隧道火灾可能毁损隧道衬砌支撑，造成隧道坍塌。通过对热损分布关系进一步了解，有助于在灾前提高材料的防火性能设计，并在灾后较精准的预测其损害范围，进而降低修缮成本。以往的研究都采用个别式热损试样准备法，无法准确预测没有试验数据的结果，故本研究提出连续热驱试样准备法，从而得出连续性的试验数据。本研究研析水泥砂浆受连续热损后，其拉力强度及破裂韧度与温度的相互关系。藉由试验结果，除可获得较为精确的预测方程外，并以LogLog交点法得到相对合理与准确的临界热损温度(540~550 ℃)，以期为隧道火灾防范提供参考。

Tunnel lining could be damaged by tunnel fire, which may directly or indirectly induces the collapsing of tunnel. If engineers could better understand the distribution of thermoinduced damage, they can either improve the design by considering the protective measures beforehand, or they can provide better repairing plans by predicting the damage zones more accurate after tunnel fire. Previous researches used discrete heat treatment method to prepare the specimens; predictions between data points cannot be accurate. In this research, continued heat treatment method was used to prepare the specimens; the tensile strength and fracture toughness of the heattreated specimens were investigated. Based on test results, a more rational and accurate prediction equation is proposed and the critical damaging temperature is found to be about 540~550 ℃. The test results can be used as reference in engineering design for better protection of tunnel lining against fire. 