炎热多雨气候影响下残积土小应变刚度特性试验研究

发布时间：2018-08-01 15:58

【摘要】：根据炎热多雨地区轨道交通周边土体的实际工程状态,开展经历不同干湿循环过程的花岗岩残积土的共振柱试验,研究炎热多雨气候影响下残积土小应变下的刚度特性。结果表明,受反复干湿循环效应影响,在10~(-6)~10~(-4)小应变范围内,残积土G_(max)随干湿循环次数n的衰变规律与常应变下黏性土强度特性衰减规律有较大差异,最大衰减出现在干湿循环中期;经历多次循环后,小围压下残积土的G γ关系曲线出现直线下降和骤降阶段;利用Martin Davidenkov模型和经验关系能较好地反映G/G_(max)和D随γ的变化规律,发现不同干湿循环次数后,G/G_(max) γ关系随围压增大逐渐出现"两极分化"现象。研究还从微观角度对残积土小应变刚度特性的干湿循环效应给与解释,说明炎热多雨气候下残积土刚度的力学行为是由于结构强度减损、微观结构重塑引起。研究可为轨道交通工程动力参数的选取,类似工程场地的设计、施工及抗震分析提供技术参考依据。
[Abstract]:According to the actual engineering state of the surrounding soil mass around rail transit in hot and rainy area, the resonance column test of granite residual soil with different dry and wet cycles was carried out, and the stiffness characteristics of residual soil under small strain under the influence of hot and rainy climate were studied. The results show that under the influence of repeated dry-wet cycle effect, in the range of 10 ~ (-6) ~ (-4) ~ (-4), the decay law of residual soil G _ (max) with the number of dry and wet cycles n is different from that of clay soil under constant strain. The maximum attenuation occurs in the middle of dry-wet cycle, after several cycles, the G 纬 -ray relation curve of residual soil under small confining pressure decreases linearly and suddenly, and the variation of G / G _ (max) and D with 纬 can be well reflected by Martin Davidenkov model and empirical relationship. It was found that the G / G _ (max) 纬 relationship gradually appeared "polarization" phenomenon with the increase of confining pressure after different dry-wet cycles. The dry and wet cycle effect of the small strain stiffness characteristics of residual soil is explained from the microscopic point of view. It is shown that the mechanical behavior of residual soil stiffness in hot and rainy climate is caused by structural strength loss and microstructure remodeling. The study can provide a technical reference for the selection of dynamic parameters of rail transit engineering, the design, construction and seismic analysis of similar engineering sites.
【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;中原工学院建筑工程学院;
【基金】：国家自然科学基金项目(41372314,11672320,41472292,41372291) 中国科学院科技服务网络计划项目(KFJ-EW-STS-122)
【分类号】：TU41

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