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为研究无侧限和有侧限条件下软岩贯入破坏特征,结合声发射检测技术和电镜扫描试验进行泥岩立方体试样常截面滚刀贯入试验,分析试验过程中荷载-贯入度曲线和声发射参数特征,并对岩石渣块断口进行细观电镜扫描,研究了破坏时细观和宏观裂纹形成过程。试验结果表明,(1)无侧限和有侧限贯入试验中荷载-贯入度曲线在跃进荷载处均出现明显峰值,跃进荷载峰值以后无侧限试样完全破坏,有侧限试样尚未完全破坏;(2)当宏观裂纹产生时无侧限试样声发射参数出现明显峰值,主要源于该宏观裂纹在试样内部的扩展。有侧限试样破坏过程中出现多次声发射参数峰值,对应多条宏观裂纹形成和扩展;(3)常截面滚刀贯入过程中试样内部出现微滑动,剪切破坏现象比较明显,可以认为滚刀贯入过程中泥岩破坏模式以剪切破坏为主。
In order to study the failure characteristics of soft rock under unconfined and confined conditions, the cutter penetration test was carried out on the normal cross section of mudstone cube with acoustic emission and electron microscopy. The load-penetration curve The characteristics of acoustic emission parameters were analyzed. The fracture of rock clinker was observed with a scanning electron microscope (SEM), and the formation of mesoscopic and macroscopic cracks during failure was studied. The results show that: (1) The load-penetration curve shows obvious peak value at the leaping load in the unconfined and confined penetration test. The unconfined sample is completely destroyed after the peak value of the leaping load, and the confined sample (2) Acoustic emission parameters of unconfined sample appear obvious peaks when macroscopic cracks occur, mainly due to the expansion of the macroscopic crack inside the sample. There are many times of acoustic emission peak in the process of specimen failure, corresponding to the formation and expansion of a number of macroscopic cracks. (3) The phenomenon of micro-slip and shear failure is obvious in the specimen during the penetration process of the normal section, It can be considered that the failure mode of mudstone during shear penetration is dominated by shear failure.