摘要
在采矿、水利、交通、地质和岩土等工程中常常会遇到关于非饱和渗流的问题。由于非饱和土的特性和工程性质不再符合经典土力学的概念和原理,而且非饱和渗流深藏于地下,可预知性较差,影响因素非常复杂,对人类工程活动造成的影响巨大,因此,非饱和土渗流在各工程领域中应用问题的研究已成为日益紧迫的研究课题。本文通过数值计算和试验研究两个方面,对非饱和土的渗透规律及渗透深度与湿度关系式的确定进行了深入研究,给出了较为合理且有一定应用价值的入渗深度模拟公式,该公式的使用非常简捷方便,适合于广大工程技术人员的使用。本文的主要研究内容如下:
(1)介绍了非饱和土的基本特性以及渗流基本微分方程。在非饱和渗透理论基础之上,利用理查德兹渗透方程常用的土壤水力本构关系式,推导出土壤水土势函数及其各阶导数公式,提供给非饱和渗透数值计算使用。
(2)研究菲利普的渗透速度计算公式,在合理的无时间差分变量计算模型基础之上提出更简捷的渗透深度与含水量模拟解析公式。同时,建立一种新型的模拟公式计算法,将渗透深度与土壤含水量的函数关系(如指数、对数、幂函数等)转换为线性函数关系。然后用最小二乘法理论及相应的计算机程序模拟计算其函数关系的系数,并给出相关度较高的模拟公式。
(3)制备出非饱和渗流试验装置,测量了非饱和土壤的渗透深度,绘制出土壤的渗透深度与湿度的关系曲线,进一步阐述非饱和渗透的规律,同时,介绍了试验的原理及试验装置的操作。最后,通过测得的入渗深度数据论证得出非饱和渗透深度模拟公式是合理快捷的。
The problems of unsaturated seepage often exist in mining engineering, water conservancy project, traffic engineering, geology engineering and geotechnical engineering. The characteristics and engineering properties of unsaturated soil don’t accord with the concept and principle of the classic soil mechanics, what’s more, unsaturated seepage flow is hidden in the underground, is hard to predict, and its influence factors is too many, thus it will cause great influence to human being’s engineering activities. Therefore, the problem of unsaturated soil has become increasingly urgent research subject. This paper, by theoretical study and experiment research, in-depth researched on the infiltration law of unsaturated soil and the determination of the relational expression between penetration depth and humidity. The main contents of this paper as the follows:
(1)Described the basic characteristics of unsaturated soil and the seepage of basic differential equations. On the basis of the unsaturated infiltration theory, the soil and water potential function and their derivative formulas are deduced by Richards’s common soil hydraulic constitutive equation, offered to the unsaturated penetration numerical calculation to use.
(2)Studied Philip’s infiltration rate formula, on the basis of reasonable non-time difference variant computation model, put forward simpler simulation analytical formulas between infiltration depth and humidity, meanwhile, established a new calculation method, transform functional relation between infiltration depth and humidity (such as exponential, logarithmic, power function, and so on) into linear function. Then used the least square method and the appropriate computer program to calculate its correlation factor, and gave high degree of correlation simulating formulas.
(3)Made an unsaturated seepage equipment in order to measuring unsaturated soil infiltration depth and drawing the relational curves between infiltration depth and humidity, further elaborated the law of unsaturated seepage, at the same time, introduced the test principle and the device operation. Finally, through the measurement of infiltration depth data, this paper demonstrated and concluded that unsaturated permeability depth simulating formulas are desirable and convenient.
引文
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