How far can a tunnel boring machine go in a day? The daily progress of a tunnel boring machine (TBM) depends on various factors, including the type of soil or rock, the TBM's size and design, and the efficiency of the crew and support systems.

　　Generally, modern TBMs are capable of tunnelling anywhere from 10 to 50 meters per day under ideal circumstances. However, this number can vary drastically based on the hardness of the rock or soil being cut through. In softer soils, TBMs can potentially dig up to 200 meters in a single day. But when encountering hard rocks like granite, the speed could be as slow as just a few centimeters per hour.

　　- Soft Ground Conditions: TBMs can achieve 15 to 40 meters (50 to 130 feet) per day, depending on the soil type and machine.

　　- Hard Rock Conditions: Progress slows to about 5 to 15 meters (16 to 50 feet) per day because of the need to cut through harder material.

　　- Mega Projects: Some advanced TBMs in ideal conditions have exceeded 40 meters (130 feet) per day, but this is relatively rare.

　　Unstable ground, water ingress, or mixed conditions can slow down operations.

　　In addition to geology, other factors that impact daily progress include maintenance requirements for the equipment, the need for continuous supply of materials such as concrete segments for lining the tunnel walls, and safety protocols which require regular inspections and checks to ensure safe operation.

　　Despite these variables, TBMs are prized for their efficiency and ability to operate continuously, making them a preferred method for large-scale tunneling projects.