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Zhang, Ping
Publications (10 of 32) Show all publications
Zhang, P., Nordlund, E., Swan, G. & Yi, C. (2019). Velocity Amplification of Seismic Waves Through Parallel Fractures Near a Free Surface in Fractured Rock: A Theoretical Study. Rock Mechanics and Rock Engineering, 52(1), 199-213
Open this publication in new window or tab >>Velocity Amplification of Seismic Waves Through Parallel Fractures Near a Free Surface in Fractured Rock: A Theoretical Study
2019 (English)In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 52, no 1, p. 199-213Article in journal (Refereed) Published
Abstract [en]

To determine the dynamic demand for support design under rockburst conditions, one of the most important issues is the prediction of ground motion parameters at the site of interest. Field monitoring has shown that the peak ground motion at the surface of an excavation in fractured rock is preferentially amplified compared to the motion in solid rock at a similar distance from the source. However, the traditional scaling laws used in rock support design do not account for the effect of free surface (excavation) and fracturing of rock. Recent studies have shown that high ground motion might be generated when a seismic wave crosses through fractures near a free surface in fractured rocks which is very complex and is not well understood. In this paper, particle velocity amplification was theoretically studied by investigating the dynamic interaction between seismic wave and multiple fractures near a free surface using the method of characteristics and the displacement discontinuity model. A harmonic load was applied on a model with a fractured zone near a free surface to investigate this phenomenon. After the harmonic wave propagated normally through multiple parallel fractures, the velocity amplification factor (VAF) was calculated as a function of the ratio of the magnitude of the peak particle velocity at the free surface of the model to the peak input velocity. The VAF can be as high as 3.77 and varies depending on the state of the fractured rock and the characteristics of the seismic wave. Parameter studies were conducted to investigate the effects of seismic load and multiple fractures on wave propagation, especially in terms of the wave frequency, the fracture spacing, the number of fractures and the stiffness of fractures. The results have proved that the interaction of the seismic wave and multiple fractures near the free surface strongly influences the ground motion. Quantitative relationships between the various influential factors and the corresponding VAF were developed. It is anticipated that such relationships can provide criteria to improve the current design procedures and help mining engineers to improve their rock support practice for rockburst-prone areas.

Place, publisher, year, edition, pages
Vienna: , 2019
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-70965 (URN)10.1007/s00603-018-1589-8 (DOI)000456673000013 ()2-s2.0-85053438929 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-25 (inah)

Available from: 2018-09-25 Created: 2018-09-25 Last updated: 2019-04-23Bibliographically approved
Chen, G., Li, X., Zhang, P., Nordlund, E. & Dong, L. (2017). Optimization of tunnel support parameters with consideration of seismic wave radiation pattern in the fault-slip burst. Journal of Mining and Safety Engineering, 34(4), 715-722
Open this publication in new window or tab >>Optimization of tunnel support parameters with consideration of seismic wave radiation pattern in the fault-slip burst
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2017 (English)In: Journal of Mining and Safety Engineering, ISSN 1673-3363, Vol. 34, no 4, p. 715-722Article in journal (Refereed) Published
Abstract [en]

As the underground mining extends gradually towards depth, more and more seismic events induced by fault slip occur and cause great damages, which have become a severe potential threat to mining safety. In view of the plane strain problems, through the three dimensional discrete model established, comparison and analysis was carried out between the equivalent calculation of plane strain in 3D model and a 2D discrete model. The results have shown that the research model developed to simulate the propagation of seismic wave in 3D is feasible and applicable. The study of the effect of radiation pattern on seismic propagation revealed and tested the direction of P-and S-wave propagation, which presents high consistency to double couple model of the fault slip. On this basis, the comparison with the design scaling law formulas proposed by Kaiser and associates finds that the existing design scaling law does not totally satisfy the demand of practical engineering. Numerical calculation and analysis with the three dimensional discrete model can further optimize the support parameters, provide better service for system design of mining support, and ensure the safety and high efficiency in mining.

