A Critical Investigation on the Reliability, Availability, and Maintainability of EPB Machines: A Case Study

Tunnelling is a vital geotechnical engineering feature of underground transportation systems that potentially hazardous if not properly investigated, studied, planned, and executed. A reliability, availability, maintainability (RAM) analysis one the main practical techniques in machinery-based projects to recognize failure repair rates machines during or after their operations. RAM mechanized tunneling can help manage project safety cost, improve availability performance machine. There are several methods obtain predict system, including Markov chain simulation other statistical methods; however, result be affected by selected method. This paper presents results critical investigation on Earth pressure balance (EPBMs) used developing an urban metro Isfahan, Iran. The five kilometer length first line Isfahan was excavated using EPBMs over four years. After overhauling making some minor changes, excavation second started, date, about 1.2 km has been refurbished machines. In present study, applied electrical, mechanical, cutter head subsystems Lines 1 2 18- 7-month period machine operation, respectively. show estimated A(t), determined method, closer reality but cannot propagated reliability R(t) M(t) analysis. It also revealed predicting required maintenance proper planning, overall EPBM improved from 45% Line 61% 2. outcomes this study future planning estimate machine, staff, logistic with least possible error, appropriately arrange factors involved system.