砂卵砾石料强度及变形大型三轴试验研究

Large-scale triaxial test study of strength and deformation behaviors of sand-grained materials

对不同相对密度的双江口心墙坝覆盖层砂卵砾石料,进行了各向等压固结排水剪切试验,研究了相对密度对砂卵砾石料的强度及变形性质的影响,结果表明:砂卵砾石料的线性强度指标Ф及非线性强度指标Ф0、△Ф均随相对密度Dr的增加而增大,且Ф0及△Ф与Dr之间均存在良好的线性关系;随着相对密度的增加,试验得到的砂卵砾石料的体变(压缩)量减小,而剪胀性则增大;砂卵砾石料的割线模量及破坏时的泊松比均随相对密度的增加而增大。根据试验数据总结了割线模量E1与Dr、围压σ3之间的关系式,以及破坏时的泊松比V1f与相对密度Dr、围压σ3之间的关系式,据此可作为砂卵砾石变形大小的判断标准。

Using large-scale shearing device, isotropically consolidated-drained triaxial test under different confining pressures are performed for relative density overburden material of Shuangjiangkou earth dam. The influence of density on strength and deformation properties of sand-grained material is studied. The results show that the linear strength index φ nonlinear strength index φ0 and Δφ all increase with the relative density increases, and the increases in nonlinear strength index φ0 and Δφ are linear. The volume strain value of sand-grained material decrease with the relative density increases and the dilatancy of sand-grained material increase with the relative density increases. The secant modulus and the failure Poisson ratio of coarse-grained soil both increase with the relative density of sand-grained material increases. According to the test data, a formula for relation of the secant modulus E1 and the relative density Dr and confining pressure is obtained, And meanwhile, a formula for relation of the failure poisson ratio Vlf and the relative density Dr and confining pressure 0-3 is also obtained under specific confining pressure.