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通过对试验设备与工艺的改进,发展出一套比较有效的渗流-流变耦合试验方法。以多孔隙石灰岩为对象,研究了不同应力及水压作用下岩石试件的流变力学特性。试验结果显示,试件的应变总体上随偏应力及水压的提高而加大。在低应力作用下,垂向应变的变化量最大。提高应力后,渗流方向应变的增加趋势显著超过垂向。试件的渗透系数与体积变化具有相似规律,在低应力作用下,试件体积不断缩小,渗透系数也随之减小,此时增大水压会使试件进一步压缩。应力增大到某值后,体积逐步扩大而出现扩容,渗透系数也随之增大,此时增大水压会使扩容进一步增大。在各级应力作用下,试件的流变速率均有减速及稳定阶段。当应力较大时,会出现加速流变阶段导致破坏。
Through the improvement of test equipment and process, a set of more effective seepage - rheological coupling test method has been developed. Taking porous limestone as an example, the rheological mechanical properties of rock specimens under different stress and hydraulic pressure were studied. The test results show that the strain of the specimen generally increases with the increase of the deviatoric stress and water pressure. Under the action of low stress, the vertical strain changes the most. After increasing the stress, the tendency of seepage direction strain increased significantly more than vertical. The permeability coefficient and volume change of the test piece have similar rules. Under the condition of low stress, the volume of the test piece keeps decreasing and the permeability coefficient decreases. At this time, increasing the water pressure will further compress the test piece. After the stress is increased to a certain value, the volume gradually expands and expansion occurs, and the permeability coefficient also increases. At this time, increasing the water pressure will further increase the expansion. At all levels of stress, the rheological rate of the specimens slowed down and stabilized. When the stress is greater, there will be accelerated rheological stage lead to damage.