泥质细砂岩材料破坏与强度衰减研究

为了认识真实的岩石材料破坏和强度衰减规律，通过多组常规的单轴压缩试验和不同围压下的三轴压缩试验对泥质细砂岩的材料破坏过程和抗压强度进行了实测．把前面试验破裂形成的不规则岩块浇注在混凝土制成的“剪切壳”中，运用XJ-1型携带式剪切仪进行了自行设计的压剪试验，获得了岩块在压剪过程中的剪切力一压应力关系曲线，以此来测得破裂岩块的自身材料强度．通过对比先前压缩试验得到的极限莫尔包络线，研究了破坏前完整岩样与破坏后损伤岩块间的强度变化．讨论了不同试验方法，损伤程度，尺寸效应，材料异性对岩石强度衰减的影响．结果表明，岩石在破坏过程中环向应变与体积应变在峰后近乎以直线形式增长，岩块抗剪强度表现出尺寸效应，岩样伴随着破裂演变材料强度发生衰减．

Study of Material Failure and Strength Degradation in Argillaceous Packsand Samples

The compressive strength and failure evolution of argillaceous packsand samples were measured via uniaxial and triaxial compression tests under varying confining pressures. An XJ- 1 portable shear apparatus was used to obtain shear-compressive stress curves of rock blocks. These are a measure of the material strength of the rock. The degradation in strength of the rock after failure was studied by comparison to the Mohr circle obtained from compression experiments. The influences of different experimental methods, of damage extent, of the effect of size and of material anisotropy on the degradation in rock strength are discussed. The results show that hoop and volumetric strains increase linearly after the peak-load point in the failure process and that the material strength of the rock drops as the failure process develops. It is also shown that the rock shear strength displays a size effect.