静偏应力下湛江结构性黏土的动力特性

发布时间：2018-04-12 09:28

本文选题：结构性黏土 + 静偏应力　；参考：《岩土力学》2017年01期

【摘要】：针对天然强结构性湛江黏土,通过开展不同静偏应力影响下的不排水循环加载三轴试验,对循环荷载作用下的动变形、动强度和动孔隙水压力特性以及与土结构性间的内在联系进行系统性的试验研究。结果表明,结构性黏土在循环荷载作用下的突然破坏,具有脆性破坏特征,静偏应力越大,土体破坏应变越小。湛江黏土的临界动应力随静偏应力呈先增大、后减小的变化规律,在静偏应力较小时存在峰值。分析认为,静偏应力对结构性黏土动力特性的影响存在分界值,小于该值时静偏应力对土体的压密作用提高了土体的临界动应力和动强度,抑制了土的变形发展;当静偏应力继续增大,则土体结构损伤,动荷载下的临界动应力和动强度均呈下降趋势。结构性土的动孔隙水压力低于一般黏土,静偏应力的存在导致孔压在土体破坏后出现负增长,初始剪应力使结构性土体产生剪胀势。
[Abstract]:In view of the natural strong structural Zhanjiang clay, the dynamic deformation of Zhanjiang clay under cyclic cyclic loading under cyclic loading under different static and deflection stresses is studied.The characteristics of dynamic strength, dynamic pore water pressure and the internal relationship with soil structure were studied systematically.The results show that the sudden failure of structural clay under cyclic loading has the characteristics of brittle failure, and the larger the static deflection stress, the smaller the soil failure strain.The critical dynamic stress of Zhanjiang clay increases first and then decreases with the static deflection stress, and there is a peak value when the static deflection stress is small.It is concluded that there exists a boundary value for the influence of static stress on the dynamic characteristics of structural clay. When the static deflection stress is less than this value, the compaction of static deflection stress on soil improves the critical dynamic stress and dynamic strength of soil and inhibits the development of soil deformation.When the static stress increases, the damage of soil structure, the critical dynamic stress and the dynamic strength under dynamic load will decrease.The dynamic pore water pressure of structural soil is lower than that of common clay, the existence of static deflection stress leads to negative increase of pore pressure after soil failure, and initial shear stress causes shear expansion potential of structural soil.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金项目(No.51179186)~~
【分类号】：TU442

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