石油科学通报2024，Vol.9Issue(3)：513-524,12.DOI:10.3969/j.issn.2096-1693.2024.03.038
砂岩双轴压缩应力状态下的拉伸强度的实验研究
Experimental study on tensile strength of sandstone under biaxial compressive stress
摘要
Abstract
The tensile strength of rock material is an important and basic parameter when it comes to wellbore stability.In general,for metal,we can obtain the tensile strength in a direct way-the Tensile Test.However,for geotechnical materials,this method is impractical from the first step of sample preparation.Generally,the most commonly used method to obtain the tensile strength of rocks in the laboratory is using the Brazilian Test,which is an indirect approach.Now,this method is recommended by ISRM and has been extensively accepted by the whole community.However,this method has certain limitations.First,since it cannot restore the initial compacted state of the rock,there may be deviations when determining the tensile strength of ultra-deep rock formation.Additionally,the underlying assumption of this method is that the rock undergoes brittle failure directly after the linear elastic stage,which does not align with the actual deformation behavior of ultra-deep sandstone.Based on the problems mentioned above,in this paper,the real tensile yield strength and ultimate tensile strength of sandstone are determined through Biaxial Compression Tests.The real tensile yield strength and ultimate tensile strength of underground sandstone can be deter-mined by a Biaxial Compression Test.The results show that they both increase along with the confining pressure,which accords with the common understanding that the denser the rock material,the higher the strength.The equivalent uniaxial tensile yield strength of sandstone can be obtained by fitting-extrapolation,which is very close to the results of Brazilian Tests,verifying the reliability of this method.By studying the tensile strength of sandstone under biaxial compressive stress,it can provide a more accurate basis for checking tensile failure under unloading conditions,as well as the theoretical and experimental support for the stability of sandstone wellbores.关键词
砂岩/拉伸屈服强度/双轴压缩应力状态/井壁稳定/理论方法Key words
sandstone/tensile yield strength/biaxial compressive stress/wellbore stability/theoretical approach分类
能源科技引用本文复制引用
鞠盈彤,陈勉,杨帅..砂岩双轴压缩应力状态下的拉伸强度的实验研究[J].石油科学通报,2024,9(3):513-524,12.基金项目
国家自然科学基金重点项目"提高超深大斜度井压裂效率的关键力学问题研究"(52334001)资助 （52334001）
