列车荷载引起心形应力路径下软土非共轴应变特征研究

发布时间：2018-04-10 09:09

本文选题：列车荷载　切入点：非共轴　出处：《岩土力学》2017年01期

【摘要】：采用空心圆柱仪对重塑空心软黏土试样开展了一系列非破坏试验,研究了列车循环动荷载作用下的性状。试验中主要选取心形应力路径,以圆形应力路径为辅助,对比分析了两种应力路径下软土的非共轴应变特征,探究循环振次对非共轴特性的影响、荷载频率的大小对非共轴角与大主应力方向角关系曲线形态变化的影响,同时进行了机制分析,并与另一动应力水平下试验结果进行了对比论证。此外,在不考虑频率影响下建立了简化的非共轴角与大主应力方向角之间的关系模型。研究发现,在大主应力方向角旋转的任意周期内,心形与圆形两种应力路径下非共轴角随大主应力方向角变化趋势各自有明显特点,相同动应力水平下两种应力路径产生的偏应力增量引起的单位偏应变增量大小也有所区别,但在大主应力方向角旋转的局部角度内,两种应力路径下的偏应变增量相近;心形应力路径下的非共轴角以及偏应力增量引发的单位偏应变增量大小受循环振次的影响不明显,任意振次中大主应力方向角在[-30°,40°]弧度区间内对应的偏应变增量远大于该区间之外的偏应变增量;随着频率增大,非共轴角随大主应力方向角的变化呈现越来越明显的波动。
[Abstract]:A series of non-destructive tests were carried out on the remolded hollow soft clay samples by a hollow cylinder instrument, and the behavior of the remolded soft clay samples under cyclic loading of trains was studied.In the experiment, the heart-shaped stress path is selected, and the circular stress path is used as the assistant. The characteristics of non-coaxial strain of soft soil under two stress paths are compared and analyzed, and the influence of cyclic vibration times on the non-coaxial characteristics is explored.The influence of load frequency on the shape change of the curve of non-coaxial angle and direction angle of large principal stress is discussed. The mechanism of the curve is analyzed, and the experimental results are compared with the experimental results under other moving-stress levels.In addition, a simplified model of the relationship between the non-coaxial angle and the direction angle of large principal stress is established without considering the influence of frequency.It is found that in any period of rotation in the direction of large principal stress, the variation trend of non-coaxial angle with the direction of large principal stress has obvious characteristics under the two stress paths of heart and circle.Under the same dynamic stress level, the increment of unit strain caused by the increment of deviant stress caused by two stress paths is also different, but the increment of strain is similar in the local angle of rotation in the direction of large principal stress direction.The non-coaxial angle and the increment of unit deflection strain caused by the increment of deviant stress are not affected by the cyclic vibration times obviously under the heart-shaped stress path.The increment of deflection strain in the range of [-30 掳~ 40 掳] radians is much larger than that outside the range, and with the increase of frequency, the variation of non-coaxial angle with the direction of large principal stress is more and more obvious.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学江苏省岩土工程技术工程研究中心;重庆大学土木工程学院;
【基金】：国家自然科学基金面上项目(No.51479060) 中央高校基本科研业务费专项资金项目(No.2015B28214)~~
【分类号】：U213.1;TU447

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