不同温度条件下三峡茅坪溪沥青混凝土三轴试验研究

Triaxial Experiments on Asphalt Concrete of Maopingxi,Three Gorges under Different Temperature Conditions

沥青混凝土具有温度敏感性,不同温度下力学性能差异较大。针对三峡茅坪溪沥青混凝土进行了基本力学性质试验及不同温度条件下的三轴剪切试验,探究温度对沥青混凝土力学性质的影响规律。结果表明:茅坪溪沥青混凝土的劈裂抗拉强度偏低,拉伸强度较小,拉伸应变较大,最大弯拉应变、挠跨比较大,单轴抗压强度较小;随着试验温度的升高,沥青混凝土的黏聚力增大,内摩擦角减小,试样破坏偏应力降低,且偏应力随着围压的增加而增大,试验结束时应力-应变关系曲线均为硬化型;变形模量数K、n及初始切线泊松比G均随试验温度的升高而降低。试验成果可为大坝沥青混凝土心墙运行状态评价提供参考。

Asphalt concrete is temperature-sensitive and its mechanical properties vary significantly at different temperatures.We conducted basic mechanical property tests and triaxial shear tests at different temperatures of asphalt concrete from Maopingxi in Three Gorges,and explored the influence of temperature on mechanical properties of asphalt concrete.Results show that asphalt concrete of Maopingxi is characterized with relatively low splitting tensile strength,low tensile strength,high tensile strain,high maximum bending tensile strain,high deflection span ratio,and low uniaxial compressive strength.As the testing temperature increases,the cohesion of asphalt concrete increases,the internal friction angle decreases,and the failure deviator stress decreases.Additionally the deviatoric stress increases with the increase of confining pressure,and the stress-strain curves are all of the hardening type at the end of tests.The values of deformation modulus K,n,and initial tangent Poisson's ratio G all decrease with the increase of test temperature.Experimental results can provide a reference for the evaluation of operational status of asphalt concrete core walls in dams.