What is the purpose of the tunneling? People dig tunnels for a variety of reasons, each serving distinct purposes that reflect human ingenuity and the need to adapt to our environment. Here are some primary reasons why we excavate these subterranean passageways:

　　I. Improving transportation

　　1. Shortening distances

　　When there are terrain obstacles such as mountains and hills between two places, building tunnels can make the transportation route more direct and greatly shorten the driving distance between the two places. For example, building highway tunnels in mountainous areas can avoid vehicles taking winding mountain roads and save time and fuel consumption.

　　For railway transportation, tunnels can make the line straighter and improve the running speed and safety of trains.

　　2. Improving traffic efficiency

　　Tunnels are not affected by bad weather such as heavy rain, heavy snow, and strong winds, and can ensure the continuity and stability of traffic. In some areas with changeable climates, the role of tunnels is particularly obvious.

　　It can relieve ground traffic pressure and reduce traffic congestion. Especially in cities, underground tunnels can divert ground vehicles and improve the overall operation efficiency of urban transportation.

　　II. Promoting economic development

　　1. Strengthening regional connections

　　Tunnels can connect different regions and promote economic exchanges and cooperation between regions. For example, tunnels connecting two cities can facilitate the movement of people and the transportation of goods and promote regional economic integration.

　　For remote areas, the construction of tunnels can break geographical barriers and better integrate them into the grand pattern of economic development, attracting investment and promoting resource development.

　　2. Driving the development of related industries

　　Tunnel construction requires a large amount of manpower, material resources, and financial resources, which will drive the development of related industries such as construction, materials, and machinery. At the same time, after the tunnel is completed, businesses and tourism in surrounding areas will also be promoted.

　　III. Resource development and utilization

　　1. Water conservancy projects

　　In water conservancy construction, tunnels can be used for water conveyance and diversion. For example, building diversion tunnels can transport water resources from abundant areas to water-scarce areas to meet the needs of agricultural irrigation, industrial water use, and urban domestic water use.

　　Diversion tunnels play a role in diverting river water and ensuring construction safety in water conservancy hub projects.

　　2. Mineral resource development

　　For the exploitation of underground mineral resources, tunnels are important channels. It can allow miners and equipment to enter underground mining areas and facilitate the transportation and lifting of minerals.

　　IV. Military and strategic significance

　　1. Concealment and safety

　　Tunnels can be part of military facilities and used to hide troops, weapons and equipment, and strategic materials. During wartime, tunnels can provide certain protection and reduce the impact of enemy attacks.

　　Underground tunnels can also be used for the construction of important facilities such as military communications and command centers to ensure the smooth progress of military operations.

　　2. Strategic channels

　　Tunnels can become important strategic channels. In times of war or emergencies, they can ensure the rapid transfer of personnel and materials. It can cross enemy blockades and connect rear bases and front battlefields, which is of great significance for national security and stability.

　　V. Recreational Uses

　　Caves and tunnels are sometimes converted into tourist attractions, offering unique experiences such as cave tours or adventure sports like spelunking.