福州市区粉质黏土动剪切模量与阻尼比试验研究

通过共振柱试验给出福州市区粉质黏土在动荷载作用下的剪切模量G、阻尼比λ,详细探讨了应变幅值γ、固结应力对试验结果的影响。结合理论分析,给出福州市区粉质黏土G/Gmax和λ随γ变化的拟合曲线及其参数,并与推荐值和规范值进行对比。结果表明:①G/Gmax-γ关系中,规范值给出的G/Gmax最低,试验值最高;在大、小剪应变时,试验值、规范值、推荐值三者给出的数值相近,但在中等剪应变时,三者相差较大,如在剪应变γ为10-4时,试验值和推荐值相差近5%,试验值和规范值相差近20%;②λ-γ关系中,试验值最大,推荐值和规范值相近,在剪应变γ为10-4时,三者阻尼比相差近50%,说明黏性土阻尼离散性较大。试验成果对本地区和东南沿海相似地质环境地区实际工程具有一定的借鉴作用。

Testing study on dynamic shear modulus and damping ratio of silty clay in Fuzhou downtown area

By means of the resonant column test,the shear modulus G and damping ratio λ under the influence of dynamic load for silty clay in Fuzhou downtown area were first attained.Then the effects of strain value γ and consolidation stress on the testing result were explored in details.Combined with theoretical analyses,the fitting curve and parameter with the change of γ for G/Gmax and λ of silty clay in Fuzhou downtown area were presented.And by comparing the recommended value and the code value,results showed that: ①In Relation G/Gmax-γ,G/Gmax given by code value was the lowest while it was the highest by test value.The values given by test value,code value and recommended value were relatively approximate during large and small strains,whereas the three values were quite different during moderate strain.For instance,when shear strain γ is 10-4,the difference between test value and recommended value is about 5%,while the difference between test value and code value is about 20%;② In Relation λ-γ,the test value was the highest whereas code value and recommended value were approximate.When shear strain γ is 10-4,the difference of damping ratio among the three values was about 50%,which means the damping discreteness of clay soil is relatively large.The test findings could be used as certain reference for practical projects in the local area and in the Southeast coastal area with similar geological environment.