Knowledge Resource Center for Ecological Environment in Arid Area
| 兰新高铁烟墩大风区风沙灾害现状及其成因研究 | |
| 其他题名 | The present situation and cause analysis of sand-blown disaster on Lanzhou-Xinjiang High-speed Railway in Yandun gale region |
| 高扬 | |
| 出版年 | 2018 |
| 学位类型 | 硕士 |
| 导师 | 张伟民 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 兰新高铁是世界上首条穿越戈壁大风区和风沙区的高速铁路。哈密以东的烟墩大风区戈壁分布集中、地貌类型复杂，特殊的地貌和气候条件导致该区成为兰新高铁风沙灾害最严重的区域之一，风沙灾害影响路段占研究区路段全长的57%，其中K2810-K2817、K2820-K2840路段受灾最为严重，威胁到高铁的安全运营。本文以K2805-K2870路段及其附近区域为研究对象，绘制了典型沙害路段的风沙地貌专题图，通过风况观测、粒度分析、3D激光扫描和风沙流监测，摸清沙害现状和沙害成因，为风沙防治工程体系的建设提供科学基础，初步结论如下：（1）据专题图显示，受灾路段沙源地貌可分为各类沙地、戈壁和风蚀红层残丘，此三类地貌约有2.5×109 m2，占受灾路段区域面积的33.21%。通过指征划分风沙危害的程度。其中危害程度严重的K2810-K2817和K2820-K2840路段具有不同的积沙现状和特殊的下垫面类型。灾害程度严重的路段占路段全长的57%。根据风沙地貌专题图和野外调查可知，区中沙物质来源主要为季节性河流冲积物、红层风化物和人类破坏地表产生的风蚀物。（2）研究区中戈壁类型以冲洪积作用下的堆积型戈壁为主，砾石覆盖度在20-70%之间，砾石以5 cm以下的细砾为主，洪积型戈壁沙粒以细砂、中砂为主，冲积型戈壁以中砂、粗砂为主。路基边缘积沙粒径多为2 Φ以上的细砂、极细砂和粉砂，占比90%以上。表明现有的防治工程措施不足以完全阻截风沙流中的此类粒径的沙粒，对列车安全运行造成影响。（3）研究区风能强劲、大风次数多，风沙活动频繁。各月起沙风平均风速在6.62-7.75 m·s-1之间，年起沙风频率为23.12%，且风向单一，偏东风对高铁的危害最为严重，占81.21%，最大观测风速为22.66 m·s-1，大风主要集中在每年3月和8月。区中年输沙势可达336.31 VU, 春夏两季风沙活动频繁，风向变率达到0.8，输沙方向与高铁夹角为41.46°。据3D激光扫描仪对两期沙害的扫描成果，K2810-K2817路段的阻沙栅栏积沙严重，将成为风沙灾害的二次沙源。（4）戈壁地区独特的沙粒跃移特征也是致灾原因之一。兰新高铁烟墩风区戈壁沙粒跃移运动的2 m临界风速达12 m·s-1，跃移沙粒主要集中分布在距地表0-50 cm范围内，与沙质地表显著不同，沙粒跃移高度与2 m平均风速遵循指数递增规律，在7级风作用下，沙粒跃移高度可达2 m，故2 m高的阻沙栅栏不足以完全阻截戈壁风沙流。戈壁输沙通量随高度变化呈现独特的垂直分布特征，最大值出现在距地表2.5-5 cm高度处，观测得到的风沙流特征值分别为4.8和3.8，均大于1，表明戈壁风沙流处于非饱和搬运状态，仍具有较大的搬运能力。（5）目前，现有工程措施不足以完全阻截跃移沙粒进入路基以及轨道，影响高铁的正常运行。应遵照以固为主，远阻近固、固阻输导相结合，尽可能降低风速是戈壁风沙流防治的主导思想。在现有的防治工程的基础上进一步完善防沙工程体系。在防护体系外缘增设加高的阻沙栅栏，实现“远阻、降风”功能。在路基附近设置2-4条窄林带，以达到降低地表风速和控制跃移沙粒的目的。从而改变以往荒漠区风沙防治只重视工程防护措施，而忽视生物防护措施的做法，最大程度的利用本区降水、洪水及地下水等资源，营造乡土灌木防护林，进行流沙戈壁地表固定，将戈壁风沙危害降到最小程度。此外，对危害最为严重的红层路段应采取喷洒化学试剂或黏土固结技术对沙源进行固定。最终形成一个科学、合理、结合各类防沙措施的综合性防护体系。 |
| 英文摘要 | Lanzhou-Xinjiang High-speed Railway is the first high-speed railway in China to cross the gobi gale region and sandy areas. The Yandun gale region on the east of Hami city is concentrated distributed with gobi and other complex geomorphic types. The special landforms and climate make this region to be one of the most vulnerable area, accounts for 57% of the study area is affected by the blown-sand disaster, which K2810-K2817 and K2820-K2840 are the most serious afflicted. This thesis takes the K2805-K2870 section and its adjacent area as the research object, a thematic map of aeolian landform of typical blown-sand disaster section is plotted. According to wind-condition observation, particle size analysis, 3D laser scanning and wind-sand flow monitoring, the thesis ascertain the present situation and the reason of the sand-blown disaster, which could provide scientific basis for establishing a scientific and reasonable control system to prevent disaster. The following main conclusions can be drawn:（1） The thematic map of aeolian landform can show that sandy landform can be divided into various sandy land, gravel cover destroyed gobi surface and wind-erosion red strata, all of which are about 2.5×109 m2, that account for 33.21% of the area of the affected sections. Through the field investigation about the disaster indications sandy land type and sediment characteristics, the hazard degree of blown-sand disaster in the study area is divided into grades. The K2810-K2817 and K2820-K2840 sections with severely disasters have different sediment-deposition president and special underlying surface types. The classification of the blown-sand disaster can take corresponding prevention measures for different types, and extend to all the affected section of the Lanzhou-Xinjiang High-speed Railway.