Measurement and estimation of unsaturated moisture properties of compacted soils and its application to analyses of embankment dams.

压实土非饱和水分特性的测量和估计及其在堤坝分析中的应用。

基本信息

批准号：
03660244
负责人：
MORII Toshihiro
金额：
$ 1.34万
依托单位：
Tottori 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：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

A numerical seepage analysis which integrates both saturated and unsaturated flows can precisely predict water movement within embankment dams. The treatment of boundary surfaces such as seepage face and ground surfaces subjected to rainfall, infiltration and evaporation is easy with this approach. The finite element mesh used in the analysis remains invariant during transient flow and numerical iterations. Using the same mesh for stress analysis, it is possible to evaluate directly the effects of seepage forces and buoyancy on stresses and stability of embankment dams.Subjects focused in RESEARCH are to develop1.an efficient method for measuring moisture properties of unsaturated soils, and2.a numerical scheme for seepage and stress analysis.A measuring equipment using small-sized pressure transducers and Radio lsotope method is designed and set up in Subject 1. Laboratory experiments show that the equipment gives reliable data. Referring to published data, modeling of unsaturated conductivity based on lrmay-type equation is discussed. In the 2nd subject, a finite element method based on the concept of effective stress is developed for seepage, stress and stability analysis of dams. The procedure is applied to evaluate stability of an earthdam during reservoiring and drawdown. Numerical results show that the stability is strongly influenced by the change of principal stresses within the dam, and that the manner of this change is governed by the distribution of body force which occurs during reservoiring and drawdown.

整合饱和和不饱和流的数值渗漏分析可以精确预测路堤大坝内的水运动。通过这种方法，对边界表面（例如渗水，浸润和蒸发）等边界表面的处理很容易。分析中使用的有限元网格在短暂流动和数值迭代过程中保持不变。使用相同的网格进行压力分析，可以直接评估渗流力和浮力对堤坝大坝的应力和稳定性的影响。研究的研究是开发1.一种有效的方法来测量不饱和土壤的水分特性的有效方法。用于渗漏和应力分析的数值方案。使用小型压力传感器和无线电lSotope方法进行测量设备是在受试者1中设计和设置的。实验室实验表明，该设备提供了可靠的数据。参考已发布的数据，讨论了基于LRMAY型方程的不饱和电导率的建模。在第二个主题中，开发了一种基于有效应力概念的有限元方法，用于渗漏，应力和稳定性分析。该程序用于评估在储层和缩减过程中Earthdam的稳定性。数值结果表明，稳定性受大坝内主应力的变化的强烈影响，并且这种变化的方式受到储量和缩减期间发生的身体力的分布的控制。