中文摘要：

以混合物理论为基础研究了非饱和土的热-水-力多场耦合问题.将非饱和土视为由土骨架、液态水、水蒸气、干燥气体及溶解气体共5种组分构成的混合物,在组分的质量、动量守恒方程及整体能量守恒方程的基础上,引入了37个补充方程以形成封闭方程组.其中,利用水与水蒸气的化学势改变量相同,推导了在气压力变化条件下水与水蒸气相变平衡所满足的限制方程.最终控制方程以增量形式给出,6个方程求解6个未知量（3个土骨架位移、水压力、气压力及温度）,充分反映了热膨胀、热渗流、水的相变、气体溶解及土骨架变形等多种现象的耦合过程.

英文摘要：

An analysis of coupled thermo-hydro-mechanical behavior of unsaturated soils was presented based on theory of mixtures.Unsaturated soil was considered as a mixture composed of soil skeleton,liquid water,vapor,dry air and dissolved air.In addition to mass and momentum conservation equations of each component and energy conservation equation of the mixture,the system was closed using other 37 constitutive （or restriction） equations.In virtue of the requirement that the change in water chemical potential was identical with the change in vapor chemical potential,a thermodynamic restriction relationship for phase transition between pore water and pore vapor was formulated,in which the impact of the change in gas pressure on the phase transition was taken into account.Six final governing equations were given in incremental form in term of six primary variables,i.e.three displacement components of soil skeleton,water pressure,gas pressure and temperature.The processes involved in the coupled model included thermal expansions of soil skeleton and soil particle,Soret effect,phase transition between water and vapor,air dissolution in pore water,deformation of soil skeleton,etc.