冶勒水电站坝基超固结粉质黏土物理力学特性

摘要

冶勒水电站大坝坝基由超过400 m厚的粉质黏土和卵砾石层组成,研究其土体物理力学特性对工程设计和施工具有重要意义.通过物性试验、静力和动力试验对坝基粉质黏土进行物理力学特性研究,结果表明:土体级配良好,属低液限、超固结、低压缩性粉质黏土,先期固结压力为4.5~6.0 MPa,压缩模量为35.7~152.3 MPa,变形模量为35.00~80.74 MPa;摩擦角为33.70°~35.94°,黏聚力为0.12~0.21 MPa,抗剪强度指标高;动剪切模量为568 MPa,动弹性模量为1686 MPa,动强度参数随振动次数的增加略有降低,但降幅较小.最终提出了一种特殊土体——超固结粉质黏土的物理力学参数指标.%The dam foundation of Yele Hydropower Station is composed of more than 400 m thick silty clay and gravel layer. Therefore,it is very important for engineering design and construction to study the physical and mechanical properties of the soil. Physical and mechanical properties of silty clay in the dam area were researched by physical test and static and dynamic tests. The results show that the soil body with good gradation belongs to the low liquid limit,over consolidation and low compressibility silty clay. The pre-consolidation pressure is 4.5-6.0 MPa. The compression modulus is 35.7-152.3 MPa.Deformation modulus is 35.00-80.74 MPa.The friction angle is 33.70°-35.94°.The co-hesion is 0.12-0.21 MPa. The shear strength is high. The dynamic shear modulus is 568 MPa. The dynamic elastic modulus is 1,686 MPa. The dynamic strength parameters are decreased slightly with the increase of vibration frequency.Finally,the physical and mechanical parame-ters of the over consolidated silty clay are presented.