（2） The gobi type in the study area is dominated by the accumulation type of gobi caused by the action of flooding, the gravel coverage is between 20%-70%, the gravel is mainly fine gravel diameter under 5 cm, and the alluvial sand grains are mainly sand and medium sands, and the proluvial gobi is medium sand and coarse sand. The sand, which cause the disaster are extremely fine sand, very fine sand and the silt, of these diameters are beyond 2 Φ, account for above 90%. The existing measures of sandstorm control are not enough to intercept these sand in the wind-sand flow completely.（3） The study area with strong wind, the gale and wind-sand activity are frequent. The average sand-driving wind speed between 6.62 m·s-1 -7.75 m·s-1, the annual frequency of sand-driving wind is 23.12%, with single wind direction, the east wind accounted for 81.21%, the maximum observation wind speed is 22.66 m·s-1, strong wind mainly concentrated in March and August. Sand drift potential can reach 336.31 VU in the study area, concentrated in spring and summer, RDP/DP is 0.8, the angle between RDP and the railway is 41.46 °.（4） The unique characteristic of sand saltation in gobi is also one of the reason of disaster. The threshold velocity for saltation in a height of 2 m in the study area reached 12 m·s-1, sand in saltation was mainly transported in a surface layer of 50 cm, which is significantly different from the 0-30 cm of the sandy surface, the saltation height of sand particles increased exponentially with wind speed in the height of 2 m, and in moderate gale, sand particles could saltated to a height of 2 m, thus, the sand fence cannot fully intercept wind-blown sand over gobi may be one of the main reasons for the sand deposition on rails of the Lanzhou-Xinjiang high-speed railway in Yandun Wind District. The curve of the sand flux profile presented an elephant trunk outline, with a maximum mass flux in the heights of 2.5-5 cm, the observed eigenvalue of structure of sand flux are 4.8 and 3.8 respectively, which are greater than 1, indicating that gobi sand flux is in unsaturated handling state and still has great handling capacity.（5）The sand control engineering system should be completed on the basis of existing prevention projects. The principle of "according to local conditions and building engineering to specific damage" should be complied, and adopt the idea of “far blocking near fixing”. Heightening the sand fence, chemical sand-fixing or manual cleaning of the sand near the railway to prevent second sand disaster. The sand control in desert area by emphasizing engineering protection measures, but ignoring the measures of biological protection in the past should be altered, we should utilize the resources of rainfall and flood, create local shrub shelterbelt, fixe the surface of shifting sandy land, and reduce the wind power gobi region, minimize the damage of blown-sand disaster. |
| 中文关键词 | 兰新高铁 ; 专题图 ; 风沙灾害 ; 戈壁风沙流 |
| 英文关键词 | Lanzhou-Xinjiang High-speed Railway blown-sand disaster aeolian landform map Sand flux in gobi region |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288144 |
| 推荐引用方式 GB/T 7714 | 高扬. 兰新高铁烟墩大风区风沙灾害现状及其成因研究[D]. 中国科学院大学,2018. |
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