摘要
针对露天矿开采过程中,爆破开挖作业对最终边坡稳定的影响问题,采用动力有限元法分析爆破过程中边坡的稳定性随时间变化情况。首先建立矿山边坡的二维有限元模型,利用有限元强度折减法求解,得到边坡的最危险滑动面及折减安全系数;再根据得到的最危险滑动面,重新建立边坡和炸药的三维实体模型,布置爆破孔网参数并设置各个炮孔的起爆时间,通过LS-DYNA大型动力有限元程序,求解边坡在炸药爆炸后30 s时间内的动力响应过程。结合极限平衡法和动力有限元法计算结果,计算边坡在同时起爆方式下每一时刻的安全系数。提出应根据边坡时程安全系数及边坡滑面单元是否同时发生整体破坏等条件综合评价边坡稳定性。数值模拟结果能够动态显示爆破过程中边坡的应力、应变状态,计算结果与极限平衡法计算结果接近,可以为露天矿爆破设计提供参考。
For the significant impact of blasting on slope stability during open-pit mining process,the dynamic finite element method is used to analyze the variation of slope stability with the time in blasting. Firstly,the finite element model of mine slope is established,then the finite element strength reduction method is adopted to get the most dangerous sliding surface and safety coefficient of the slope. After that,based on the most dangerous sliding surface obtained,a three-dimensional entity model of slope and explosives was created,the blasting parameters are arranged and the initiation time for each hole is set up. Next,this model is calculated after the initiation. The dynamic response process after slope explosive for 30 s is solved by LS-DYNA large dynamic finite element program. Combining with the limit equilibrium method and dynamic finite element method,the safety factors of slope at every moment under unified detonation are calculated. Slope stability should be comprehensively evaluated by the time-history safety coefficient and whether the elements of the sliding surface are destroyed at the same time. The simulation results can dynamically display the security status of slope blasting process,and the result is very close to that by the limit equilibrium method. This research could make a reference for the blasting design.
引文
[1]刘立平,雷尊宇,周富春.地震边坡稳定分析方法综述[J].重庆交通学院学报,2001,20(3):83-88.Liu Liping,Lei Zunyu,Zhou Fuchun.The evaluation of seismic slope stability analysis methods[J].Journal of Chongqing Jiaotong University,2001,20(3):83-88.
[2]郑颖人,叶海林,黄润秋,等.边坡地震稳定性分析探讨[J].地震工程与工程振动,2010(2):173-180.Zheng Yingren,Ye Hailin,Huang Runqiu,et al.Study on the seismic stability analysis of a slope[J].Journal of Earthquake Engineering and Engineering Vibration,2010(2):173-180.
[3]刘汉龙,费康,高玉峰.边坡地震稳定性时程分析方法[J].岩土力学,2003(4):553-556.Liu Hanlong,Fei Kang,Gao Yufeng.Time history analysis method of slope seismic stability[J].Rock and Soil Mechanics,2003(4):553-556.
[4]许名标,彭德红.边坡爆破振动测试及响应规律ANSYS时程分析[J].岩石力学与工程学报,2012(S1):2629-2635.Xu Mingbiao,Peng Dehong.Blasting vibration tests and analysis time-history analyses of slope responses[J].Chinese Journal of Rock Mechanics and Engineering,2012(S1):2629-2635.
[5]陈明,卢文波,舒大强,等.爆破振动作用下边坡极限平衡分析的等效加速度计算方法[J].岩石力学与工程学报,2009(4):784-790.Chen Ming,Lu Wenbo,Shu Daqiang,et al.Calculation method of equivalent acceleration for limit equilibrium analysis of slope under blasting vibration[J].Chinese Journal of Rock Mechanics and Engineering,2009(4):784-790.
[6]赵婉婷,卢文波,杨建华,等.深孔台阶爆破振动模拟中的等效荷载施加边界比较[J].爆破,2012(2):10-14.Zhao Wanting,Lu Wenbo,Yang Jianhua,et al.Comparison of equivalent load in boundaries in deep-hole bench blasting vibration simulation[J].Blasting,2012(2):10-14.
[7]许红涛,卢文波,周创兵,等.基于时程分析的岩质高边坡开挖爆破动力稳定性计算方法[J].岩石力学与工程学报,2006(11):2213-2219.Xu Hongtao,Lu Wenbo,Zhou Chuangbing,et al.Time history analysis method for evaluating dynamic stability of high rock slope under excavation blasting[J].Chinese Journal of Rock Mechanics and Engineering,2006(11):2213-2219.
[8]陈祖煜.土质边披稳定分析——原理·方法·程序[M].北京:中国水利水电出版社,2003:255-256.Chen Zuyu.Soil Slope Stability Analysis:Theory Methods and Programs[M].Beijing:China Water Power Press,2003:255-256.
[9]王成华.土力学[M].武汉:华中科技大学出版社,2010:346-348.Wang Chenghua.Soil Mechanics[M].Wuhan:Huazhong University of Science&Technology Press,2010:346-348.
[10]郑颖人,赵尚毅.有限元强度折减法在土坡与岩坡中的应用[J].岩石力学与工程学报,2004,19:3381-3388.Zheng Yingren,Zhao Shangyi.Application of strength reduction fem in soil and rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2004,19:3381-3388.
[11]赵尚毅,郑颖人,张玉芳.有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005(2):332-336.Zhao Shangyi,Zheng Yingren,Zhang Yufang.Study on slope failure criterion in strength reduction finite element method[J].Rock and Soil Mechanics,2005(2):332-336.
[12]马建勋,赖志生,蔡庆娥,等.基于强度折减法的边坡稳定性三维有限元分析[J].岩石力学与工程学报,2004,16:2690-2693.Ma Jianxun,Lai Zhisheng,Cai Qing'e,et al.3D FEM analysis of slope stability based on strength reduction method[J].Chinese Journal of Rock Mechanics and Engineering,2004,16:2690-2693.
[13]郑颖人,赵尚毅.岩土工程极限分析有限元法及其应用[J].土木工程学报,2005(1):91-98.Zheng Yingren,Zhao Shangyi.Limit state finite element method for geotechnical engineering analysis and its applications[J].China Civil Engineering Journal,2005(1):91-98
[14]Livemore Software Technology Corporation.LS-DYNA Version 971Keyword User's Manual[M].California:Livemore Software Technology Corporation,2007.