【作者】 罗俊宝；

【导师】 孙保平；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2005， 博士

【摘要】 公路是沙漠地区主要的运输通道,日趋严重的风沙危害阻碍了公路的正常通行,降低了其使用效率和投资效益,影响了沙漠地区经济发展、资源开发和产业结构的调整。为了保证公路畅通,促进物流、人员的正常流动,本文依据不同沙漠类型区风沙危害严重程度的不同,通过理论分析、风洞实验、沙害路段固沙试验相结合的方法研究了公路风沙危害的防治机理及技术措施。主要研究成果如下: 针对干旱区公路风沙危害严重的特点,研究了有鳍无鳍沙障、土工方格沙障、化学固沙新方法(沙埂沙障)的固沙机理,风洞实验表明;有鳍沙袋沙障对风速有强烈的扰动作用,障后弱风区范围远远大于无鳍沙障,风速流线的发散程度随着风速的增加而减小,障后弱风区的范围随着沙障和风向夹角的增大而增大,正交时达到最大。吹蚀研究发现,在无沙源时,相同间距,有鳍沙障的固沙效能明显优于无鳍沙障,间距为50cm的带状沙障固沙效果较好。有沙源时,随着风速和带距加大,0-10cm总的输沙量都在增加,间距为50cm时,无鳍沙障的输沙量是有鳍沙障的3.8倍,间距是100cm时是10倍多,沙障间距越小、相对阻沙能力指数越大,同风速、同间距,有鳍沙障相对阻沙能力指数大于无鳍沙障。野外固沙试验结果显示,规格为1m×1m的沙袋沙障固沙效果最好。 土工方格风洞实验表明,在障前存在一个阻滞减速区,障顶有一个风速抬升区,障后有一个涡旋减速区,障中有风速加速区。沙障的透风率由零增加到20%时,平均积沙厚度的减少均保持在15.8%-19.7%之间,不论透风与否,单位沙障规格面积增大一倍,积沙厚度递减范围是16.88%-19.07%之间。 沙埂沙障随着规格的加大,障内积沙逐步减少,风洞实验表明,固化材料为40%时,沙埂沙障抗风蚀性能最强,30%稍差,从固沙成本考虑,30%比较合理。 结合以上三种固沙技术的室内外实验,经和传统固沙技术比较分析,提出了公路沙害防治的“以沙治沙、调控固沙”的观点。 干旱区公路沿线的植被恢复与重建措施可极大地增加地表粗糙度,增加了路域植被的盖度和物种多样性,可彻底根除公路沙害。 边坡防护试验表明,固化剂、土工网垫防护效果较好,边坡为1∶4时,不易积沙。 半干旱区采用黄柳活沙障预先固定流沙,然后在障中种植固沙植物的模式,植被恢复效果显著,可有效地防治公路风沙危害。经实地观测,规格为4m×4m的黄柳活沙障较为合理。 亚湿润干旱区公路路域植被管理技术措施可改善其结构,强化其防沙功能,增加了植被的物种多样性。 工程防沙体系风沙危害实验研究表明,沙障破损率与输沙量呈幂指数关系,沙障沙埋率与粗糙度呈负相关关系。更多还原

【Abstract】 The highway is the main transport passageway in the deserted region, the more servewindy and sandy hazard has blocked the normal road passageway, reduced its service efficiency and invest returns, influenced the economic development, resource development and redistribution of industrial structure in deserted area. In order to ensure the highway go unhindered and advance the normal circulation of goods and people, this paper based on different extent of windy and sandy hazard in different type of deserted area, studied the prevented and controlled principle of road windy and sandy jeopardize and technique measure though the combination of theoretical analysis, wind tunnel test and sand-fixing test in the road hazarded by desert. The main research results are showing as follow:Against at the characteristic that is the windy and sandy hazard on road is server studied the sand-fixing mechanics of sand-barrier with fin, without fin, geotechnical checkered sand-barrier and new chemical sand-fixing method (sand embankments and sand-barrier). The wind tunnel test shows that sand-bag and sand-barrier with fin have strong disturb action on wind speed. The atmosphere of weaken wind region behind the barrier is larger than the sand-barrier without fin, the divergent extent of wind streamline is reducing with the increase of wind speed, the atmosphere of weaken wind region enlarge with the enlargement of included angle between sand-barrier and wind direction, the biggest is the orthogonal intersection.The wind-erosion research finds out that the sand-fixing effectiveness of sand-barrier with fin is better than that without fin as the distance between two barriers is same and there is no sand source, the better sand-fixing effectiveness is the banding sand-barrier, the distance of which is 50cm. When there is sand source, the amount of sediment about 0-10cm is increasing with the increase of wind speed and distance between the belts. As the distance is 50cm, the amount of sediment of sand-barrier with fin is 3.8 times than that without fin, which is more than 10 times. As the distance is 100cm, the shorter of the distance between two sand-barriers, the larger of the relative index of sand distance ability. The index of sand distance ability of sand-barriers with fin is larger than that without fin as the wind speed and distance is same.The field test shows that the best result of sand-fixing result is the sand-bag and sand-barrier with the size of 1*1. Geotechnical checkered wind tunnel test shows that a blocked deceleration area existed in front of sand-barrier, there is a lifting region on the top of the barrier, and a gyred deceleration area exist behind the barrier, in the middle of barrier has wind speed acceleration. When the wind penetration degree of sand-barrierincrease from 0 to 20%, the decrease of average accumulated sand thickness keep in the atmosphere of 15.8%-19.7%, weather the barrier penetrate wind or not, the decrease atmosphere of accumulated sand thickness is from 16.88% to 19.07% as the size of sand-barrier become bigger one time. With the enlargements of sand-barrier and low bank of earth between sand lands, the accumulated sand decrease successively. Wind tunnel test are showing as follow: when the content of chemical sand-fixing material is 40%, the wind-erosion resistance function of sand embankments and sand-barrier is best, the worse is 30%, and the later is more suitable than the former, considering the cost of sand-fixing.Combined the indoor and field test of the listed three sand-fixing technique, compared and analyzed the traditional sand-fixing technique, put forward the prevented and controlled view point of road sand hazard that is "fixing sand dynamically, controlling sand with sand, making the sand-barrier regulated". The vegetation restoration and rebuild measure along the road in arid region can greatly aggravate the roughness of the surface, advance the cover degree of vegetation near the road and the species diversity, cancel the road hazard thoroughly. The side slopes prevent and control t更多还原