53rd U.S. Rock Mechanics/Geomechanics Symposium,
New York City, New York
2019. American Rock Mechanics Association
0 in the last 30 days
13 since 2007
Show more detail
ARMA Member Price:
ARMA Non-Member Price:
ABSTRACT: The 1150 m deep man shaft at Boulby Mine in Yorkshire, UK was sunk between 1968 and 1974. At the 1056 m level in the Upper Halite, shortly after the excavation and close behind the shaft wall, several 4.5 m long multipoint extensometers were installed at various orientations to monitor the long-term shaft wall convergence. Monitoring of the extensometers occurred sporadically both prior to and after the installation of the lining over an approximately 2430 day duration. This data set provides important insight into the in-situ behavior of large scale creep deformations around the shaft over a long period of time. This paper reviews the long-term convergence data, previous studies of the data and provides several new methods and results from back-calculation exercises using a coupled Python-FLAC3D interface. The coupled interface allowed analysis of thousands of parameters sets with minimal human interaction. Comparisons with analytical solutions and deterministic model runs are also provided to verify that automation is an economical tool that can improve project efficiency.
Back-Analysis of observed or measured behavior for structures built in or on rock masses is a powerful tool to:
(ii) test the appropriateness of constitutive models;
(iii) mimic realistic failure modes; and
(iv) capture ground-support interactions.
This paper presents a back-analysis undertaken to replicate the radial displacement of a deep shaft excavated as part of the Boulby Mine development and highlights the importance of measuring the long-term behavior of formations exhibiting time-dependent deformations.
The long-term response of the deep shaft was back-calculated using numerical modelling (2D & 3D) and analytical solutions and a series of parametric runs were performed using a Python-FLAC3D interface to investigate the sensitivity of the predicted shaft closure beyond the monitoring period. The study also provided insight, to some extent, on the influence of scale effects on creep properties by examining if laboratory scale derived visco-elastic properties can be used to predict the in-situ large scale shaft displacements.
Number of Pages
Looking for more?
Some of the OnePetro partner societies have developed subject- specific wikis that may help.