Place, publisher, year, edition, pages
China University of Mining and Technology, 2017
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-65467 (URN)10.13545/j.cnki.jmse.2017.04.016 (DOI)2-s2.0-85027967448 (Scopus ID)
Note

Chinese journal title: Caikuang yu Anquan Gongcheng Xuebao

Available from: 2017-09-04 Created: 2017-09-04 Last updated: 2019-04-23Bibliographically approved
Yi, C., Lu, W., Zhang, P., Johansson, D. & Nyberg, U. (2016). Effect of imperfect interface on the dynamic response of a circular lined tunnel impacted by plane P-waves (ed.). Paper presented at . Tunnelling and Underground Space Technology, 51, 68-74
Open this publication in new window or tab >>Effect of imperfect interface on the dynamic response of a circular lined tunnel impacted by plane P-waves
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2016 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 51, p. 68-74Article in journal (Refereed) Published
Abstract [en]

A theoretical method for studying the dynamic response of a circular lined tunnel with an imperfectly bonded interface subjected to plane P-waves is presented in the paper. The wave function expansion method was used and the imperfect interface was modeled with a spring model. Two cases were discussed in the paper. In the first case rock is harder than the lining and vice-versa in the second case. The results indicated that the variation in the stiffness of the interface has much influence on the distribution of dynamic stress concentration factors (DSCF) in the rock and the lining. The imperfection of the interface has a more noticeable influence on the DSCF in the rock mass and the lining at high frequency incident wave's scenario than low frequency incident wave's scenario. The resonance scattering phenomena can be observed when the bond is extremely weak. Limiting cases were considered and a good agreement with the solutions available in the literature was obtained.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-15085 (URN)10.1016/j.tust.2015.10.011 (DOI)000367493200008 ()2-s2.0-84944346092 (Scopus ID)e8c88ef1-1254-4b5b-83b0-a0010b0b0d4a (Local ID)e8c88ef1-1254-4b5b-83b0-a0010b0b0d4a (Archive number)e8c88ef1-1254-4b5b-83b0-a0010b0b0d4a (OAI)
Note
Validerad; 2015; Nivå 2; 20151015 (chayir)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zhang, P., Dineva, S., Nordlund, E., Hansen-Haug, J., Woldemedhin, B., Töyrä, J., . . . Mozaffari, S. (2016). Establishment of experimental sites in three Swedish mines to monitor the in-situ performance of ground support systems associated with mining-induced seismicity (ed.). In: (Ed.), E . N ordlund, T.H. Jones and A. Eitzenberger (eds) (Ed.), Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction: . Paper presented at Ground Support 2016 : 11/09/2016 - 14/09/2016.
Open this publication in new window or tab >>Establishment of experimental sites in three Swedish mines to monitor the in-situ performance of ground support systems associated with mining-induced seismicity
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2016 (English)In: Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction / [ed] E . N ordlund, T.H. Jones and A. Eitzenberger (eds), 2016Conference paper, Published paper (Refereed)
Abstract [en]

In order to assess the performance of ground support components and systems when subjected to seismic activity and strong ground motion, Luleå University of Technology together with three Swedish mining companies (Lundin Mining, LKAB and Boliden) started a three year research project in September 2014. The aim of the project is to develop new methods for evaluating the rock support performance in-situ that use all available information about i) the source of the seismic event (obtained from the seismic network in the mine and additional seismic sensors), ii) seismic loading (ground motion) recorded by temporary local seismic networks, and iii) the consequences of the seismic loading in terms of damage to the underground excavations and the rock support.The sites with high potential of seismic damage were defined after the historical damaging seismic events were reviewed and the mining-induced stress disturbance was investigated with 3D numerical models. As of 31 December 2015, four sites in three different mines have been instrumented. Geophones (in depth and at surface), multi-points extensometers and instrumented bolts were installed to monitor the ground motion, the deformation of the rock mass and the elongation of the bolts. Observation boreholes were drilled to investigate the rock lithology, structures as well as fracture distribution and development. The data from locally installed geophones will be integrated with seismic data recorded by the mine-wide network. For each monitoring point, all of the instruments and observation boreholes were located at very close area within 0.5-1 m distance from each other. These results will be used to establish the relationship between the dynamic loading and the response of rock mass and rock bolts. Additionally, laser scanning is used to measure the surface deformation of the whole volume of instrumented sites with time. Two damaging seismic events occurred near the instrumented sites after the instruments were installed and the results of site investigation show that installed instruments have captured the response of the rock mass and bolts due to production blasting and seismic events.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-61081 (URN)978-91-7583-804-5 (ISBN)
Conference
Ground Support 2016 : 11/09/2016 - 14/09/2016
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2017-11-24Bibliographically approved
Shirzadegan, S., Nordlund, E. & Zhang, P. (2016). In-situ dynamic testing of rock support at LKAB Kiirunavaara mine (ed.). In: (Ed.), E . Nordlund, T.H. Jones and A. Eitzenberger (eds) (Ed.), Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction: . Paper presented at Ground Support 2016 : 11/09/2016 - 14/09/2016.
Open this publication in new window or tab >>In-situ dynamic testing of rock support at LKAB Kiirunavaara mine
2016 (English)In: Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction / [ed] E . Nordlund, T.H. Jones and A. Eitzenberger (eds), 2016Conference paper, Published paper (Refereed)
Abstract [en]

