不同应力路径下岩石破坏面细观形貌研究

以大理岩为研究对象,进行三轴卸荷试验及破裂面粗糙度扫描试验,并借助PFC~(3D)颗粒流软件对试样最终破裂面进行提取与重建,研究了粗糙度参数的变化与试样破坏过程及机理之间的关联,得到的主要结论有:加荷路径下S_a随着围压的增加呈递减趋势且两者呈线性关系,高围压条件下岩样破坏面高度分布的对称性好于低围压条件下;卸荷路径下S_a与S_(ku)可以较好的描述破坏面形貌的分布特性,S_(sk)随卸荷速率的增加变化规律不明显,破裂面的粗糙程度受卸荷速率与卸荷初始围压的共同影响;卸荷试验中试样内部的损伤不再是一个逐步累积的过程,而是瞬时劣化失去承载能力。

Experimental Study on Meso-topography of Rock Surfaceunder Various Stress Path

By grating projection scanning system, the relationship between the roughness parameters and failure mechanism of marble was systematically studied. The final fracture surface was extracted and reconstructed through PFC^3D. The surface characteristics were quantified and analyzed. The results show that S_a decreases linearly with the increase of the enclosure pressure under the loading path. The symmetry of the failure plane height of the rock sample under the high enclosure pressure condition is better than that under the low enclosure pressure condition. The S_a and S_ku can better describe the distribution characteristics of the failure surface morphology under unloading path. S_sk does not change significantly with the increase of unloading rate. The roughness of the fractured surface is affected by the unloading rate and the initial enclosure pressure of the unloading process. The internal damage of the sample during unloading test deteriorates instantaneously and loss its bearing capacity instead of a gradual damage accumulation process.