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Geomechanics and Engineering   Volume 16, Number 5, December10 2018, pages 539-545
DOI: https://doi.org/10.12989/gae.2018.16.5.539
 
A new formulation for calculation of longitudinal displacement profile (LDP) on the basis of rock mass quality
Ali Rooh, Hamid Reza Nejati and Kamran Goshtasbi

 
Abstract     [Buy Article]
    Longitudinal Displacement Profile (LDP) is an appropriate tool for determination of the displacement magnitude of the tunnel walls as a function of the distance to the tunnel face. Some useful formulations for calculation of LDP have been developed based on the monitoring data on site or by 3D numerical simulations. However, the presented equations are only based on the tunnel dimensions and for different quality of rock masses proposed a unique LDP. In the present study, it is tried to present a new formulation, for calculation of LDP, on the basis of Rock mass quality. For this purpose, a comprehensive numerical simulation program was developed to investigate the effect of rock mass quality on the LDP. Results of the numerical modelling were analyzed and the least square technique was used for fitting an appropriate curve on the derived data from the numerical simulations. The proposed formulation in the present study, is a logistic function and the constants of the logistic function were predicted by rock mass quality index (GSI). Results of this study revealed that, the LDP curves of the tunnel surrounded by rock masses with high quality (GSI>60) match together; because the rock mass deformation varies over an elastic range.
 
Key Words
    : longitudinal displacement profile (LDP); logistic function; least square technique; rock mass quality
 
Address
Ali Rooh, Hamid Reza Nejati and Kamran Goshtasbi: Rock Mechanics Division, School of Engineering, Tarbiat Modares University
 

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