A series of large scale dynamic tests were conducted at the LKAB Kiirunavaara mine using explosives to generate the dynamic load on the support system. This was done with the aim of developing a testing methodology for in-situ testing of ground support. Furthermore, the response of the installed rock support system to strong dynamic loading was evaluated. The results of the Tests 1, 2, 3, 4 and 5 indicated that the relation between the burden and the used amount of explosive had a vital role in either reducing or involving the effect of the detonation gases in the test results. Higher peak particle velocities were measured compared to those of similar large scale tests carried out in other countries. However, the level of induced damage in Tests 1 and 2 was limited to a fractured zone behind the support system while in Tests 4 and 5 the burden was unexpectedly destroyed. Based on the test results and preliminary numerical analysis, a modified test (Test 6) was designed at the same mine. The aim was to avoid the unexpected damage of burden as was observed in earlier tests, and to modify the dynamic loading leading to increase the depth of fractured zone and if possible pushing the support system beyond its limit. Results indicated that a larger fractured zone compare to earlier tests was developed behind the support system while the installed support system was still functional. Evidence from the damage to the tested cross-cuts in Test 6 indicated a reduction of radial cracks that provide access for the gas expansion. The results indicated that the installed support system, designed for dynamic conditions, performed well under the loading conditions which can cause ejection

Keywords
s
National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-61132 (URN)978-91-7583-804-5 (ISBN)
Conference
Ground Support 2016 : 11/09/2016 - 14/09/2016
Available from: 2016-12-19 Created: 2016-12-19 Last updated: 2017-11-24Bibliographically approved
Shirzadegan, S., Nordlund, E. & Zhang, P. (2016). Large scale dynamic testing of rock support at Kiirunavaara: Improved test design (ed.). Tunnelling and Underground Space Technology, 59, 183-198
Open this publication in new window or tab >>Large scale dynamic testing of rock support at Kiirunavaara: Improved test design
2016 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 59, p. 183-198Article in journal (Refereed) Published
Abstract [en]

Based on the test results and preliminary numerical analysis of four large scale dynamic testing of rock support (Tests 1, 2, 4, and 5), a modified test (Test 6) was designed at LKAB Kiirunavaara underground mine. The aim of the modified design was to avoid the unexpected damage of burden as was observed in earlier tests, and to modify the dynamic loading leading to increase the depth of fractured zone and if possible pushing the support system beyond its limit. In this test, ground motion measurements were conducted using accelerometers, fracture investigations were made using an inspection borehole camera, and ground motion imaging and laser scanning were performed before and after blast. In Test 6, the columns of explosive were located in the middle of a pillar between two cross-cuts one supported by a rock support for seismic conditions, and the other supported by only plain shotcrete. Results indicated that a larger fractured zone compare to earlier tests was developed behind the support system while the installed support system was still functional. In cross-cut without support system, the ejection of blocks of rock from the test wall was observed. Evidence from two cross-cuts indicated a reduction of radial cracks that provide access for the gas expansion. Furthermore, the performance of the rock support was investigated by comparing with the results from the unsupported cross-cut. The results indicated that the installed support system, designed for dynamic conditions, performed well under the loading conditions which can cause ejection.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-13813 (URN)10.1016/j.tust.2016.07.005 (DOI)000384774700019 ()2-s2.0-84979255949 (Scopus ID)d1a34f22-92de-4746-8678-8403d7fe9c0d (Local ID)d1a34f22-92de-4746-8678-8403d7fe9c0d (Archive number)d1a34f22-92de-4746-8678-8403d7fe9c0d (OAI)
Note

