共查询到19条相似文献，搜索用时 494 毫秒
1.
测定研究了3种不同配置格局沙柳林的风速廓线梯度,得出行带式配置防风效果最好,均匀式次之,随机式最差。通过实地观测近地表输沙率和地表粗糙度,计算行带式配置中不同规格沙柳林的防护成本效益。结果表明:一行一带、带高1.5 m、带距7.5 m、插深0.5 m配置规格的行带式沙柳林防护成本效益最好,但限于15倍带高以内;行数一定的情况下,防护林带越高,防护成本效益越大。 相似文献
2.
基于对乌兰布和沙漠刘拐沙头黄河沿岸相近株距(10~15 cm)、不同行距(1 m,2 m)、不同留茬高度(10cm,30 cm)巨菌草的防风阻沙试验的观测数据分析。结果表明:(1)巨菌草留茬沙障的防风固沙效益与沙障的高度和行距有直接关系,高度一定,行数越多,带距越小,防护效果越好,但所需材料增加。(2)巨菌草留茬沙障内输沙量主要集中在地表15 cm以下,近地表0~5 cm处沙障对风沙流的阻碍能力较强。沙障行距为1 m、2 m时,高10 cm的沙障分别经9带、12带后风速降至起沙风速以下;高30 cm的沙障对风的阻碍能力增强,分别经7带、9带后地表无流沙运动。(3)沙障的设置应在保证高效的前提下降低成本。行距2 m、高30 cm的巨菌草留茬沙障,气流经过9个条带(18 m宽)后,风速可降至起沙风速以下,此设置模式宜在干旱地区推广。 相似文献
3.
土壤凝结剂沙障防沙机理的风洞模拟实验研究 总被引：10，自引：3，他引：7
模型按 1 :1 0比例设计 ,在 7m/s、1 5 m/s和 2 0 m/s的实验风速下 ,对不同浓度土壤凝结剂处理的沙障模型进行风洞实验 ,测定其蚀积状况。实验结果表明 :抗风蚀强度以 40 %浓度处理的固沙模型最强 ,2 0 %最弱 ,但 30 %浓度防风蚀效果较为实用。积沙状况与浓度关系不明显 ,水平放置与坡面 ( 30°)放置时均以 1× 1 m规格的沙障积沙最多 ,1 .5× 1 .5 cm次之 ,2×2 cm最差。风速在障前受阻减弱 ,而后沿流速方向在沙障间逐渐增大 ,在第二格上方障埂处出现最大值 ,障后逐渐减速 ,直至障高 1 0倍处趋于稳定。障前、障后风速降低是引起障前、障后积沙的主要原因 ,也是土壤凝结剂沙障的防沙机理。 相似文献
4.
《干旱区研究》2021,38(3):882-891
高立式沙障在线性工程风沙灾害防护中被广泛应用,布置模式直接影响工程防风阻沙效率和成本效益。在乌兰布和沙漠穿沙公路迎风侧,选择上疏下密式尼龙阻沙网分别设计4种高度单行、4种高度3种间距双行沙障来模拟风沙灾害防治观测场,使用阶梯式集沙仪与HOBO风速采集仪对不同风速下防风阻沙效率参数进行观测。结果表明:(1)低风速(12 m·s-1)背景下,高立式尼龙阻沙网沙障障后有效防护距离单行为3H(相同沙障高度的距离)以内,双行为12H。(2)单行高立式尼龙阻沙网沙障的障后3H沙障截留率平均为85.14%,障后5H平均为91.23%;双行障后3H平均为93.53%。(3)在中低风能地区线性工程防护中配置尼龙阻沙网时,不建议使用0.6 m及以下高度沙障;8 m·s~(-1)风速及以下可配置1 m高度单行尼龙阻沙网沙障;8～12 m·s~(-1)风速可配置间距8H、高度0.8～1.0 m双行尼龙阻沙网;在大风速区(12 m·s~(-1))选择拓宽间距至10H、高度1.2 m尼龙网沙障多条带复式配置。此模式可优化治沙工程设计,完善线路工程沙害防治体系。 相似文献
5.
