大西沟水库粘土心墙过渡性粘土的湿化变形试验研究

Experimental Study on Slaking Deformation of Transitional Clay of Core Wall for Daxigou Reservoir

土石筑坝材料在库水位快速变化时往往会由于材料湿化产生附加应变,从而影响土石坝的变形及应力应变状态。现状研究集中于粗粒料,对粘土类材料湿化变形的研究很少。为此,结合大西沟水库大坝心墙过渡性粘土,采用“单线法”开展了湿化变形试验。结果表明,粘土材料的湿化变形小于粗粒料,应力水平高时差距更为明显;湿化轴向应变和剪应变关系与粗粒料变化规律相似;粘土的湿化轴向应变和体积应变总体呈线性关系。现有的粗粒料湿化变形经验模型不太适用于反映粘土的湿化剪应变,为此提出了一个综合考虑参数数量和准确度的粘土湿化经验模型以精确描述粘土材料的湿化变形。

When the water level of the earth-rockfill dam changes rapidly,additional deformation often occurs due to material slaking,which affects the deformation and stress-strain state of the earth-rockfill dam.The current research focuses on the slaking deformation of coarse-grained materials,and the research on the slaking deformation of clay materials is rare.In this study,the slaking deformation test was carried out by using the"single-line method"combined with the transitional clay of the dam core wall of Daxigou reservoir.The results show that the slaking deformation of clay material is smaller than that of coarse-grained material,and the difference is more obvious when the stress level is high.The relationship between slaking axial strain and shear strain is similar to that of coarse-grained material,and the slaking axial strain and volumetric strain of clay are generally linear.The existing slaking deformation model of coarse-grained materials is not suitable for reflecting the slaking shear strain of clay.In order to accurately describe the slaking deformation model of clay materials,considering the number of parameters and accuracy was proposed.