石板冲击凿入的变形与破坏规律研究

Deformation and Failure Characteristics of Rock Plates Under Percussive Penetration

对花岗岩板进行了低速冲击凿入实验.实验表明:石板在冲击凿入时主要产生径向裂纹和锥形裂纹,径向裂纹由侵入点的背面向外向正面发展,锥形裂纹由冲击点向背面发展;径向裂纹主要是由局部挠曲产生的,锥形裂纹是由赫兹接触拉应力产生的.由于石板的尺寸有限,锥形裂纹可以发展到石板背面,石板上被冲出小锥体;径向裂纹可以导致石板整体破坏.由于局部挠曲和破裂的相互斗争,石板的冲击凿入载荷-侵深曲线为双驼峰形.

The experiments of percussive penetration into rock plates at low velocities were made. The experimental results indicate that radial cracks and cone cracks are main cracks in rock plates penetrated by percussive penetration system. The radial cracks start at the opposite of penetrating point, and then develop to out and to obverse, but the cone cracks are develop from penetrating point to reverse. The radial cracks are caused by local bend, and the cone cracks are caused by Hertzian tensile stress. By the size limit of rock plates, cone cracks may reach rear face, therefore, a cone body will be dashed out on the plate, and the rock plate can be broke out totally by the radial cracks. Because of the struggle between local bend and failure, the percussive fore-penetration curves have two peaks.