODULUS OF SATURATED FINE SAND IN JINGJIANG LEVEES

以采自长江荆江大堤江陵段下伏冲积成因饱和粉细砂为研究对象,参照原位试验成果重塑粉细砂试样,并在其实际固结应力比（Kc≈1.6）条件下,对试样的动剪切模量特性及最大动剪模量经验估算方法进行研究。结果表明：相同的相对密度条件下,围压升高可减缓动模量随应变的衰减速度;而当围压相同、相对密度Dr=0.5-0.6时,动模量衰减曲线形态则高度吻合;基于最大动剪模量估算公式,分别采用相对密度和标贯击数2个指标,对饱和粉细砂的最大动剪模量进行估算,通过与试验成果的对比,证明该经验公式可很好地用于估算本区饱和粉细砂的最大动剪切模量。

The saturated fine sand with alluvial origin in Jingjiang levees was collected,and specimens were reshaped refer to the in-situ tests results. Combining with the actual consolidation ratio Kc（Kc≈1.6）,the dynamic triaxial tests were conducted to research the characteristics of dynamic shear modulus,and then a suitable empirical formula was explored to estimate the maximum shear modulus. Results show that：Under the condition of same relative density（Dr）,the release velocity of dynamic shear modulus will slow down with the increasing of confining pressure;However,when Dr changes from 0.5 to 0.6,the decay curves of dynamic shear modulus can match well with the same confining pressure;Based on the empirical estimate formula,relative density and standard penetration test blow count are taken into account respectively to estimate the maximum shear modulus of saturated fine sand. Compared with the testing results,it is verified that the formula can estimate the maximum shear modulus of this kind of saturated fine sand well.