花岗岩隧道脆性破坏的温度效应研究

目前深埋硬岩隧道的岩爆等脆性破坏研究还较少考虑到温度的作用效应。采用精细网格数值模型，提出热-脆性-精细力学计算方法，应用能反映高地应力下硬岩脆性破坏特点的岩体劣化模型，结合能量计算指标，开展了不同温度作用下隧道硬岩脆性破坏的热力耦合分析。以瑞典APSE花岗岩隧洞岩柱为例，进行不同地温下隧道破坏区、能量释放值和应力指标的定量化对比研究。研究结果表明，隧道地温的增加将使岩体产生附加温度应力，进而增大其脆性破坏程度，计算结果与隧道现场的破坏规律基本一致。热-脆性-精细力学计算能合理描述硬岩的损伤和渐进破坏过程，计算结果较好地揭示了花岗岩等硬岩深埋隧道脆性破坏的温度作用效应，对于高应力、高地温下深部工程的稳定性评价具有指导意义。

Thermal effect of brittle failure for granite tunnel

Thermal effect of brittle failure for hard rock tunnel under high geostress and high ground temperature need to be studied urgently; and the calculation analysis related to brittle failure rarely considers thermal effect. Based on the method of thermal-brittle-fine mechanical calculation, the thermal effect of excavation unloading for hard rock tunnel is calculated by using a new constitutive model reflecting the brittle failure of hard rock; and the energy release rate index is also analyzed. Taking the rock pillars of APSE tunnel in Sweden for example, the mechanical response of tunnel excavation is analyzed under different ground temperatures. Then the damage degree of surrounding rock is analyzed under the action of temperature loading. The failure zone, energy release value and stress index are compared under different ground temperatures. The result shows that increased temperature will strengthen the brittle failure because temperature will make rock mass to generate additional thermal stress. The method of thermal-brittle-fine mechanical calculation can reasonably describe the progressive failure process of hard rock. The proposed method reveals the thermal effect of brittle failure for deep hard rock tunnel, and could benefit the stability evaluation for deep hard rock tunnel under high ground temperature.