流纹岩双轴抗压力学特性及破坏机理研究

在隧道和边坡开挖过后,其边界部分位置的岩石近似处于双轴受压状态。通过对泥巴山隧道流纹岩试件的双轴压缩试验,均表现出明显的脆性,部分双轴高侧压试件呈现出一定的塑性;试件的双轴抗压强度呈现出一个增大再降低的过程,发现侧压对弹性模量E的影响并不显著,而侧压对变形模量E50的影响显著;双轴压缩条件下,随着侧向约束的增加,试件破裂时破裂面数量减小,由呈板裂的多个破裂面逐渐向单个破裂面变化。DP3破坏准则与试验结果相关性较好,能够应用于双轴条件下流纹岩强度特性研究。

Study on Mechanical Property of Biaxial Compression in Rhyolite and the Failure Mechanism

After tunnel or slope is excavated, the rock at some positions on the boundary is in the state of biaxial compression approximately. The rhyolite specimens from Nibashan Tunnel, on which biaxial compression test was conducted, showed obvious fragility, but some ones for biaxial test under high lateral pressure present certain plasticity. The biaxial compressive strength of the specimens is represented by a process of first increase then decrease ; however, it was found that the lateral pressure has unremarkable effect on elastic modulus E, but significant influence on deformation modulus E50; under the condition of biaxial compression, as the lateral constraint increases, the number of rupture surface in the specimen failure reduced, which changes from the multiple rupture surfaces of plate cracking to single rupture surface. The correlation between DP3 failure criteria and the test result is good and capable of being applied to the research on the rhyolite＇s strength properties under biaxial condition.