基于Skempton有效应力原理的岩石压缩系数研究

Study on Rock Compressibility Coefficients Based on Skempton Effective Stress Principle

基于适用于岩石的Skempton有效应力原理,系统地推导了岩石表观压缩系数、颗粒压缩系数、孔隙压缩系数在3种不同应力条件下的关系式,得到一组岩石各压缩系数的定量计算式,并进行了实例论证。研究表明:恒总应力下的岩石表观压缩系数、孔隙压缩系数分别为恒流压下的岩石表观压缩系数、孔隙压缩系数与颗粒压缩系数之差,封闭条件下的岩石压缩系数关系式与Gassmann方程认识一致;在相同应力条件下,岩石的孔隙压缩系数远大于表观压缩系数,表观压缩系数又大于颗粒压缩系数,不同压缩系数之间差距可达2~3个数量级;新计算式基于岩石的应力应变原理,厘清了各压缩系数之间的相互关系,计算简便,实用性好。

Based on the Skempton effective stress principle suitable for rocks,the expressions of the apparent compress on coefficient,particle compression coefficient and pore compression coefficient of rock under three stress conditions were derived,and they were verified by an example. The results show that the apparent compression coefficient and pore compression coefficient under constant total stress condition are respectively the difference between the corresponding compression coefficient and particle compression coefficient under constant pore pressure condition. The expressions of the compression coefficients of rock under the closed condition are consistent with those based on Gassmann equation. Under the same stress condition,the pore compression coefficient is far greater than the apparent compression coefficient,and the apparent compression coefficient is bigger than the particle compression coefficient. The difference between different compression coefficients of rock is up to 2 ~ 3 orders of magnitude. The calculation formulas are based on the stressstrain principle of rock,and the relationships between different compression coefficients of rock are clarified. They are simple and practical.