层状盐穴储库中盐岩和泥岩蠕变特性试验研究

针对层状盐穴储气库中不同岩性之间变形不协调问题，本文利用四川大学大型程控流变仪对盐岩和含盐泥岩两种岩石进行了常规单轴加载和单轴多级加载的蠕变的对比试验研究，重点探讨了两者蠕变力学特性之间的异同。研究结果表明：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，稳态蠕变率随着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-应变曲线拐点法对两种岩石的长期强度值进行分析，得到盐岩的长期强度值为12MPa，为短期抗压强度的48%，含盐泥岩的长期强度值为34~36MPa，较短期抗压强度下降约30%，盐岩的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。

Experimental study on creep properties of salt rock and mudstone from bedded salt rock gas storage

: In order to study the uncoordinated deformation of different rocks in the salt cavern of China, the conventional uniaxial loading test and Multi-level load creep test on pure rock salt and Salt mud were carried out by using large-scale programmable rheometer of Sichuan University. Based on the tests, the differences of mechanical characteristics between pure rock salt and Salt mud were studied. The results show that the plastic deformation ability and rheological property of salt rock are obviously stronger than salt bearing mudstone. The instantaneous strain generated by loading stress firstly decreased and then increased. Both rocks damaged with the shear characteristic under the condition of long-term creep test, which was different from rocks with the tension damage under the conventional uniaxial. The steady creep rate of salt rock was obviously higher than that of salt bearing mudstone in the same stress percentage and both are exponential function of growth, and the sensitivity of the salt stress is stronger than the salt bearing mudstone. The long-term strength of two kinds of rock was analyzed by using the stress-strain curve inflection point method. The long-term strength of salt rock was 12MPa, which was 48% of short-term compressive strength. The long-term strength of salt bearing mudstone was 34~36MPa, which was lower by 30% than the short-term compressive strength. The ratio of long-term strength and short-term compressive strength of salt rock was much lower than that of most rocks.