首页|沙土内摩擦角与粒径、含水率及天然坡角的关系

沙土内摩擦角与粒径、含水率及天然坡角的关系

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沙的摩擦性质是影响沙丘形态的重要因素之一,研究沙土内摩擦角对于探讨床面沙波形态、沙丘流动性、沙丘稳定性、沙丘防护等都具有实际意义.本文实验研究了内摩擦角与粒径、含水率及天然坡角的定量关系.结果表明:当粒径从<0.125 mm增大到0.315~0.4 mm时,内摩擦角从32.25°减小到28.06°;而粒径从0.315~0.4mm增大到o.63~0.8 mm时,内摩擦角却从28.06°增大到31.47°.主要原因是,粒径小时颗粒的比表面积大,颗粒间接触面积大使得内摩擦角大.粒径大时,颗粒表面棱角突出,颗粒间嵌入咬合作用明显使得内摩擦角大.当含水率从0%增加到15%时,内摩擦角从29.07°增大到31.84°;而含水率从15%增加到20%时,内摩擦角却从31.84°减小到30.75°.主要原因是一定含水率下沙土表现出黏聚性,而高含水率下水的润滑作用使得颗粒间摩擦力减小.内摩擦角与天然坡角都反映沙土摩擦特性,两者相等.
The Relationship between Sand Particle Internal Friction Angle and Particle Size, Water Content and Slope Angle
The sand particle friction property is one of the most important factors affecting the morphology of sand dunes.It has practical significance to discuss the bed morphology,the mobility,the stability and the protection of sand dunes.In this paper,we did some experiments to explore the quantitative relationship between internal friction angle and particle size,water content and slope angle.The results showed that when the particle size varied from <0.125 mm to 0.315-0.4 mm,the sand particle internal friction angle decreased from 32.25 to 28.06.When the sand particle size varied from 0.315-0.4 mm to 0.63-0.8 mm,the sand particle internal friction angle increased from 28.06 to 31.47.Smaller particles have larger surface which makes the contact area between particles larger.Larger particles have obvious effect of interlock function due to their rough surface.When the water content varied from 0 to 15%,the sand particle internal friction angle increased from 29.07 to31.84.When the water content varied from 15% to 20%,the sand particle internal friction angle decreased from 31.84 to 30.75.Water makes sands show some cohesion which makes the internal friction angle larger,but lubrication weaken the friction between particles when high water content.The internal friction angle and the slope angle are natural reactions of sand particle friction characteristic.The maximum slope angle is equal to the internal friction angle.

internal friction anglewater contentparticle sizeslope angle

范智杰、屈建军、周焕

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中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室/敦煌戈壁荒漠生态与环境研究站/甘肃省风沙灾害防治工程技术研究中心,甘肃兰州730000

内摩擦角 含水率 粒径 天然坡角

国家自然科学基金

40930741

2015

中国沙漠
中国科学院寒区旱区环境与工程研究所

中国沙漠

CSTPCDCSCD北大核心
影响因子:1.504
ISSN:1000-694X
年,卷(期):2015.35(2)
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