锦屏水电站大理岩加卸荷本构模型研究

以锦屏水电站深埋引水隧洞开挖稳定分析为背景,开展大理岩加卸荷变形特性试验,发现无论加载还是卸荷破坏,大理岩试件破坏前都经历显著的体积膨胀过程.从描述岩石体积变形规律的角度出发,在对Weng模型改进的基础上,建立锦屏大理岩加、卸荷本构模型.研究结果表明:模型计算结果与试验结果具有较好的一致性,能较好地描述大理岩加、卸荷体积变形特征.模型可以考虑岩石加卸荷强度特性的差异,能够描述从轴向压缩状态开始卸荷的情况,具有较为广泛的适用性.

RESEARCH ON CONSTITUTIVE MODEL OF MARBLE OF JINPING HYDROPOWER STATION UNDER LOADING AND UNLOADING CONDITIONS

A series of loading and unloading tests of marble from deep-buried diversion tunnel of Jinping hydropower station are carried out，which reveal that marble specimens have remarkable volumetric dilatancy before failure in both loading and unloading conditions. To describe the law of volumetric deformation of marble in the tests，a new constitutive model is presented based on modifying Weng¢s model13] of rock mass. Comparison between theoretical and test results indicated that the proposed model can describe the characteristics of marble volumetric deformation well. This model can consider the discrepancy of rock strength under loading and unloading conditions；and it can be used to describe unloading process from uniaxial compression stage；the proposed model is of high applicability.