爆破振动作用下含软弱夹层边坡稳定性及安全判据
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摘要
运用FLAC3D软件建立了顺层台阶边坡数值模型,首先分析爆破振动作用下边坡的振速响应规律,然后通过边坡的位移、剪应变增量分析其稳定性,最后根据边坡稳定性判据,制定爆破振速安全阈值。研究表明,随着爆心距的增大,振速传播规律为近处衰减快、远处衰减慢,坡面存在高程放大效应,临空面中由于软弱夹层的阻隔影响,使得坡脚的振速最大;边坡的变形破坏受软弱夹层控制,其上覆岩体为潜在滑体,破裂面可以根据水平位移云图和塑性区分布图综合确定;边坡的破坏是一个渐进性的累积过程,位移和剪应变的累积会导致岩体的力学参数不断弱化,爆破振动劣化作用后仍有较大安全储备的边坡只会累积产生永久位移,而接近极限平衡状态的边坡将会失稳;当岩层倾角为15°~23°时,边坡振速安全阀值为21cm/s;当软弱夹层剪出口距离坡顶高度为14m,倾角分别为24°、29°、31°、34°时,安全阀值分别为10、8、6、5cm/s。
A numerical model of bedding bench slope was established by using the FLAC3 Dsoftware.First,the dynamic response law of the slope under the blasting waves was analyzed.Then the stability of the slope was analyzed based on the displacement and the shear strain increment.Finally,according to the judgment of the slope stability,the appropriate velocity safety threshold of blasting vibration was developed.Studies reveal that the attenuation rate of the vibration amplitude decreases with higher blaster center distance value.There is elevation amplification effect on the slope and the main vibration velocity reaches the maximum at the foot of the free surface due to the existence of the weak interlayer.The deformation and failure of the slope is controlled by the weak interlayer.The upper rock mass becomes the potential sliding mass when there is tensile and shear failure in the weak interlayer,and the fracture surface can be determined according to the horizontal displacement map and the plastic zone distribution map.The slope failure is a progressive accumulation,displacement and shear strain accumulation will lead to the mechanical parameters of the rock weakening.There is a permanent displacement after blasting vibration if the slope has a great safety margin,while the slope near the state of limit equilibrium will be instability.The safety threshold of the slope is 21 cm/s if the strata inclination is from 15°to 23°.When the cut out height of the slope with the weak interlayer is 14 m and the strata inclinations are 24°,29°,31°and 34°,the corresponding safety threshold will be 10,8,6 and 5 cm/s.
A numerical model of bedding bench slope was established by using the FLAC3 Dsoftware.First,the dynamic response law of the slope under the blasting waves was analyzed.Then the stability of the slope was analyzed based on the displacement and the shear strain increment.Finally,according to the judgment of the slope stability,the appropriate velocity safety threshold of blasting vibration was developed.Studies reveal that the attenuation rate of the vibration amplitude decreases with higher blaster center distance value.There is elevation amplification effect on the slope and the main vibration velocity reaches the maximum at the foot of the free surface due to the existence of the weak interlayer.The deformation and failure of the slope is controlled by the weak interlayer.The upper rock mass becomes the potential sliding mass when there is tensile and shear failure in the weak interlayer,and the fracture surface can be determined according to the horizontal displacement map and the plastic zone distribution map.The slope failure is a progressive accumulation,displacement and shear strain accumulation will lead to the mechanical parameters of the rock weakening.There is a permanent displacement after blasting vibration if the slope has a great safety margin,while the slope near the state of limit equilibrium will be instability.The safety threshold of the slope is 21 cm/s if the strata inclination is from 15°to 23°.When the cut out height of the slope with the weak interlayer is 14 m and the strata inclinations are 24°,29°,31°and 34°,the corresponding safety threshold will be 10,8,6 and 5 cm/s.
引文
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[14]余海兵,胡斌,甘露,等.峨眉黄山石灰岩矿露天边坡爆破振动测试与分析[J].爆破,2015,32(4):55-59.YU Haibing,HU Bin,GAN Lu,et al.Test and analysis of blasting vibration in Ermei Mount Huangshan limestone mine open-pit slope[J].Blasting,2015,32(4):55-59.
[15]戴妙林,李春同.基于降参法数值计算的复杂岩质边坡动力稳定性安全评价[J].岩石力学与工程学报,2007,26(增刊1):2749-2754.DAI Miaolin,LI Chuntong.Analysis of dynamic stability safety evaluation for complex rock slopes by strength reduction numerical method[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(suppl 1):2749-2754.
