An introduction to RAM analysis of EPB tunnel boring machine

Earth pressure balance tunnel boring machines (EPB - TBMs) are favorably used in construction of tunnels in urban areas. These more expensive machines with high operational costs require an exclusive study and knowledge on these machine components and subsystems and their failure and downtimes for time planning, cost control and performance prediction with a high accuracy. For achieving these aims, guidelines for reliability, availability and maintainability (RAM) analysis of an EPB machine are completely expressed in present study. Gathering and recording all daily failure and repair times and other maintenance tasks, dividing the machine into subsystems (including mechanical subsystem, electrical subsystem, hydraulic subsystem, pneumatic subsystem and water subsystem), graphical tests (trend test and correlation test), statistical tests and analysis are discussed in detail. Therefore, RAM analysis can be applied for EPBTBMs in all mechanized tunneling projects and it is suggested to the tunneling communities and companies to fix these instructions in their programs.