Hysteresis Effect of Water Retention and Permeability of Unsaturated Soils on Instability of Slope Due to Rainfall

非饱和土保水性和渗透性对降雨导致边坡失稳的滞后效应

• 批准号: 10660227
• 负责人: SHIMADA Kiyoshi
• 金额: $ 1.79万
• 依托单位: Tokyo University of Agriculture & Technology (1999)Okayama University (1998)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660227/
• 关键词: Slope Stability; Rainfall; Water Retention Curve; Hysteresis; Earthquake; Numerical analysis; 不飽和透水係数

The test for hysteresis of water retention curve and that for unsaturated permeability were carried out on Masa soils produced in Okayama. The effect of the unsaturated properties of slope soils on the reduction behavior of the safety factor is examined with the numerical program of the slope stability analysis considering the reduction of the shear strength of unsaturated soils due to the rain infiltration. The numerical program is also improved for considering both the effect of the rain infiltration and that of an earthquake on the slope stability. The numerical results give the following conclusions.(1) The hysteresis of the relationship between the volumetric water contents and the relative permeability can be neglected.(2) The safety factor of a slope, whose soil has the water retention curve showing a small magnitude near saturation, can show the sudden drop due to rain infiltration.(3) The test obtaining the water retention curve should be carried out under absorbing condition, when the results are supposed to be applied to the instability problem due to rain infiltration.(4) The slope suffering from the rain infiltration becomes more unstable when the earthquake strikes the slope.

对产自冈山的Masa土进行了持水曲线滞后和非饱和渗透性试验。利用考虑降雨入渗降低非饱和土抗剪强度的边坡稳定性分析数值程序，研究了非饱和土性质对边坡安全系数降低的影响。同时，对数值计算程序进行了改进，使其能同时考虑降雨入渗和地震对边坡稳定性的影响。数值结果给出了以下结论。(1)体积含水率与相对渗透率之间的滞后关系可以忽略不计。(2)当土体的持水曲线在饱和状态附近呈小幅值时，边坡的安全系数可表现为降雨入渗后的突然下降。(3)当研究结果应用于降雨入渗引起的不稳定性问题时，获得水分特征曲线的试验应在吸水条件下进行。(4)地震作用下，受雨水渗透的边坡将变得更加不稳定。

项目成果

Shimada, K, H. Fujii, S. Nishimura, T. Nishiyama and T. Mrii: "Slope instability due to rainfall and earthquake"Proc. of International Synposium on Slope Stability Engineering. 1. 653-656 (1999)

Shimada、K、H. Fujii、S. Nishimura、T. Nishiyama 和 T. Mrii：“降雨和地震导致的斜坡不稳定”Proc。

Shimada,K, H.Fujii, S.Nishimura, T.Nishiyama and T.Morii: "Hysteresis effect of decomposed granite soil on slope instability due to rainfall"Proc. of 8th Congress of International Association of Engineering Geology. 3. 1981-1986 (1998)

Shimada，K，H.Fujii，S.Nishimura，T.Nishiyama 和 T.Morii：“风化花岗岩土对降雨引起的边坡失稳的滞后效应”Proc。

Shimada,K, H.Fujii, S.Nishimura, T.Nishiyama and T.Morii: "Slope instability due to rainfall earthquake"Proc. of International Symposium on Slope Stability Engineering. 1. 653-656 (1999)

Shimada，K，H.Fujii，S.Nishimura，T.Nishiyama 和 T.Morii：“降雨地震导致的斜坡不稳定”Proc。

Shimada, K, H. Fujii, S. Nishimura, T. Nishiyama and T. Morii: "Hysteresis effect of decomposed granite soil on slope instability due to rainfall"Proc. of 8th Congress of International Association of Engineering Geology. 3. 1981-1986 (1998)

Shimada、K、H. Fujii、S. Nishimura、T. Nishiyama 和 T. Morii：“风化花岗岩土对降雨引起的边坡失稳的滞后效应”Proc。

Shimada, k. h. Fujii, S, Nishimura, T. Nishiyama and T. Morii: "Hysteresis effect of decomposed granite soil on slope instability due to rainfall"Proc. Of 8th Cong. Of the Int. Association of Engineering Geology and the Environment. 3. 1981-1986 (1998)

岛田，K.