Research on the Method of Determining Unsaturated Soil Hydraulic Properties by In-Situ or Laboratory Tests

现场或室内试验测定非饱和土水力特性方法的研究

• 批准号: 01550390
• 负责人: NISHIGAKI Makoto
• 金额: $ 1.28万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550390/
• 关键词: Unsaturated Soil; Hydraulic properties; Laboratory Test; In-situ-Test; Ground water; 浸透; 逆解析

Knowledge of unsaturated soil hydraulic properties is an essential requirement for prediction of flow and contaminant transport through the vadose zone. It is, however, difficult to obtain unsaturated soil hydraulic properties. Because the method of determining unsaturated soil hydraulic properties is not yet established and there are few data accumulation for Japanese soils. In this research, some new methods to determine unsaturated soil hydraulic properties are investigated. The results obtained in this research are as follows :1. A new method of estimating unsaturated soil hydraulic properties from pF tests in the laboratory or in-situ pumping test data is proposed. In this method a nonlinear least squares algorithm incorporating finite element analysis of non-steady saturated-unsaturated seepage flow is used. The advantages of the proposed method are in the possibility of identifying the optimal unsaturated soil hydraulic properties and diminishing experimental time.2. Soil hydrau … More lic properties are assumed to be represented by van Genuchten's closed-form expressions involving five unknown parameters. These unknown parameters allow great flexibility in the shaped of the hydraulic functions. Therefore when these functions are determined, the cumbersome handling of unsaturated soil hydraulic properties data in models of unsaturated flow can be avoided.3. The proposed method for pumping test data is applicable to the examples of pumping test data which are measured by a hypothetical unconfined aquifer model in the laboratory experiments. Predicted the saturated conductivity and unsaturated soil hydraulic properties are compared with independently determined hydraulic properties for the same soil. Good agreement is found.4. Pressure head data in pF test are measured to judge the equilibrium state of the gravity drainage. Water content versus time measurements are used to estimate three unknown coefficients in the van Genuvhten's expressions. This procedure is applied to Toyoura sand and decomposed granite soil. Less

对非饱和土壤水力性质的了解是预测渗流区水流和污染物运移的基本要求。然而，很难获得非饱和土壤的水力特性。由于确定非饱和土壤水力性质的方法尚未建立，日本土壤的数据积累也很少。本研究探讨了一些确定非饱和土水力性质的新方法。研究结果如下：1.提出了一种根据室内PF试验或现场抽水试验资料估算非饱和土水力性质的新方法。该方法采用非线性最小二乘算法，结合了非稳定饱和-非饱和渗流的有限元分析。该方法的优点在于可以确定最佳的非饱和土水力性质，缩短了试验时间。土壤HYLU…假设更多的LIC性质由van Genuchten涉及五个未知参数的闭合形式的表达式来表示。这些未知参数使液压功能的形状具有很大的灵活性。因此，当这些函数确定时，可以避免非饱和渗流模型中对非饱和土壤水力特性数据的繁琐处理。所提出的抽水试验数据处理方法适用于室内试验中假设的无承压含水层模型所测得的抽水试验数据实例。对于同一土壤，预测的饱和导水率和非饱和土壤水力特性与独立确定的水力特性进行了比较。找到了很好的一致意见。通过测量PF试验中的压头数据来判断重力排水的平衡状态。水分随时间的测量被用来估计van Genuvhten公式中的三个未知系数。此程序适用于Toyoua沙土和分解的花岗岩土壤。较少

项目成果

竹下祐二、西垣誠、河野伊一郎: "不圧帯水層での揚水試験結果による不飽和浸透特性の算定方法" 土質工学会論文報告集.

Yuji Takeshita、Makoto Nishigaki、Iichiro Kono：“基于无承压含水层抽水试验结果计算非饱和渗流特性的方法”日本土壤工程学会论文集。

Iichiro Kohno,Makoto Nishigaki and Yuji Takeshita: "Determination of Unsaturated Soil Hydraulic Properties by Transient Flow Experimcnts and Parameter Estimation" Memoirs of the Faculty of Engineering,Okayama University. Vol.24,No.1. 107-114 (1989)

Iichiro Kohno，Makoto Nishigaki和Yuji Takeshita：“通过瞬态流实验和参数估计确定非饱和土的水力特性”冈山大学工学部回忆录。

Mokoto NISHIGAKI: "A Study on the method of In-situ Permeability Test for Unsaturated Soils." Proceedings of the 45th Annual Conference of the Japan Society of Civil Engineers. 3. 185-190 (1990)

Mokoto NISHIGAKI：“非饱和土原位渗透性测试方法的研究”。

西垣 誠: "原位置における不飽和領域の透水試験法に関する考察" 土木学会 第45回年次学術講演会 講演概要集. 第3部. 838-839 (1990)

Makoto Nishigaki：“非饱和区域原位渗透率测试方法的考虑”第 45 届学术年会，日本土木工程师学会，演讲摘要第 3 部分。838-839 (1990)。

西垣 誠: "原位置における不飽和土の透水係数の測定法" 第26回土質工学研究発表会.

西垣诚：《原位非饱和土导水率测量方法》第26届土壤工程研究会议。