In terms of shape design, round manhole covers are widely used in underground water manholes due to their high safety, ease of construction, and largest surface area for the same perimeter, making them economical. Square manhole covers are mostly used in specific scenarios such as cable wells where daily loads are not high. The main materials include ductile iron, which is high in strength and corrosion-resistant, suitable for high-load applications, and composite materials such as resin, which are lightweight but have limited load-bearing capacity and are mostly used on sidewalks, where they are easily damaged by heavy vehicle traffic.
Traditional manhole covers are prone to problems such as settlement, displacement, damage, and abnormal noise. New manhole covers emphasize "five protections" (anti-noise, anti-jump, anti-theft, anti-fall, and anti-displacement) or "six protections" (added anti-settlement) functions, achieved through technologies such as machined contact surfaces, the addition of elastic spring clips, anchor bolts, built-in anti-fall mesh, and the installation of anti-theft concealed boxes.
The smart manhole cover integrates sensors to monitor tilt, displacement, water level, temperature and other conditions. It adopts communication technologies such as NB-IoT, is powered by solar energy or batteries, has an IP68 protection rating, and can be remotely monitored, alarmed, located and managed through a management platform and mobile APP, realizing the transformation from "passive maintenance" to "proactive prevention".
