Study of soil abrasivity impact on TBM tunnelling efficiency at the Tabriz metro L1

Document Type : research - paper

Authors

1 Assistant Professor of Engineering Geology, Department of Earth Sciences, University of Tabriz

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

Abstract

Wear issues in TBM tunnelling specially in soft ground application have become one of the most common critical problems which involves all parties of projects including employer, consultant and contractor and always give rise to design, contractual and construction problems and difficulties. In this research the abrasivity of alluvium deposits on the Tabriz metro line l has been evaluated and the rate of TBM cutting tools consumption and the impact of soil abrasivity on project schedule have been studied. Mineralogical studies of samples taken from various distances of the first half of the studied tunnel route indicates the equivalent quartz content is between 40 to 60 percent. Evaluation of abrasivity of the studied tunnel line deposits on the bases EQC, Cerchar test, LCPC and the new SATC apparatus grades the deposit abrasivity as moderate to very abrasive in dry condition and low to moderate abrasive in saturation condition.
It was found that the delay caused by the soil abrasivity in the first part of Tabriz metro L1 is almost equal or more than twice of the sum of excavation and lining time of the tunnel. On the basis of filed data, in order to predict the TBM wear and cutting tools life time an estimate of equivalent quartz content is not enough. There are various parameters effects tools wear and cover the effects of quartz content. The data analysis showed a decrease in the soil abrasivity in the section with relative low SPT and below the groundwater table.
 

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History

  • Receive Date: 23 July 2014
  • Revise Date: 05 August 2015
  • Accept Date: 08 September 2015

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