裂隙形式对岩体强度特征及破坏模式影响的试验研究

Experimental study of effects of fracture type on strength characteristics and failure modes of fractured rockmass

利用RMT-150C电液伺服机对含不同预制裂隙形式(单、双、T形交叉及X形交叉裂隙)的类岩石试样进行了单轴压缩试验,系统地研究了裂隙形式对试样强度特征及失稳模式的影响。试验发现,(1)不同裂隙形式下裂隙的起裂破坏模式主要表现为初始裂隙起裂破坏,裂隙形式与破坏模式关系不突出;(2)单轴抗压强度受裂隙形式影响明显,随着裂隙形式由单裂隙到X形交叉裂隙变化,裂隙试样抗压强度呈现增高趋势,同时试样起裂和失稳时的声发射总能量也逐渐增大。进一步对裂隙形式影响强度特征的机制进行了初步分析,研究成果可以反映不同裂隙形式组合对工程岩体稳定性的影响规律。

A series of uniaxial compression tests is carried out on the gypsum specimens with different fracture types, including single fracture, two coplanar fractures, T-shape and X-shape cross-fractures, through the electrohydraulic servo machine RMT-150 C. Then, influences of fracture types on failure modes and strength characteristics are investigated. The experimental results show that:(1) The failure mode is initial fractures propagation for all the specimens with different fracture types, which means that the relationship between failure mode and fracture type is not obvious.(2) The fracture type can affect the uniaxial compressive strength(UCS) of specimens significantly, with the fracture type transfer from single fracture to the X-shape cross-fractures, the UCS increase gradually; and the total acoustic emission energy of fracture specimens initiation and unstable increase too. Furthermore, the mechanism of how the fracture type affects the UCS is studied preliminarily. The research results can reflect the influence laws of different fracture types on the stability of rock mass.