Abstract
When residual pillars are extracted in a short time in room and pillar mining, the load transferred from the removed pillar acts on neighbouring pillar workings in a dynamic manner. This study aims to investigate the instability of large mined-out areas triggered by dynamic disturbance resulting from residual pillar recovery. A mechanical model combining the pressure arch theory (PAT) based method and structural dynamics was first established to assess the stress state and deformation of a pillar subjected to combined effects of static and dynamic loads. The process of residual pillar recovery and potential induced instability of neighbouring pillar workings in a five-pillar system was further numerically simulated in both static and dynamic modes, and the response of adjacent pillars was investigated. It was found that the induced disturbance to a pillar can be characterised by the dynamic amplification coefficient R, the ratio of the increased vertical pillar load to the transferred load. Rmax can exceed 1.5 or even approach 2 in practical pillar recovery using the blasting method. Modelling results showed that while pillar workings adjacent to a removed pillar remain stable in static analysis, violent and large-scale pillar collapses can be triggered in the event of quick pillar recovery of blasting method. Results indicated that when the dynamic effect of pillar recovery is not considered, the load undertaken by adjacent pillar workings would be largely underestimated. To ensure mining safety, the induced dynamic effect should be accounted for in the design of the pillar recovery method.
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Abbreviations
- DEM:
-
Discrete element method
- PAT:
-
Pressure arch theory
- D :
-
Fraction of critical damping
- E :
-
Elastic modulus of a pillar
- EA:
-
Excavated area
- e :
-
Extraction ratio
- g :
-
Gravitational acceleration
- H :
-
Depth of pillars
- K :
-
Elastic stiffness of a pillar
- LTD:
-
Load transfer distance
- m :
-
Mass of a pillar
- R :
-
Dynamic amplification coefficient
- r :
-
Pillar radius
- T :
-
Natural vibration period of a pillar
- t 0 :
-
Load transfer duration
- U :
-
Total released energy in extraction
- U d :
-
External energy from the dynamic disturbance
- U f :
-
Energy needed to be consumed in fracturing rock masses
- U s :
-
Strain energy stored in the rock mass to be extracted
- w e :
-
Effective width for non-square pillars
- y s :
-
Pillar deformation increment
- ZI:
-
Area of zone of influence
- α :
-
Damping coefficient
- ρ :
-
Rock density
- σ cri :
-
Critical stress
- σ d :
-
Dynamic vertical pillar load
- ∆σ d :
-
Dynamic transferred vertical pillar load
- \({\sigma _{{H_{\rm{max} }}}}\) :
-
The maximum horizontal principal stress
- σ s :
-
Static (final) vertical pillar load
- ∆σ s :
-
Static (final) transferred vertical pillar load
- σ V :
-
Vertical stress
- σ v :
-
Vertical pillar load
- \(\sigma _{{\text{v}}}^{{{\rm{max}}}}\) :
-
The maximum vertical pillar load
- Ω:
-
Natural vibration frequency of a pillar
References
Abel JF (1988) Soft rock pillars. Int J Min Geol Eng 6:215–248. https://doi.org/10.1007/BF00880975
Brady B, Brown E (2013) Rock mechanics: for underground mining. Springer Science & Business Media, New York
Cai M (2008) Influence of stress path on tunnel excavation response—numerical tool selection and modeling strategy. Tunn Undergr Space Tech 23:618–628. https://doi.org/10.1016/j.tust.2007.11.005
Cao W, Li X, Tao M, Zhou Z (2016) Vibrations induced by high initial stress release during underground excavations. Tunn Undergr Space Tech 53:78–95. https://doi.org/10.1016/j.tust.2016.01.017
Cao W, Shi J, Si G et al (2018) Numerical modelling of microseismicity associated with longwall coal mining. Int J Coal Geol 193:30–45. https://doi.org/10.1016/j.coal.2018.04.010
