白云岩力学强度特性的孔隙影响研究  

Investigation of porosity effect on mechanical strength characteristics of dolostone

作　　者：吴文[1] 王贵宾[1] 冒海军[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《岩土力学》2010年第12期3709-3714,共6页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973计划)(No.2010CB226701)

摘　　要：为了研究孔隙对白云岩力学特性的影响,从四川某地露头和深度大于5000m的深部白云岩地层进行了取样,系统地研究了孔隙对白云岩的力学特性的影响。孔隙度是石油或天然气白云岩储层的重要特征之一。白云岩的试样孔隙度变化范围在6%～12%之间。在实验室对白云岩进行了单轴抗压强度试验、巴西劈裂法抗拉强度试验、直剪试验和三轴抗压强度试验。单轴抗压强度试验结果表明,岩石中孔隙度越高,岩石强度就越低。在不同围压作用下的多轴试验结果表明,在某一围压作用下,岩石的强度随着孔隙度的增加而减少;在相同孔隙度的岩石,应力偏量(三轴峰值应力)随着围压的增加而增加。介绍了孔隙岩石的MSDPu屈服本构模型,结果显示该模型能够较好地描述孔隙岩石的屈服特性。Mechanical characteristics of porous dolostone was conducted systematically in order to investigate porosity effects on mechanical properties of dolostone samples, which were sampled from surface and more than 5000 m deep in Southeast Sichuan Province. The porosity is one of the critical physical properties of dolostone, which is often categorized into storage strata of petroleum or natural gas. The porosity ranges from 6% to 12% for these samples of dolostone. The experiments in the laboratory were performed with regard to uniaxial compressive test （UCT）, Brazilian Split test （tension strength）, direct shear test, as well as triaxial compressive test （TCT）. The results of uniaxial compressive tests indicate that the uniaxial compressive strength decreases with increase of the porosity in dolostone; meanwhile similar results were achieved in the multiaxial tests, namely, the strength reduces as increase of porosity at the fixed confining pressure; whereas the peak strength of the triaxial compressive stress increases with the increase of confining pressure when the porosity is fixed. Finally, the yield function of MSPDu （Mises-Schleicher-Drucker-Prager Universal） model was introduced, which was employed to porous dolostone; the results of porous dolostone show that MSDPu model can describe well yield oroperties of the norous dolostone.

关 键 词：白云岩 孔隙度 屈服模型 岩石强度 

分 类 号：TU452[建筑科学—岩土工程]