【作者】 谭文彬；

【导师】 何昌荣；

【作者基本信息】 中国地震局地质研究所 ， 构造地质学， 2007， 硕士

【摘要】 岩石摩擦滑动的力学行为能够很好地用速率和状态依赖性摩擦本构关系来描述。在速率和状态依赖性本构关系中，参数a-b的值非常重要，它控制着摩擦滑动稳定性。微小扰动对摩擦滑动的影响的分析(线性分析)表明，摩擦滑动中不稳定产生的重要条件是速率依赖性参数a-b＜0。本实验室以辉长岩为例已对下地壳中典型的基性岩进行了摩擦实验研究，并用这些实验结果分析了下地壳的地震成因，论证了下地壳地震发生的可能性。笔者对辉长岩中主要矿物(斜长石和辉石)的摩擦性质重点研究，进行了斜长石和辉石的不同加载条件下的3个系列的摩擦滑动实验。实验中发现，辉石的摩擦滑动比斜长石更难进入位移强化影响较小的近稳态滑动的状态，而正压力恒定控制能使辉石进入更接近稳态滑动的状态。对于辉石和斜长石摩擦稳定性的研究，得到以下结论：(a)．辉长岩的两种主要矿物(斜长石和辉石)共同决定辉长岩的摩擦滑动稳定性参数a-b的值，但是两种矿物对辉长岩摩擦滑动稳定性的影响程度却还不能定量分析。(b)．在高温段辉长岩和辉石的a-b的值为负，而斜长石为正。辉长岩在高温段摩擦滑动出现速度弱化，甚至出现粘滑现象，这是由辉石的摩擦滑动稳定性决定的。(c)．而辉石和斜长石摩擦滑动稳定性数据应用到分析其它岩石(如闪长岩)的滑动稳定性，需要考虑各种矿物成分对岩石摩擦滑动稳定性的贡献。更多还原

【Abstract】 Mechanical behaviors of frictional sliding of rocks can be described well by rate- and state- dependence friction laws. The parameter a - b in the friction laws is important in controlling stability of frictional sliding. Analysis of small perturbation around steady state sliding for a spring-slider system (linear analysis) shows that the condition for self-sustained instability to occur is a negative rate dependence of friction (a - b < 0).Our laboratory has performed experimental studies on frictional sliding of gabbro, a typical mafic rock in the lower crust. Based on the results, analysis has been made on the possible cause of earthquakes in the lower crust. Focusing on plagioclase and pyroxene, the major minerals of gabbro, in this study the author conducted 3 sets of experiments of frictional sliding on plagioclase and pyroxene under different loading conditions. It has been found from these experiments that frictional sliding of pyroxene is more difficult to approach a steady state than that of plagioclase, and the constant normal stress control makes it easier for pyroxene gouge to approach the steady state. Research on the frictional stability of plagioclase and pyroxene draws conclusions as follows: (a). two major constituents of gabbro, plagioclase and pyroxene codetermine the parameter a-b critical for sliding stability of gabbro, but quantitative contributions by the two constituents on sliding stability of gabbro is not available. (b). Compared to the positive a-b values of plagioclase, negative values of a-b occurred for gabbro and pyroxene in the higher temperature range. Velocity weakening or stick-slip behaviors of gabbro under higher temperature are consequently determined by the property of frictional sliding of pyroxene. (c). If data for frictional sliding of plagioclase and pyroxene are employed to analyze sliding stability of other rocks, such as diorite, contributions of different mineral constituents of rocks should be considered.更多还原