季节性冻土区引水暗渠的临界埋深数值分析

Numerical analysis of the critical buried depth of the culvert in seasonally frozen ground regions

在季节性冻土地区,输水暗渠受低温作用,不但引起混凝土结构的冻胀破坏,还将影响暗渠内的引水水体温度,导致水体结冰及暗渠阻塞.因此,需要对季节性冻土地区的暗渠结构在不同埋深情况下的温度场进行数值计算,确定其临界埋深.通过瞬态温度场的导热微分方程,采用迦辽金法推导出温度场的二维有限元公式,根据甘肃引洮工程的工程地质勘探报告及施工设计图纸,建立了暗渠数值计算模型.通过数值分析可知:埋深越大,对渠体结构的冻胀影响越小,低温季节时,地表低温对引水运行的影响也越小;通过对低温季节环境下的回归拟合分析,得出该地区季节性冻土中引水暗渠的临界埋深为3.31 m.

In seasonally frozen ground regions, low-temperature condition would cause frost heave damage to the concrete configuration of the culvert and change the water temperature, which would result in water freezing and block. Therefore, it is necessary to determine the critical buried depth of the culvert in seasonally frozen ground regions. In this study, a numerical model for culverts in seasonally frozen ground is established by using transient heat transfer equation and Galerkin method. According to the engineering geological prospecting and construction design of the Taohe River Water Diverting Project in Gansu Province, the critical buried depth of the culvert is calculated. The numerical analysis shows that larger buried depth has less frost heave influence on the configuration and that the lower surface temperature in cold seasons has less influence on water diverting. According to fitting analysis, the critical buried depth of culvert is 3.31 m in this seasonally frozen ground region.