We performed friction experiments using Scaglia Bianca limestone gouge through a gas medium tri-axial apparatus.The experimental conditions are temperatures from 50℃to 300℃with confining pressure of 150MPa, and different pore pressure.A series of experiments were conducted with pore pressure of 50MPa, no pore pressure but saturated with water, and completely dry condition.Mechanical data and microstructures analysis show that slow slip occurs at 120℃with completely dry condition, without dissolution and precipitation in deformed gouge sample.Under the condition of no pore pressure but saturated with water, typical slow slip occurs, accompanied with little dissolution and precipitation in fault gouge under temperatures of 100℃, 120℃, 150℃, whereas, stick-slip occurs with a lot of dissolution and precipitation in gouge at 300℃.It is stable sliding with main mechanism of dissolution in gouge at temperatures of 50℃and pore pressure of 50MPa.It shows slow slip with main mechanism of dissolution and supplemented by precipitation in deformed gouge at temperatures of 100150℃, stick-slip occurred at 200300℃with main mechanism of precipitation.The results indicated that the transition from steady-state slip to slow slip and to stick-slip with temperatures increasing, which was controlled by dissolution and precipitation of limestone gouge, that may help to understand the chemical effect of fluid to fault sliding.%在气体介质三轴高温岩石力学实验仪器上, 采用意大利Scaglia Bianca石灰岩, 在温度50300℃、围压150MPa, 含50MPa孔隙压、无孔隙压含饱和水和完全干燥三种条件下, 开展摩擦滑动实验.实验力学数据和显微结构表明, 完全干燥样品在120℃时出现慢滑移, 实验样品中没有出现溶解与沉淀.无孔隙压含饱和水条件下, 100℃、120℃、150℃条件下出现典型的慢滑移, 实验样品中含有微弱的溶解与沉淀;300℃条件下出现黏滑, 实验样品中出现沉淀.在含50MPa孔隙压条件下, 50℃时的实验表现为典型的稳滑, 实验样品中以溶解为主;在100150℃时, 出现慢滑移, 实验样品中以溶解为主, 沉淀为辅;在200300℃时, 出现典型黏滑, 实验样品中以沉淀为主.实验结果表明, 石灰岩断层泥摩擦滑动稳定性随温度变化, 受流体中碳酸钙的溶解和沉淀作用控制, 因此, 流体中矿物质的饱和度这一化学性质对断层带的摩擦强度和摩擦滑动稳定性具有显著影响.
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