塔里木沙漠公路防沙体系建设几个问题的探讨 总被引：9，自引：1，他引：8
沙害主要取决于两个系统因素的共同作用 :动力系统—风力和响应系统—下垫面状况。塔里木沙漠公路沿线风沙地貌形态类型复杂多样 ,沙源充足 ;起沙风频数高 ,作用时间长 ,防沙难度极大。已建成的高立式芦苇阻沙栅栏和 1 m× 1 m半隐蔽芦苇草方格固沙沙障结合的“阻固”体系 ,有效控制了沙害 ,但也存在一定问题。定位观测表明 ,沿线起沙风和输沙方向集中于 NE、ENE、E三个方向 ,占 46%～ 68% ,从理论上说 ,应加大风侧 (路东侧 )防护力度 ,而实际上固沙带内部强烈的风蚀与沙埋过程 ,使其有效年限与设置宽度关系不明显 ,宜采取窄宽度勤维修原则 ,上风侧宽度控制在 3 0 m～ 40 m,每 3～ 4年更新一次并及时维修。下风侧可不设置高立式沙障 ,固沙带宽度控制在 1 0 m～ 1 5 m为宜 ;高立式沙障与半隐蔽方格沙障前沿之间空留宽度控制在 8H以内较为适宜。依沙害程度 ,以单一原状芦苇固定沙障、复膜沙袋阻沙体活动沙障及固定沙障与活动沙障有机结合加强前沿阻沙力度 ;不同沙害部位设置不同规格不同高度的半隐蔽方格沙障、固化路肩边坡创造输沙断面等技术 ,形成立体防护体系 ,足以控制沙害。 相似文献
6.
草原灌木带空气动力学粗糙度研究 总被引：1，自引：0，他引：1
为了定量研究灌木带修复退化草原的机理,采用集沙仪和风速廓线仪野外采集了不同高度灌木带及退化草原的风蚀物及风速廓线,利用最小二乘法对风速廓线数据进行计算得到了相应的空气动力学粗糙度。结果表明:灌木带对草地的防护机理在于提升了地表的空气动力学粗糙度,降低了近地表的风速,从而导致灌木带相对退化草原的抗风蚀能力增强,大量风蚀物集中在近地表30 cm范围内;距灌木带的距离越远,空气动力学粗糙度呈现下降趋势;同时对不同高度灌木带的研究发现,0.3 m、0.7 m和1.5 m高的灌木带分别在距背风面3 m、5 m和6 m处的空气动力学粗糙度与退化草原的值趋于一致,此距离为该灌木带的有效防风蚀范围,空气动力学粗糙度及有效防护范围均随灌木高度的增加而增大。 相似文献
7.
通过对吉兰泰盐湖上风向的戈壁、灌木林地表层颗粒空间格局特点及其空间分布特征的研究,揭示该地区的风沙运动规律,对加强相关地区的植被类型及其空间配置格局的防沙效应研究具有重要意义。以乌兰布和沙漠西南边缘的吉兰泰盐湖为试验区,以试验区内戈壁、灌木林地表层颗粒为研究对象,利用样方法和数字图像处理技术,获取地表层不同土壤风蚀颗粒的百分含量,采用经典描述性统计及地统计学方法,分析不同抗风蚀能力颗粒百分含量的小尺度空间特征。结果表明:1 2个样地颗粒越小,空间分布的变异性越大,峰度越尖锐。2裸露戈壁样地内3种风蚀颗粒含量的半方差函数模型均为线性模型,模型决定系数均在0.8以上,分布形态为随机分布,空间相关性中等;灌丛林地内3种风蚀颗粒的分布特征比较复杂,0.42 mm颗粒的随机因素引起的空间变异大。3由于灌丛对样地内不同风蚀颗粒分布的影响,导致灌丛林地及其周边0.84 mm的不可蚀颗粒呈聚集分布,空间分布比较强烈。 相似文献
8.
方格沙障的布设参数直接影响防风效应的复变作用,定量表达其复变规律,对于沙障配置模式的确定具有重要意义。在乌兰布和沙漠机械整平的风沙观测场,铺设9种不同高度、规格的尼龙网方格沙障,观测其在不同风速背景下的风速流场特征,揭示方格沙障防风效应的复变规律。结果表明:尼龙网方格沙障防风效应复合变化受不同指示风速下,沙障高度与规格共同的影响。沙障内部0. 1 m高度的风速随防护宽度的增加呈对数函数递减,指示风速增大1 m·s~(-1),风速衰减率增加0. 07倍;沙障高度增大0. 1 m,风速衰减率增加0. 20倍;方格边长增大1 m,风速衰减率减小0. 07倍。观测的9种规格方格沙障,30 cm高度1 m×1 m规格沙障复变作用最强,15 cm高度2 m×2 m规格沙障复变作用最弱。该结果可为确定沙障合理防护宽度、节约沙障铺设成本、优化沙障布设技术提供基础数据和理论支撑。 相似文献
9.
