一种新的胶凝砂砾石坝坝料应变预测模型

A new model for prediction of deformation on CSG material

为了研究胶凝砂砾石料的变形特性,对胶凝掺量60kg/m^3的胶凝砂砾石料在围压为300,600,900和1 200k Pa条件下进行三轴剪切试验,在此基础上,分别采用摩尔库仑准则、改进双曲线及抛物线描述胶凝砂砾石料的强度特性、应力-应变及体积应变-轴向应变关系,形成胶凝砂砾石料的应变预测模型。研究结果表明:高围压时峰值强度之前的应力应变曲线斜率比低围压时的斜率大,但软化不明显;与高围压相比,低围压下的试件会较早出现剪胀现象;轴向应变相同时,围压越高的试件主应力差与体积应变越大。模型计算结果与三轴剪切排水试验数据较为吻合,表明该模型能较准确地反映胶凝砂砾石料应力应变关系。

In order to study deformation on cement-sand-gravel（CSG） material, a series of triaxial compression tests of CSG material with 60 kg/m^3 content were conducted under confining pressures of 300, 600, 900 and 1 200 k Pa. Combined with the test results, Mohr coulomb criteria, improved hyperbolic curve and parabolic curve, were respectively used to describe the strength characteristics of CSG material, the relationship of stress versus strain and volumetric strain versus axial strain, and a new model for prediction of deformation on CSG material was built. The results show that the slope of the stress-strain curve under high confining pressures is bigger than that under low confining pressure before peak strength. The dilatancy of CSG material under low confining pressure is displayed faster than that under high confining pressure. The shear stress and volumetric strain increase with confining pressure increasing under the same axial strain. The calculation results of model are consistent with the experimental data, showing that the model accurately reflects the relationship of stress versus strain for CSG material.