|
|
|
| Continuous-discrete coupling simulation of progressive failure of mining overburden rock
|
| LI Hao1，TANG Shibin2，3，MA Liqiang4，BAI Haibo5，KANG Zhiqin1，WU Pengfei1，MIAO Xiaocheng6 |
| (1. Key Laboratory of In-situ Property Improving Mining of Ministry of Education，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China；2. School of Civil Engineering，Dalian University of Technology，Dalian，Liaoning 116024，China；
3. Institute of Rock Instability and Seismicity Research，Dalian University of Technology，Dalian，Liaoning 116024，China；
4. School of Mining Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；5. State
Key Laboratory for Geomechanics and Deep Underground Engineering，China University of Mining and Technology，
Xuzhou，Jiangsu 221116，China；6. Jinneng Holding Coal Industry Group，Datong，Shanxi 037003，China) |
|
|
|
|
Abstract The key to the accuracy of the numerical results of the fracture evolution of mining overburden is to establish the mechanical constitutive model and numerical method reflecting the continuous-discrete medium transformation of mining rock. The yield function and plastic potential function with deviatoric stress and spherical stress as basic variables were constructed，and the elastic-plastic constitutive model of complete rock block was obtained by combining with generalized Hooke?s law. By introducing the elastic-plastic damage theory，taking the square tensile-shear stress criterion as the initial damage criterion and combined with the Benzeggagh-Kenane fracture criterion，the constitutive model of tensile-shear mixed mode fracture was obtained. The discrete block compression constitutive model was constructed，and the Sargin?s shear friction constitutive model of rough discontinuities was modified based on the direct shear experimental data. Therefore，a continuous-discrete coupling simulation program reflecting the progressive failure of rock was compiled. On the basis of verifying the constitutive model，the numerical calculation model was established according to the engineering geological conditions of the DaTong mine. The results show that：(1) The progressive failure constitutive model of rock and the corresponding continuous-discrete coupling simulation method can numerically realize the transformation process of rock from continuum to discrete body. (2) Under the disturbance of repeated mining in multiple coal seams，the distribution of overburden fractures in Carboniferous coal seams is complex，and its height is about 21 times of the mining height，far exceeding the results obtained by empirical formula. (3) Under the coupling action of concentrated stress and mining stress of Jurassic coal pillar，the peak value of advanced support pressure of Carboniferous mining face reaches 42 MPa，which is about 8–10 MPa higher than that in the area without coal pillar，and the ground pressure shows strongly. The above results have been preliminarily applied in Datong mining area，which provides theoretical support for further water retaining mining，fracturing and pressure relief.
|
|
|
|
|
|
| [1] 许家林，秦 伟，轩大洋，等. 采动覆岩卸荷膨胀累积效应[J]. 煤炭学报，2020，45(1)：35–43.(XU Jialin，QIN Wei，XUAN Dayang，et al. Accumulative effect of overburden strata expansion induced by stress relief[J]. Journal of China Coal Society，2020，45(1)：35–43.(in Chinese))
[2] 李江华，王东昊，黎 灵，等. 不同覆岩类型高强度采动裂隙发育特征对比研究[J]. 煤炭科学技术，2021，49(10)：9–15.(LI Jianghua，WANG Donghao，LI Ling，et al. Comparative study on development characteristics of high-intensive mining fissures in different overburden types[J]. Coal Science and Technology，2021，49(10)：9–15.(in Chinese))
[3] QI D H，RU X H，LI D Y，et al. Study of the height of water flowing fracture zone based on strain energy failure criterion[C]// IOP Conference Series：Earth and Environmental Science. [S. l.]：IOP Publishing，2019：022065.
[4] 王 君，朱卫兵，谢建林. 特厚煤层充分采动覆岩下沉规律研究[J]. 工矿自动化，2021，47(10)：21–26.(WANG Jun，ZHU Weibing，XIE Jianlin. Research on subsidence law of overlying strata in full mining of extra-thick coal seam[J]. Industry and Mine Automation，2021，47(10)：21–26.(in Chinese))
[5] 伊茂森，朱卫兵，李 林，等. 补连塔煤矿四盘区顶板突水机制及防治[J]. 煤炭学报，2008，33(3)：241–245.(YI Maosen，ZHU Weibing，LI Lin，et al. Water-inrush mechanism and prevention for fourth panel roof in Bulianta coal mine[J]. Journal of China Coal Society，2008，33(3)：241–245.(in Chinese))
[6] CHEN Y，ZHU S Y. Determination of caved and water-conducting fractured zones of “two soft and one hard” unstable coal seam[J]. Acta Geodaetica et Geophysica，2020，55(3)：451–475.
