Interaction of rock-bolt supports while weak rock reinforcing by means of injection rock bolts

Using the method of numerical modeling, the stability of mine working under difficult conditions of crossing a tectonic fault was studied as well as effectiveness of using steel rock bolts in combination with injection rock bolts. It was shown that steel and injection rock bolts complemented each other very well, increasing the stability of the mine working and reducing permeability of the host rocks. Injection rock bolts exclude the possibility of destruction of host rocks and more effectively reduce permeability of disturbed rocks in the zone of the tectonic fault. At the same time, steel rock bolts better restrain the expansion of the zone of high difference of the stress tensor components. Therefore, in case of heavily watered rocks or a high probability of methane breakthroughs into the mine working, it is better to install injection rock bolts as close to the mine face as possible. Then a water- and gas-proof shell arch around the mine working will be created in the immediate vicinity of the mine face. If there is no such threat and the priority is to maintain the long-term stability of the mine working, then first of all it is necessary to install steel bolts.

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“…The coupled processes of rock deformation and liquid polymer filtration in the fissured rock mass are described by a system of equations [19,20]…”

Section: Methodsmentioning

confidence: 99%

The use of steel and injection rock bolts to support mine workings when crossing tectonic faults

Krukovskyi

Krukovska

Kurnosov

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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“…The coupled processes of rock deformation and liquid polymer filtration in the disturbed rock are described by a system of equations [19] , ( ) ( )…”

Section: Methodsmentioning

confidence: 99%

The Use of Injection Rock Bolts in He Mining and Geological Conditions of Ukrainian Coal Mines

Krukovskyi¹,

Krukovska²,

Vynohradov³

2023

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The article presents the results of simulation of coupled processes of rock deformation and liquid polymer filtration in the disturbed area around the mine working. The problem formulation takes into account the initial permeability of host rocks as well as the permeability due to the mine working driving, time of polymer delivery and hardening, and foaming effect of the polymeric composition in the process of mixing of its components. Certain changes in physicomechanical and filtration characteristics of rocks during the polymer hardening also were taken into account in the problem formulation as well as the fact that a metal delivery pipe starts operating as a reinforcing element after hardening of the polymeric composition is over. It was demonstrated that the location of rock bolts is important to form a rockbolts arch. With sufficient density of injection rock bolts, the formed rock-bolts arch may serve as a barrier controlling both water inflow and gas emission from the undermined rocks into the mine working. Dependence of changes in the reinforced area upon the value of initial permeability of the host rocks was derived. If the values of initial permeability are low then size of the rock-bolt supports and their shape are determined using only a value of the unloaded zone around the mine working. It was shown that steel and injection rock bolts complement each other very well, increasing the stability of the mine working and reducing the filtration permeability of the host rocks. Injection rock bolts exclude the possibility of destruction of host rocks and more effectively reduce the permeability of disturbed rocks in the zone of influence of the tectonic fault. And steel rock bolts better restrain the expansion of the zone of increased difference of the stress tensor components. Therefore, in the case of heavily watered rocks or a high probability of methane breakthroughs into the mine working, it is better to install injection rock bolts and deliver the polymer into the disturbed rock as close as possible to the mine face. Then a water- and gas-proof shell arch around the mine working will be created in the immediate vicinity of the mine face, which will make it possible to quickly prevent emergency water inflows and gas emissions. If there is no such threat and the priority is to maintain the long-term stability of the mine working, then first of all it is necessary to install steel rock bolts with polymer fixing in the borehole. Key words: injection rock bolts, complicated mining and geological conditions, numerical simulation, supporting technology, mine workings.

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“…As further research continues to investigate combined support systems subject to dynamic loading through the use of numerical analysis, testing can be replicated in a safe, repeatable and cost-friendly manner [6,30]. (Krykovskyi, Krykovska, & Skipochka, 2021) [30][31][32][33][34][35][36][37][38] also presented a significant contribution to the latest research in the current field.…”

Section: Numerical Analysismentioning

confidence: 99%

A Numerical Investigation to Calculate Ultimate Limit State Capacity of Cable Bolts Subjected to Impact Loading

et al. 2022

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As rock bursts are unavoidable in deep mines and excavations with high in-situ stresses, ground support systems are implemented to manage and mitigate rock bursts. Cable bolts are commonly used as reinforcing elements in ground support systems, which are subject to dynamic loads in burst-prone excavations. To design an efficient cable bolt in burst-prone conditions, shear and energy absorption capacity must be considered. Numerical modelling is an advantageous method of repeatable testing and it is inexpensive and non-destructive. This study develops a statically and dynamically loaded numerical model of a double shear test in ABAQUS/Explicit. A total of 36 static and 576 dynamic tests are carried out, which examine the influence of bolt diameter, steel yield and ultimate strength, dynamic load velocity and dynamic load mass on the displacement, shear force and energy absorption capacity of cable bolts. As bolt diameter and steel yield strength increases, the maximum shear force resisted and bolt displacement increases. Similarly, as the mass and velocity of the dynamic load increases, the amount of energy absorbed by the cable bolt increases. The main novelty of the current research is to suggest a reliable computational tool to investigate the influence of the different key parameters in the cable bolts on the ultimate capacity. The suggested method is a significantly cost-effective technique compared with the experimental investigations.

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Interaction of rock-bolt supports while weak rock reinforcing by means of injection rock bolts

Cited by 28 publications

References 7 publications

The use of steel and injection rock bolts to support mine workings when crossing tectonic faults

The use of steel and injection rock bolts to support mine workings when crossing tectonic faults

The Use of Injection Rock Bolts in He Mining and Geological Conditions of Ukrainian Coal Mines

A Numerical Investigation to Calculate Ultimate Limit State Capacity of Cable Bolts Subjected to Impact Loading

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