某水电站高边坡煤系软弱结构面流变特性试验研究

EXPERIMENTAL RESEARCH ON RHEOLOGICAL CHARACTERISTICS OF WEAK STRUCTURAL PLANES OF HIGH SLOPES IN COAL STRATA IN A HYDROPOWER STATION

针对坝区开挖高边坡煤系地层软弱结构面的发育特点,设计和开发饱水条件,软弱结构面剪切流变试验装置,系统开展高边坡煤系地层中软弱结构面的时效变形特性研究,尤其是通过长达近1a的流变力学试验,应用Burgers流变本构方程,建立各种类型软弱结构面的综合时效本构方程,获取坝区煤系地层软弱结构面的长期强度参数。剪切流变试验结果表明,饱水状态下软弱结构面长期强度参数c值为57～160kPa,φ值为12°～18°,比利用携剪试验所获得的软弱结构面饱水快剪强度参数折减约60%。研究结果为水库蓄水运行期的边坡安全反馈分析、变形机制、边坡加固防治对策的采取及支护设计优化提供重要的理论依据,也为类似工程边坡软弱结构面提供具有参考价值的本构模型。

In view of developmental features of the weak structural planes of excavation high slopes in the coal strata, the shearing rheological test device for the weak structural planes is designed and built in the saturated situation. The time-dependent deformation characteristics of the weak structural planes in the coal strata are studied systematically. On the basis of rheological mechanical tests, which lasts for nearly 1 year, the comprehensive time-dependent constitutive equations of each type of the weak structural planes are established, and the long-time strength parameters are acquired by adopting Burgers theological constitutive equation. The results of theological tests show that the long-term cohesive force of the weak structural planes c ranges from 57 to 160 kPa under the saturated conditions, and （o is between 12° and 18°, which decreases about 60% in contrast with that of saturated quick portable shearing test. The results obtained are important for feedback analysis, deformation mechanism and optimum design of slope related to safety of stabilization during the reservoir operation in engineering region. And referenced constitutive model is provided for the similar weak structural planes of high slopes.