昆明盆地第四系上更新统褐煤物理力学特性研究

Study on physical and mechanical properties of the Quaternary upper Pleistocene lignite in Kunming basin

通过对昆明盆地第四系上更新统不同埋深处褐煤在不同饱水状态时的力学测试,重点探讨褐煤的遇水软化规律。试验对不同埋深处的褐煤按照天然状态、饱水6d、12d、18d及24d的设计进行采样分析,测定了其吸水率变化、抗压强度变化及相应的抗剪参数变化,并同时分析了埋深与饱水时间相互耦合时褐煤的力学特性。结果表明:天然状态下褐煤随着埋深的增大其抗压强度、内聚力及内摩擦角随之增大;褐煤的吸水率随着饱水时间增大呈对数关系增大;不同埋深处的褐煤抗压强度、内聚力及内摩擦角随着饱水时间的增大均呈现负指数函数形式降低;不同饱水时间时的褐煤应力应变曲线表征了褐煤遇水极强的软化效应。

Through the different saturated state mechanical test of the Quaternary upper Pleistocene lignite in different buried depths in Kunming basin,the water softening law of lignite is discussed. The test is designed to analysis different depths lignite in accordance with the natural state,full water for 6 days,12 days,18 days and 24 days,and the change of water absorption,compressive strength and shear parameters are measured,at the same time,the mechanical properties of lignite is analyzed when the buried depth and time of full water is coupled. The results show that the compressive strength,cohesive force and internal friction angle of lignite increase with the increase of the depth in natural state; the water absorption rate of lignite increase with the increase of water saturation time according to the logarithmic relationship; the compressive strength,cohesive force and internal friction angle of lignite in different depths decrease with the increase of the time of full water; the strong water softening effect of lignite is characterized by the stress and strain curves in different saturated time.