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How should air‑shield dams achieve anti‑freezing protection and safe operation under extreme freezing‑weather conditions?

Under extreme freezing conditions, the main operational hazards for air‑shield dams include ice‑layer extrusion, pipeline freeze‑blockage, low‑temperature embrittlement and cracking of rubber airbags, as well as jamming caused by ice adhesion. Drawing on years‑long R&D, manufacturing and operation‑maintenance experience of air‑shield dams in cold‑region projects, Huahai Environmental Protection Industry Co., Ltd. has developed practical and streamlined anti‑freezing management schemes to ensure the dam’s safety through winter.

Two operation modes are adopted according to water‑storage requirements. If winter water storage is unnecessary, fully collapse the dam body as the priority measure. Retract the airbags beneath the shield plates to fit closely against the bottom slab, so as to largely avoid impact from static ice pressure. Drain condensed water inside air‑supply pipelines and gas storage tanks in advance, implement intermittent blow‑down for valves, and lower the water level in front of the dam to reduce large‑area ice coverage over the dam structure.

If year‑round water retaining and storage are required, install non‑freezing ice‑troughs continuously running along the front edge of shield plates. Equip underwater aerators and submersible pumps for water‑body disturbance to isolate ice cover from the dam surface and release expansion stress generated by ice mass. Adjust the dam height slightly at regular intervals to prevent freezing‑adhesion between ice layers and steel shield plates. Forcibly lifting or lowering the dam after ice formation is strictly prohibited, as it may tear the airbags.

The air‑supply control system is critical for anti‑freezing purposes. Treat compressed air via drying and purification to strictly control air dew‑point. Lay electric heat tracing and thermal insulation layers for outdoor air pipes and valves, and perform regular blow‑down at low‑points of pipelines every day. Install constant‑temperature heating devices inside automatic‑control cabinets to guarantee normal performance of electrical components. Meanwhile, equip standby air compressors and emergency generators to cope with power‑cut and pressure‑loss risks.

When ice floes approach, arrange ice‑guiding and ice‑retaining facilities in the upstream. Appropriately lower the dam to divert large ice blocks for overflow. Striking or blasting ice in front of the dam is forbidden. Intensify routine inspections for air temperature, ice thickness, airbag pressure and pipeline working conditions. In case of ice jamming or pipeline freeze‑blockage faults, adopt hydraulic disturbance to melt ice slowly. Never use open‑fire or hot‑water direct baking for airbags. This complete set of anti‑freezing measures can effectively resist freeze‑related damages in severe cold, extend the service life of air‑shield dams, and guarantee stable continuous operation in winter.