Preparation and mechanical behaviors of macroscopically isotropic bimrocks

• Main Authors: Chih-Chun Ku, 古智君
• Other Authors: Yong-Ming Tien
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/01715526211961118112

碩士 === 國立中央大學 === 土木工程研究所 === 92 === The main purpose of this research is to study the mechanical properties and behaviors of bimrocks that composed of blocks in matrix. An uniaxial bi-directional compaction mold were designed to prepare the artificial bimrocks. By using different composite materials, the mechanical properties and behaviors with distinct block proportions and stiffnesses of the block and matrix are investigated. For the testing results, the mechanical properties of bimrock are controlled by matrix itself or the interface between block and matrix in uniaxial compression. With increasing confining pressures, the global mechanical properties and behaviors are controlled by both blocks and matrix in triaxial compression. Generally, increasing of block proportions decreased the cohesion and increased the internal friction angle and the material parameter m in Hoek-Brown criteria. Based on the experimental observation, the failure modes of the artificial bimrocks at different block proportions and confining pressures can be classified into four categories: axial splitting mode; shear fracture mode; conjugate shear mode with a main shear plane, and multiple conjugate shear planes mode. For theoretical prediction, the prediction models with assuming perfectly bonded interfaces in composite materials can fit the young’s modulus of the specimens at lower block proportions in uniaxial compression, but the prediction models can’t fit the data at higher block proportions. In triaxial compression, the micromechanics model can be used to predict the test data well.