充填与非充填双裂隙巴西圆盘试样力学特性试验研究

Experimental Study on Mechanical Behavior of Brazilian Disk with Two Filled and Unfilled Fissures

在验证类岩石材料可行性的基础上,制作了双裂隙巴西圆盘试样.基于巴西劈裂试验,研究了裂隙充填情况对不同岩桥倾角下双裂隙巴西圆盘试样力学特性的影响规律.结果表明,无论裂隙是否充填,试样的峰值强度和峰值应变随着岩桥倾角的增加都呈现先降低后稳定的变化趋势,但充填双裂隙圆盘试样力学参数整体高于非充填试样.结合声发射和数字散斑应变测量系统分析了试样的裂纹扩展特征,将试样破坏模式分为非贯通破坏、次生裂纹贯通破坏和翼裂纹贯通破坏3类,认为试样表面拉应变集中带的形成方式与最终破坏模式直接相关.最后总结了充填物对双裂隙圆盘试样力学特性的影响规律:当裂隙非重叠时,充填物能够显著影响试样的裂纹扩展行为,强化双裂隙圆盘试样的力学特性;裂隙重叠时,充填物主要提升双裂隙圆盘试样峰后承载能力,而对其破裂模式的影响有限;临界重叠状态时,充填物对试样的力学特性几乎没有影响.

A rock-like material was verified and used to make double-fissured Brazilian disks(DFBD).The effect of fissure fillings on mechanical behavior of DFBD with different ligament angle were investigated under Brazilian test.Experiment result shows that,with the increasing of ligament angle,the peak strength and peak strain of DFBD decrease first and then remain stable.However,the mechanical parameters of filled DFBD are generally greater than unfilled.Base on the observations from acoustic emission and digital speckle strain measurement system,the initiation,propagation and coalescence of macroscopic crack was recognize.The failure pattern of DFBD corresponds closely to the formation and expansion of tensile strain concentration band,and can be divided into three categories:non-coalescence,secondary crack coalescence and wing crack coalescence failure.Finally,the effects of fillings on the mechanical properties of DFBD are summarized:when fissures not overlapping,fillings can significantly affect the crack propagation path and strengthen the mechanical properties of DFBD;when fissures overlap,fillings mainly enhance the post-peak bearing capacity;when at critical overlapping state,fillings had little influence on the specimens.