A numerical study of the pullout behavior of grout anchors underreamed by pulse discharge technology

Park, Hyunku; Lee, Seung Rae; Kim, Nak Kyung; Kim, Tae Hoon

doi:10.1016/j.compgeo.2012.07.005

Cited by 11 publications

(5 citation statements)

References 27 publications

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“…Moreover, the former Soviet Union and the United States successfully utilized electric pulse technology to improve oil production efficiency [17]. The HVEP rock-breaking technology is considered a new green technology with near-industrialization potential [18,19].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical simulation research on shock wave rock-breaking by high voltage electric pulse

Liu,

Zhou,

Zhu

2024

Phys. Scr.

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High-voltage electric pulse(HVEP) drilling technology has the advantages of high rock-breaking efficiency, green and non-polluting. Aiming at the importance of HVEP drilling technology in generating plasma channels, plasma shock waves, and rock-breaking pits, this paper carries out multi-physics field numerical simulations and indoor electric pulse breakdown experiments. This paper first constructs a two-dimensional numerical model of rock electric breakdown. The simulation of HVEP rock breaking, plasma channel and plasma shock wave is realized from the five-field coupling and combined with the wave control equations. The effects of different electrode shapes on the plasma channel, breakdown channel and shock wave are analyzed. Then, this paper designed an indoor HVEP rock-breaking experiment to investigate the influence of different electrode shapes on rock breakdown and plasma shock waves. The simulation and experimental results show that the indoor electric pulse breakdown experiment results are consistent with the simulation results; The plasma channels are formed by the ‘electrical damage’ through each other, and the secondary plasma channel is often generated inside the rock. The generation of the secondary plasma channel means that the rock fragmentation depth and the fragmentation area will be increased; The larger the contact area of the electrode bit with the rock, the larger the radius (volume) of the plasma channel and the smaller the amplitude of the plasma shock wave; The quadrangular electrode bits have the best rock-breaking effect and are recommended; The conical electrode bit has the most excellent dispersion in the statistical analysis of the electric pulse rock-breaking effect, and the stability of the rock-breaking effect is poor, so it is recommended to use it together with the composite drill bit; The cylindrical electrode bit has the best aggregation degree of electric pulse rock-breaking and the most stable rock-breaking effect.

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Section: Introductionmentioning

confidence: 99%

Experimental and numerical simulation research on shock wave rock-breaking by high voltage electric pulse

Liu,

Zhou,

Zhu

2024

Phys. Scr.

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“…For enlarged head anchors with a relatively large diameter, the failure surface formed by the upper soil in the drawing process does not extend to the surface; thus, separating the deeply buried and shallowly buried enlarged head anchors was proposed. For expanding the bearing characteristics of the enlarged head anchor, many scholars have made theoretical predictions [8,9] and conducted laboratory tests [10], field measurements [11], and numerical simulations [12,13], finding that the enhanced bearing capacity of under-reamed anchors mainly comes from the end-bearing resistance of the "shoulders" and shear strength along the interface between soil and enlargement. Golait [14] found, by pulling enlarged head anchors, that lateral friction did not reach the peak when the end bearing capacity was at its maximum.…”