乌兰布和沙漠沿黄段不同治理措施的风沙运移特征及其防护效果 总被引：1，自引：0，他引：1
为科学治理黄河乌兰布和沙漠沿岸风沙入黄问题,以该河段沿线流沙为对照,开展了麦草沙障、沙柳沙障、葵花杆沙障和梭梭林为代表的工程与植物固沙实验,对不同治理措施下的风速廓线、粗糙度、风沙流结构、防护效果及其相互关系进行了野外观测与室内分析。结果表明:1)各沙障和梭梭林内风速廓线发生改变,近地表风速显著降低,地表粗糙度和摩阻风速显著增加。2)流沙表面输沙量分布随高度增加呈对数递减,90%集中在0~10cm范围,98%分布在0~30m范围内。3)不同措施的输沙率随风速的增加呈增加趋势,但输沙率仅为流沙的1.07%~38.27%,可很好的控制近地表的流沙活动。4)各类固沙措施的实施效果排序葵花杆沙障>梭梭林>沙柳沙障>麦草沙障,控制流沙效果均达到75%以上,对固定流沙均能起到积极作用。综合考虑固沙效果、成本、运输以及使用寿命等,该地区选择葵花杆沙障和梭梭较为合适。该研究结果可为解决风沙入黄问题、完善黄河沿岸风沙防护体系提供参考。 相似文献
10.
PLA沙障对沙丘迎风坡土壤水分的影响 总被引：1，自引：0，他引：1
选取风季和雨季两个典型时期,对铺设不同规格PLA沙障沙丘迎风坡不同坡位0-60cm土层的土壤含水量进行测定,并以裸沙丘为对照,探究PLA沙障对沙丘迎风坡土壤水分的影响.结果表明:1m×1m和2m × 2m沙障在不同时期对沙丘迎风坡整体和坡位间土壤水分影响明显,而菱形沙障作用效果差;1m×1m、2m×2m沙障使风季形成迎风坡浅层(5-20cm)土壤含水量低于裸沙丘的水分特征,雨季形成迎风坡表层(0-10cm)土壤含水量优于裸沙丘的水分特征,从而影响了植物的入侵与定居方式;不同时期1m×1m和2m×2m沙障对迎风坡中部和下部土壤水分的影响均较上部明显,迎风坡中部和下部应为重点关注区域,而在上部应采取相伴措施弥补不足. 相似文献
11.
The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion. In this study, three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region, China and placed in a wind tunnel where they were subjected to six different wind speeds (10, 15, 17, 20, 25, and 30 m/s) to simulate wind erosion in the wind tunnel. After each test, the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model (DEM), and the changes in wind erosion mass and microtopography were quantified. Based on this, we performed further analysis of wind erosion-controlling factors. The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23% for the three undisturbed soil samples. With increasing wind speed, the microtopography on the undisturbed soil surface first became smooth, and then fine stripes and pits gradually developed. In the initial stage of wind erosion processes, the ability of the soil to resist wind erosion was mainly affected by the soil hardness. In the late stage of wind erosion processes, the degree of soil erosion was mainly affected by soil organic matter and CaCO3 content. The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring. 相似文献
12.
土壤风蚀量随风速的变化规律研究 总被引：16，自引：1，他引：16
使用野外风洞作为风蚀研究的试验手段,通过农田土壤、沙及生土的风洞试验研究发现,农田土壤的风蚀量随风速呈指数函数变化,沙及生土的风蚀量随风速呈幂函数变化。试验研究还表明,农田土壤的风蚀量与表土层(3cm)的含水量呈显著负相关,沙的风蚀量与含水量的相关性不显著。风蚀导致土壤中的细颗粒成分大量损失,这是土壤颗粒粗化的原因所在。 相似文献
13.
