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Behavior of seepage pore-water pressure and its influence on slope stability in embankment by rainfall

降雨渗流孔隙水压力行为及其对路堤边坡稳定性的影响

基本信息

批准号：
13650552
负责人：
NARITA Kunitomo
金额：
$ 0.9万
依托单位：
Aichi Institute of Technology (A.I.T.)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650552/
关键词：
Centrifuge Model Test Seepage by Rainfall Pore Water Pressure Saturated Zone Slope Failure Saturated-Unsaturated Seepage Seepage Properties of Unsaturated Soil 遠心模型型実験

项目摘要

The behavior of seepage flow developed in an embankment due to rainfall and its associated features of extension of the saturated wet zone and those of pore-water pressure development, which promotes instability of slopes., were studied in this research project. Centrifuge seepage tests were conducted on several model fills, in which small size measuring devices of pore-water pressure were installed in matrix, by use of a device which can supply a uniform and constant strength of rainfall over the slope surface. Finite element unsteady saturated-unsaturated seepage analyses were made on the prototype of the model fill for the same rainfall conditions as adopted in the tests. Concluding remarks drawn from the present study are summarized in the following.(1)Seepage behavior due to rainfall is strongly affected by the intensity of rain r, and the permeability k, inclination of slope and the initial moisture of the fill ; Extension of the saturated wet zone is controlled by the difference … More of seepage water flowing in and out from the fill.(2)During rainfall, the front face of the wet zone gradually falls down from the slope surface, making the saturated wet zone at the toe, and it enlarges from the toe to the interior of embankment as the time elapses.(3)A sign of slope failure and the reduction of safety factor were confirmed in the test at the total amount of about 150mm and the intensity of 30mm/h of rainfall, which is often experienced in the past case histories of slope failure.(4)Extension of the saturated wet zone and reduction of safety in the fill are largely dependent on the initial moisture ; in the fill having high initial moisture, like a fill which has experienced a long-term rainfall beforehand, enlargement of the saturated wet zone and corresponding reduction of safety are remarkably fast and intensive in an early stage of rainfall.(5)The influence of rainfall seepage on slope stability is rather small for fills with a moderate slope, even if extension of the saturated wet zone is remarkable, because they have essentially higher safety in slope stability.(6)As for centrifuge testing method on moisture and permeability of unsaturated soils, the procedure using centrifuge test together with 1G test is verified to be much advantageous because centrifuge acceleration applied in the test made the drainage process faster and realized a considerably large reduction of the test period, and because successive measurement was satisfactorily done in a fairly wide range from saturated state to a state of low moisture content. Less

由于降雨，路堤中的渗流行为以及与之相关的饱和湿区扩展和孔隙水压力发展特征，促进了边坡的失稳。在这个研究项目中进行了研究。利用一种能在坡面上提供均匀、恒定降雨强度的装置，在模型填土中安装了小型孔隙水压力测量装置，进行了土柱渗流试验。在相同的降雨条件下，对模型填土原型进行了非稳定饱和-非饱和渗流有限元分析。本研究的结论总结如下。（1）降雨强度r、渗透系数k、边坡坡度和填土初始含水量对降雨渗流特性有很大影响，饱和湿带的扩展受降雨强度r、渗透系数k、边坡坡度和填土初始含水量的差异控制。 ...更多信息渗流水从填充物中流入流出。（2）降雨过程中，湿带前缘从坡面逐渐向下福尔斯，使坡脚处的湿带饱和，随着时间的推移，湿带从坡脚向路堤内部扩大。(3)A在降雨总量约150 mm、降雨强度为30 mm/h的条件下，试验证实了边坡失稳的迹象和安全系数的降低，这在以往的边坡失稳案例中是常见的。（4）填土中饱和湿区的扩大和安全性的降低在很大程度上取决于初始含水量，在初始含水量较高的填土中，如经历过长期降雨的填土，在降雨初期，饱和湿区的扩大和相应的安全性的降低是非常迅速和强烈的。（5）对于中等坡度的填土，即使饱和湿带扩展显著，降雨渗流对边坡稳定性的影响也很小，因为它们具有更高的边坡稳定安全性。(6)As对于非饱和土水分和渗透性的离心试验方法，由于离心加速度的作用使排水过程加快，试验周期大大缩短，并且因为在从饱和状态到低水分含量状态的相当宽的范围内令人满意地进行连续测量。少