Assessment of Double Shield TBM performance by using downtime index (DTI)

Document Type : Research Paper


Department of Engineering Geology, Tarbiat Modares University, Tehran, Iran


PIn mechanized tunneling, TBM performance prediction is vital to estimate the time and cost of the project. Therefore, calculating the performance parameters is so important. The utilization coefficient depends on management parameters, personal ability, logistic utility and equipment, tunnel characteristics, objectives and geological conditions. Although in each of the main models same as CSM, NTNU and QTBM , the specific parameters used to estimate the utilization coefficient, the effect of management factor and interactions and overlapping factors not considered. On the other hand, many parameters have a severe dependence on each other and may simultaneously affect the performance of the TBM. Therefore, the interaction matrix can be used to evaluate the interaction of parameters on each other and on TBM performance. The effect of 18 parameters on the utilization coefficient was evaluated by the matrix method in Karaj water conveyance tunnel. The interactions of these parameters show that the lack of utility services and shift change have the most significant impact on TBM performance. By recording the actual delays in each parts of tunnel, the downtime index (DTI) is obtained; this index has a direct relationship with tunnel boring time and is inversely related to TBM performance.


Main Subjects

Article Title [Persian]


Articles in Press, Accepted Manuscript
Available Online from 03 October 2022
  • Receive Date: 14 October 2021
  • Revise Date: 12 July 2022
  • Accept Date: 03 October 2022
  • First Publish Date: 03 October 2022