[7] 丁其乐. 端帮压煤井工开采覆岩运动规律及控制研究[博士学位论文][D]. 中国矿业大学，2017.(DING Qile. Overlying strata movement law and control of underground mining in end slope[Ph. D. Thesis][D]. Xuzhou：China University of Mining and Technology，2017.(in Chinese))
[8] 李 浩. 围压作用下岩石塑性与流固耦合特性研究及其应用[博士学位论文][D]. 中国矿业大学，2018.(LI Hao. Study on the rock characteristics of plasticity and fluid-solid coupling under confining pressure and its application[Ph. D. Thesis][D]. Xuzhou：China University of Mining and Technology，2018.(in Chinese))
[9] JI Y D，CAO H D，ZHAO B F. Mechanism and control of water inrush from separated roof layers in the Jurassic coalfields[J]. Mine Water and the Environment，2021，40(2)：357–365.
[10] QI D，RU X，LI D，et al. Study of the height of water flowing fracture zone based on strain energy failure criterion[C]// IOP Conference Series：Earth and Environmental Science. [S. l.]：IOP Publishing，2019：022065.
[11] LIU Y，LIU Q M，LI W P，et al. Height of water-conducting fractured zone in coal mining in the soil-rock composite structure overburdens[J]. Environmental Earth Sciences，2019，78(7)：1–13.
[12] ZHU T，LI W，WANG Q，et al. Study on the height of the mining-induced water-conducting fracture zone under the Q 2l loess cover of the Jurassic coal seam in Northern Shaanxi，China[J]. Mine Water and the Environment，2020，39(1)：57–67.
[13] SUN W B，WANG Y，QIU H F，et al. Numerical simulation study of strip filling for water-preserved coal mining[J]. Environmental Science and Pollution Research，2019，27(12)：12 899–12 970.
[14] LLANOS E M，JEFFREY R G，HILLIS R，et al. Hydraulic fracture propagation through an orthogonal discontinuity：A laboratory，analytical and numerical study[J]. Rock Mechanics and Rock Engineering，2017，50：2 101–2 118.
[15] 李 浩，白海波，武建军，等. D-P随机损伤本构模型及其在预防陷落柱突水中的应用[J]. 岩土力学，2018，39(12)：4 577–4 587.(LI Hao，BAI Haibo，WU Jianjun，et al. D-P stochastic damage constitutive model and its application in preventing water inrush of karst collapsed column[J]. Rock and Soil Mechanics，2018，39(12)：4 577–4 587.(in Chinese))
[16] BENZEGGAGH M L，KENANE M. Measurement of mixed-mode delamination fracture toughness of unidirectional glass/epoxy composites with mixed-mode bending apparatus[J]. Composites Science and Technology，1996，56(4)：439–449.
[17] LI H，LIANG W，WANG J，et al. Research on main controlling factors and its influencing laws on hydraulic fracture network in the fractured soft and low-permeability coal[J]. Journal of Natural Gas Science and Engineering，2021，95：104147.
[18] 朱卫兵，许家林，陈 璐. 浅埋近距离煤层开采房式煤柱群动态失稳致灾机制[J]. 煤炭学报，2019，44(2)：358–366.(ZHU Weibing，XU Jialin，CHEN Lu，et al. Mechanism of disaster induced by dynamic instability of coal pillar group in room-and-pillar mining of shallow and close coal seams[J]. Journal of China Coal Society，2019，44(2)：358–366.(in Chinese))
[19] SARGIN M. Stress-Strain relationships for concrete and analysis of structural concrete sections[R]. Waterloo，Ontario，Canada：University of Waterloo，1971.
[20] MUNJIZA A，ANDREWS K. NBS contact detection algorithm for bodies of similar size[J]. International Journal for Numerical Methods in Engineering，1998，43(1)：131–149.
[21] 尤明庆. 围压对岩石试样强度的影响及离散性[J]. 岩石力学与工程学报，2014，33(5)：929–937.(YOU Mingqing. Effect of confining pressure on strength scattering of rock specimen[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(5)：929–937.(in Chinese))
[22] PANZA E，AGOSTA F，ZAMBRANO M，et al. Structural architecture and Discrete Fracture Network modelling of layered fractured carbonates(Altamura Fm.，Italy)[J]. Italian Journal of Geosciences，2015，134(3)：409–422.
[23] YAN S，WANG F G，YANG Y L，et al. Integration of carbon geological storage and geothermal energy development in low-permeability reservoirs[C]// Applied Mechanics and Materials. [S. l.]：Trans Tech Publications Ltd.，2014：4 350–4 357.
[24] 李 浩，白海波，马立强，等. 双系煤层采动导水裂隙演化规律的FDEM耦合模拟研究[J/OL]. 煤炭学报，DOI：10.13225/ j. cnki. jccs. 2021. 2077.(LI Hao，BAI Haibo，MA Liqiang，et al. Research on the evolution law of water flowing fractures in of Jurassic and Carboniferous coal seams based on FDEM simulation[J/OL]. Journal of China Coal Society，DOI：10.13225/j.cnki.jccs.2021.2077.(in Chinese))
|
|
|
|
2022, Vol. 41 
