天然与饱水状态下石膏岩蠕变试验研究

发布时间：2018-05-27 00:24

本文选题：石膏岩 + 蠕变　；参考：《岩土力学》2017年S1期

【摘要】：石膏岩的饱水软化蠕变特性是影响石膏矿采空区安全评价的重要因素。以荆门石膏矿岩为研究对象,开展天然与饱水状态下的单试样逐级增量加载试验,分析了饱水软化作用下石膏岩的蠕变特性,选取西原模型描述石膏岩的本构关系。分析结果可得,饱水试样总蠕变量大于天然试样;饱水试样蠕变破坏强度(11 MPa)是天然试样蠕变破坏强度(21.5 MPa)的0.54倍,长期强度(10 MPa)是天然试样长期强度(19.5 MPa)的0.49倍。利用西原模型对蠕变曲线进行拟合并分析拟合参数可知,饱水试样参数E_1是天然试样的0.1~0.5倍,η_1是天然试样的0.2~0.7倍,E_2是天然试样的2~10倍。以上结论均表明饱水试样的蠕变特性更加明显。分析讨论饱水软化作用对石膏岩蠕变特性影响机制可知,荆门石膏岩软化作用主要由物理软化作用及化学软化作用耦合而成,物理软化作用主要为静水作用下的孔压效应,化学软化作用主要为石膏岩的重结晶作用。试验分析结果可为石膏矿采空区安全评价提供依据,具有重要的工程实际意义。
[Abstract]:The creep property of saturated water softening of gypsum rock is an important factor affecting the safety evaluation of gypsum goaf. Taking Jingmen gypsum ore rock as the research object, the creep characteristics of the gypsum rock under the action of saturated water softening are analyzed, and the constitutive relationship of the gypsum rock is described by selecting the Xiyuan model to describe the constitutive relation of the gypsum rock under the condition of natural and saturated water. The results show that the total creep strength of the saturated sample is greater than that of the natural sample, and the creep failure strength of the saturated sample is 0.54 times higher than that of the natural specimen (21.5 MPa), and the long-term strength of the water saturated specimen is 0.49 times higher than that of the natural specimen (19.5 MPA). The fitting parameters of creep curve of Xiyuan model show that the parameter E _ 1 of saturated sample is 0.5 times of that of natural sample, and 畏 _ s _ 1 is 0.2 ~ 0.7 times of natural sample and E _ 2 of natural sample is 210 times of that of natural sample. The above conclusions show that the creep characteristics of saturated samples are more obvious. Through analyzing and discussing the influence mechanism of saturated water softening on creep characteristics of gypsum rock, it can be seen that the softening effect of Jingmen gypsum rock is mainly formed by coupling physical softening and chemical softening, and physical softening is mainly pore pressure effect under hydrostatic action. The chemical softening is mainly the recrystallization of gypsum rock. The test results can provide the basis for the safety evaluation of the goaf of gypsum mine and have important engineering significance.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(No.51274188)~~
【分类号】：TU45

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