兰州大学机构库 >土木工程与力学学院
机械沙障阻固理的数值模拟研究
Alternative TitleNumerical simulation study on the mechanism of mechanical sand barrier
徐彬
Thesis Advisor黄宁
2018-05-21
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword治沙工程 防风挡沙墙 草方格 数值模拟
Abstract

随着近年来土地荒漠化的加剧,风沙流运动对农田、交通、居民点造成了严重的危害。在人类与土地荒漠化的斗争过程中,科技工作者们做了大量的工作,探索并提出了一批富有成效的防沙治沙措施。但是,目前对于这些工程措施的改进优化仍以经验为主,缺乏深入的理论支持。因此,本文通过较为先进的数值计算手段,针对目前使用广泛并且成效显著的两种防沙治沙工程措施——防风挡沙墙、草方格沙障进行深入研究,主要研究内容如下:1)调查回顾了目前针对风沙流的数值计算模型,分析并选取了较为合理易用的沙粒-沙床碰撞过程的数学模型。通过模型简化与经验性调整,提出了适用于戈壁地表的二维沙粒-戈壁碰撞过程的数学模型。在此基础上进行平坦床面风沙流数值模拟,并将结果与风洞实验进行对比,验证风沙流计算模型的可靠性。2)对沙和戈壁下垫面情况下铁路路基、带有防风挡沙墙的铁路路基、改进防风挡沙墙的铁路路基周围的风沙流情况进行数值模拟。得到了不同风速,不同路基形态下风场、水平/垂直输沙率通量、颗粒速度、颗粒粒径等信息,分析了防风挡沙墙防风防沙的机理以及后侧路基积沙的形成原因。3)对草方格周围风沙流进行数值模拟,并将部分数值模拟结果与风洞实验结果进行对比验证。通过对流向、垂向、展向输沙率的分析,评估了草方格的阻沙固沙效果,讨论了草方格内部中间低四周高的独特积蚀形态形成的原因。通过对沙粒粒径的分析,发现了草方格对大颗粒的防护效果较好。

Other Abstract

With the intensification of land desertification in recent years, the wind-blown sand flow has caused serious damage to farmland, transportation, and residential areas. In the struggle between mankind and desertification, scientists and engineers did a lot of work. They explored and proposed a number of effective measures to prevent desert expansion. However, the improvement and optimization of these engineering measures are mainly based on experience and lack of in-depth theoretical support at present. Therefore, this paper uses advanced numerical methods to conduct in-depth research on two types of sand resistance and fixation engineering measures: wind-break wall and straw checkerboard barrier, which are currently widely used and have achieved remarkable results. The main research contents are as follows:1) Reviewed the current numerical model for wind-blown sand flow, analyzed and selected a mathematical model that is reasonable and easy to use. A mathematical model for the two-dimensional sand-Gobi collision process applied to the Gobi surface was proposed through model simplification and empirical adjustment.  Based on this, the numerical simulation of the wind-sand flow on a flat sand/Gobi surface is carried out, and the results are compared with the wind tunnel experiments to verify the reliability of the wind-blown sand flow calculation model.2) The numerical simulation of the wind-blown sand flow around the railway subgrade, the railway subgrade with wind wall, and the improvement of the wind subsidence around the railway subgrade with different underlying surfaces in sand and Gobi are carried out. The wind speed, horizontal/vertical transport rate flux, particle velocity, particle size, etc. were obtained under different wind speeds and different roadbed patterns. The sand-resistance mechanism and the cause of sand accumulation on the backside of the wind-break wall were analyzed. 3) Simulate the wind-blown sand flow around straw checkerboard barriers, and some results are verified with wind tunnel experiments. By analyzing the flow, vertical and lateral sand transport rates, the effect of straw checkerboard barriers on sand resistance and fixation was evaluated, and the cause of the formation of unique erosion pattern inside the straw checkerboard barriers were discussed. Through the analysis of the sand particle size, it was found that the resistance and fixation effect of the straw checkerboard barriers on large particles is better than that of small particles.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226300
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
徐彬. 机械沙障阻固理的数值模拟研究[D]. 兰州. 兰州大学,2018.
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