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针对层状盐穴储气库中不同岩性之间变形不协调的问题,利用大型程控流变仪对盐岩和含盐泥岩2种岩石进行常规单轴加载和单轴多级加载蠕变对比试验研究,重点探讨两者蠕变力学特性之间的异同。结果表明:盐岩的塑性变形能力、流变特性明显强于含盐泥岩,因加载应力产生的瞬时应变量均呈先减小后增大的趋势,与常规单轴下张拉破坏不同,长期蠕变试验条件下,两者均以张剪型破坏为主;同等应力百分比情况下,盐岩的稳态蠕变率明显高于含盐泥岩,稳态蠕变率随加载应力的增加而增大,并呈指数型函数变化,盐岩对应力的敏感性明显强于含盐泥岩;利用等时应力-应变曲线拐点法对2种岩石的长期强度值进行分析,得到盐岩的长期强度值为12 MPa,为短期抗压强度的48%,含盐泥岩的长期强度值为34~36 MPa,较短期抗压强度下降约30%,盐岩长期强度值与短期抗压强度的比值远低于大多数岩石的比值。
In view of the uncoordinated deformation of different lithologies in layered salt cavern gas reservoirs, conventional uniaxial and uniaxial multi-stage creep creep tests of two kinds of rocks of salt rock and salt mudstone were carried out using a large program-controlled rheometer Experimental research, focusing on the similarities and differences between the two creep mechanical properties. The results show that the plastic deformation capacity and rheological properties of salt rock are obviously stronger than that of salt mudstone. The transient strain induced by loading stress decreases first and then increases, which is different from the conventional uniaxial tension failure. Under the same stress percentage, the steady state creep rate of salt rock is obviously higher than that of saline salt mudstone, and the steady state creep rate increases with the increase of loading stress Large and exponential function, the sensitivity of rock salt to stress is obviously stronger than that of salt mudstone. The long-term strength of salt rock is obtained by using the isochronal stress-strain curve inflection point method to analyze the long- Is 12 MPa, 48% of the short-term compressive strength, the long-term strength of salt mudstone is 34-36 MPa, the short-term compressive strength is reduced by about 30%, the ratio of long-term strength to short-term compressive strength of salt rock is much lower The ratio of most rocks.