Stability Investigation of a Deep Shaft Using Different Methods

Kaya, Ayberk; Tarakçi, Ümit Cihat

doi:10.1061/(asce)gm.1943-5622.0001917

Cited by 7 publications

(1 citation statement)

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“…According to the failure depth calculation results, Q and RMR rock mass quality classification results and their support chart (Rahim and Mohamad 2019;Kaya and Tarak, 2021), different support parameters, including bolt length and bolt spacing, are compared in Table 6. Table 6 shows the primary selection results of support parameters, the bolt length is chosen according to the simulation results, and the bolt spacing is chosen by the Q rock quality index and its support chart.…”

Section: Temporary Supportmentioning

confidence: 99%

Sequential stress control and delayed support in deep shaft construction

et al. 2022

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In constructing hard rock mine deep shafts, the failure caused by high stress is a significant problem. A construction section extending from the -930 m to -1271 m level of a 1527 m deep shaft was selected as a case study. Q, RMR, and GSI rock mass quality classifications of the surrounding rock were obtained to determine the shaft’s maximum unsupported sinking cycle height in different construction sections. The potential failure mode, failure zone shape, and failure depth of the surrounding rock shaft under high stress were then analyzed theoretically, empirically, and by numerical simulation, sequential stress control and delayed support technology was proposed according to the results. The temporary and permanent support timing parameters were calculated and verified by the empirical chart, numerical simulation, convergence-confinement theory, and theoretical formula. Results show that the surrounding rock in all the construction sections from -930 m to -1271 m belongs to the mild or severely pressure squeezed strata. The potential failure mode is stress-controlled, and the failure zone of the surrounding rock is “ear” shaped. Temporary support strengthens the rock mass, improves the shear capacity of surrounding rock, and prevents the broken rock from falling but does not release stress. Permanent support, conversely, cannot bear the stress of surrounding rock. The stress and elastic strain energy in rock mass should be released to the greatest extent possible before installing permanent support; it is not advisable to install it too early. The time and cycle height of delayed permanent shaft support were comprehensively determined to be four days and 16 m, respectively. The numerical simulation and safety factor proof show that the sequential stress control process effectively minimizes stress in surrounding rock and ensures long-term shaft stability.

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Section: Temporary Supportmentioning

confidence: 99%