The general requirements of this standard stipulate that ductile iron used for manhole covers should conform to GB/T1348-2019. Based on load-bearing capacity, they are classified into three grades: B125, C250, and D400, suitable for different locations such as green belts/sidewalks, areas within 0.5m of road curbs, and urban main roads/highways. Based on structure, they can be divided into direct-bearing and anti-settlement adjustable types. Based on appearance, they can be divided into standard, landscape, and infill types. The surface of the manhole cover should be intact, smooth, and clearly marked, with a permissible height difference of ±1mm between the cover and the manhole seat.
Acceptance requirements include key control items and general items. Key control items require that the load-bearing capacity of the manhole cover conform to GB/T 23858-2009, the perimeter compaction meet the design requirements, and the installation be stable without damage, noise, warping, or misalignment. General items specify requirements for appearance, etc.
Routine maintenance requires the establishment of a supervisory and management department, the implementation of a "one cover, one number; one well, one file" system, and the establishment of an information management system. Maintenance units must establish a 24-hour repair reporting system and a regular inspection and maintenance system, promptly addressing any issues such as loosening, breakage, loss, subsidence, or damage.
Emergency response requires the responsible unit to develop an emergency plan and establish a sound multi-departmental coordination mechanism. Upon discovering or receiving a report of a missing or severely damaged well cover, warning signs must be set up within 2 hours, and the cover must be repaired and restored within 6 hours. If it is necessary to move the well cover during flood drainage, safety precautions must be taken, and the cover must be restored promptly.
