【摘要】 从砂质泥岩常规三轴试验出发,通过研究体积应变的变化规律,得到不同围压下砂质泥岩完全扩容应变与完全扩容极限.结果表明,软岩在力学作用下产生非弹性的扩容变形.进一步的试验及理论分析认为,砂质泥岩的体积变形存在一个门槛值即压缩扩容边界cd,完全扩容应变既是岩石试件体积应变的最小值同时也是最大压缩应变值.完全扩容应变及完全扩容极限与围压变化幅度一致,说明围压对扩容具有抑制作用.围压越高,压缩扩容边界cd出现的越迟,扩容之前的压缩变形愈大.更多还原

【Abstract】 Based on the conventional triaxial compression test of sandy mudstone,the absolute dilatancy strain and threshold of absolute dilatancy under confining pressures were obtained by studying the volumetric strain.The result shows that the inelastic volume increase is generated by mechanical action.Through experimental and theoretical analyses,it is found that there is a compression-dilatancy boundary in the volumetric deformation;and the absolute dilatancy strain was estimated by determining the the minimal in pore volume change in other words maximum compression.Furthermore,the absolute dilatancy strain and threshold of absolute dilatancy change at the same extent with confining pressure,which shows that confining pressure strongly inhibites dilatant behavior.The higher confining pressures,the later occurrence of compression-dilatancy boundary is,which means higher values of the compaction changes.更多还原