基于非等温管道流竖井地基热排水固结模拟

针对新技术热排水固结法，采用非等温管道流模拟竖井中U型导热管的传热过程，考虑温度对竖井扰动区和未扰动区渗透性的影响，在COMSOL Multiphysics有限元软件中进行二次开发，建立了竖井地基热排水固结法的有限元模型。以热排水固结软基处理原型试验为例，重点分析了模型耦合、部分耦合和不耦合情况下软土地基的固结度。结果表明，相对于传统排水固结法的不耦合模型，部分耦合模型下因温度产生的孔压增量延缓了地基固结的发展，固结速率有所减慢；耦合模型下温度虽也产生一定的孔压增量，但温度有效地改善了竖井涂抹区土的渗透特性，地基的固结速率加快，固结周期缩短，与试验结果一致。

Simulation of consolidation by vertical thermal drain based on non-isothermal conduit flow

Regarding the new technique of thermal drainage consolidation method, the finite element model of thermal drainage consolidation method for vertical drain foundation is developed through secondary development on the base of COMSOL. Multiphysics software in which the heat transfer process of U-shaped heat transfer tube in the vertical drains is simulated with the theory of non-isothermal conduit flow, and the effect of temperature on permeability of disturbed and undisturbed zone of the vertical drains is considered. Then, taking the prototype test of thermal drainage and consolidation of soft foundation treatment as an example, the consolidation degree of soft soil foundation is analyzed mainly on the condition of coupling, partial coupling and non-coupling model. It is shown that the rate of consolidation in the partial coupling model decreases in comparison with the non-coupling model used in the traditional drainage consolidation method, because the extra pore pressure induced by the temperature delays the development of consolidation of soil. In case of coupling model, the rate of consolidation is accelerated and consolidation period is shortened because the temperature effectively improves the permeability of soil in vertical drain smear zone, although the extra pore pressure can also be induced by the temperature. The result of computation is in agreement with the test results.