Research On Solar Radiation Law And Thermal Boundary Model Of Typical Engineering In Permafrost Region

The stability of engineering of the permafrost is closely related to the temperature field of the frozen soil surrounding the engineer. Taking engineering thermal boundary conditions, the key to calculation temperature field, as the research object, a series of research works of typical engineering in permafrost regions have been carried out.Field measurement and model test show that the solar radiation is a very important influencing factor of the thermal boundary, but it has not taken the influence of sunshade engineering into full consideration. By analyzing changes of solar radiation intensity and the shadow track over time, we build a analytical method of solar radiation proposed based on the shading theory, and verify the analytical method by model test.Concepts of direct radiation rate and diffuse radiation rate come forward based on shading theory. Physical and mathematical models of direct and diffuse solar radiation, used to study radiation law of typical engineering and surrounding permafrost surface, are established respectively in roadbed, land bridge, roadbed-bridge transition section and other kinds of typical cases.The thermal boundary of engineering and permafrost is a hybrid thermal boundary under the influence of multiple factors. There are two methods to solve the mixed thermal boundary. The first one is the equivalent air temperature method. By using Fourier series superposition principle build the equivalent air temperature of the periodic hybrid thermal boundary condition, as the third kind thermal boundary condition is directly used for thermal analysis of frozen soil and engineering structure. Another is the numerical analysis method. Numerical analysis method is more reliable in practical engineering.In order to facilitate the engineering application, the thermal boundary simplified model is studied here. The simplified model, fitting well, is validated by satellite remote sensing data and field test data. As long as fewer factors involved in the simplified thermal boundary model to solve the thermal boundary temperature of Qinghai-Tibet corridor engineering, it can be extended to the whole Tibetan engineering corridor for thermal analysis of all kinds of engineering.