完整岩石的强度和强度准则

Strength and Strength Criteria for Intact Rocks

岩石是天然材料,种类繁多,力学性质复杂.给出岩石反复加载强化、材料损伤对承载能力影响、软弱岩石强度与杨氏模量的关系以及孔道试样拉应力下破坏的试验结果,分析材料非均质性对岩石剪切破坏和拉伸破坏的影响.岩石内粘结和摩擦在同一点不能同时存在,应力状态达到承载极限时黏结力随变形降低,同时引起摩擦力变化;该变化与应力状态相关,就此讨论岩石变形、载荷与破坏的关系.总结常规三轴和真三轴强度准则的构造方式,讨论指数强度准则的适用性,并说明强度准则参数应以偏差绝对值之和最小为目标拟合试验数据来确定.

There are numerous rocks in nature with complicated mechanical properties. Test results are presented to reveal the effect of rock heterogeneity on shear and tension failure, including strengthen of marble in reloading process, material damage and supporting capacity, relationship between strength and Young＇s modulus of weak rocks, and tensile failure of rings and hollow cylinders. Cohesion and friction in rock do not act on one po{nt; and the cohesion decreases with plastic deformation and internal friction changes on the stress state, when the stresses reach the supporting capacity crack initiates in the rock. The relationship among deformation, stresses and failure is discussed. Conventional and true triaxial strength criteria are reviewed; and characteristics of the exponential criterion are illustrated. Parameters in strength criteria should be determined on the least absolute deviation of fitting solutions