供热管道穿跨越城区景观河设计与应力验算

Design and Stress Checking Calculation of Heating Pipeline Crossing across Urban Landscape River

在某供热工程中,供热管道(供回水管道规格为DN 1 200 mm)沿城区主干路机动车道敷设,沿途多处需穿跨越城区景观河。针对供热管道穿跨越河面宽度为25 m景观河(过河桥采用暗桥方式),对设计方案进行筛选,对供热管道进行应力验算与位移计算。在比较3种穿跨越设计方案(河底开挖直埋穿越、河底非开挖顶管穿越、河面架空跨越)的施工难度、工程造价、对城区景观影响的基础上,最终选取河底开挖直埋穿越设计方案。在穿越景观河时,供热管道倾斜向下至景观河暗桥以外区域进行直埋敷设(埋深要求为稳定河床下1 m)。采用START Prof软件对供热管道进行应力验算与位移计算。各节点均满足应力验算要求。供热管道倾斜向下位置的弯头位移较大,为防止运行时保温层出现挤压变形而失去保温作用,可在弯头出现位移一侧设置柔性泡沫垫,吸收部分位移。

In a heating project,the heating pipeline（ water supply and return pipes of DN 1 200 mm） is laid along the main trunk roads in urban areas,needing to cross across the urban landscape rivers at many places. Aimed at a landscape river with a width of 25 m（ the river bridge is the dark bridge）,the design scheme is screened,and the stress checking and displacement calculation of the heating pipeline are performed. On the basis of comparing the construction difficulty,the project cost and the influence on urban landscape of 3 kinds of crossing across design schemes（ directly buried crossing by excavation at river bottom,pipe-jacking crossing by trenchless at river bottom and river overhead crossing）,the design scheme of directly buried crossing by excavation at river bottom is selected finally. While crossing the landscape river,the heating pipeline inclines downward to the area outside the landscape river dark bridge to be directly buried（ the buried depth is required to 1 m below the stable river bed）. The stress checking and displacement calculation of the heating pipeline are carried out by the Start Prof software. Each node satisfies the stress checking requirement. The elbow displacement of the heating pipeline at an inclined downward position is larger. In order to prevent that the thermal insulation layer is deformed by pressure and loses its insulation effect during operation,a flexible foam pad can be installed on the displacement side of the elbow to absorb part of the displacement.