EXPERIMENTAL STUDIES ON THE WATER BALANCE AND THE ROLE OF PORE PRESSURE IN THE PROCESS OF SLOPE FAILURE

以降雨形式供给边坡的水渗透并储存在土层中。边坡失稳就是在这些过程中发生的。因此，从这个意义上讲，边坡失稳现象可以是土层中的水平衡问题之一。本文是以“水平衡”和“孔隙水压力”为关键词的试验研究。HIURA博士是首席研究员，他通过模型斜坡和人工降雨系统进行了研究。共同研究者凯堀博士研究了水和桑迪混合物中产生的孔隙压力的消散过程。研究结果表明：（1）边坡破坏分为两种类型：一种是在坡面径流开始之前发生的流动型破坏，另一种是在坡面径流量恒定之后发生的渐进型破坏;（2）体积含水量指标，即补给水量与降雨渗透体积的比值 ...更多信息 d土层在降雨开始后的任意时间段内的位移，表现为初期快速上升，之后趋于稳定，与土壤条件和降雨强度无关。3）边坡的地表移动表现为蠕变变形特征，虽然这种运动似乎与体积含水量和坡面径流量无关。实测超静孔隙水压力为整个土层厚度的1.5倍，但未发现孔隙水压力波动对边坡破坏的预测作用。5）人工边坡破坏时产生的超静孔隙水压力，在桑迪和水混合物中进行的搅拌试验表明，孔隙压力的消散速率取决于比粉土细的颗粒的比例。在高浓度混合物（体积密度为63%）的振动实验中，孔压在振动停止后很快消散。少

Water supplied to the slope in the form of rainfall penetrates and stored in the soil stratum. Slope failure occurs during these processes. So, in this meaning, slope failure phenomena can be one of the problems of water balance in the soil stratum. This is the experimental study whose key words are "water balance "and" pore pressure". Dr.HIURA who is the head investigator executed his study by the model slope and artificial rainfall system. Dr.KAIBORI who is the coinvestigator has examined the dissipation process of pore pressure generated in the mixture of water and sandy soil. Results obtained are summarized below ;1) Two types of failure were recognized : one is the flow type failure which occurs before the runoff from the slope begins and the other is the progressive type which occurs after the quantity of runoff water from the slope becomes constant.2) The index of volumetric water content, which is the ratio of amount of the supplied water to the volume of the rainfall penetrate … More d soil stratum at an arbitrary time interval from the beginning of the rain, shows the fast rise at the beginning and becomes constant afterwards independent of the soil condition and rainfall intensity.3) Surfacial movements of the slope showed the creep deformation characteristics, though the movements seem to have no relation to the volumetric water content and the amount of the runoff water from the slope.4) The measured excess pore pressure showed 1.5 times as much as the thickness of the whole soil stratum, though no fluctuation of pore pressure to predict the occurrence of the slope failure was observed.5) The excess pore pressure, which is produced in case of an artificial slope failure, dissipates faster than that produced in case of natural failure.6) The stirring experiments in use of sandy soil and water mixture have revealed that the dissipation rate of the pore pressure depends on the ratio of grains finer than silt.7) In case of the vivration experiment of highly concentrated mixture (63% of volumetric density) , pore pressure dissipates soon after the vivration has stopped. Less