基于裂隙形状函数的自然环境高温下花岗岩裂隙尖部非线性温度场

Nonlinear temperature field of granite fracture tip induced by high natural environmental temperature based on fracture shape function

高温环境下,南方地区隧道洞口段岩体温度波动剧烈,长期累积作用引起隧道热病害。针对岩体裂隙尖部热传导性质非线性,应用格林函数法和镜像法建立裂隙岩体三角形热源函数表达式,计算裂隙尖部温度场,并分析裂隙形状参数和裂隙间相互作用的影响。计算表明,太阳辐射时段内裂隙岩体内部较不含裂隙岩体内部温度高;相同长度的三角形裂隙,顶角越大岩体温度变化幅度越大;对于平行裂隙与共面裂隙,间距越小裂隙尖部温度场叠加效应越强,间距越大温度值越趋于单裂隙温度值。裂隙岩体比不含裂隙岩体温度传递快,温度等值线围绕裂隙呈现,裂隙周围温度明显升高。研究结果为高温环境下隧道洞口裂隙岩体热应力分析提供理论依据。

Thermal deterioration of rock occurs in tunnel portal section due to temperature fluctuation of rock in high temperature environment in southern China.As heat conduction of fracture tip is nonlinear,a triangular heat source function of fractured rock mass is established based on Green’s function method and mirror image method.Temperature distribution of fracture tip is calculated,and influences of fracture shape parameters and multi-fracture interaction on temperature are analyzed.It is found that the internal temperature of fractured rock mass is higher than that of non-fractured rock mass during solar radiation period.For triangular fractures with the same length,the temperature varies greatly as apex angle of triangle is large.When spacing between parallel fractures or coplanar fractures is small,the superposition effect of temperature of fracture tip is strong,and the temperature value tends to that of single fracture with increase of spacing.The temperature of fractured rock mass transfers faster than that of non-fractured rock mass.Temperature isolines appear around fractures,and temperature around fractures increases significantly.The result provides theoretical basis for thermal stress analysis of fractured rock mass in tunnel portal section in high temperature environment.