求取现场黄土饱和渗透系数的双环入渗法

发布时间：2018-06-02 15:16

本文选题：饱和渗透性 + 土水特征曲线　；参考：《水科学进展》2017年04期

【摘要】：土体渗透性参数的测定是解决与水有关的岩土工程问题的关键所在。为使现场原状土体饱和渗透系数的测定更为准确,通过一种易于安装和固定的防蒸发型双环入渗仪,研究黄土的入渗规律与特点,试验结果表明:黄土的入渗分区可分为饱和区、湿润区与干土区,其中饱和区的入渗深度约占总入渗深度的1/2,而湿润区土体的饱和度在70%以上,这一特征与Green-Ampt入渗模型的假设较为接近,但在应用基于Green-Ampt模型的规范法(SL237-042—1999)求取黄土的饱和渗透系数时,发现该法会高估黄土的饱和渗透系数。因此,结合Green-Ampt入渗模型与土水特征曲线主要增湿路径的特点,提出了能合理测定现场黄土饱和渗透系数的双环入渗法,对GreenAmpt入渗模型参数加以修正,即直接采用干土区的初始基质吸力水头值,且该值由张力计实测或由主要增湿曲线求得;需采用入渗试验前期的平均入渗率;所对应的湿润锋发展深度需经由水分传感器实测而得。研究结果表明该法能合理估算现场黄土的饱和渗透系数。
[Abstract]:The determination of soil permeability parameters is the key to solve geotechnical engineering problems related to water. In order to make the measurement of saturation permeability coefficient of undisturbed soil more accurate, the infiltration law and characteristics of loess are studied by a kind of evaporation-proof double-ring infiltration instrument which is easy to install and fix. The results show that the infiltration zone of loess can be divided into saturated zone, wetted zone and dry soil area. The infiltration depth of saturated area accounts for about 1 / 2 of the total infiltration depth, and the saturation of soil in wetted area is more than 70%. This characteristic is close to the assumption of Green-Ampt infiltration model, but it is found that the saturated permeability coefficient of loess can be overestimated by this method when we use the Green-Ampt model based canonical method to calculate the saturated permeability coefficient of loess (SL237-042-1999). Therefore, according to the characteristics of Green-Ampt infiltration model and the main humidification path of soil-water characteristic curve, a two-ring infiltration method which can reasonably measure the saturation permeability coefficient of loess in situ is put forward, and the parameters of GreenAmpt infiltration model are modified. That is to say, the initial matrix suction head of dry soil is directly used, which is measured by the tensor or obtained from the main humidification curve, and the average infiltration rate in the early stage of the infiltration test should be used. The corresponding development depth of wetting front needs to be measured by water sensor. The results show that this method can reasonably estimate the saturation permeability coefficient of loess in situ.
【作者单位】：长安大学西部矿产与地质工程教育部重点实验室;山西交通职业技术学院;
【基金】：国家重点基础研究发展计划(973计划)资助项目(2014CB44701) 国家自然科学基金资助项目(41272283)~~
【分类号】：S152.7

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