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Effects of permeability and compressibility on liquefaction screening using cone penetration resistance.

机译：渗透性和可压缩性对使用抗锥入性的液化筛选的影响。

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摘要

Empirical relationships between normalized cone penetration resistance (qc1N), cyclic resistance ratio (CRR), magnitude of earthquake, and silt content, derived from field observations, are widely used for liquefaction potential assessment of loose saturated sands and silty sands (Robertson and Wride 1998). This dissertation examines the effects of non-plastic fines content on the relationship between qc1N and CRR. A brief review of recent work on the effects of fines content on liquefaction resistance is presented. It indicates that liquefaction resistance of sands and silty sands are nearly the same when compared at the same 'equivalent' intergranular void ratios (Thevanayagam et al. 2002a). Stress-strain relationships are also nearly the same for sand and silty sand at the same 'equivalent' intergranular void ratio. However, permeability k and coefficient of consolidation ch of sand and silty sand are not the same at the same 'equivalent' intergranular void ratio. k and ch decrease significantly with an increase in silt content (Shenthan 2001). A brief literature review of explanations for the dependence of qc1N versus CRR on silt content is presented. One of the hypotheses in the literature (Thevanayagam and Martin 2002) proposes that qc1N of sands and silty sands, at the same equivalent' intergranular void ratio but with different k and compressibility mv, would be very sensitive to k and compressibility; Since k and mv are sensitive to fines content, the relationship between CRR and qc1N would depend on fines content. Numerical simulations of cone penetration in sands and silty sands conducted as a part of this dissertation indicate that silty sand shows smaller qc1N than qc1N for sand at the same 'equivalent' intergranular void ratio. The ch (=k/(mvgammaw)) has a major influence on qc1N. This is due to significant differences in concurrent pore pressure generation and dissipation around the cone tip during penetration in low permeable silty sands compared to highly permeable sand. In highly permeable sand cone resistance is a 'drained' response whereas it is an 'undrained' response in very low permeable silty sand, even if both soils have the same stress-strain constitutive relationships. At intermediate ch values, there is a transitional behavior between 'drained' and 'undrained' response. The respective cone resistances are very different. Further numerical simulations indicate that qc1N is also dependent on diameter of cone d, and velocity of penetration v. A relationship is found between liquefaction resistance, qc1N, and a normalized penetration rate T (=vd/ch). The effect of silt content appears in this relationship through ch. The numerical simulations results are expected to reflect the limitations of the material model. Yet the trends provide an understanding the effects of permeability and compressibility on cone penetration resistance. A limited number of large scale 1-g laminar box liquefaction experiments and cone penetration tests conducted in sands support this relationship. Additional numerical simulation studies and large scale liquefaction experiments are needed to further refine and validate this relationship for silty sands.
机译：实地观察得出的归一化圆锥渗透阻力（qc1N），循环阻力比（CRR），地震震级和淤泥含量之间的经验关系被广泛用于松散饱和砂土和粉质砂土的液化潜力评估（Robertson and Wride 1998） ）。本文研究了非塑料细粉含量对qc1N和CRR之间关系的影响。本文简要介绍了粉尘含量对抗液化性影响的最新研究成果。它表明，在相同的“等效”粒间空隙率下，砂和粉质砂的抗液化性几乎相同（Thevanayagam等，2002a）。对于砂和粉质砂，在相同的“等效”晶界空隙率下，应力-应变关系也几乎相同。但是，在相同的“当量”粒间空隙率下，砂和粉质砂的渗透率k和固结系数ch并不相同。随着泥沙含量的增加，k和ch显着下降（Shenthan 2001）。简要文献综述解释了qc1N和CRR对泥沙含量的依赖性。文献中的一种假设（Thevanayagam和Martin 2002）提出，当砂和粉质砂的qc1N具有相同的当量晶界空隙率，但具有不同的k和可压缩性mv时，对k和可压缩性非常敏感。由于k和mv对细粉含量敏感，因此CRR和qc1N之间的关系将取决于细粉含量。作为本文的一部分，在砂和粉质砂中进行锥入度的数值模拟表明，在相同的“等效”粒间空隙率下，粉砂的qc1N比qc1N小。 ch（= k /（mvgammaw））对qc1N具有重要影响。这是由于与高渗透性砂岩相比，在低渗透性粉质砂岩渗透过程中，并发孔隙压力的产生和锥尖周围的耗散差异很大。在高渗透性砂土中，即使两种土壤都具有相同的应力-应变本构关系，在极低渗透性的粉质砂土中，锥阻力都是“排水”响应。在中间ch值处，“排水”和“不排水”响应之间存在过渡行为。各自的锥电阻非常不同。进一步的数值模拟表明，qc1N也取决于圆锥体d的直径和渗透速度v。在液化阻力qc1N和归一化渗透率T（= vd / ch）之间发现了一种关系。淤泥含量的影响通过ch出现在这种关系中。数值模拟结果有望反映材料模型的局限性。然而，这些趋势提供了对渗透性和可压缩性对锥形穿透阻力的影响的理解。在沙子中进行的有限数量的大规模1-g层流箱液化实验和圆锥渗透试验支持了这种关系。需要进一步的数值模拟研究和大规模的液化实验，以进一步完善和验证粉砂的这种关系。

著录项

  • 作者

    Ecemis, Nurhan.;

  • 作者单位

    State University of New York at Buffalo.;

  • 授予单位 State University of New York at Buffalo.;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 315 p.
  • 总页数 315
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 建筑科学;
  • 关键词

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