黄土节理结构对强度作用的试验研究

Experimental study on the effect of joint structure on loess strength

针对黄土节理对其拉压强度和破坏形式的影响,采用两种材料模拟节理面,通过液压重塑法分别制作含水平向或竖向节理的黄土试样,开展无侧限抗压强度试验和轴向劈裂抗拉强度试验,分析含水率与节理方向对拉压强度的影响,建立节理性黄土拉压强度关系。结果表明,节理性对较低含水率的黄土的拉压强度与破坏形式有更强的控制作用,含水率升高后节理性的控制作用明显降低;节理性黄土的抗压强度与抗拉强度存在良好对应关系,抗拉强度不可忽略;典型抗压破坏形式可归纳为竖撇型与压碎式两类。

Considering the influence of joints on soil strength and failure mode in loess,two kinds of materials are used to simulate the joint surface.The loess samples with horizontal or vertical joints are made by hydraulic remolding.Based on the unconfined compressive strength test and axial splitting tensile strength test,the influence of water content and joint direction on the strength of loess specimens is analyzed,and the relationship between compressive strength and tensile strength of loess is established.The results show that when the water content is low,the joint is the controlling factor of strength and failure mode of loess.With the increase of water content,the influence of joint on mechanical properties decreases gradually.There is a good correspondence between compressive strength and tensile strength of jointed loess,and the tensile strength of the loess cannot be ignored.The typical compressive failure modes can be classified into vertical oblique type and crushing type.