Study on deformation and strength characteristics of course grained soils under wide variety of stress and strain states

多种应力应变状态下粒状土的变形和强度特性研究

• 批准号: 10450176
• 负责人: KOSEKI Junichi
• 金额: $ 8.13万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450176/
• 关键词: Course grained soil; Triaxial test; Hollow cylindrical torsional test; Deformation property; Local deformation measurement; Cyclic loading; Young's modulus; Shear modulus; ポアソン比; 締固め; 拘束圧

In order to investigate and model the mechanical behavior of course grained soils under a variety of stress states with different stress histories, two series of triaxial tests were conducted on rectangular specimen (with cross-section of 23^*23 cm and height of 58 cm) of densely compacted gravel. Based on results from a series of cyclic triaxial tests following different stress paths under several levels of confining stress, a unique relationship between modified stress and strain parameters during monotonic loading was proposed. By combining this relationship with newly modified hysteresis laws, it was demonstrated that the proposed model could reasonably simulate the cyclic behaviors of dense gravel. Based on results from another series of triaxial tests, their creep behaviors were found to be not negligible, with considerable effects of change in the strain rate on the monotonic loading properties.Studies were also made on the elastic wave velocities of sands and gravel. On Toyoura … More sand, primary wave velocities measured with small accelerometers that were set on the side surface of rectangular specimen were found to be consistent with the static Young's moduli evaluated by applying small amplitude cyclic loading. On gravel with larger particle size, however, the wave velocities were much higher than the statically evaluated values, due possibly to the effects of inhomogeneity in the structure of soil particles.In addition, a large scale true-triaxial apparatus equipped with a pair of horizontal loading plates and a medium scale triaxial and torsional shear apparatus equipped with a local deformation measurement system for hollow cylindrical specimen (with outer diamete of 20 cm, inner diameter of 16 cm and height of 30 cm) were newly introduced. Based on results from preliminary tests, their accuracy in controlling and measuring stresses and strains was confirmed.These apparatuses enabled to make comprehensive studies on anisotropy of deformation properties in the vertical and horizontal directions and their changes due to rotation of principal stress direction. Less

为了研究和模拟不同应力历史下粗粒土的力学行为，对密实砾石矩形试样（截面为23^*23 cm，高为58 cm）进行了两组三轴试验。基于一系列不同应力路径下的循环三轴试验结果，提出了单调加载条件下修正应力与应变参数之间的唯一关系。通过将该关系与新修正的滞回规律相结合，表明所提出的模型能够合理地模拟密实砾石的循环特性。根据另一系列三轴试验的结果，发现它们的蠕变特性是不可忽略的，应变率的变化对它们的单调加载特性有相当大的影响，并对砂和砾石的弹性波速进行了研究。关于丰浦 ...更多信息 砂，一次波的速度与小加速度计，设置在矩形试样的侧面被发现是一致的静态杨氏模量评估通过施加小振幅循环加载。然而，在粒径较大的砾石上，波速远高于静态评估值，这可能是由于土颗粒结构的不均匀性的影响。大型真三轴仪和中型三轴扭剪仪，前者配有一对水平加载板，后者配有空心圆柱试样局部变形测量系统（外径20 cm，内径16 cm，高30 cm）。根据初步试验结果，确认了该仪器在控制和测量应力应变方面的准确性，能够全面研究垂直方向和水平方向变形特性的各向异性及其随主应力方向旋转而发生的变化。少

项目成果

Balakrishnaiyer,K.,Koseki,J.: "Modeling of stress-strain relationships of a reconstituted gravel subjected to large cyclic loading"Proc. of 3rd Japan-UK Workshop on Implications of Recent Earthquakes on Seismic Risk. 105-114 (2000)

Balakrishnayer，K.，Koseki，J.：“模拟大循环荷载下的再生砾石的应力-应变关系”Proc。

Ogata,T.,Kurachi,Y. ほか: "In-situ horizontal loading tests on gravelly subsoil and their numerical simulations"Proc.of 2nd International Symposium on Pre-failure Deformation Characteristics of Geomaterials. Vol.1. 379-386 (1999)

Ogata, T., Kurachi, Y. 等：“砾石地基土的原位水平加载试验及其数值模拟”，第二届岩土材料破坏前变形特征国际研讨会论文集，第 1 卷，第 379-386 卷。 (1999)

Santucci de Magistris, F.,Koseki, J. ほか: "A triaxial testing system to evaluate stress-strain behaviour of soils for wide range of strain and strain rate"Geotechnical Testing Journal. 22. 44-60 (1999)

Santucci de Magistris, F., Koseki, J. 等人：“用于评估大范围应变和应变率下土壤应力应变行为的三轴测试系统”《岩土工程测试杂志》22. 44-60 (1999)。

Dan,L.Q.A.ほか: "Anisotropy in elastic deformation properties of a dense gravel" 土木学会第53回年次学術講演会講演概要集. 第3部(B). 790-791 (1998)

Dan, L.Q.A. 等人：“致密砾石的弹性变形特性的各向异性”日本土木工程师学会第 53 届学术年会摘要第 3 部分 (B) (1998)。

Balakrishnaiyer,K.,古関潤一: "Modified stress-strain state parameter for representing small strain deformation characteristics of dense gravel"第35回地盤工学研究発表会発表講演集. 313-314 (2000)

Balakrishnayer, K.，Junichi Koseki：“用于表示致密砾石小应变变形特征的修正应力-应变状态参数”第 35 届岩土工程研究会议论文集 313-314 (2000)。