地震作用下岩质边坡块体倾倒破坏分析
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摘要
基于传递系数法的概念,在建立地震作用下岩质边坡倾倒破坏地质力学模型的基础上,提出考虑地震作用边坡倾倒破坏的解析分析方法,并进一步分析地震作用对边坡倾倒稳定性的影响。该方法采用边坡几何力学参数以及潜在倾倒岩块编号来表征边坡倾倒稳定性分析中变量,从而使每个倾倒岩块的计算变量具有统一的表达式,因此很容易采用Microsoft Excel进行程序化分析。分析结果表明,地震作用下边坡的破坏模式取决于地震影响系数与其临界值的关系,地震影响系数临界值的大小取决于地震力方向以及缓倾结构面的倾角和内摩擦角,当地震影响系数小于该临界值时,按倾倒破坏分析边坡稳定性,否则边坡发生滑动破坏;边坡倾倒稳定性受地震力作用方向和地震影响系数的影响,地震作用方向对边坡倾倒稳定性影响较小,而边坡倾倒稳定性随地震影响系数的增加而显著降低。
Toppling is an important failure mode of rock slopes,which is dominantly controlled by the discontinuities existing in the slopes.Adopting the concept of the transfer coefficient,an analytical approach of toppling failure of rock slopes due to earthquakes is developed based on the corresponding geomechanical model,and influence of seismic actions on the toppling stability of rock slopes is analyzed.The variables of every rock block potential to toppling,used for stability analysis of a rock slope,are expressed by the geomechanical parameters of the slope and the serial number of the blocks,and hence have uniform expressions.Consequently,the method is easily implemented using a Microsoft Excel spreadsheet.An idealized example is analyzed adopting the Excel procedure.The results show that the failure mode of a rock slope,such as sliding or toppling,depends on the relationship between the seismic influence coefficient and its critical value which is determined by the direction of the seismic force,the dip angle and the friction angle of the slightly dipping discontinuities.The rock slope is potential to topple if the seismic influence coefficient is less than the critical value,or it will slide.It is also indicated that the toppling stability of rock slopes increases slightly with the angle of the seismic force with respect to the horizontal plane rising but descends markedly with the seismic coefficient increasing.
Toppling is an important failure mode of rock slopes,which is dominantly controlled by the discontinuities existing in the slopes.Adopting the concept of the transfer coefficient,an analytical approach of toppling failure of rock slopes due to earthquakes is developed based on the corresponding geomechanical model,and influence of seismic actions on the toppling stability of rock slopes is analyzed.The variables of every rock block potential to toppling,used for stability analysis of a rock slope,are expressed by the geomechanical parameters of the slope and the serial number of the blocks,and hence have uniform expressions.Consequently,the method is easily implemented using a Microsoft Excel spreadsheet.An idealized example is analyzed adopting the Excel procedure.The results show that the failure mode of a rock slope,such as sliding or toppling,depends on the relationship between the seismic influence coefficient and its critical value which is determined by the direction of the seismic force,the dip angle and the friction angle of the slightly dipping discontinuities.The rock slope is potential to topple if the seismic influence coefficient is less than the critical value,or it will slide.It is also indicated that the toppling stability of rock slopes increases slightly with the angle of the seismic force with respect to the horizontal plane rising but descends markedly with the seismic coefficient increasing.
引文
[1]GOODMAN R E,BRAY J W.Toppling of rock slopes[C]//Proceedings of Specialty Conference on Rock Engineering for Foundations and Slopes.Boulder,CO:ASCE,1977:201-34.
[2]WYLLIE D C.Toppling rock slope failure examples of analysis and stabilization[J].Rock Mechanics and Rock Engineering,1980,13(2):89-98.
[3]ZANBAK C.Design charts for rock slopes susceptible to toppling[J].Journal of Geotechnical Engineering,1983,109(8):1039-1062.
[4]SAGASETA C.On the modes of instability of a rigid block on an inclined plane[J].Rock Mechanics and Rock Engineering,1986,19(4):261-266.
