含石率对石英砂岩类碎石土力学特性的影响研究

为探究含石率对石英砂岩类碎石土力学特性的影响,以湖南益阳某滑坡石英砂岩类碎石土为研究对象,对24组碎石土试样在不同围压(100,200和300 kPa)下进行三轴力学试验。研究结果表明:10%~30%含石率碎石土的应力应变曲线与正常固结土的应力应变曲线不同,在较高围压下出现了应变软化现象。这表明碎石的加入,会改变原有正常固结土的受力特性。该类碎石土的黏聚力随含石率的增加基本呈下降趋势,但摩擦角的大小则随含石率的变化存在一定的波动,相对来说,中等含石率范围内的摩擦角相对最大。低围压下(100 kPa),该类碎石土抗剪强度随含石率的升高而降低,中高围压下(200 kPa和300 kPa),其抗剪强度随含石率的变化总体呈降低趋势,但含石率为30%与50%时出现了峰值抗剪强度,表明该类碎石土的强度与稳定性同含石量的多少有关,在分析该类地层对工程的影响时应结合具体工程目的而做出相应的决定。

Study on the influence of gravel content on the mechanical properties of crushed aggregates containing quartz and sandstone

To explore the influence of stone content on the mechanical properties of quartz sandstone gravel soil,the landslide quartz sandstone gravel soil in Yiyang,Hunan Province was studied.The triaxial shear tests under different confining pressures(100,200 and 300 kPa)were carried out on 24 groups of gravel soil samples.The results show that:the stress-strain curve of the gravel soil with 10%~30%stone content is different from that of normally consolidated soil,and strain softening occurs under higher confining pressure.This indicates that the addition of gravel will change the mechanical characteristics of the original normally consolidated soil.The cohesive force of this kind of gravel soil generally decreases with the increase of stone content,but the friction angle fluctuates with the change of stone content,and the friction angle of the gravel soil with medium stone content is relatively the largest.Under low confining pressure(100 kPa),the shear strength of this kind of gravel soil decreases with the increase of stone content.While under medium and high confining pressure(200 kPa and 300 kPa),the shear strength generally decreases with the increase of stone content,and the peak shear strength occurs when the stone content is 30%and 50%.The above research shows that the strength and stability of this kind of gravel soil are related to the amount of stone content,and the corresponding decision should be made in combination with the specific engineering purpose when analyzing the influence of this kind of stratum on the project.