黏粒含量对砂土强度和压缩特性的影响

Effect of Clay Content on the Strength and Compressibility of Sandy Soil

利用四联直剪仪和高压固结仪,研究膨润土和高岭土含量对漓江砂土的强度和压缩特性的影响。试验结果表明:膨润土和高岭土对砂土的强度存在不同的影响,不同的黏粒含量对砂土强度影响略有不同。黏聚力随着黏粒含量的增加而增加,摩擦角与黏粒含量并非呈单调关系,而呈抛物线型;存在一个黏粒的含量使得砂土的摩擦角最小,并且这个值为10%~15%。固结试验中,黏粒含量对砂土压缩性的影响很大,相同初始孔隙比下加载导致的最小孔隙比并不一致,随黏粒含量增加最小孔隙比先增大先减小;同时,黏粒成分不同,最小孔隙比也不同。高岭土黏粒对砂土的回弹指数基本上没有什么影响,而膨润土在黏粒含量小于5%时也没影响,但黏粒含量超过5%时回弹曲线非线性。

The effects of clay with different clay content on the strength and compressive properties of Lijiang sand were studied by using quadruple direct shear apparatus and high pressure consolidation apparatus. The results show that bentonite and kaolin have different effects on the strength of sand. The effect of different clay content on sand strength is slightly different. The cohesion increases with the increase of clay content. The friction angle and clay content is not monotonous,and parabolic type,there is a clay content of sand so that the friction angle is the smallest and the value of 10% to 15%. In the consolidation test,the clay content has great influence on the compressibility of the sand,and the minimum void ratio is not the same with the initial initial pore ratio. With the increase of the clay cont,ent,the minimum porosity decreases first,The minimum void fraction is different for different grain compositions. The kaolin clay has little effect on the rebound index of sand,but the bentonite has no effect when the clay content is less than 5%,but the rebound curve is nonlinear when the content of clay is more than 5%.