Chao X, Zheng H, Hou X, Zhang X (2015) A stability study of goaf based on mechanical properties degradation of rock caused by rheological and disturbing loads. Int J Min Sci Technol 25:741–747. https://doi.org/10.1016/J.IJMST.2015.07.007
Chen Y, Ma S, Yu Y (2017) Stability control of underground roadways subjected to stresses caused by extraction of a 10-m-thick coal seam: a Case Study. Rock Mech Rock Eng 50:2511–2520. https://doi.org/10.1007/s00603-017-1217-z
Clough R, Penzien J (2003) Dynamics of structures. Computers & Structures, Inc., New York
Dou L, He J, Cao A et al (2015) Rock burst prevention methods based on theory of dynamic and static combined load induced in coal mine. J China Coal Soc 40:1469–1476 (in Chinese)
Hauquin T, Deck O, Gunzburger Y (2016) Average vertical stress on irregular elastic pillars estimated by a function of the relative extraction ratio. Int J Rock Mech Min Sci 83:122–134. https://doi.org/10.1016/j.ijrmms.2015.12.004
Itasca (2008) Particle flow code in 2 dimensions. Itasca Consult. Gr. Inc., Minneapolis
Kaiser PK, Cai M (2012) Design of rock support system under rockburst condition. J Rock Mech Geotech Eng 4:215–227. https://doi.org/10.3724/SP.J.1235.2012.00215
Kaiser P, McCreath D, Tannant D (1996) Canadian rockburst support handbook. Geomechanics Research Centre, Laurentian University, Sudbury, Ontario
Li QM (2001) Strain energy density failure criterion. Int J Solids Struct 38:6997–7013. https://doi.org/10.1016/S0020-7683(01)00005-1
Li X, Zuo Y, Ma C (2005) Failure criterion of strain energy density and catastrophe theory analysis of rock subjected to static-dynamic coupling loading. Chin J Rock Mech Eng 24:2814–2824 (in Chinese)
Li W, Ma C, Li K et al (2010) Measurement and distribution of 3D geostress in Kaiyang phosphate mine in Guizhou. Min Technol 10(5):31–33
Li X, Cao W, Zhou Z, Zou Y (2014) Influence of stress path on excavation unloading response. Tunn Undergr Space Tech 42:237–246. https://doi.org/10.1016/j.tust.2014.03.002
Li X, Cao W, Tao M et al (2016) Influence of unloading disturbance on adjacent tunnels. Int J Rock Mech Min Sci 84:10–24. https://doi.org/10.1016/j.ijrmms.2016.01.014
Li X, Li C, Cao W, Tao M (2018) Dynamic stress concentration and energy evolution of deep-buried tunnels under blasting loads. Int J Rock Mech Min Sci 104:131–146. https://doi.org/10.1016/j.ijrmms.2018.02.018
Lu W, Yang J, Yan P et al (2012) Dynamic response of rock mass induced by the transient release of in-situ stress. Int J Rock Mech Min Sci 53:129–141. https://doi.org/10.1016/j.ijrmms.2012.05.001
Lunder P, Pakalnis R (1997) Determination of the strength of hard-rock mine pillars. CIM Bull 90:51–55
Pan Y, Zhao Y, Guan F et al (2007) Study on rockburst monitoring and orientation system and its application. Chin J Rock Mech Eng 26:1002–1011 (in Chinese)
Pao Y, Mow C (1973) Diffraction of elastic waves and dynamics stress concentrations. Rand Corporation, New York
Petukhov IM, Linkov AM (1979) The theory of post-failure deformations and the problem of stability in rock mechanics. Int J Rock Mech Min Sci 16:57–76. https://doi.org/10.1016/0148-9062(79)91444-X
Potyondy DO, Cundall PA (2004) A bonded-particle model for rock. Int J Rock Mech Min Sci 41:1329–1364. https://doi.org/10.1016/j.ijrmms.2004.09.011
Poulsen BA (2010) Coal pillar load calculation by pressure arch theory and near field extraction ratio. Int J Rock Mech Min Sci 47:1158–1165. https://doi.org/10.1016/j.ijrmms.2010.06.011
Poulsen BA, Shen B (2013) Subsidence risk assessment of decommissioned bord-and-pillar collieries. Int J Rock Mech Min Sci 60:312–320. https://doi.org/10.1016/j.ijrmms.2013.01.014
Roberts DP, van der Merwe JN, Canbulat I et al (2002) Development of a method to estimate coal pillar loading. Safety in Mines Research Advisory Committee, COL 709, pp 1–90
Salamon MDG (1970) Stability, instability and design of pillar workings. Int J Rock Mech Min Sci 7:613–631. https://doi.org/10.1016/0148-9062(70)90022-7
