汶川地震区崩滑堆积体强度现场直剪试验研究

发布时间：2018-03-07 05:17

本文选题：汶川地震　切入点：崩滑堆积体　出处：《地质力学学报》2017年01期 　论文类型：期刊论文

【摘要】：以汶川震区漩口一带地震诱发的松散堆积体为研究对象,开展碎石土原状样和重塑样的现场直剪对比试验,探讨不同法向应力、不同粒度组成和不同含水率等条件下碎石土的剪切强度特性。研究结果表明,地质成因和岩土体结构相似、粒度组成不同且级配不良的碎石土的剪切强度特性具有相似性;原状样剪切强度明显高于相同干密度和含水率的重塑样;级配良好的碎石土应变硬化程度略高于级配不良的碎石土,当粒径大于5 mm的粗颗粒含量大于42.9%时,随粗颗粒含量增加,碎石土的内摩擦角增加,而粘聚力则先减小后增大;抗剪强度指标与含水率呈线性负相关关系,随着含水率增高,碎石土抗剪强度降低,其中粘聚力较内摩擦角下降更明显。综合前人研究和本次试验结果,建议汶川震区类似结构组分碎石土天然状态下的剪切强度指标c值取15±3 k Pa,φ值取30°±2°。
[Abstract]:Taking the loose accumulations induced by earthquakes in the Waikou area of Wenchuan earthquake area as the research object, the field direct shear contrast tests of the undisturbed and remolded samples of crushed stone soil were carried out, and the different normal stresses were discussed. The results show that the shear strength characteristics of gravel soil with different grain size composition and poor gradation are similar to those of rock and soil structure. The shear strength of the undisturbed sample was significantly higher than that of the remolded sample with the same dry density and moisture content, and the strain hardening degree of the well-graded gravel soil was slightly higher than that of the ungraded gravel soil, and when the coarse particle content of the grain-size larger than 5 mm was greater than 42.9%, With the increase of coarse particle content, the internal friction angle of gravel soil increases, while the cohesion decreases first and then increases, the shear strength index and moisture content show a linear negative correlation, with the increase of water content, the shear strength of crushed stone soil decreases. The cohesive force decreases more obviously than the internal friction angle. Based on the previous studies and the experimental results, it is suggested that the shear strength index c should be taken as 15 卤3 k Paand 蠁 30 掳卤2 掳in natural state of similar structural macadam soil in Wenchuan earthquake region.
【作者单位】：中国地质科学院地质力学研究所;国土资源部新构造运动与地质灾害重点实验室;四川省川建勘察设计院;
【基金】：中国地质调查局项目(1212010914025) 国家十二五科技支撑课题(2011BAK12B09)
【分类号】：P642.22

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