In this paper, a series of experiments were conducted on typical volcanic breccia collected from the foundation of Baihetan Dam. Considering previous work, the mechanical behavior and permeability of the volcanic breccia were further investigated. The experimental results showed that the compressive strength and Young’s modulus of the volcanic breccia decrease due to the presence of water. However, the Poisson’s ratio of the wet specimens was higher than that of the dried specimens. The permeability evolution under triaxial compression was divided into 5 stages. The fluid pressure showed a great influence on the permeability of the volcanic breccia. The water weakening mechanism and the effect of fluid pressure on the permeability were discussed. The effect of water on the strength of volcanic breccia is influenced by both subcritical crack growth and calcite dissolution. Due to the pore pressure gradient and the water weakening effect, the change in permeability with volumetric strain varies greatly.

本文对从白鹤滩大坝基础采集的典型火山角砾岩进行了一系列实验。考虑到先前的工作，进一步研究了火山角砾岩的力学行为和渗透性。实验结果表明，由于水的存在，火山角砾岩的抗压强度和杨氏模量降低。但是，湿样品的泊松比高于干样品的泊松比。将三轴压缩下的渗透率演化分为五个阶段。流体压力对火山角砾岩的渗透性影响很大。讨论了水弱化机理和流体压力对渗透率的影响。水对火山角砾岩强度的影响受亚临界裂纹扩展和方解石溶解的影响。由于孔隙压力梯度和水减弱作用，渗透率随体积应变的变化很大。