干湿循环对层理片岩动态力学性质的影响研究

Study on the Influence of Dry-Wet Cycles on the Dynamic Mechanical Properties of Layered Schist

摘要: 为研究干湿循环对层理片岩动态力学性质的影响。利用分离式霍普金森压杆对经历不同干湿循环次数的片岩展开动态冲击压缩试验，研究不同层理倾角片岩经历不同程度干湿循环作用下的动态力学特性及破裂特征的影响。结果表明：片岩在受到瞬态加载过程中应力应变曲线有多个显著阶段：压密阶段、线弹性阶段、应变硬化阶段、应变软化阶段、快速卸载阶段。当层理倾角为0˚和90˚时，试件表现出较高的动态抗压强度值，并且在破坏后形成的岩石碎片尺寸相对较大。在层理倾角分别为30˚、45˚和60˚的试件中，抗压强度呈现下降趋势，同时伴随较高的破碎程度。试件破坏形式主要为0˚倾角的沿层理面发生的劈裂破坏，30˚、45˚与60˚沿层理面的剪切破坏与一定程度的局部压剪破坏，90˚倾角的穿越层理面的轴向劈裂破坏与局部沿层理面的拉伸破坏。

Abstract: To study the influence of dry-wet cycles on the dynamic mechanical properties of schist layers. Using the separated Hopkinson pressure bar, dynamic impact compression tests were conducted on schist samples that had undergone different numbers of dry-wet cycles. The dynamic mechanical characteristics and fracture features of schist samples with different bedding angles under varying degrees of dry-wet cycling were investigated. The results show that during the transient loading process, the stress-strain curve of the schist exhibits multiple significant stages: compaction stage, linear elastic stage, strain hardening stage, strain softening stage, and rapid unloading stage. When the bedding angle is 0˚ or 90˚, the specimens exhibit higher dynamic compressive strength values, and the formed rock fragments are relatively larger in size after failure. In specimens with bedding angles of 30˚, 45˚, and 60˚, the compressive strength shows a downward trend, accompanied by a higher degree of fragmentation. The failure forms of the specimens mainly include Splitting failure along the bedding plane at 0˚ inclination, shear failure along the bedding plane at 30˚, 45˚, and 60˚, and a certain degree of local compressive-shear failure at 90˚ inclination.