岩体复合型裂纹的扩展规律 Ⅰ.无水作用条件下

Propagation of the Complex Cracks in Rocks Without Water Pressure

基于最大周向正应力理论 ,研究并给出了无水作用的复合型裂纹在不同应力状态下扩展的临界应力强度因子和扩展方向角。结果表明 ,①Ⅰ型裂纹将沿裂纹面延伸方向扩展而无分支裂纹 ,Ⅱ型裂纹沿与原裂纹面成 70 5°延伸方向扩展 ;②单轴拉伸应力状态下裂纹面有逐渐向垂直于荷载方向上扩展 ,而单轴压缩应力状态下裂纹面有逐渐平行于荷载方向上扩展 ;③双轴应力状态下 ,裂纹扩展方向不仅取决于原裂纹的倾角 ,而且与所受应力状态及σ3 σ1 有关。

The theory of maximum surrounding primary stress is applied to the study of the stress intensity factor and the propagation orientation of the complex cracks in rocks under different external stress, considering the effect of chemical damage and water pressure.It is revaeled that Mode Ⅰ crack propagates along this crack surface and has not branches of the crack,while the propagation orientation of Mode Ⅱ crack is angled 70 5° to the crack.The crack under simple extension propagates along the vertical plane of the orientation of the crack,and the crack under simple compression propagates gradually along the orientation of the crack.The propagation orientation of the crack under twin stress depends not only on the crack angle,but also on the external stress and σ 3/σ 1.