应力状态对粗颗粒材料动力特性影响试验研究

发布时间：2018-05-23 19:02

本文选题：应力状态 + 粗颗粒材料　；参考：《工程科学与技术》2017年S1期

【摘要】：土石坝在运营过程中,不同部位往往处于不同的应力水平。坝体在遭遇地震工况下,导致坝体内部不同部位会产生不同的地震附加应力,应力状态是影响粗颗粒材料动力特性的重要因素。为研究地震过程中应力状态的变化对坝体抗震性能的影响,本文开展不同围压、不同固结应力比及不同动应力条件下粗颗粒材料动力特性试验研究工作。研究表明:不同围压下最大动弹性模量值随着围压和固结应力比的提高逐渐增大,随着动应变的增大呈逐渐衰减趋势,衰减率随着围压和固结应力比的增加逐渐减慢;不同围压下阻尼比随着动应变的增大呈逐渐增大趋势;随着围压增加,阻尼比λ呈逐渐减小趋势;各级围压下最大动弹性模量值及阻尼比值均比较分散,不能依靠动应变对其进行归一化描述。在相同围压和固结应力比作用下,随着动应力的提高,动永久轴向变形和动永久体积均产生一定的增加;在相同围压和动应力作用下,动永久轴向变形随着固结应力比的提高而增加,动永久体积变形随着固结应力比的提高而略有降低;在相同的固结应力比和动应力作用下,随着围压的提高,动永久轴向变形和动永久体积均产生一定的增加;轴向动应变幅值是不均匀的,一般开始几周较大,后期会逐渐变小,在第10次循环左右,轴向动应变幅值逐渐趋向于定值。
[Abstract]:In the operation of earth-rock dam, different parts are often in different stress levels. When the dam is subjected to earthquake conditions, different additional stresses will be produced in different parts of the dam body, and the stress state is an important factor affecting the dynamic characteristics of coarse granular materials. In order to study the effect of stress state change on seismic behavior of dam during earthquake, the dynamic characteristics of coarse granular materials under different confining pressures, different consolidation stress ratios and different dynamic stresses are studied experimentally in this paper. The results show that the maximum dynamic elastic modulus increases with the increase of confining pressure and consolidation stress ratio, and decreases with the increase of dynamic strain, and the attenuation rate decreases with the increase of confining pressure and consolidation stress ratio. Under different confining pressures, the damping ratio increases gradually with the increase of dynamic strain, and decreases with the increase of confining pressure, and the maximum dynamic elastic modulus and damping ratio are dispersed at different confining pressures. It can not be normalized by dynamic strain. Under the same confining pressure and consolidation stress ratio, dynamic permanent axial deformation and dynamic permanent volume increase with the increase of dynamic stress, and under the same confining pressure and dynamic stress, The dynamic permanent axial deformation increases with the increase of the consolidation stress ratio, the dynamic permanent volume deformation decreases slightly with the increase of the consolidation stress ratio, and under the same consolidation stress ratio and dynamic stress, the dynamic permanent volume deformation increases with the increase of the confining pressure. Both the dynamic permanent axial deformation and the dynamic permanent volume increase to a certain extent, and the amplitude of the axial dynamic strain is non-uniform, generally larger at the beginning of several weeks, and gradually smaller at the later stage. At the 10th cycle or so, the amplitude of the axial dynamic strain tends to be fixed gradually.
【作者单位】：南京水利科学研究院;水利部土石坝破坏机理与防控技术重点实验室;中国电建中南勘测设计研究院有限公司;
【基金】：国家自然科学基金重大研究计划集成项目资助(91215301);国家自然科学基金重点资助项目(51539006);国家自然科学基金青年基金资助项目(51309161)
【分类号】：TV41

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