类岩石材料中表面裂纹扩展模式的实验研究

采用粘贴式轴拉方法实现了类岩石材料的直接拉伸实验,通过在类岩石材料试件中预制表面裂纹研究了类岩石材料中表面裂纹的扩展模式.研究发现,粘贴式轴拉方法可以满足一般类岩石材料的直接拉伸实验;类岩石材料中表面裂纹首先从试件正面开始扩展;表面裂纹的存在极大地影响着材料的破坏模式,类岩石材料在试件的正面上会表现出明显的二维穿透性裂纹的扩展形态,但是受其影响裂纹在厚度方向扩展会发生偏转,从而使得试件背面的最终贯通方向没有与加载方向垂直,而是呈一倾角,并且和表面裂纹的倾角和深度有关.

Experimental Study of the Surface Crack Propagation Mode in Rock-like Materials

Direct tension experiments of rock-like materials were carried out by adhesive axial tension. Surface crack was preformed by placing polyester thin plate in the rock-like specimen and the surface crack propagation mode was studied. Study has found that direct tension experiments based on adhesive axial tension may adapt to most rock-like materials. Surface crack in the rock-like materials influences heavily their fracture mode. The surface crack initiates from the front face where the preformed surface crack exists. In the front face the surface crack exhibits obviously a two-dimensional propagation mode. Owing to the influence of preforming surface crack, the crack will deflect through the specimen and finally the fracture on the back face is not perpendicular to the loading direction but presents an acute angle to the loading direction, which is related with dip angle and depth of the preformed surface crack.