[2]言志信,彭宁波,江平.爆破振动安全标准探讨[J].煤炭学报,2011,36(8):1281-1284.YAN Zhixin,PENG Ningbo,JIANG Ping.Research about blasting vibration safety criteria[J].Journal of China Coal Society,2011,36(8):1281-1284.
[3]胡军,钟龙.露天矿爆破荷载等效施加方式的探究[J].金属矿山,2014(6):37-41.HU Jun,ZHONG Long.Exploration for open-pit mine blasting load equivalent way[J].Metal Mine,2014(6):37-41.
[4]刘亚群,李海波,李俊如,等.爆破荷载作用下黄麦岭磷矿岩质边坡动态响应的UDEC模拟研究[J].岩石力学与工程学报,2004,23(21):3659-3663.LIU Yaqun,LI Haibo,LI Junru,et al.Udec simulation on dynamic response of rock slope of huang mailing phosphorite mine under explosion[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(21):3659-3663.
[5]陈明,卢文波,李鹏.岩质边坡爆破振动速度的高程放大效应研究[J].岩石力学与工程学报,2011,30(11):2189-2195.CEHN Ming,LU Wenbo,LI Peng.Elevation amplification effect of blasting vibration velocity in rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(11):2189-2195.
[6]陈占军,朱传云,周小恒.爆破荷载作用下岩石边坡动态响应的FLAC3D模拟研究[J].爆破,2005,22(4):8-13.CHEN Zhanjun,ZHU Chuanyun,ZHOU Xiaoheng.FLAC3Dsimulation for dynamic response of rock slope under explosion[J].Blasting,2005,22(4):8-13.
[7]万宝安,黎杉,熊茂东.基于FLAC3D的边坡爆破临界振速的确定[J].铁道建筑,2013(8):115-118.WAN Baoan,LI Shan,XIONG Maodong.Determination of critical vibration velocity of blasting for slopes based on FLAC3D[J].Railway Engineering,2013(8):115-118
[8]李海波,肖克强,刘亚群.地震荷载作用下顺层岩质边坡安全系数分析[J].岩石力学与工程学报,2007,26(12):2385-2394.LI Haibo,XIAO Keqiang,LIU Yaqun.Factor of safety analysis of bedding rock slope under seismic load[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(12):2385-2394.
[9]徐光兴,姚令侃,李朝红,等.边坡地震动力响应规律及地震动参数影响研究[J].岩土工程学报,2008,30(6):918-923.XU Guangxing,YAO Lingkan,LI Chaohong,et al.Dynamic response of slopes under earthquakes and influence of ground motion parameters[J].Chinese Journal of Geotechnical Engineering,2008,30(6):918-923.
[10]Itasca Consulting Group Inc.FLAC-2D(version 5.00)users manual:Volume V[M].USA:Itasca Consulting Group Inc.,2005.
[11]陈建平,高学文,陶连金.爆破工程地质控制论[J].工程地质学报,2006,15(5):616-619.CHEN Jianping,GAO Xuewen,TAO Lianjin,et al.Theory of rock blasting controlling geology engineering[J].Journal of Engineering Geology,2006,15(5):616-619.
[12]夏详,李俊如,李海波,等.爆破荷载作用下岩体振动特征的数值模拟[J].岩土力学,2005,26(1):50-56.XIA Xiang,LI Junru,LI Haibo,et al.Udec modeling of vibration characteristics of jointed rock mass under explosion[J].Rock and Soil Mechanics,2005,26(1):50-56.
[13]范留明,李宁.软弱夹层的透射模型及其隔震特性研究[J].岩石力学与工程学报,2005,24(14):2456-2462.FAN Liuming,LI Ning.Transmission model of weak intercalation and its vibration isolation properties[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(14):2456-2462.
[14]余海兵,胡斌,甘露,等.峨眉黄山石灰岩矿露天边坡爆破振动测试与分析[J].爆破,2015,32(4):55-59.YU Haibing,HU Bin,GAN Lu,et al.Test and analysis of blasting vibration in Ermei Mount Huangshan limestone mine open-pit slope[J].Blasting,2015,32(4):55-59.
[15]戴妙林,李春同.基于降参法数值计算的复杂岩质边坡动力稳定性安全评价[J].岩石力学与工程学报,2007,26(增刊1):2749-2754.DAI Miaolin,LI Chuntong.Analysis of dynamic stability safety evaluation for complex rock slopes by strength reduction numerical method[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(suppl 1):2749-2754.