超高沥青混凝土心墙坝砂板岩堆石料试验研究

Experimental study on sand slate rockfill materials for ultra-high asphalt concrete core dams

开展了超高沥青混凝土心墙坝砂板岩堆石混合料的试验研究。研究结果表明:随板岩含量的提升和孔隙率的增大,应力应变曲线软化特性趋弱硬化特性增强、剪切峰值降低,剪切过程中的体变增大且剪胀现象减弱,相应的线性强度c,φ和非线性强度指标φ_(0),Δφ均降低,邓肯模型参数K与Kb减小;建立了同时可反映孔隙率、板岩含量的强度指标及邓肯模型参数经验公式,能较高精度地预测不同板岩含量、不同孔隙率砂板岩堆石混合料的工程力学特性;板岩含量是影响渗透性能的重要因素,随板岩含量的提升渗透系数降低,工程建设中对于含板岩的堆石料应关注排水设计。

A series of tests are conducted on the engineering mechanical properties of sand slate rockfill materials for an ultra-high asphalt concrete core dam.It is found that with the increase of the porosity and slate content,the softening behavior of stress-strain curve weakens and the peak strength decreases.The volume change increases,and the shear dilation phenomenon fades during the shearing process.The linear strength indexes c and φ,the nonlinear strength indexes φ_(0)and Δφ,and the Duncan model parameters K and K_(b) all decrease.The empirical formulas for the strength indexes and deformation parameters are proposed to predict the engineering mechanical properties of the sand slate rockfill materials with different slate contents and porosities precisely.It is also found that the permeability decreases with the increase of the slate content.The slate content is one important factor for the permeability performance of rockfill materials,and the drainage design of the rockfill area should be considered in the dam design.