深部矿井岩石水稳性微观机理及强度软化特性研究  

Micro-mechanism of water stability and characteristics of strength softening of rock in deep mines

作　　者：段宏飞[1] 姜振泉[1] 朱术云[1] 肖为国[1] 李冬林[1] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116

出　　处：《岩土工程学报》2012年第9期1636-1645,共10页Chinese Journal of Geotechnical Engineering

基　　金：江苏省普通高校研究生科研创新计划资助项目(CXZZ11-0306);中国矿业大学青年科研基金资助项目(2009A029)

摘　　要：为了研究深部矿井岩石水稳性性质及遇水后强度软化的规律,对巨野煤田千米深部矿井岩石进行了系统的水解试验,表现出6种水解变形破坏形式,结合极限膨胀量特征总结了4类水稳性特征类型,并从饱水试验空隙率的角度论证了分类的合理性。在此基础上,分析了岩石水稳性差异的微观机理,认为微观结构的差异是影响水稳性特征类型的主要原因,而岩石内部高岭石、伊利石和伊蒙混层的相对定量含量是另一原因。岩石饱水后其强度软化明显,而岩石水稳性特征类型对其软化特征具有明显影响并具有一致性,其中饱水后抗拉强度试验中岩石主要呈现层状破坏,而岩石抗剪强度软化的关键是内摩擦角值的变化。不同饱水时间抗拉强度试验表明,岩石抗拉强度随饱水时间的增加呈指数规律减小,最后趋于稳定值;重复浸水-压缩试验表明,多次重复浸水-压缩使得岩样的最终破坏应力下降,出现了强度疲劳现象,其值小于饱和试样一次性加压破坏时的应力,更小于天然状态试样加压破坏时的应力。这是因为岩石每次浸水后内部结构的膨胀效应使得其内部结构发生了软化,从而降低了岩石的结构连接强度。In order to study the properties of water stability and the rules of strength softening of rock, systematic hydrolysis tests are carried out on rock samples from deep mines of Juye Coal Field at depth below one kilometer. The results show six types of hydrolysis deformation and failure. Based on the limit expansion quantity feature, four types of water stability properties are summarized, to demonstrate the rationality of classification by voidage. On this basis, the micro-mechanism of difference in water stability is analyzed, and the main reason lies in the difference in micro-structure and the other reasons include the relative quantitative contents of clay mineral of kaolinite, illite, illite/montmorillonite mixing layer. The strength softening feature of rock samples changes obviously after saturation and is affected by the type of their water stability properties. Moreover, it has good consistency. Layered failure mainly appears in the saturated tensile strength tests. Change in internal friction angle ~p is the key to change in shear strength softening feature. The tensile strength tests on saturated rock samples show that the tensile strength of rock samples decreases with the increase of saturated time with a trend of an exponential decline and has a stable value at the end. The repeated immersion compression tests show that the final failure stress drops on condition of repeated immersion compression of rock samples, and strength fatigue appears. Its value is less than the failure stress of saturated samples under one-time pressure condition, and is much less than the failure stress of natural state samples. This is because the expansion effect of the internal structure of rock samples after immersion makes their internal structure soften, which reduces the connection strength of rock structure.

关 键 词：深部矿井 水稳性 微观结构 强度软化 

分 类 号：TU451[建筑科学—岩土工程]