粗粒含量对珊瑚礁砂混合体剪切特性的影响

Effect of Coarse-grain Content on Shear Properties of CoralReef-Sand Mixtures

珊瑚礁砂混合体是基础设施重要持力层,为了探究颗粒级配组成对珊瑚礁砂混合体的抗剪强度及剪胀性的影响,利用全自动中型叠环直剪仪,在相同密实度下,对不同P5含量、不同含水率的试样,在50、100、200、400 kPa这4种不同法向应力下进行单剪试验。试验结果表明,珊瑚礁砂混合体的抗剪强度随着P5含量的增加呈现先增大后减小的趋势,并在P5含量为25%~50%时达到最大值;珊瑚礁砂混合体在剪切过程中,总体存在先减缩后剪胀的特点,P5含量对剪胀性、内摩擦角、似黏聚力都有着显著影响;含水率对珊瑚礁砂混合体的抗剪强度有着减弱作用。

Coral reef-sand mixture is an important supporting layer of infrastructure.To investigate the effect of particle gradation composition on shear strength and dilatation of coral reef-sand mixtures,simple shear tests were performed using fully automatic medium-sized stacked ring direct shear instrument.The tests were conducted on samples with varied P 5 content and water content under four different normal stresses of 50,100,200,and 400 kPa.The experimental results show that the shear strength of coral reef-sand mixtures first increases and then decreases with the increase of P 5 content.The shear strength reaches its maximum when P 5 content is 25%-50%.In the shearing process,coral reef-sand mixtures contracted first and then dilated.P 5 content has a significant effect on dilatation,internal friction angle,and apparent cohesion.Water content weakens the shear strength of coral reef sand mixture.