Validerad; 2016; Nivå 2; 20160815 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Shirzadegan, S., Nordlund, E. & Zhang, P. (2016). Large Scale Dynamic Testing of Rock Support System at Kiirunavaara Underground Mine (ed.). Paper presented at . Rock Mechanics and Rock Engineering, 49(7), 2773-2794
Open this publication in new window or tab >>Large Scale Dynamic Testing of Rock Support System at Kiirunavaara Underground Mine
2016 (English)In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 49, no 7, p. 2773-2794Article in journal (Refereed) Published
Abstract [en]

A series of five large scale dynamic tests were conducted at the LKAB Kiirunavaara mine using explosives to generate the dynamic load on the support system. This was done with the aim of developing a testing methodology for in situ testing of ground support. Furthermore, the response of the installed rock support system to strong dynamic loading was evaluated. The tests included ground motion measurements, fracture investigation, ground and support motion imaging, as well as deformation measurements. The results indicated that the relation between the burden and the used amount of explosive had a vital role in either reducing or involving the effect of the detonation gases in the test results. In addition, the type of explosive which was used in the tests had a great impact on minimising the gas expansion effects. Higher peak particle velocities were measured compared to those of similar large scale tests carried out in other countries. However, the level of induced damage was limited to a fractured zone behind the support system and propagation of cracks in the shotcrete. Measured peak particle velocities were used to calculate the kinetic energy transmitted to the fractured zone of the test wall. The energy absorption by the Swellex, reinforced shotcrete and weld mesh was estimated by measuring the elongation/deflection of the support elements and relating these measurements to previously conducted laboratory tests. The comparison of maximum estimated energy absorbed by support system with the maximum estimated kinetic energy indicated that as the support system is still functional, the energy is partly reflected back to the surrounding rock. The results of the measurements in Tests 1, 2, 4 and 5 are presented in this paper and the methodology used to design the tests is discussed.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-9664 (URN)10.1007/s00603-016-0939-7 (DOI)000379015700018 ()2-s2.0-84961207075 (Scopus ID)8550fb71-5139-44c2-a2eb-ec06d447323b (Local ID)8550fb71-5139-44c2-a2eb-ec06d447323b (Archive number)8550fb71-5139-44c2-a2eb-ec06d447323b (OAI)
Note
Validerad; 2016; Nivå 2; 20160321 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Yi, C., Zhang, P., Nordlund, E., Shirzadegan, S. & Nyberg, U. (2016). Numerical modelling of dynamic response of underground openings under blasting based on field tests (ed.). In: (Ed.), E. Nordlund, T.H. Jones and A. Eitzenberger (eds) (Ed.), Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction: . Paper presented at Ground Support 2016 : 11/09/2016 - 14/09/2016.
Open this publication in new window or tab >>Numerical modelling of dynamic response of underground openings under blasting based on field tests
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2016 (English)In: Proceedings of the 8th International Symposium on Ground Support in Mining and Underground Construction / [ed] E. Nordlund, T.H. Jones and A. Eitzenberger (eds), 2016Conference paper, Published paper (Refereed)
Abstract [en]

