水饱和边坡夹层热-孔隙水-力耦合作用模型及应用

为了研究温度对水饱和边坡夹层力学参数的影响，将水饱和边坡夹层视为固-液两相的线弹性体，建立了水饱和边坡夹层热-孔隙水-力耦合作用的力学模型，并推导了其耦合控制方程；采用物理相似模拟的方法，建立了与边坡原型相似的试验模型，研究温度引起的边坡夹层力学参数的变化特征；通过比较分析理论计算结果与模型试验结果，验证了所建立的耦合力学模型的适用性。研究结果表明：孔隙水压力系数和热压力系数是引起水饱和边坡夹层孔隙水压力增加的关键控制因素；孔隙水压力系数取决于孔隙排水压缩特性和固相介质压缩特性，这两者差值越大，孔隙水压力系数越大；孔隙水热膨胀系数和孔隙体积热膨胀系数是影响热压力系数的主要因素，这两者差值越大，热压力系数也越大；边坡夹层孔隙水压力随温度升高呈现出先缓慢增加而后急剧增加的变化特征，而黏聚力和抗剪强度随温度升高而缓慢降低，且孔隙水压力的理论计算结果与试验测试结果吻合良好。因此，水饱和边坡夹层热-孔隙水-力耦合作用的力学模型能较好地反映孔隙水压力在加热升温过程中的变化特征，为科学地预测和控制类似边坡工程的稳定性提供了参考。

A coupled thermo-pore water-mechanical model for a weak interlayer in water saturated slope and its application

To investigate the effect of temperature on mechanical parameters of a weak interlayer in water-saturated slope, the interlayer is regarded as a linear elastic body of coupled solid-liquid phase. A mechanical model for the thermal-pore water-mechanical interaction of the interlayer in water-saturated slope is established, and its coupling control equation is deduced. Using the physical similarity method, an experimental model similar to the slope prototype is established to study the variations of the inerlayer mechanical parameters caused by temperature. The proposed model is verified by comparing the theoretical results with the corresponding experimental results. It is found that the pore water pressure coefficient and thermal expansion coefficient are the key factors causing the increase of pore water pressure in the saturated interlayer. The pore water pressure coefficient depends on the compression characteristics of pore drainage and the solid medium. The larger the difference between these two compression characteristics, the larger the pore water pressure coefficient. Thermal expansion coefficient of pore water and thermal expansion coefficient of pore volume are the main factors affecting thermal pressure coefficient. A larger difference between them can result in a greater thermal pressure coefficient. Pore water pressure in the saturated interlayer slowly increases first and then dramatically increases with the increase of temperature, while the cohesion and shear strength of the saturated interlayer tardily decrease with the increase of temperature. Theoretical values of the saturated interlayer pore water pressure are in good agreement with the results from model test. Therefore, the proposed model can reflect the change characteristics of pore water pressure at different temperatures, which can provide some useful references to predict and control the stability of similar saturated slopes containing a weak interlayer.