The Hoek–Brown (HB) failure criterion provides reasonable estimates of the peak strength of isotropic rocks for shear failure; however, this is less so for tensile fractures. Hoek and Brown advised against the direct application of the HB criterion during excavation at deep depths and introduced a tension cut-off (TC) based on reliable extension test data. However, its influence on rock structures remains unclear, with no previous studies on safety assessment considering TC. In this study, a stability analysis of deep tunnel roofs was performed using the HB yield function with reduced or eliminated tensile strength. The parabolic form of the HB envelope was terminated using a circular arc in the tensile stress regime. Such a modification allows some part of the failure mechanism to be separated from the stationary rock with a large volumetric strain governed by the TC. The kinematic approach of limit analysis was utilized as the study approach. The computation results revealed that, among the two common tunnel cross-sections, rectangular tunnels were susceptible to the TC, i.e., the stability number with 10% of the theoretical tensile strength was more than twice that of the original envelope. Circular tunnel roofs can be self-supported even with a zero tensile strength (19% increase in the stability number) owing to the addition of a confining stress. For different HB constants, the relative increase in the stability number subjected to the TC was surprisingly consistent. The factor of safety, defined as the shear strength and required supporting pressure, was derived from the envelope with a TC.

Hoek–Brown (HB) 破坏准则提供了对各向同性岩石剪切破坏的峰值强度的合理估计；但是，对于拉伸性骨折而言，情况并非如此。Hoek 和 Brown 建议不要在深部开挖过程中直接应用 HB 标准，并根据可靠的延伸试验数据引入张力截止 (TC)。然而，其对岩石结构的影响尚不清楚，之前没有关于考虑 TC 的安全评估的研究。在这项研究中，使用降低或消除抗拉强度的 HB 屈服函数对深隧道顶板进行了稳定性分析。HB 包络线的抛物线形式在拉伸应力状态下使用圆弧终止。这种修改允许破坏机制的某些部分与具有由 TC 控制的大体积应变的静止岩石分离。极限分析的运动学方法被用作研究方法。计算结果表明，在两种常见的隧道断面中，矩形隧道易受TC影响，即10%理论抗拉强度下的稳定数是原围护结构的两倍以上。由于增加了围压，即使抗拉强度为零（稳定数增加 19%），圆形隧道顶板也可以自支撑。对于不同的 HB 常数，受 TC 影响的稳定性数的相对增加惊人地一致。安全系数，定义为剪切强度和所需的支撑压力，