节理泥质粉砂岩卸荷流变试验及流变规律研究

Study of unloading triaxial rheological tests and rules of joint pelitic siltstone

为了解节理对泥质粉砂岩卸荷流变规律的影响,进行了同起始围压,不同应力水平下的节理泥质粉砂岩分级卸荷流变试验。首先,详细介绍了节理试样的预制方法及卸荷流变试验的过程,然后,研究了节理试样在不同应力水平作用下的轴向及侧向流变应变变化规律,得出节理倾角为0°的试样轴向及侧向流变应变随围压降低的增大趋势最陡,节理倾角为60°的试样其次,节理倾角为40°的试样最缓。同时,分析了节理对轴向及侧向流变速率变化趋势的影响,探讨了不同倾角节理试样的卸荷流变破裂机制。研究结果较为全面地掌握了节理泥质粉砂岩的卸荷流变基本规律,为进一步建立节理岩体的流变本构模型及参数辨识提供了可靠依据。

In order to know about the joint effect on the unloading triaxial rheological rules of pelitic siltstone, step unloading triaxial rheological experiments with the same initial confining pressure were carried out under different deviatoric stresses. The precast method of joint specimen and the test process are introduced; then the variance law of axial and lateral rheological strains of joint specimen under different deviatoric stresses is investigated. The results show that the axial and lateral rheological strains of jointed specimen increase with the decrease of confining pressure; and the increasing tendency of jointed specimen with the dip angle fl of 0° is the steepest; and followed by jointed specimen with the dip angle fl of 60° ; and is rather gentle with the dip angle fl of 40° . Meanwhile, the effect of joint on the variance tendency of axial and lateral rheological rates is analyzed; and the unloading theological failure mechanism of specimen with different joint inclinations is also discussed in detail. Based on the experimental results, the unloading triaxial rheological law of joint pelitic siltstone is mastered, so as to bring important reference for the establishment of rheological constitutive model of joint rock mass and the identification of parameters.