高温变温条件下喷射混凝土-花岗岩胶结面剪切强度

Shear Strength of Cementation Plane between Shotcrete and Granite under High and Variable Temperature

选取法向应力、养护初始温度、养护湿度、胶结面粗糙度(JRC)等级4个影响因素,采用正交设计确定并开展25组喷射混凝土与花岗岩不规则胶结面的直剪试验,试件养护采用基于高岩温隧道喷射混凝土温度变化规律的高温变温养护方法。结果表明:法向应力、养护初始温度、养护湿度、胶结面粗糙度均对喷射混凝土与花岗岩不规则胶结面的剪切强度影响明显;各因素对剪切强度影响由强到弱依次为法向应力、养护湿度、养护初始温度、胶结面粗糙度;剪切强度随法向应力和养护湿度的增加而增大,随养护初始温度和胶结面粗糙度的增加先增大后减小;剪切强度计算公式可表示为包含法向应力、温度、湿度、胶结面粗糙度等级的多项式。

The four factors of normal stress,initial curing temperature,curing relative humidity and roughness of cementation plane were chosen and their level values were determined.A total of 25 groups of direct shear tests on cementation plane between shotcrete and granite were carried out using orthogonal design.The specimens were cured by the high and variable temperature curing method which was based on the temperature changing law of shotcrete in high rock temperature tunnel.The results show a significant influence of normal stress,initial curing temperature,roughness of cementation plane,and curing relative humidity on the shear strength of irregular cementation plane between the shotcrete and granite.The influence of various factors on the shear strength in an order from strong to weak is normal stress,curing relative humidity,initial curing temperature and roughness of cementation plane.The shear strength increases with the increase of normal stress and curing relative humidity.It increases first and then decreases with the increase of initial curing temperature and roughness of cementation plane.The mathematical expression of the shear strength is a polynomial of normal stress,initial curing temperature,curing relative humidity and roughness.