统一强度理论下非均匀应力隧洞围岩抗力系数

Rock Resistance Coefficient in Non-uniform Stress Tunnel under the Unified Strength Theory

基于统一强度理论,合理考虑了围岩的中间主应力和剪胀特性的影响,采用岩石材料的弹塑性模型和非关联线性流动法则,通过引入地应力侧压力系数λ,推导了非均匀应力场下圆形隧洞围岩抗力系数的通用计算公式。由于统一强度理论具有明确的物理意义和广泛的适用性,而侧压力系数的引入能更好地描述隧洞开挖后围岩所处的真实应力状态,因此推导出的抗力系数公式具有更广泛的意义。最后通过实例分析了围岩抗力系数与侧压力系数λ、极轴夹角θ和剪胀系数h之间的关系。分析表明:随着侧压力系数和剪胀系数的增大,围岩抗力系数逐渐减小,隧洞不同位置处围岩抗力系数也不相同,在隧洞两侧,围岩抗力系数值最大,在拱顶和拱底处最小。

Based on the unified strength theory, rationally considering the impact of the rock intermediate principal stress and dilation, using the elastic-plastic model of rock material and non-associated linear flow rule, through the introduction of ground stress lateral pressure coefficient k, a general calculation formula of tunnel rock resistant coefficient under non-uniform stress field was deduced. As the unified strength theory has clear physical meaning and broad applicability, and the introduction of lateral pressure coefficients can better describe the rock real stress state after the excavation of tunnel, so the derived resistance coefficient formula has more extensive use significance. Finally, an example is given to analyze the relationship among the resistance coefficient and lateral pressure coefficient A, the polar angle 0 and dilation coefficient h. Analysis shows that： with the increase of lateral pressure coefficients and dilation coefficients, rock resistant coefficient decreases. At different locations in tunnel, rock resistant coefficient is not the same. On both sides of the tunnel, the rock resistant coefficient values are maxi- mal, and at the top and bottom of the arch, they are minimal.