天津某厂锅炉房烟囱高45米,筒体用200号混凝土浇筑,衬里为75号红砖,内有4道圈梁,外有爬梯,大、小钢平台各一个。筒壁最大外径4240毫米,衬里最小内径1800毫米;筒壁厚度为150～350毫米,衬里厚度为120～240毫米,空气隔热层厚10毫米,烟囱坡度为2%。一、施工方法 A boiler plant in Tianjin has a 45-meter-high chimney and the barrel is cast with No. 200 concrete. The lining is No. 75 red brick. There are four ring beams inside, and there are ladders outside, one each for large and small steel platforms. The maximum outer diameter of the cylinder wall is 4240 mm, the minimum inner diameter of the liner is 1800 mm, the thickness of the cylinder wall is 150-350 mm, the thickness of the lining is 120-240 mm, the thickness of the air insulation layer is 10 mm, and the chimney slope is 2%. First, the construction method