In order to assess the capacity of ground support systems when subjected to dynamic loading, simulated rockburst tests by using blasting have been conducted at LKAB Kiirunavaara underground mine. In this paper, a numerical simulation for one of the field tests is conducted using LS-DYNA code to numerically investigate the effect of the different aspects of the charge design including the initiation point and the geometry on the test results. In the simulation, an explosive material model is used to model the detonation of explosive used in field tests and the Riedel-Hiermaier -Thoma (RHT) material model is used to model the dynamic response of the rock mass. The decoupling effect between the explosive and the wall of borehole is also taken into account in the model. The numerical results show a similar particle vibration pattern and a crack pattern to those of the field measurment. The effects of the position of the initiation point and the charge structure on the dynamic response of rock mass are also discussed. The results can be a reference for blast design for future field tests.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-61089 (URN)978-91-7583-804-5 (ISBN)
Conference
Ground Support 2016 : 11/09/2016 - 14/09/2016
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2018-04-17Bibliographically approved
Zhang, P., Swan, G. & Nordlund, E. (2015). 1D numerical simulation of velocity amplification of P-waves travelling through fractured rock near a free surface (ed.). The Southern African Journal of Mining and Metallurgy, 115(11), 1121-1126
Open this publication in new window or tab >>1D numerical simulation of velocity amplification of P-waves travelling through fractured rock near a free surface
2015 (English)In: The Southern African Journal of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 1543-9518, Vol. 115, no 11, p. 1121-1126Article in journal (Refereed) Published
Abstract [en]

The most widely used support design damage criterion for rockburst-prone mines is based upon kinetic energy, which is proportional to the square of the ejection velocity and is commonly expressed in terms of peak particle velocity (PPV). Field monitoring and back-analyses have shown that ejection velocities of the order of 10 m/s and higher can result from seismic events of moderate magnitude. Such velocities are much higher than those predicted using PPV obtained from scaling laws. It has also been found that the peak ground motion (i.e. PPV) on the surface of an excavation is preferentially amplified (by four-to tenfold) compared to the motion in solid rock at a similar distance from the source. However, the wave propagation and interaction processes involved within the fractured rock in generating high ground motion are very complex and are not well understood at this time. In this paper, velocity amplification was investigated by modelling the dynamic interaction between fractured rock and a free surface using a 2D discontinuum-based numerical program, UDEC (Universal Distinct Element Code). A 1D model with a fractured zone was used to represent the fractured rock. Velocity amplification, quantified by PPV, predicted at the free end of the model was 2.0-3.6 times higher than the input velocity. It was found that the wave frequency, fracture stiffness, fracture spacing, and thickness of fractured zone are the main factors that affect the velocity amplification. The results have proved that the interaction of the seismic wave and multiple fractures near the free surface strongly influences the ground motion

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-13622 (URN)10.17159/2411-9717/2015/v115n11a16 (DOI)2-s2.0-84958700166 (Scopus ID)cdf51836-a58c-45da-9752-5ec40dab3a69 (Local ID)cdf51836-a58c-45da-9752-5ec40dab3a69 (Archive number)cdf51836-a58c-45da-9752-5ec40dab3a69 (OAI)
Note

Validerad; 2016; Nivå 2; 20160301 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2019-02-11Bibliographically approved
Shirzadegan, S., Nordlund, E. & Zhang, P. (2015). Development of a methodology for in-situ dynamic testing of ground support (ed.). Paper presented at Bergmekanikdag 2015 : 09/03/2015. Paper presented at Bergmekanikdag 2015 : 09/03/2015.
Open this publication in new window or tab >>Development of a methodology for in-situ dynamic testing of ground support
2015 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

A series of seven large scale dynamic tests were conducted at LKAB Kiruna mine using explosives in the vicinity of cross-cuts to generate dynamic load on the support system. The aim was to develop an in-situ testing method for rock support, i.e., to determine the dynamic load that causes failure to the test wall and/or support system. The methodology used to design Tests 1 to 7 is discussed in this paper and the level of damage to the test wall and support system in each test is described. Comparison of results in different test designs indicated that increasing burden and number of blasthole at the same time, increases the possibilities of obtaining more planar waves and decreases the destructive effect of detonation gases.

National Category
Other Civil Engineering
Research subject
Mining and Rock Engineering
Identifiers
urn:nbn:se:ltu:diva-31450 (URN)5a09cc5a-0228-4854-8477-9be825cd7081 (Local ID)5a09cc5a-0228-4854-8477-9be825cd7081 (Archive number)5a09cc5a-0228-4854-8477-9be825cd7081 (OAI)
Conference
Bergmekanikdag 2015 : 09/03/2015
Note
Godkänd; 2015; 20150513 (shashi)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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