ZOU Xueyong 《干旱区科学》2020,12(3):423-435
The shear stress generated by the wind on the land surface is the driving force that results in the wind erosion of the soil. It is an independent factor influencing soil wind erosion. The factors related to wind erosivity, known as submodels, mainly include the weather factor(WF) in revised wind erosion equation(RWEQ), the erosion submodel(ES) in wind erosion prediction system(WEPS), as well as the drift potential(DP) in wind energy environmental assessment. However, the essential factors of WF and ES contain wind, soil characteristics and surface coverings, which therefore results in the interdependence between WF or ES and other factors(e.g., soil erodible factor) in soil erosion models. Considering that DP is a relative indicator of the wind energy environment and does not have the value of expressing wind to induce shear stress on the surface. Therefore, a new factor is needed to express accurately wind erosivity. Based on the theoretical basis that the soil loss by wind erosion(Q) is proportional to the shear stress of the wind on the soil surface, a new model of wind driving force(WDF) was established, which expresses the potential capacity of wind to drive soil mass in per unit area and a period of time. Through the calculations in the typical area, the WDF, WF and DP are compared and analyzed from the theoretical basis, construction goal, problem-solving ability and typical area application; the spatial distribution of soil wind erosion intensity was concurrently compared with the spatial distributions of the WDF, WF and DP values in the typical area. The results indicate that the WDF is better to reflect the potential capacity of wind erosivity than WF and DP, and that the WDF model is a good model with universal applicability and can be logically incorporated into the soil wind erosion models. 相似文献
14.
NAN Ling DONG Zhibao XIAO Weiqiang LI Chao XIAO Nan SONG Shaopeng XIAO Fengjun DU Lingtong 《干旱区科学》2018,10(1):27-38
The farming–pastoral ecotone in northern China is an extremely fragile ecological zone where wind erosion of cropland and rangeland is easy to occur. In this study, using a portable wind tunnel as a wind simulator, we conducted field simulated wind erosion experiments combined with laboratory analysis to investigate wind erosion of soils in trampled rangeland, non-tilled cropland and tilled cropland in Yanchi County, China. The results showed that compared with rangeland, the cropland had a higher soil water holding capacity and lower soil bulk density. The wind erosion rate of trampled rangeland was much higher than those of non-tilled cropland and tilled cropland. For cropland, the wind erosion rate of the soil after tilling was surprisingly less than that of the soil before tilling. With increasing of wind speed, the volume mean diameter of the eroded sediment collected by the trough in the wind tunnel generally increased while the clay and silt content decreased for all soils. The temporal variation in wind erosion of the trampled rangeland indicated that particle entrainment and dust emission decreased exponentially with erosion time through the successive wind erosion events due to the exhaustion of erodible particles. 相似文献
15.
农田耕作方式与土壤风蚀强度关系的风洞模拟实验 总被引：1，自引：0，他引：1
以土壤风蚀严重的河北坝上康保县为研究区,采用风洞试验的技术手段,对农田耕作方式与土壤风蚀强度的关系进行研究。结果表明,农田留茬与翻耕、农田垄向及农作物残茬高度的差异对土壤风蚀强度有较大影响。垄向平行主风向的风蚀强度大于垄向垂直主风向的风蚀强度。风速越大,垄向不同造成的风蚀强度的差异越大,尤其是当风速≥15m/s时,风蚀强度的差异表现得较为明显;风蚀强度与留茬高度呈负相关;翻耕地的风蚀强度大于任何留茬地的风蚀强度;风蚀强度与风速变化呈现出指数函数变化规律。因此,农田垄向垂直主风向、作物收获后不进行翻耕、留有适度茬高、优先种植残茬硬度较大的莜麦作物,这样的耕作方式可有效降低土壤风蚀强度,缓解河北坝上地区农田土壤风蚀状况。 相似文献
16.
