Study on landslide mechanism and mechanical property of clay due to large deformation

大变形滑坡机制及粘土力学特性研究

• 批准号: 11650502
• 负责人: OHTSUKA Satoru
• 金额: $ 2.3万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650502/
• 关键词: Landslide; Shear strength; Triaxial testing; Pore water pressure; Clay; 過圧密

Pore water pressure loading test on clay under constant deviator stress has been conducted to investigate the behavior of landslide. From the observation on soil specimen, two thresholds in pore water pressure for deformation were obtained. One was a yield point defined from the discrepancy from the swelling line in the void ratio and mean effective stress space. The other was a failure point where the soil specimen deforms largely and the deviator stress could not keep constant. A series of tests resulted in the yield points locating on the critical state line. At the failure point the soil specimen already got heterogeneous and deformed progressively. The soil dilated with shear due to overconsolidation and deformed with water migration. It caused the soil deformed with time for a long time. It was thought a reason for the slow failure of landslide. Numerical simulation with the Hashiguchi model well presented the soil behavior of pore water pressure loading test. It predicted the soil, which was initially overconsolidated, would get to the normally consolidated state by the repeats of pore water pressure loading. The failure point line was obtained in the void ratio and mean effective stress space for pore water pressure loading. This failure point line was empirically examined, but the effect of causes on the failure point line was still left to future stubjects. The steady state of soil after the repeats of pore water pressure loading was investigated numerically. It was found to depend on the recovery in mean effective stress. When the recovery was large, the soil would stand for larger pore water pressure loading. From the viewpoint of strain level, the ring shear test was conducted on the soil to investigate the angle for shear resistance at the residual state. The angle for shear resistance got lower with large deformation and it inspired the landslide for gentle slope.

为研究土体在恒定偏应力作用下的孔隙水压力加载特性，进行了土体孔隙水压力加载试验。通过对土样的观察，得到了孔隙水压力的两个变形阈值。一个是屈服点，由孔隙比和平均有效应力空间的膨胀线的差异来定义。另一个是土样变形较大，偏离应力不能保持恒定的破坏点。一系列试验结果表明，屈服点位于临界状态线上。在破坏点，土样已呈非均质性，并逐渐变形。土因超固结而发生剪切膨胀，因水分迁移而发生变形。长期以来造成土壤随时间的推移而变形。这被认为是滑坡缓慢失败的原因之一。Hashiguchi模型的数值模拟较好地反映了孔隙水压力加载试验的土体特性。预测了孔隙水压力加载的重复作用将使土体从最初的超固结状态恢复到正常固结状态。在孔隙水压力作用下，得到了孔隙比和平均有效应力空间的破坏点线。这条失效点线是经过经验检验的，但原因对失效点线的影响仍然留给未来的研究对象。用数值方法研究了反复孔隙水压力加载后土体的稳态特性。结果表明，这取决于平均有效应力的恢复。当回收量较大时，土体承受较大的孔隙水压力载荷。从应变水平的角度出发，对土进行环剪试验，研究土在残余状态下的抗剪角。大变形时抗剪角变小，引发缓坡滑坡。

项目成果

大塚悟: "Slope stability analysis taking into account pre-existed slip lines"Proc.of 10th Int.Conf.on the International Association for Computer Methods and Advances in Geomechanics.. 2. 1601-1604 (2001)

Satoru Otsuka：“考虑预先存在的滑移线的边坡稳定性分析”Proc.of 10th Int.Conf.on the International Association for ComputerMethods and Advances in Geomechanics.. 2. 1601-1604 (2001)

大塚悟: "Pore Water Pressure Loading Tests of A Clay"Proc.of International Symposium on Slope Stability Engineering.. 731-734 (1999)

Satoru Otsuka：“粘土的孔隙水压力加载试验”Proc.of International Symposium on Slope Stability Engineering.. 731-734 (1999)

Ohtsuka, S.& Miyata, Y.: "Slope stability analysis taking into account pre-existed slip lines"Proc.of 10th Int.Conf.on the International Association for Computer Methods and Advances in Geomechanics. Vol.2. 1601-1604 (2001)

大冢，S.

吉田宏一: "間隙水圧増加試験を用いた地すべり斜面の崩壊メカニズムに関する基礎的研究"第17回土木学会関東支部新潟会研究調査発表会論文集. 131-134 (1999)

吉田浩一：《利用孔隙水压力增加试验对滑坡边坡破坏机理进行基础研究》第17届日本土木学会关东分会新泻会议研究暨发表会议论文集131-134（1999）。

大塚悟: "Consideration on landslide mechanism based on pore water pressure loading test"Proc.of 15th International Conference on Soil Mechanics and Geotechnical Engineering. (掲載決定). (2001)

大冢悟：“基于孔隙水压力加载试验的滑坡机理思考”第15届国际土壤力学与岩土工程会议论文集（2001年出版）。