KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 巴楚—莎车高速公路路面风沙危害形成机制及防治对策研究 | |
| Alternative Title | The mechanism of wind-blown sand deposition and sand prevention measures of Bachu-Shache expressway |
| 王翠 | |
| Subtype | 博士 |
| Thesis Advisor | 雷加强 |
| 2020-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 沙漠高速公路 mechanism of wind-blown sand deposition 护栏结构 sand prevention systems 沙害机制 沙害防治 desert expressway guardrail types |
| Abstract | 沙漠高速公路较低等级公路来说，普遍存在路基高、路面宽、公路安全设施等级高等特点，这些特点的综合作用减弱了道路断面的输沙能力，导致沙漠高速公路出现新的沙害问题。针对目前工程实际情况，本文以巴楚—莎车高速公路为例，探究沙漠高速公路路面风沙危害形成机制及其沙害防治措施。论文采用野外调研、室内风洞试验与野外测试相结合的方式， 对巴楚—莎车高速公路风沙环境致灾能力和公路沙害程度进行了评价，测定了公路路基高度、边坡坡度和不同护栏组合形式对流场、风沙流结构及其积沙形态的影响， 通过沙粒受力分析阐明路面沙害机制， 最终提出巴楚—莎车高速公路沙害防治对策。 研究结果表明：（1）巴楚—莎车高速公路沿线年输沙势属低风能环境，地貌类型流动沙漠区 28.84km、戈壁荒漠区 112.78km、绿洲农田区 91.98km，沙害严重路段占路线总长度的 1.46%， 沙害中度路段占 7.48%， 沙害轻度路段占 39.20%， 无沙害路段占 51.86%。（2） 道路断面对气流水平速度的影响主要表现为气流在迎风坡坡脚、路面和背风侧坡脚呈现三个风速减弱区，路基横断面对流场的影响可以分为四个区：外流区、尾流区、恢复区和涡流区。波形护栏对流场的作用特点为护栏下部的正向喷射与护栏后方的反向流相遇，气流附着点在护栏后侧 2.5-5H。混凝土护栏为密实结构，气流在栅栏前抬升剧烈，无喷射流，在护栏前后均有涡流区。缆索护栏喷射流为护栏后侧的主要气流，气流在护栏后侧动能减弱不显著，随着缆索护栏上方附着气流的下沉混合和动量交换，气流逐步恢复加强。路基和护栏对风沙流结构的影响主要表现为路基上方风沙流结构呈现出的“象鼻效应”和护栏阻挡引起护栏正后方输沙通量的减少，护栏对气流的抬升导致护栏上方垂直沙通量的增加，其中以混凝土护栏作用最为显著，缆索护栏影响最小。路基影响下迎风坡和背风坡坡脚是沙粒沉降的主要部位。波形护栏中央隔离带背风侧的超车带上容易积沙，积沙呈条带状分布，积沙厚度与沙通量预测值较为一致， 混凝土护栏积沙主要发生在护栏的前面，护栏前方为风沙沉降首发区，且沉降体积会不断增加，护栏背风侧也会形成少量积沙体，积沙量远少于护栏迎风侧底部。沙漠高速公路较低等级公路来说，普遍存在路基高、路面宽、公路安全设施等级高等特点，这些特点的综合作用减弱了道路断面的输沙能力，导致沙漠高速公路出现新的沙害问题。针对目前工程实际情况，本文以巴楚—莎车高速公路为例，探究沙漠高速公路路面风沙危害形成机制及其沙害防治措施。论文采用野外调研、室内风洞试验与野外测试相结合的方式， 对巴楚—莎车高速公路风沙环境致灾能力和公路沙害程度进行了评价，测定了公路路基高度、边坡坡度和不同护栏组合形式对流场、风沙流结构及其积沙形态的影响， 通过沙粒受力分析阐明路面沙害机制， 最终提出巴楚—莎车高速公路沙害防治对策。 研究结果表明：（1）巴楚—莎车高速公路沿线年输沙势属低风能环境，地貌类型流动沙漠区 28.84km、戈壁荒漠区 112.78km、绿洲农田区 91.98km，沙害严重路段占路线总长度的 1.46%， 沙害中度路段占 7.48%， 沙害轻度路段占 39.20%， 无沙害路段占 51.86%。（2） 道路断面对气流水平速度的影响主要表现为气流在迎风坡坡脚、路面和背风侧坡脚呈现三个风速减弱区，路基横断面对流场的影响可以分为四个区：外流区、尾流区、恢复区和涡流区。波形护栏对流场的作用特点为护栏下部的正向喷射与护栏后方的反向流相遇，气流附着点在护栏后侧 2.5-5H。混凝土护栏为密实结构，气流在栅栏前抬升剧烈，无喷射流，在护栏前后均有涡流区。缆索护栏喷射流为护栏后侧的主要气流，气流在护栏后侧动能减弱不显著，随着缆索护栏上方附着气流的下沉混合和动量交换，气流逐步恢复加强。路基和护栏对风沙流结构的影响主要表现为路基上方风沙流结构呈现出的“象鼻效应”和护栏阻挡引起护栏正后方输沙通量的减少，护栏对气流的抬升导致护栏上方垂直沙通量的增加，其中以混凝土护栏作用最为显著，缆索护栏影响最小。路基影响下迎风坡和背风坡坡脚是沙粒沉降的主要部位。波形护栏中央隔离带背风侧的超车带上容易积沙，积沙呈条带状分布，积沙厚度与沙通量预测值较为一致， 混凝土护栏积沙主要发生在护栏的前面，护栏前方为风沙沉降首发区，且沉降体积会不断增加，护栏背风侧也会形成少量积沙体，积沙量远少于护栏迎风侧底部。 |
| Other Abstract | Compared with secondary and sub-secondary highways, desert highways aregenerally characterized by high roadbed and more guardrail facilities, which weakenthe sand-transport capacity and lead to new sand-damage problems on deserthighways. In view of the actual situation of the project, this paper takes the BachuShache expressway as an example to explore the causes of sand damage and sandprevention measures of the desert expressway. By combining field investigation, fieldtest and wind tunnel test, this paper explores the influence of subgrade height, slopegradient and different guardrail combination forms on flow field, wind-sand flowstructure and the forms of sand deposition, through the stress analysis of sand grainsto clarify the sand deposition mechanism on pavemen. Finally, this paper put forwardthe comprehensive prevention and control countermeasures of Bachu-Shache highway.The results show that:（ 1） The meteorological condition along the Bachu-Shache expressway is in alow wind energy environment. The length of moving desert along the highway is in28.84 km, the gobi desert area is in 112.78 km, and the oasis farmland area is in 91.98km. A total length of 66.47 km of sand control system is constructed. The length ofwind-blown sand disaster of severe, moderate, mild and no sand damage were 1.46%,7.48%, 39.20% and 51.87%, respectively.