基于大型三轴试验的筑坝材料动力特性对比分析

Comparative Analysis of Dynamic Characteristics of Different Dam Materials Based on Large Triaxial Test

堆石料和砂砾料在土石坝建设中应用广泛,研究堆石料和砂砾料的动力特性对坝体抗震安全评价有重要意义。基于WYS-2000大型多功能静动三轴试验机,开展了堆石料与砂砾料动弹模量和阻尼比试验,对比分析了围压和固结比对两种材料动模量和阻尼比的影响,并提出阻尼比计算方法。结果表明,围压和固结比的增大均使得两种材料的最大动弹模量和最大动剪切模量提高,围压和固结比相同时,砂砾料的最大动弹模量和最大动剪切模量均较堆石料的高,低围压作用时砂砾料的最大动模量比堆石料高13.4%~26.8%;两种材料动剪切模量比Gd/Gdmax-γr具有良好的归一性;随着固结比的增大,堆石料和砂砾料的最大阻尼比λdmax均在增大,在相同固结比作用下,堆石料的最大阻尼比λdmax比砂砾料高10%~13%。

Rockfill materials and sand gravel materials are widely used in the construction of earth rock dams.The study of dynamic characteristics of rockfill materials and sand gravel materials plays an important role in anti-seismic safety evaluation of dam body.Based on WYS-2000 large-scale multi-functional static and dynamic triaxial testing machine,the dynamic elastic modulus and damping ratio tests of rockfill materials and gravel materials are carried out.The influence of confining pressure and consolidation ratio on dynamic modulus and damping ratio of the two materials are compared,and a calculation method of damping ratio is proposed.The results show that the maximum dynamic elastic modulus and maximum dynamic shear modulus of the two materials increase with the increase of confining pressure and consolidation ratio.When the confining pressure and consolidation ratio are the same,the maximum dynamic elastic modulus and maximum dynamic shear modulus of sand gravel are higher than those of rockfill materials,and the maximum dynamic modulus of sand gravel is 13.4%-26.8%higher than that of rockfill under low confining pressure;The dynamic shear modulus ratio G_(d)/G_(dmex-γ)r of the two materials has good normalization;With the increase of consolidation ratio,the maximum damping ratioλdmax of rockfill material and sand gravel material increases.Under the same consolidation ratio,the maximum damping ratio of rockfill material is 10%-13%higher than that of sand gravel material.