The so-called common ditch is the "underground city pipeline comprehensive corridor", that is, building a tunnel space underground in the city, integrating various pipelines such as municipal, electric power, communication, gas, water supply and drainage, and setting up special inspection ports, hoisting ports and monitoring systems to implement unified planning, design, construction and management.

Types of comprehensive tunnels:

Characteristics of trunk common ditch: Trunk common ditch is generally located below the road center and is responsible for providing power distribution services to branch common ditch. The main pipelines are communication, cable TV, electricity, gas and tap water, and some trunk common ditches include rainwater and sewage systems. It is characterized by large structural section size, deep soil cover, stable system, large conveying capacity, high safety and high maintenance and testing requirements.

Characteristics of feeder common ditch: feeder common ditch is a channel connecting trunk common ditch and end users, generally located under sidewalks on both sides of the road. The main accommodating pipelines are communication, cable TV, electric power, gas, tap water and other direct service pipelines, and the structural sections are mostly rectangular. It has the characteristics of small effective section, low cost, high system stability and safety.

Characteristics of cable common trench: Cable common trench is generally buried under the sidewalk, and its pipelines include power, communication, cable TV and so on. Pipes are supplied directly to all end users. It is characterized by small space section, shallow burial depth, low construction cost, no need for ventilation, monitoring and other equipment, and simple maintenance and management.

Planning of common ditch:

In the process of planning and implementation of common ditch, scientific planning and moderate advance are required to meet the needs of urban development. For different pipeline capacity, the future capacity should be predicted according to the current actual demand, combined with urban development planning, economic development and the improvement of people's living standards.