结合锦屏水电站引水隧洞的工程实际，采用TLW-2000岩石三轴蠕变试验机对锦屏大理岩试样进行了分级卸围压流变试验。详细分析了恒轴压分级卸围压应力路径下岩石试样的轴向及侧向应变随时间的变化规律，并探讨了卸荷流变过程中岩样的应力应变关系以及流变过程中对岩样不可恢复变形的变化规律。分析认为卸围压不仅影响岩样的瞬时变形而且对流变变形也有很大影响；与卸荷瞬时相比，流变过程中侧向不可恢复变形相对于轴向发展更快；岩样破坏前在侧向的反应要比轴向更为剧烈和明显。通过试验研究掌握了大理岩卸荷流变的基本规律，从而为进一步理论模型的研究提供了可靠的试验数据。

Triaxial rheological test was carried out for marble from Jinping Hydraulic Power Station under step unloading confining pressure with constant axial stress on the basis of the engineering practice. According to the experimental results the creep law of axial and lateral deformation under unloading stress path was studied. The irreversible deformation property of rock in the process of unloading rheological test was also analyzed. Some conclusions were made from the test and the analyzed results show as follows：(1)Unloading confining pressure affects creep deformation and instantaneous deformation of rock. (2)Development of lateral irreversible deformation is more rapid than that of the axial direction in? comparison with the moment of unloading. (3)The response to failure in lateral direction is more obvious than that in axial direction. Through research of the test the unloading creep law of the marble is grasped, and meanwhile the test provides important test data for following theory model research.