针对我国层状盐岩的地质赋存特征,开展了层状模型材料的三轴压缩试验,探讨了界面倾角对层状交互模型材料试样的应力-应变曲线、压缩强度、弹性模量、峰后应力跌幅和破坏形态的影响,并对不同界面倾角试样的破坏形态进行了理论分析。分析结果表明,(1)三轴峰值强度随界面倾角的增大呈先减小后增大的变化趋势,60°时取得最小值,90°时取得最大值;(2)弹性模量随界面倾角的增大而增大,刚开始随角度增大而增大的趋势很平缓,倾角接近90°时增大趋势明显,0°时取得最小值,90°时取得最大值;(3)随界面倾角增大,峰后应力跌幅先减小后增大,30°最小,90°最大;(4)破坏形态随界面倾角增大依次呈现出共轭剪切(0°)、沿弱面的剪切破坏(30°和60°)和剪切-局部劈裂破坏形态(90°)三种破坏模式;(5)储库腔顶和腔底部位强度较高,但脆性很强,须采取一定措施控制这些部位的变形和位移,腔体30°和60°的腰部部位及附近强度较低,塑性变形能力较强,须对储库形状和运营压力进行精细设计。针对试验结果进行的理论分析,可为进一步分析层状盐岩地层中储库的围岩稳定性和局部破损特性提供一定参考。
Considering the geological formation characteristics of bedded salt rock in China, triaxial compression tests were carried out on samples of bedded model material. The influences of interface inclination on stress-strain curves, compressive strength, elastic modulus, stress decreases after the peak stresses and damage modes of samples of bedded model material are discussed; and theoretical analyses are carried out on the damage modes of samples with varying inclinations. Testing results and theoretical analyses show that: (1) The triaxial compressive strength increases firstly and decreases afterwards as the interface inclination increase; and it reaches the minimum and the maximum when the interface inclination is 60°and 90°, respectively. (2) Its elastic modulus increases as the inclination increase with the increasing trend slow at the start of inclination increasing, and then fast when the inclination gets near 90°. (3) The Stress decreases after peak stresses lessen firstly and increase afterwards as the interface inclination increase; and it reaches its minimum and maximum when the inclination is 30°and 90°, respectively. (4) As the interface inclination increase, damage modes show the law of damage from conjugate shear damage(the interface inclination is 0°), shear failure along the poor-strength surface(the interface inclinations are 30°and 60°) to shear and local splitting failure(the inclination is 90°). (5) The top and bottom of the storage are of high-strength but high brittleness; and measures should be taken to control their displacement and deformation; and the waist and adjacent places of the storage(30°and 60°of the storage) are of low strength and high plasticity; and careful design should be adopted for its shape and running pressure. Theoretical analyses are carried out on the results of the triaxial compression experiments, so as to offer a certain reference to further analyses of storage stability in bedded salt rock areas.