不同加载速率下砂浆-岩石界面黏结性能试验研究

Experimental Study on Bond Behavior of Mortar-rock Interface under Different Loading Rates

岩石锚固体系中界面的黏结性能对锚固体系的承载力及可靠度意义重大。采用改进的砂浆推出试验方法,探究加载速率对砂浆-岩石界面黏结性能的影响。试验结果表明:当加载速率达到72 mm/min(应变率为1.12×10-4 s-1)及以上时,砂浆-岩石界面发生黏滑现象。黏滑现象通常用于地震发生机理的描述,此次在砂浆-岩石界面力学性能的相关试验研究中也发现了黏滑现象。建立高加载速率下砂浆-岩石界面黏结滑移的细观力学模型,并分析在此条件下界面黏滑作用机理。同时,通过参数分析研究界面黏结性能的加载速率、水灰比、砂浆体长度、砂浆体直径等影响因素。

The bond behavior of the interface in the rock anchor system is of great significance to the bearing capacity and reliability of the anchor system.In this study,a modified push-out method was used to study the bond characteristics of the mortar-rock interface under different loading rates.The test results show that the loading rate,equal to or greater than 72 mm/min(with strain rate of 1.12×10-4 s-1),leads to the stick-slip phenomenon at the mortar-rock interface.The stick-slip phenomenon is usually used to describe the mechanism of earthquake,which was found in the related experimental research on the mechanical properties of the mortar-rock interface for the first time.The micro-mechanical model of the bond-slip at the mortar-rock interface under high loading rate was established,and the mechanism of the interface stick-slip was also analyzed.Meanwhile,the factors affecting the bond performance of the interface,such as loading rate,water-cement ratio,mortar length and mortar diameter were studied based on parameter analysis.