Hoek-Brown强度准则在隧道围岩卸荷试验中的应用研究

Application of Hoek-Brown Strength Criterion in Tunnel Surrounding Rock Unloading Test

针对含水隧道围岩开挖卸荷后的强度准则适用性问题,以辽宁某在建隧道工程为背景,对该隧道围岩进行了考虑孔隙水压作用下的恒轴压、卸围压三轴卸荷试验,分析H-B强度准则在砂岩卸荷试验中适用性,结果表明:相同孔隙水压条件下,围压越大,试样的卸围压峰值强度越大,但增幅略有降低;相同围压条件下,孔隙水压越大,试样的卸围压峰值强度越小;不同孔隙水压下的H-B强度准则拟合相关系数均在0.95以上,拟合效果良好;建立了考虑围压及孔隙水压作用下的砂岩三轴卸荷H-B强度准则经验模型,并根据试验数据验证了经验模型的合理性.

Aiming at the applicability of strength criterion after excavation and unloading of surrounding rock of water-bearing tunnel,taking a tunnel under construction in Liaoning as the engineering background,the triaxial unloading test of surrounding rock of tunnel under constant axial pressure and unloading confining pressure was carried out,and the applicability of H-B strength criterion in sandstone unloading test was analyzed.The results showed that:under the same pore pressure condition,the unloading peak strength of confining pressure increases with the increase of confining pressure,but the amplification decreases slightly;under the same confining pressure condition,the peak strength of unloading confining pressure decreases with the increase of pore pressure;the fitting correlation coefficients of H-B strength criterion under different pore pressure are all above 0.95,indicating that the fitting effect is good;an empirical model of H-B strength criterion for triaxial unloading of sandstone considering confining pressure and pore pressure is established,and the rationality of the empirical model in this paper is verified according to the experimental data.