不同养护温度下充填体-围岩胶结面剪切破坏特征

Shear failure characteristics of cemented interface between filling material and surrounding rock at different curing temperatures

针对深井矿山高地温影响充填体-围岩胶结面剪切破坏特征的问题,开展了养护温度20℃、40℃、60℃和80℃,法向应力为0、0.3MPa、0.6MPa的充填体-围岩胶结面剪切试验,并利用三维激光扫描系统对剪切断面进行扫描,获取断面的破坏特征和参数。研究结果表明:养护温度和法向应力均对充填体-围岩胶结面剪切强度和破坏特征有明显影响。养护温度增大,法向应力不变时,胶结面的抗剪强度先增大再减小,40℃时剪切强度最高;养护温度不变,法向应力增大时,胶结面抗剪强度呈线性增大;断面三维形貌特征参数S_(p)、S_(v)、S_(z)、S_(a)和S_(q)的大小与法向应力的变化呈反比,养护温度变化时其变化趋势与强度变化规律相反,40℃时达到最小值,而S_(sk)的大小与养护温度、法向应力大小无明显关联,S_(ku)的大小随法向应力的增大而增大,养护温度变化时其变化趋势为与抗剪强度变化规律相同。研究结果可为深部矿山井下充填体强度设计和顶板稳定性分析提供理论依据。

In view of the problem that the high temperature of deep underground mine may affect the shear failure characteristics of the cemented interface between the filling material and surrounding rock,the shear tests were carried out on the cemented interface between the filling material and surrounding rock under the curing temperature of 20℃,40℃,60℃and 80℃and with normal stress of 0,0.3 and 0.6 MPa.The failure plane is scanned by 3 D laser scanning system to obtain the fracture characteristics and parameters of the section.The results show that the temperature and normal stress have obvious influence on the shear strength and failure characteristics of the cemented interface of the filling material and surrounding rock.When the curing temperature increases,the normal stress is constant,the shear strength of the cemented interface increases first and then decreases,and the shear strength is the highest at 40℃;the curing temperature remains the same,and the normal stress increases,the shear strength of the cemented interface increases linearly;the shape characteristic parameters S_(p)、S_(v)、S_(z)、S_(a) and S_(q) of the section are inversely proportional to the normal stress.The change trend and strength change when the curing temperature changes.On the contrary,the minimum value is reached at 40℃,while the value of S_(sk) is not significantly related to the curing temperature and normal stress.The value of S_(ku) increases with the increase of normal stress,and the trend of the change of curing temperature is the same as that of shear strength.The research results can provide a theoretical basis for the strength design of underground filling material and the stability analysis of roof in deep mines.