Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

Korzeniowski, W.; Skrzypkowski, Krzysztof; Zagórski, Krzysztof

doi:10.1515/sgem-2017-0004

Cited by 28 publications

(15 citation statements)

References 21 publications

(9 reference statements)

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“…Bearing capacity of such anchors is limited by the latch mechanism fixation effort. Modern anchors with the turned fastening are of rather high bearing capacity; thus, according to data of experiments by Korzeniowski (Korzeniowski, Skrzypkowski, & Zagórski, 2017), bearing capacity of such modified anchors as Phase II with deforming elements of latch mechanisms is 165 MPa. Basic disadvantage of such specific anchors is their complicated design and high labour intensity involved in their installation.…”

Section: Introductionmentioning

confidence: 99%

Studies of new nonadhesive anchoring

Sakhno¹,

Sakhno²,

Kurdiumow³

et al. 2018

Min. miner. depos.

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Purpose is to develop anchoring with nonadhesive high-strength roof bolting in terms of large pre-destructive deformations and its testing under laboratory conditions.Methods. Laboratory studies of hydration hardening of self-extending mixtures, carried out with the use of digital microscope Bresser LCD 40-1600x, have determined the features of hydration of the modified mixtures. The developed mixture, testing by means of unevenly-component three-axial pressure (UCTAP), has determined its strength within post-hydration period, elasticity module, and deformation module. Bench tests concerning anchor fastening by means of self-expending mixtures as well as anchor glue Cement KL have helped perform comparative analysis of adhesive technique to hold anchors fixed and nonadhesive one. Underground on-site research to fasten anchors while Franciszek Karol chamber strengthening in the context of Wieliczka mine made it possible to determine dynamics of anchor loading.Findings. It has been grounded experimentally that adding of Sika BV 3M ingredient to self-extending mixture results in up to 30% intensification of its strength limit on uniaxial compression. It has also been grounded experimentally that maximum effort to fasten anchor bolts by means of self-extending mixtures, excesses efforts for those bolts fastened with the help of resins more than twice. Analysis of operation mode of such anchors means that the action of anchor -fastener -rock system is close to that by modern energy absorbing bolts. Originality.A new concept of anchor fixation at the expense of their fastening by means of self-extending mixtures throughout the hole length has been formulated. During the hardening process, 30 -50 MPa pressure is developed making it possible to intensify maximum fastening effort being more than two times higher to compare with adhesive technique. Moreover, constant resistance is provided in the process of the anchor bolts displacement within a hole; the resistance is similar to that provided by adhesive technique. Practical implications.The obtained results, having sufficient practical accuracy, can be used for the development of new anchoring in the context of large deformations of a stope boundary. If the parameters are substantiated theoretically and bench testing is passed, the proposed anchoring technique can be implemented in the stopes of coal mines, ore mines as well as nonmetallic ones. That favours the increase in load bearing capacity of the anchorage and rock support in terms of their elastic deformation.

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Section: Introductionmentioning

confidence: 99%

Studies of new nonadhesive anchoring

Sakhno¹,

Sakhno²,

Kurdiumow³

et al. 2018

Min. miner. depos.

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“…There are also bolts that have an additional absorbing element added from the roof side of the excavation, e.g. "Deformable component" [14] or on the bottom of the borehole, e.g. "Dynatork" [15], "Yiel-Lok" [16] or inside the borehole (the so-called absorber), e.g.…”

Section: Energy-absorbing Boltsmentioning

confidence: 99%

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Skrzypkowski

2018

E3S Web Conf.

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Abstract. The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Po mines. In the underground mines of the Legnica-(LGOM) the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

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“…In the underground mines of the LGCB, the basic support of the preparatory and exploitation excavations are rock bolts with expansion shells and steel bolts installed with resin cartridges. The length of the bolt rods varies from 1.2 to 2.6 m. Bolting net is 1 x 1 m, 1.5 x 1.5 m and 2.0 x 2.0 m. Annually about 2.5 ÷ 3 millions units of bolts are used in underground Polish copper ore mines [8]. The choice of the excavation support is made by the manager of the Mining Department on the basis of understanding the geological and mining conditions.…”

Section: Additional Mining Support For Underground Exploitation Of Comentioning

confidence: 99%

“…Drilling of technological holes, making the bolting support and other auxiliary works is carried out from the working platform. The number of additional installed long bolts is around 10 ÷ 11 thousand units per year [8].…”

Section: Additional Mining Support For Underground Exploitation Of Comentioning

confidence: 99%

A new design of support for burst-prone rock mass in underground ore mining

Skrzypkowski

2018

E3S Web Conf.

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The article presents the basic methods of strengthening room and roadway excavations in underground ore mining. In particular, it was pointed out that the mining support is very often exposed to additional dynamic loads resulting from the mining of the deposit by means of explosives (slight) as well as from the load arising from rock mass tremors. In the article a new design of arch yielding support adapted to dynamic loads, which can be used in long-term access excavations was proposed. For this case, an exemplary spring deflection, which is located in the support foot cylinder, based on the principle of work and energy was calculated. In the case of exploitation room excavations, laboratory tensile tests of the long expansion rock bolt support, which were carried out in the rock bolting laboratory at the Department of Underground Mining AGH were presented. Load-displacement characteristics for long expansion rock bolt support with a particular indication of the elastic and plastic range were presented. In the summary, it was concluded that with the increase in the depth of exploitation, safe and efficient mining will be possible only due to the use of a support with appropriate yielding.

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Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

Cited by 28 publications

References 21 publications

Studies of new nonadhesive anchoring

Studies of new nonadhesive anchoring

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

A new design of support for burst-prone rock mass in underground ore mining

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