【Haichuan Construction Technology】Construction Technical Plan for the New Construction of Boiler Chimneys Using Slip Forming Method

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Key technologies for slipform construction of 180-meter chimneys: a dual-sliding process is used for simultaneous pouring of the cylinder wall and lining; the hydraulic system enables lifting of 3–5 meters per day; laser-based real-time correction ensures deviations remain within 15 mm; the strength of the concrete upon removal from the formwork is controlled with precision to 0.2–0.5 MPa; double-layer safety nets and an automatic sprinkler system ensure safety and quality. I. Project Overview: The new boiler chimney project employs the slipform construction method, which is suitable for reinforced concrete cylindrical structures with a height of up to 180 meters. The chimney lining is constructed using ceramsite concrete or refractory bricks, while the insulation layer is made from materials such as blast furnace slag (with a dry bulk density of 500 kg/m³). For chimney anti-corrosion repairs, call 138—5109—0882 immediately.

II. Construction Process
Site leveling → Measurement and positioning → Earthwork excavation
Foundation construction (inverted T-shaped foundation, including slab pouring, rebar installation, and embedded parts setup)
Assembly of the slipform system (including operating platform, hydraulic lifting device, and formwork system)
Dual-slip construction of the cylinder body (simultaneous pouring of cylinder wall concrete and lining material)
Installation of auxiliary facilities (lightning protection system, aviation markers, ladders, etc.)
Dismantling of the slipform device

III. Key Technical Points
(A) Slipform System Configuration
Formwork system: Steel or aluminum alloy formwork, with a height of 1.2–1.5 meters
Lifting system: Hydraulic jacks (working load ≥ 3 tons per jack); support rods made of φ48×3.5 steel pipes
Operating platform: Circular platform with a width of ≥ 1.2 meters, equipped with a lifting frame (1200×1200 mm)

(B) Control of Cylinder Body Construction
Sliding speed: 3–5 meters per day; concrete strength upon removal from the formwork should be controlled at 0.2–0.5 MPa
Correction measures: Platform tilting method (maximum tilt rate ≤ 1%); forced correction using guide rods (activated when deviation exceeds 15 mm)
Concrete mix ratio: Slump of 6–10 cm, initial setting time of 4–6 hours

(C) Vertical Transportation System
Dual-cage winches (loading capacity ≥ 1 ton)
Auxiliary pulling rod system (lifting capacity ≥ 3 tons)
Concrete delivery is carried out through a combination of pumping and lifting

IV. Quality Assurance Measures
Control of central deviation: Monitored in real time using a laser plumb bob; allowable deviation ≤ 15 mm
Rebar cover thickness: Controlled using positioning fixtures; tolerance ±5 mm
Settlement monitoring: Measurements taken every 30 meters of sliding
Concrete curing: Automatic spraying system used for curing for ≥ 7 days

V. Safety Control Points
High-altitude protection: Double-layer safety nets installed (first layer at 10 meters below the platform)
Lightning protection and grounding: Permanent grounding electrodes used, with a grounding resistance ≤ 10 Ω
Load limitation: Maximum load on the platform ≤ 1.5 kN/m²
Emergency measures: Backup power system (allows jacks to continue working for 2 hours in case of power outage)