Research on the Techniques of Slope Stability through an introduction of suction

引入吸力的边坡稳定技术研究

• 批准号: 08555121
• 负责人: KAWAKAMI Hiroshi
• 金额: $ 1.09万
• 依托单位: SHINSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 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-08555121/
• 关键词: SUCTION; SLOPE STABILITY; GEO-TEXTILE; CAPILLARY TENSION; VACUUM TECHNIQUE; ジオメンブレン

The negative porewater pressure (suction)exists in the natural slopes in fine day and contributes to the slope stability. In rainy days, the porewater pressure rises to the positive values and the stability of the slope may be lost. If the geo-textiles or the drainpipes with capillary membrane are embeded, negative porewater pressure may remain in the slope even on rainy days and stability of the slope can be kept. The geo-textile should have capillary tension more than 1m waterhead. According to the test results, there are no applicable materials directly. However, if a few geo-textiles are compressed together and a new geo-textile having high density is obtained, the problem will be solved. It is necessary to cover the slope surface by a sheet in order to keep the textile-end dry. When vacuum pressure applies to the backside of the sheet, slope surface is pressed by the atmospheric pressure and slope stability increase. Moreover, the soils of the slope may change to unsaturated condition.According to the triaxial tests, the strength of the soils increases due to consolidation of vaccum pressure and due to occurrence of unsaturated condition. Strength increase ratio reaches to 10%. It is necessary to arrange the geotextiles in order to introduce vacuum pressure into the slope.

天然边坡在晴天时存在负孔隙水压力（吸力），对边坡的稳定性有一定的贡献。在雨天，孔隙水压力上升到正值，边坡可能失去稳定性。在边坡中埋设土工布或毛细膜排水管，即使在雨天也能保持负孔隙水压力，保持边坡的稳定。土工织物的毛管张力应大于1m水头。根据测试结果，没有直接适用的材料。然而，如果将几个土工织物压缩在一起，并获得具有高密度的新土工织物，则该问题将得到解决。为了保持织物端部干燥，需要用片材覆盖斜坡表面。当真空压力施加到片材的背面时，斜坡表面被大气压力挤压，并且斜坡稳定性增加。三轴试验结果表明，由于真空压力固结和非饱和状态的出现，边坡土体的强度增加。强度增长率达到10%。为了将真空压力引入边坡，需要布置土工织物。