软岩冻融损伤的水热力耦合研究初探

Preliminary study on moisture-heat-stress couple of soft rock freezing-thawing damage

冻融力学研究正温-负温环境交替变化对材料的物理力学性质的影响。由于软岩强度低,孔隙度大,胶结程度差,含有大量膨胀性粘土矿物的松,散,软,弱岩层。因此软岩的水热力的耦合不是一个简单的过程,本文初步提出软岩的水热迁移机理进而提出了了软岩水、热、力耦合的基本数学模型。最后用ANSYS模拟了隧道围岩温度场与应力场,得到了隧道围岩冻胀力的分布趋势。

Freezing-thawing environment affect the stability of cold region soft rock mass structure. Because the soft rock possess the special weak, high void ratio, expensive mineral and loose characteristics, it is not easy to master clearly the process of soft rock freezing-thawing. This thesis base on the analysis of the physics properties of soft rock and the water-rock interaction, according to the continuum medium theory, heat conduct and mass transfer theory, the basic equation takes into account the main processes during soft rock freezing-thawing, including rock water movement, heat conduct, phase change of water and relevant latent heat. With the application of FEM software ANSYS simulating the temperature field distribution of soft rock tunnel, and the coupled simulation of temperature-stress field. The result is accorded with the practice. Regarding the soft rock as space elasticity mass, we set up the moisture-heat-stress coupling models, the damage of the mechanical properties should also be taken into account. Through analytical method to work out the value of frost heaving force, utilizing the equation of rheologial damage to determine the soft rock damage parameter and elastic modulus in the different stage.