Singh AK, Singh R, Maiti J et al (2011a) Assessment of mining induced stress development over coal pillars during depillaring. Int J Rock Mech Min Sci 48:805–818. https://doi.org/10.1016/j.ijrmms.2011.04.004
Singh R, Singh AK, Maiti J et al (2011b) An observational approach for assessment of dynamic loading during underground coal pillar extraction. Int J Rock Mech Min Sci 48:794–804. https://doi.org/10.1016/j.ijrmms.2011.04.003
Suorineni FT, Kaiser PK, Mgumbwa JJ, Thibodeau D (2011) Mining of orebodies under shear loading Part 1—case histories. Min Technol 120:137–147. https://doi.org/10.1179/1743286311Y.0000000012
Suorineni FT, Mgumbwa JJ, Kaiser PK, Thibodeau D (2014) Mining of orebodies under shear loading Part 2—failure modes and mechanisms. Min Technol 123:240–249. https://doi.org/10.1179/1743286314Y.0000000072
Tao M, Li X, Li D (2013) Rock failure induced by dynamic unloading under 3D stress state. Theor Appl Fract Mech 65:47–54. https://doi.org/10.1016/j.tafmec.2013.05.007
Wang H, Jiang Y, Zhao Y et al (2013) Numerical investigation of the dynamic mechanical state of a coal pillar during longwall mining panel extraction. Rock Mech Rock Eng 46:1211–1221. https://doi.org/10.1007/s00603-012-0337-8
Wang SL, Hao SP, Chen Y et al (2016) Numerical investigation of coal pillar failure under simultaneous static and dynamic loading. Int J Rock Mech Min Sci 84:59–68. https://doi.org/10.1016/j.ijrmms.2016.01.017
Xiao X, Xiao P, Dai F et al (2017) Large deformation characteristics and reinforcement measures for a rock pillar in the Houziyan underground powerhouse. Rock Mech Rock Eng. https://doi.org/10.1007/s00603-017-1329-5
Yang J, Lu W, Chen M et al (2013) Microseism induced by transient release of in situ stress during deep rock mass excavation by blasting. Rock Mech Rock Eng 46:859–875. https://doi.org/10.1007/s00603-012-0308-0
Yao J, Ma C, Li X, Yang J (2012) Numerical simulation of optimum mining design for high stress hard-rock deposit based on inducing fracturing mechanism. Trans Nonferrous Met Soc China 22:2241–2247. https://doi.org/10.1016/S1003-6326(11)61455-6
Zhang G, He F, Jia H, Lai Y (2017) Analysis of gateroad stability in relation to yield pillar size: a Case Study. Rock Mech Rock Eng 50:1263–1278. https://doi.org/10.1007/s00603-016-1155-1
Zhao T, Guo W, Tan Y (2018) Case Studies of rock bursts under complicated geological conditions during multi‑seam mining at a depth of 800 m. Rock Mech Rock Eng. https://doi.org/10.1007/s00603-018-1411-7
Zhou Z, Cai X, Ma D et al (2018a) Effects of water content on fracture and mechanical behavior of sandstone with a low clay mineral content. Eng Fract Mech. https://doi.org/10.1016/j.engfracmech.2018.02.028
Zhou Z, Chen L, Cai X et al (2018b) Experimental investigation of the progressive failure of multiple pillar–roof system. Rock Mech Rock Eng. https://doi.org/10.1007/s00603-018-1441-1
Zubelewicz A, Mroz Z (1983) Numerical simulation of rock burst processes treated as problems of dynamic instability. Rock Mech Rock Eng 16:253–274. https://doi.org/10.1007/BF01042360
Zuo Y, Li X, Ma C et al (2005) Catastrophic model and testing study on failure of static loading rock system under dynamic loading. Chin J Rock Mech Eng 24:741–746 (in Chinese)
Acknowledgements
This research is supported by financial grants from the National Basic Research Program of China (2015CB060200), the National Natural Science Foundation of China (No. 41772313) and the Hunan Natural Science Foundation (2015JJ4067). The authors are very grateful to the financial contribution and convey their appreciation of the organization for supporting this basic research.
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Zhou, Z., Zhao, Y., Cao, W. et al. Dynamic Response of Pillar Workings Induced by Sudden Pillar Recovery. Rock Mech Rock Eng 51, 3075–3090 (2018). https://doi.org/10.1007/s00603-018-1505-2
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DOI: https://doi.org/10.1007/s00603-018-1505-2