Study on Lipuefation Behavior of Sandy Ground Using Online Test with Drainage Control

排水控制在线测试沙地脂化行为研究

• 批准号: 08650567
• 负责人: YAMADA Yasuo
• 金额: $ 1.34万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650567/
• 关键词: online test; drainage control; torsional shear appatus; cyclic loading; sand; liquefaction; fine content; permeability coefficient; 砂地盤; 繰返し荷重; 粗粒材料

The liquefaction behavior of sandy ground was investigated by means of the online test with drainage control based on Drecy's law, which incorporated both effects of the softening of ground due to cyclic loading and the volumetric change due to drainage. We developed a system consisting of a linear positioning table and a piston-cylinder for precise drainage control. The system was capable of direct control of volumetric strain, which reduced data scattering and improved precision in control.The tests employed a control rule in which the volumetric strain per unit time was equal to the product of a drainage coefficient and excess pore water pressure. The larger values of the drainage coefficients corresponded to the higher permeability of ground and the shorter drainage distance. A series of online tests with different drainage coefficients showed the gradual changes in shear behavior from truly undrained condition with correction for the membrance compliance to drained conditions. In … More the case of speciments subjected to relatively low accelerations under higher drainage coefficients did not liquefied. Meanwhile specimens that developed excess pore water pressure equivalent to 65 to 70 % of the effective confining stress did liquefy immediately after because insufficient drainage.The online tests were also carried out on sand specimens added with 5,10, and 15 % fines (kaolin). The resistance against liquefaction became highest in the specimens with 5 % fines, then decreased with increasing fine content. While in the case of static triaxial compression tests pure sand speciments showed the greatest strength and the shear strength decreased with increasing fine content. The static tests on the speciments with 5 % fines, however, showed the highest dilatancy ratio in the medium strain region, which might be reflected in the cyclic behavior mentioned above.A series of triaxial tests was also carried out on a gravel in order to study the effects of the maximum size and membrane compliance. Less

通过基于Drecy定律的排水控制在线试验，研究了砂土地基的液化特性，该试验同时考虑了循环荷载引起的地基软化和排水引起的体积变化的影响。我们开发了一个由直线定位工作台和活塞-气缸组成的系统，用于精确的排水控制。该系统能够直接控制体积应变，减少了数据的散布，提高了控制精度。试验采用了单位时间的体积应变等于排水系数与超孔隙水压力的乘积的控制规则。排水系数值越大，地基的渗透性越高，排水距离越短。一系列不同滤水系数的在线试验表明，剪切行为从真正的不排水状态逐渐变化到排水状态。在…中更重要的是，在较高的排水系数下受到相对较低的加速度的试件不会液化。同时，超孔隙水压力相当于有效围压的65%~70%的试件在排水不足后立即液化。在线试验也在添加5，10和15%细粉(高岭土)的砂样上进行。当细粉含量为5%时，其抗液化性能最好，然后随细粉含量的增加而降低。而在静三轴压缩试验中，纯砂的强度最大，抗剪强度随着细粒含量的增加而降低。然而，对于含有5%细粉的试件，在中等应变区的剪胀率最高，这可能反映在上述循环行为中。为了研究最大尺寸和膜柔度的影响，还在砾石上进行了一系列三轴试验。较少

项目成果

佐藤 貴史、山田 恭央、松尾 修、近藤 浩市、佐々木 哲也: "ある砂質土の残留強度特性に関するねじり単純せん断試験" 第33回地盤工学研究発表会講演集. (1998)

Takashi Sato、Yasuo Yamada、Osamu Matsuo、Koichi Kondo、Tetsuya Sasaki：“某些砂土剩余强度特性的简单扭剪试验”第33届岩土工程研究会议论文集（1998）。

K.Murayama & Y.Yamada: "Effects of maximum grain size in triaxial tests on gravel (in Japanese)" Proc.33rd.Annual Meetings of JGS. (to appear). (1988)

村山

平井 洋次、山田 恭央: "細粒分を含む砂のオンライン液状化試験" 土木学会第52回年次学術講演会概要集. III(A). 184-185 (1997)

Yoji Hirai、Yasuo Yamada：“含细粒砂的在线液化试验”日本土木工程学会第 52 届学术年会摘要 III(A)（1997 年）。

Y.Hirai & Y.Yamada: "Online liquefaction tests on sand with fines" Proc.52nd.Annual Meetings of JSCE (in Japanese). III (A). 184-185 (1997)

平井一夫

平井洋次, 山田恭央: "細粒分を含む砂のオンライン液状化試験" 土木学会第52回年次学術講演会概要集. III(A). 184-185 (1997)

Yoji Hirai、Yasuo Yamada：“含细颗粒砂的在线液化试验”日本土木工程学会第 52 届学术年会摘要 III(A)（1997 年）。