The concept of mining method

An underground excavation method, which mainly adopts drilling and blasting method to excavate sections, build tunnels and underground projects. It is named after drawing lessons from the method of mine roadway development. When the mining method is used for construction, the whole section is excavated to the design outline, and the lining is built accordingly. When the stratum is soft, a simple excavator can be used to carry out excavation and support when necessary according to the stability of surrounding rock. For partial excavation, the pilot tunnel shall be excavated in this section first, and then the pilot tunnel shall be excavated to the design outline of this section. The main purpose of partition excavation is to reduce the disturbance to surrounding rock. The size and number of partitions depend on geological conditions, tunnel section size and support type. In the hard and complete rock stratum, for the tunnel with small and medium section, the whole section can be excavated at one time without division. In case of soft and broken strata, excavation shall be carried out in sections, and temporary supports shall be set up in time to prevent the earth and rock from collapsing. The appearance of shotcrete and bolt support reduced the number of branches and further developed into NATM.