（ 2） The influence of road cross-section on the horizontal velocity of airflow ismainly manifested in three wind velocity weakening zones at the foot of windwardslope, road surface and leeward slope. The influence of subgrade cross-section on theflow field can be divided into four zones: outflow zone, wake zone, recovery zone andeddy zone.The characteristics of the W-beam guardrail in the flow field are that thelower air jet zone meets the reverse flow behind the W-beam guardrail, and the airattachment point is between 2.5H to 5H behind the guardrail.The concrete guardrail isa dense structure, the air flow in front of the fence lifts violently, no jet flow appears,there are vortex areas in windward and leeward of the guardrail.The jet flow of thecable guardrail is still the main airflow on the leeward side of the guardrail, and theairflow loses momentum on the leeward side of the guardrail. With the momentumexchange of the airflow attached above the cable guardrail, the airflow gradually recovers and strengthens. The sand flow structure affected by roadbed and guardrailsmainly presented the "trunk effect" and guardrails blocking causes the decrease ofsediment flux behind the guardrals, uplift of the guardrail on airflow lead to increaseof the vertical sediment flux above the fence, of which the concrete guardrail affectssignificantly, and cable guardrail affects little. Under the influence of roadbed, the feetof windward slope and leeward slope are the main parts of sand settlement. The sanddeposition is easy to accumulate on overtaking lane in the leeward side of W-beamcentral guardrails, the thickness of sediment deposition is relatively consistent withthe sediment flux prediction. The sand deposition affected by concrete guardrail ismainly in the front of the fence, and the sand sediment will increase, guardrailsleeward side is close to the fence also can form many sands, sediment deposition is farless than the bottom of the fence windward.(3) The wind field characteristics of the wind tunnel test under the influence ofthe subgrade and the median W-beam guardrails on the Bachu-Shache expressway arerelatively consistent. The simulation of the structural characteristics of the sand flowis quite different from the field test results due to the shrinkage of the model.(4) As increasing with the thickness of sand deposition, the pavement skidresistance coefficient first decreases and then increases with the pavement thickness.When the pavement thickness is below 0.2cm, the pavement skid resistancecoefficient decreases with the increase of the pavement thickness; when the pavementthickness is above 0.2cm, the pavement skid resistance coefficient increases with theincrease of the pavement thickness.(5) On the premise of satisfying the linear and structural construction of theexpressway, the height of the embankment on the desert expressway should bereduced as far as possible, and the slope should be moderately reduced. Guardrailstructure sparse structure should be greater than 0.6, the cable guardrail is anappropriate type. Based on the comprehensive consideration of the disaster-causingcapacity and the current status of hazards along the highway of this project, theoptimization scheme of the sand control system is proposed for the severe andmoderate sand damage sections, and the closure and restoration measures areproposed for the sections suitable for biological sand control systems. |
| Subject Area | 自然地理学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15477 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 王翠. 巴楚—莎车高速公路路面风沙危害形成机制及防治对策研究[D]. 北京. 中国科学院大学,2020. |
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