Study On Techniques And Its Mechanism For Controlling Sand Hazard To Highway In Different Type Regions Of Desert In China

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...