Investigation of Soil-water Coupled Behavior of Saturated Clay near/at Critical State and Its Application to Deformation and Failure Problems

饱和粘土近/临界状态的土水耦合行为研究及其在变形和破坏问题中的应用

• 批准号: 06452267
• 负责人: ASAOKA Akira
• 金额: $ 4.1万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06452267/
• 关键词: Load Controlled Test; Bifurcation; Finite Element Method; Undrained Creep; Progressive Failure; Finite Deformation Theory; Cam-clay Model; Pore Water Migration; 三軸圧縮試験; 飽和粘土; 3軸圧縮試験; 非線形問題; 破壊; 間隙水のマイグレーション

In order to investigate "time dependent behavior" of normally consolidated/overconsolidated clay, triaxial compression tests and the soil-water coupled analysis employing the sub-loading surface Cam clay model have been carried out. The bifurcation analysis can explain "time dependent behavior" of clays by using pore water migration effect instead of visco-plasticity. The triaxial compression tests carried out in this research showed that : 1) Undrained creep failure occurs due to the change of 1^<st> failure mode to 2^<nd> mode of soil specimen that associated with pore water migration. 2) Overconsolidated clay exhibits progressive failure under constant loading in drained condition due to the absorbed water during testing. It took about 6 hours for the failure of overconsolidated clay specimen. The progressive failure is observed with the fluctuations of axial strain rates against axial strain.Imperfection-sensitive bifurcation of a plane strain saturated soil column with undrained b … More oundaries is investigated by soil-water coupled finite deformation analysis. An initial cosine-curve geometrical imperfection of 2nd mode is applied to the soil specimen. The linear constraint conditions, "no angle change and no direction change" are imposed over the loaded boundary. The soil is assumed to follow the sub-loading surface Cam-clay model. When the load application to the specimen is held at a point near the bifurcation point, load displacement curve starts to deviate from the main path, ultimately approaching unstable 1st mode path. This mode switching due to pore-water migration after the peak in load-displacement curve, that yield low undrained shear strength describes the undrained creep, which is traditionally attributed to visco-plasticity. Similar to the experiment, the increase in axial strain rate against axial strain in heavily overconsolidated soil specimen when the applied load is kept constant, illustrates the initiation of progressive failure due to softening in the highly sheared zones. Less

为了研究正常固结/超固结粘土的“时间依赖特性”，进行了三轴压缩试验和采用次加载面Cam粘土模型的土-水耦合分析。分岔分析可以用孔隙水迁移效应代替粘塑性来解释粘土的“时间依赖行为”。本研究开展的三轴压缩试验表明：1)不排水蠕变破坏是由于土样的1^<st>破坏模式转变为与孔隙水迁移相关的2^<和>破坏模式。2)在排水条件下，超固结粘土受试验过程中吸水的影响，在恒定荷载作用下呈现渐进式破坏。超固结黏土试件的破坏时间约为6小时。随着轴向应变率随轴向应变的波动，可以观察到渐进式破坏。采用土-水耦合有限变形分析方法，研究了不排水饱和土柱平面应变的缺陷敏感分岔问题。将二阶模态的初始余弦曲线几何缺陷应用于土样。在加载边界上施加“无角度变化和无方向变化”的线性约束条件。假定土体遵循次加载面-粘土模型。当对试件施加的荷载保持在分岔点附近时，荷载位移曲线开始偏离主路径，最终接近不稳定的第一模态路径。这种模式切换是由于荷载-位移曲线峰值后的孔隙-水迁移，产生低不排水抗剪强度，描述了传统上归因于粘塑性的不排水蠕变。与试验结果相似，在荷载保持不变的情况下，重度超固结土试件的轴向应变速率相对于轴向应变的增加说明了高剪切区由于软化而开始的渐进式破坏。少

项目成果

浅岡 顕 他1名: "Effects of pore water migration on the ultimate behaviour of Soils" Proccedings of 5th international Symposium on Plasticity and lts Current Application(IS' HIROSIMA),JSSFME. 1. 407-410 (1995)

Ken Asaoka 等 1 人：“孔隙水迁移对土壤最终行为的影响”第五届国际塑性研讨会论文集及其当前应用（IS HIROSIMA），JSSFME 1. 407-410（1995）。

浅岡 顕 他2名: "Soil-water coupled behavior of heavily overconsolidated clay near/at critical state" Soils and Foundations. (1996)

Ken Asaoka 和其他 2 人：“接近/临界状态下严重超固结粘土的土水耦合行为”《土壤与基础》（1996 年）。

浅岡 顕 他3名: "飽和土の「非排水クリープ」の1考察" 第31回地盤工学研究発表会. (1996)

Ken Asaoka 等 3 人：“饱和土中不排水蠕变的研究”第 31 届岩土工程研究会议（1996 年）。

浅岡 顕 他2名: "Soil-Water coupled Behaviour of Saturated Clay near/at Critical State" Vol.34 No.1. 91-105 (1994)

Ken Asaoka 和其他 2 人：“临界状态附近饱和粘土的水土耦合行为”Vol.34 No.1 (1994)。

AKIRA ASAOKA and TOSHIHIRO NODA: "Imperfection-sensitive bifurcation of Cam-clay under plane strain compression with undrained boundaries" Soils and Foundations. Vol.35, No.1. 83-100 (1995)

AKIRA ASAOKA 和 TOSHIHIRO NODA：“在不排水边界的平面应变压缩下 Cam-clay 的不完美敏感分叉”土壤和基础。