An experimental study on the influences of water erosion on wind erosion in arid and semi-arid regions 总被引：2，自引：0，他引：2
Huimin YANG 《干旱区科学》2019,11(2):208-216
Complex erosion by wind and water causes serious harm in arid and semi-arid regions. The interaction mechanisms between water erosion and wind erosion is the key to further our understanding of the complex erosion. Therefore, in-depth understandings of the influences of water erosion on wind erosion is needed. This research used a wind tunnel and two rainfall simulators to investigate the influences of water erosion on succeeding wind erosion. The wind erosion measurements before and after water erosion were run on semi-fixed aeolian sandy soil configured with three slopes(5°, 10° and 15°), six wind speeds(0, 9, 11, 13, 15 and 20 m/s), and five rainfall intensities(0, 30, 45, 60 and 75 mm/h). Results showed that water erosion generally restrained the succeeding wind erosion. At a same slope, the restraining effects decreased as rainfall intensity increased, which decreased from 70.63% to 50.20% with rainfall intensity increased from 30 to 75 mm/h. Rills shaped by water erosion could weaken the restraining effects at wind speed exceeding 15 m/s mainly by cutting through the fine grain layer, exposing the sand layer prone to wind erosion to airflow. In addition, the restraining effects varied greatly among different soil types. The restraining effects of rainfall on the succeeding wind erosion depend on the formation of a coarsening layer with a crust and a compact fine grain layer after rainfall. The findings can deepen the understanding of the complex erosion and provide scientific basis for regional soil and water conservation in arid and semi-arid regions. 相似文献
17.
The rapid desertification of grasslands in Inner Mongolia of China poses a significant ecological threaten to northern China. The combined effects of anthropogenic disturbances(e.g., overgrazing) and biophysical processes(e.g., soil erosion) have led to vegetation degradation and the consequent acceleration of regional desertification. Thus, mitigating the accelerated wind erosion, a cause and effect of grassland desertification, is critical for the sustainable management of grasslands. Here, a combination of mobile wind tunnel experiments and wind erosion model was used to explore the effects of different levels of vegetation coverage, soil moisture and wind speed on wind erosion at different positions of a slope inside an enclosed desert steppe in the Xilamuren grassland of Inner Mongolia. The results indicated a significant spatial difference in wind erosion intensities depending on the vegetation coverage, with a strong decreasing trend from the top to the base of the slope. Increasing vegetation coverage resulted in a rapid decrease in wind erosion as explained by a power function correlation. Vegetation coverage was found to be a dominant control on wind erosion by increasing the surface roughness and by lowering the threshold wind velocity for erosion. The critical vegetation coverage required for effectively controlling wind erosion was found to be higher than 60%. Further, the wind erosion rates were negatively correlated with surface soil moisture and the mass flux in aeolian sand transport increased with increasing wind speed. We developed a mathematical model of wind erosion based on the results of an orthogonal array design. The results from the model simulation indicated that the standardized regression coefficients of the main effects of the three factors(vegetation coverage, soil moisture and wind speed) on the mass flux in aeolian sand transport were in the following order: wind speedvegetation coveragesoil moisture. These three factors had different levels of interactive effects on the mass flux in aeolian sand transport. Our results will improve the understanding of the interactive effects of wind speed, vegetation coverage and soil moisture in controlling wind erosion in desert steppes, and will be helpful for the design of desertification control programs in future. 相似文献
18.
土壤风蚀的野外风洞实验研究 总被引：3，自引：0，他引：3
朱朝云 《干旱区资源与环境》1987,(1)
<正> 土地的不断沙漠化已给自然的生产潜力和人类的生活环境带来了巨大的危害,目前这种危害正在加速地强化着。因此作为沙漠化研究中的一个重要内容——土壤风蚀的研究就显得十分重要了。我们内蒙古林学院在国内外专家的帮助下,于1986年初,顺利地 相似文献
19.
Ali Mamtimin 《干旱区科学》2011,3(1):9-14
The development and progress of soil wind erosion are influenced by the factors of climate,terrain,soil and vegetation,etc. This paper,taking Tazhong region,a town in the centre of the Taklimakan Desert,as an example and using comparative and quantitative methods,discussed the effects of climate,surface roughness(including vegetation cover) and surface soil properties on soil wind erosion. The results showed that the climate factor index C of annual wind erosion is 28.3,while the maximum of C is 13.9 in summer and it is only 0.7 in winter. The value of C has a very good exponential relationship with the wind speed. In Tazhong region,the surface roughness height is relatively small with a mean of 6.32 × 10-5 m,which is in favor of soil wind erosion. The wind erosion is further enhanced by its sandy soil types,soil particle size,lacking of vegetation and low soil moisture content. The present situation of soil wind erosion is the result of concurrent effects of climate,vegetation and surface soil properties. 相似文献