非胁迫条件下埋深对潜水蒸发影响机理研究

发布时间：2018-06-02 17:42

本文选题：埋深 + 风速　；参考：《合肥工业大学》2017年硕士论文

【摘要】：近些年,国内外对潜水蒸发影响因素及影响机理进行了相关的研究,但是多数只在宏观上给出了潜水蒸发与土质及埋深的关系,鲜有研究不同潜水埋深和有、无风的影响下(即不同空气流通情况下)土壤含水量的分布特征及分布机理。本文选取渗透系数较小的砂土做为研究对象,研究了砂土的物理性质,设计了一个可以改变潜水位和空气流速的非胁迫潜水蒸发试验装置。在该试验中设计了两个初始条件相同的砂柱,通过改变砂柱表面的空气流速,来达到改变其表面的大气条件的目的,利用放置在试验砂柱固定埋深处的土壤温度传感器以及土壤水分传感器,收集两个砂柱固定观测点处的土壤水分和土壤温度随时间变化的数据。在试验范围内,通过对不同潜水埋深与空气流速下的数据分析认为,空气温度与空气湿度的关联性较差,而空气温度与土表温度的关联性较强,土表温度随空气温度起伏变化。通过对不同潜水埋深以及风速下的土壤温度研究得出,随着埋深不断增加,土表温度和深层土壤温度的差异性越大。在相同潜水埋深下,随着空气流速的加快,土表温度和深层土壤温度的差异性减小。通过对不同风速条件下蒸发量的对比可知,大气条件对土壤的水分分布以及水汽的运移有很大的影响作用,对于某种均匀介质而言,潜水稳定蒸发强度与空气流速在一定范围内呈正相关,但当空气流速达到一定程度时,潜水稳定蒸发强度达到极限值。基于PdV方程,通过hydrus-1D建模软件建立砂柱的土壤水热运移模型,经过相同条件下的实测值与模拟值对比,可以验证该试验中潜水蒸发量的计算是有效的。
[Abstract]:In recent years, the influencing factors and mechanism of phreatic evaporation have been studied at home and abroad, but most of them have only given the relationship between phreatic evaporation and soil quality and burial depth. The distribution characteristics and mechanism of soil water content under the influence of wind (I. E. under different air circulation conditions). In this paper, sand with small permeability coefficient is selected as the research object, the physical properties of sand are studied, and a non-stress phreatic evaporation test device is designed, which can change the water level and air velocity. In this experiment, two sand columns with the same initial conditions were designed to change the atmospheric conditions of the sand column surface by changing the air velocity on the surface of the sand column. Using the soil temperature sensor and the soil moisture sensor placed in the fixed buried depth of the test sand column, the data of soil moisture and soil temperature change with time at two fixed observation points of sand column were collected. In the range of test, through the analysis of the data under different diving depth and air velocity, it is concluded that the correlation between air temperature and air humidity is not good, but the correlation between air temperature and soil surface temperature is stronger, and the soil surface temperature varies with air temperature fluctuation. Through the study of soil temperature under different depth of groundwater and wind speed, it is concluded that the difference between soil surface temperature and deep soil temperature is greater with the increasing of buried depth. Under the same diving depth, the difference between soil surface temperature and deep soil temperature decreases with the acceleration of air velocity. The comparison of evaporation under different wind speeds shows that atmospheric conditions have a great effect on soil moisture distribution and water vapor migration. The steady evaporation intensity of phreatic water is positively correlated with the air velocity in a certain range, but when the air velocity reaches a certain degree, the evaporation intensity reaches the limit value. Based on PdV equation and hydrus-1D modeling software, the soil hydrothermal transport model of sand column is established. By comparing the measured values with the simulated values under the same conditions, it can be verified that the calculation of phreatic evaporation in this experiment is effective.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152.7

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