Section: Introductionmentioning

confidence: 99%

Study on the Style Design and Anchoring Mechanism of Enlarged Head Anchors

Zhang

Wang

et al. 2023

Sustainability

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To resolve insufficient traditional bolt supports due to the complexity of geological conditions, the optimal design of an expanded head bolt was investigated by using theoretical calculations and experiments. The results show that the drawing capacity of an expanded head bolt is affected by the bearing capacity of front and rear ends, side bearing capacity, and side friction resistance. For a circular anchor bolt, stepped anchor bolt, and semi-ellipsoidal anchor bolt, with an increase in the front section’s radius, the lateral friction resistance of the inner anchor section is gradually shared by the bearing force of the front end of the inner anchor section; the bearing effect of the front end of the inner anchor section is enhanced; and the pulling performance of the anchor bolt is enhanced. Therefore, the pulling force of the circular anchor bolt is at the maximum, followed by the stepped anchor bolt, and the semi-ellipsoidal bolt is at the minimum. The increase in the rear section can provide greater lateral friction resistance and end-bearing force. Compared with cylindrical enlarged head anchors, the circular, stepped, and semi-elliptic enlarged head anchors have a smaller front section but a larger rear section, and the reduction in the front section’s bearing capacity is less than the increase in the side bearing capacity and rear-end bearing capacity; thus, the cylindrical bolt has the lowest pulling force. Compared with the front radius, the back radius has more influence on the drawing ability of the enlarged head anchor. The longer the inner anchorage section, the larger the distribution range in the compression zone that is formed in the soil body and the smaller the range in the tension zone that is formed in the rear. The increase in the length of the inner anchorage section is conducive to improving the reinforcement effect of the soil in front of the anchorage section in the bolt. Therefore, this parameter plays an important role in the redistribution of the soil in front of the force. The ultimate pull-out force of a circular table-shaped tensile bolt is the highest, followed by the stepped bolt, and the semi-elliptic bolt comes in third, with the cylindrical bolt exhibiting the lowest pull-out force; the circular table-shaped enlarged head anchor constitutes the best style design.

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“…High-voltage discharge rock breaking is a highly effective technique that has been widely used in the fields of underground drilling, mineral processing, micro-ore decomposition, and incrustation cleaning (Burkin et al, 2009a; Yan et al, 2016; Wang et al, 2015; Duan et al, 2015; Touzé et al, 2016; Yudin et al, 2019) [ 4 , 5 , 6 , 7 , 8 , 9 ]. The advantage of high-voltage discharge drilling technology, which is close to industrialization at the moment (Yudin et al, 2019; Dzhantimirov et al, 2005; Park et al, 2013) [ 9 , 10 , 11 ], is its high breaking efficiency, controllability and low cost in deep welling (Biela et al, 2009) [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanism Analysis of Rock Failure Process under High-Voltage Electropulse: Analytical Solution and Simulation

et al. 2022

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This work aims to investigate and analyse the mechanism of rock failure under high-voltage electropulses in order to evaluate and increase the efficiency of high-voltage pulse technology in geological well drilling, tunnel boring, and other geotechnical engineering applications. To this end, this paper discusses the equivalent circuit of electric pulse rock breaking, the model of shock wave in electro channel plasma, and, particularly, the model of rock failure in order to disclose the rock failure process when exposed to high-voltage electropulse. This article uses granite as an example to present an analytical approach for predicting the mechanical behaviour of high-voltage electropulses and to analyse the damage that occurs. A numerical model based on equivalent circuit, shock wave model, and elasto-brittle failure criterion is developed for granite under electropulse to further examine the granite failure process. Under the conditions described in this study, and using granite as an example, the granite is impacted by a discharge device (Marx generator) with an initial voltage U0 that is 10 kV and a capacitance F that is 5 µF before it begins to degrade at about 40 µs after discharge, with the current reaching its peak at approximately 50 µs. The shock wave pressure then attains a peak at about 70 µs. Dense short cracks form around granite and the dominant cracks grow to an average length of about 20 cm at around 200 µs. The crack width dcr is predicted to be approximately 1.6 mm. This study detects dense cracks in a few centimetres surrounding the borehole, while around seven dominant cracks expand outward. The distribution of the length of the dominating cracks can be inhomogeneous because of the spatial heterogeneity of granite’s tensile strength, however the heterogeneity has an insignificant effect on the crack growth rate, total cracked area, or the number of main cracks. The mechanism of rock failure under electropulse can be well supported by the findings of numerical simulations and analytical studies.

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A numerical study of the pullout behavior of grout anchors underreamed by pulse discharge technology

Cited by 11 publications

References 27 publications

Experimental and numerical simulation research on shock wave rock-breaking by high voltage electric pulse

Experimental and numerical simulation research on shock wave rock-breaking by high voltage electric pulse

Study on the Style Design and Anchoring Mechanism of Enlarged Head Anchors

Mechanism Analysis of Rock Failure Process under High-Voltage Electropulse: Analytical Solution and Simulation

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