The methods for handling hard rock and soft soil during underground construction with a tunnel boring machine (TBM) differ significantly due to the varying demands these geological conditions place on the TBM's operation and equipment performance.

　　Handling Hard Rock:

　　1. Adjust Cutterhead Configuration: Use cutting tools suitable for hard rock, such as carbide or diamond tools. Optimize the cutterhead configuration based on the hardness and distribution of the rock.

　　2. Enhance the Thrust System: Hard rock requires a robust thrust system, potentially necessitating increased thrust and torque to ensure the TBM can advance smoothly.

　　3. Control Earth Pressure Balance: In hard rock layers, it is crucial to manage the earth pressure balance carefully to avoid excessive slurry extraction and prevent ground subsidence.

　　4. Monitor Cutterhead Rotation Speed and Advance Rate: Adjust the cutterhead rotation speed and advance rate according to the cutting conditions in the hard rock to maintain optimal cutting efficiency and advance rate.

　　Handling Soft Soil:

　　1. Use Appropriate Cutterhead and Cutting Tools: In soft soil layers, use softer cutting tools, such as soil cutters or rotary brushes, to reduce wear on the cutterhead.

　　2. Strengthen Earth Pressure Balance Control: Strictly control the earth pressure balance to prevent ground subsidence and tunnel collapse, potentially using grouting techniques to enhance soil bearing capacity.

　　3. Control Advance Rate and Cutterhead Rotation Speed: A high advance rate may cause ground subsidence, while a slow rate may lead to cutterhead clogging. Adjust these parameters based on actual conditions.

　　4. Utilize Auxiliary Equipment: If necessary, use auxiliary equipment such as slurry pumps and mixers to improve the working environment and assist the TBM in advancing smoothly.

　　5. Enhance Cutterhead Maintenance: Although soft soil causes less wear on the cutterhead, it is essential to regularly clean the cutterhead and cutting tools to maintain good working condition.

　　The TBM operation team must possess extensive experience and professional knowledge to adjust construction parameters and take appropriate measures promptly, ensuring safety and efficiency. Additionally, it is necessary to develop detailed construction plans and emergency response plans based on specific geological conditions.