What are the common problems encountered by shield machines in underground construction? Shield machines may encounter a variety of common problems in underground construction, which may affect the construction progress, safety and cost. Here are some typical problems:

   1. Changes in geological conditions: Shield machines may encounter unexpected difficulties when crossing different geological structures, such as hard rock, soft soil, broken belts, groundwater, etc., which may lead to reduced cutting efficiency, increased wear of the cutterhead, ground subsidence and other problems.

   2. Cutterhead wear: The cutterhead is one of the core components of the shield machine. Long-term contact with hard rock will cause wear and tear, and it needs to be replaced and maintained regularly, otherwise it will affect the cutting efficiency and construction quality.

   3. Seal failure: The sealing system of the shield machine is the key to preventing groundwater infiltration. If the sealing ring is worn or damaged, it may cause leakage, increase construction risks, and need to be replaced or repaired in time.

  4. Propulsion system failure: The propulsion system of the shield machine is responsible for providing forward power. Any failure may cause construction to stagnate and require emergency repairs, which may delay the construction progress.

  5. Bearing failure: The main bearing and other bearings of the shield machine are components that bear huge pressure. Once a failure occurs, it may cause the entire machine to stop working and require major repairs or replacement.

   6. Electrical system problems: The electrical system of the shield machine is complex. Any short circuit of the wires, control system failure, etc. may cause the machine to be partially or completely paralyzed.

   7. Earth pressure balance problem: When constructing in soft soil layers, the shield machine needs to maintain proper earth pressure balance to prevent ground subsidence and tunnel collapse. Failure of the earth pressure balance system may lead to serious consequences.

   8. Cutterhead cooling system failure: The cutterhead generates a lot of heat when it rotates at high speed. Failure of the cooling system may cause the cutterhead to overheat, affecting cutting efficiency and equipment life.

   9. Installation error: The accuracy of the shield machine installation is crucial to subsequent construction. Any installation error may cause deviation of the tunnel axis, increasing the difficulty and cost of later corrections.

   10. Operational errors: Operator errors may cause equipment damage, construction accidents, etc., so the training and management of operators are very important.

   In response to these common problems, the shield machine maintenance team needs to conduct regular inspections and maintenance to promptly detect and solve problems to ensure the normal operation of the shield machine and construction progress. In addition, special construction measures and technical means may be required to deal with complex geological conditions.