INVESTIGATION FOR NEW TEST METHOD OF WATER RETENTIVITY AND SEEPAGE OF UNSATURATED SOILS

研究结果表明，新方案中提出的土体保水性能测试方法是一项非常实用的技术。将非饱和土体的保水入渗特性应用于降雨条件下的边坡稳定问题。此外，近年来非饱和土特性在土壤污染问题中的应用也受到重视。然而，目前保水率测试方法的缺点是测试需要很长的时间。目前的测试方法需要至少几天到大约一个月或更长的测试时间。因此，实验数据并不一定是在一种情况下积累的。本研究的目的是建立一套测试方法，以便更快地将测试方法应用于土的保水性能测试中。采用了对试件连续加载吸力的新方法，并对新的试验方法进行了试错研究。结果表明，与现有的保水率测试方法相比，可以大大缩短测试时间。此外，这种新的测试方法使排水和吸水过程的反复测试成为可能，相信这项新技术和测试设备的推广将为今后非饱和土勘察的发展做出贡献。

The result of this investigation was to have clarified that the method of the new proposal for the water retentivity test of soil was a very useful technique.The characteristic of water retention and the infiltration for the unsaturated soils are applied to the slope stability problems at the rainfall. Moreover, the character of the unsaturated soil is paid to attention for application to the soil pollution problem in recent years. However, the weak point of a current testing method for water retentivity is to need very long time for the test. A current testing method needs the testing time from several days of at least to about one month or more. Therefore the experimental data is not accumulated in a situation necessarily. it is one of the causes to not become widespread of the test equipments.The purpose of this investigation is to establish the testing method to put into the water retentivity test of the soils more promptly. The new method to load the suction continuously for the specimen was adopted, and tried and erred research on the new test method was advanced. As a result, it was clarified to be able to shorten the testing time greatly compared with a current test method for water retentivity. Moreover, the examination that repeated tests for process to drain and absorption became possible in a new testing method.It is confidented that the spread of this new technique and the test equipments contributes to the development of the investigation for the unsaturated soil in the future.