Tensile strength is a key parameter controlling the formation of desiccation cracks in soils. Desiccation cracks are triggered in unsaturated soils due to drying imposed by natural processes or engineering applications mainly involving elevated temperatures. However, there is no closed-form model in the literature to capture the effect of temperature on tensile strength. This study presents a temperature-dependent model for the tensile strength characteristic curve (TSCC) of unsaturated soils. The model employs the suction stress characteristic curve (SSCC) to represent the uniaxial tensile strength of unsaturated soils at different water contents and temperatures. The model incorporates the effects of temperature into adsorptive and capillary suction stress components. The temperature-dependent adsorptive suction stress is obtained by accounting for thermal induced changes in suction stress at dry state through the Hamaker constant and the density of water. The temperature-dependent form of capillary suction stress is derived by employing temperature-dependent forms of surface tension, contact angle and enthalpy of immersion. Upon comparison, results from the proposed TSCC exhibited a very good agreement against laboratory-measured tensile strength data for two clayey soils tested at different temperatures ranging from 20 to 60 °C. The presented model can improve the analysis of desiccation cracking in unsaturated soils.

抗拉强度是控制土壤干燥裂缝形成的关键参数。由于自然过程或主要涉及高温的工程应用造成的干燥，不饱和土壤中会引发干燥裂缝。然而，文献中没有封闭形式的模型来捕捉温度对拉伸强度的影响。本研究提出了非饱和土的抗拉强度特征曲线 (TSCC) 的温度相关模型。该模型采用吸力特征曲线（SSCC）来表示不同含水量和温度下非饱和土的单轴抗拉强度。该模型将温度的影响合并到吸附和毛细管吸入应力分量中。通过 Hamaker 常数和水的密度，通过考虑干燥状态下吸力的热诱导变化，获得与温度相关的吸附吸力。毛细管吸入应力的温度相关形式是通过采用表面张力、接触角和浸没焓的温度相关形式得出的。经比较，所提出的 TSCC 的结果与实验室测量的在 20 至 60 °C 不同温度下测试的两种粘土的抗拉强度数据非常吻合。所提出的模型可以改进非饱和土中干燥开裂的分析。毛细管吸入应力的温度相关形式是通过采用表面张力、接触角和浸没焓的温度相关形式得出的。经比较，所提出的 TSCC 的结果与实验室测量的在 20 至 60 °C 不同温度下测试的两种粘土的抗拉强度数据非常吻合。所提出的模型可以改进非饱和土中干燥开裂的分析。毛细管吸入应力的温度相关形式是通过采用表面张力、接触角和浸没焓的温度相关形式得出的。经比较，所提出的 TSCC 的结果与实验室测量的在 20 至 60 °C 不同温度下测试的两种粘土的抗拉强度数据非常吻合。所提出的模型可以改进非饱和土中干燥开裂的分析。