等效岩体技术在岩体工程中的应用

 以某露天矿边坡为工程背景，结合岩石力学参数室内和现场原位试验，基于颗粒流理论和PFC3D程序，运用等效岩体技术，建立充分反映节理分布特征并考虑细观破裂效应的等效岩体模型，采用Fish语言编制加卸载命令流，研究岩体的强度和力学效应。研究结果表明：(1) 等效岩体在单轴压缩时，轴向应力–应变曲线分为弹性变形阶段、非稳定破裂塑性阶段和破裂后阶段，抗压强度和弹性模量与标准岩块试样相比，有较大幅度降低；(2) 随围压增大，等效岩体抗压强度和残余强度明显提高，延性特征增强，逐渐向理想塑性过渡；(3) 等效岩体技术能有效地描述岩体受节理分布影响而表现的各向异性特征；(4) 等效岩体内部微裂纹主要沿节理走向分布并扩展，破坏形式受主导节理面产状及性质控制。

APPLICATION OF EQUIVALENT ROCK MASS TECHNIQUE TO ROCK MASS ENGINEERING

On the background of an open-pit rock masses，some rock mechanics laboratory and field tests are implemented. Based on the particle flow theory and PFC3D(particle flow code in 3 dimensions)，equivalent rock mass(ERM) technique is used to construct ERM model，which reflects the distribution feature of the joints and meso-scale fracture effect. A load-unload code is developed by Fish language in PFC3D to study the strength and mechanical effect of the rock mass. Some study results are drawn as follows：(1) Under the condition of uniaxial compression，the axial stress-strain curve of ERM is divided into three stages，which includes elastic deformation，plastic deformation of unsteady fracture and deformation of post-failure. Compared with standard rock samples，compressive strength and elastic modulus of the ERM are significantly decreased. (2) With increase of confining pressure，compressive strength，residual strength and plasticity of ERM are enhanced. (3) The ERM technique efficiently can describe rock mass anisotropy induced by joints distribution. (4) Microcrack in ERM is distributed and extends along strike direction of joints. Therefore rock mass failures are controlled by properties of the dominant joints.