[5]ISHIDA T,CHIGIRA M,HIBINO S.Application of the distinct element method for analysis of toppling observed on a fissured slope[J].Rock Mechanics and Rock Engineering,1987,20(4):277-283.
[6]AYDAN,SHIMIZU Y,ICHIKAWA Y.The effective failure modes and stability of slopes in rock mass with two discontinuity sets[J].Rock Mechanics and Rock Engineering,1989,22(3):163-188.
[7]张布荣.倾倒型岩石边坡工程加固的研究[J].土木工程学报,1995,28(5):70-75.(ZHANG Burong.Study on strengthening technique for toppling rock slope[J].China Civil Engineering Journal,1995,28(5):70-75.(in Chinese))
[8]汪小刚,张建红,赵毓芝,等.用离心模型研究岩石边坡的倾倒破坏[J].岩土工程学报,1996,18(5):14-21.(WANG Xiaogang,ZHANG Jianhong,ZHAO Yuzhi,et al.Investigations on mechanism of slope toppling failure by centrifuge model testing[J].Chinese Journal of Geotechnical Engineering,1996,18(5):14-21.(in Chinese))
[9]陈祖煜,张建红,汪小刚.岩石边坡倾倒稳定分析的简化方法[J].岩土工程学报,1996,18(6):92-95.(CHEN Zuyu,ZHANG Jianhong,WANG Xiaogang.A simplified method for stability analysis of rock slopes[J].Chinese Journal of Geotechnical Engineering,1996,18(6):92-95.(in Chinese))
[10]KLICHE C A.Rock slope stability[M].Littleton:Society for Mining,Metallurgy and Exploration,Inc.,1999.
[11]孙东亚,彭一江,王兴珍.DDA数值方法在岩质边坡倾倒破坏分析中的应用[J].岩石力学与工程学报,2002,21(1):39-42.(SUN Dongya,PENG Yijiang,WANG Xingzhen.Application of DDA method to stability analysis of toppling rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(1):39-42.(in Chinese))
[12]张国新,赵妍,石根华,等.模拟岩石边坡倾倒破坏的数值流形法[J].岩土工程学报,2007,29(6):800-805.(ZHANG Guoxin,ZHAO Yan,SHI Genhua,et al.Toppling failure simulation of rock slopes by numerical manifold method[J].Chinese Journal of Geotechnical Engineering,2007,29(6):800-805.(in Chinese))
[13]王建锋,WILSON H T,崔政权.块状岩体边坡倾倒破坏稳定性分析[J].中国地质灾害与防治学报,2001,12(4):1-8.(WANG Jianfeng,WILSON H T,CUI Zhengquan.Stability analysis of toppling failure of block rock slopes[J].The Chinese Journal of Geological Hazard and Control,2001,12(4):1-8.(in Chinese))
[14]SCAVIA C,BARLA G,BERNAUDO V.Probabilistic stability analysis of block toppling failure in rock slopes[J].International Journal of Rock Mechanics and Mining Sciences,1990,27(6):465-478.
[15]BOBET A.Analytical solutions for toppling failure[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(7):971-980.
[16]SAGASETA C,SáNCHEZ J M,CA IZAL J.A general analytical solution for the required anchor force in rock slopes with toppling failure[J].International Journal of Rock Mechanics and Mining Sciences,2001,38(3):421-435.
[17]LIU C H,JAKSA M B,MEYERS A G.Improved analytical solution for toppling stability analysis of rock slopes[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(8):1361-1372.
[18]LIU C H,JAKSA M B,MEYERS A G.A transfer coefficient method for rock slope toppling[J].Canadian Geotechnical Journal,2009,46(1):1-9.
[2]WYLLIE D C.Toppling rock slope failure examples of analysis and stabilization[J].Rock Mechanics and Rock Engineering,1980,13(2):89-98.
[3]ZANBAK C.Design charts for rock slopes susceptible to toppling[J].Journal of Geotechnical Engineering,1983,109(8):1039-1062.
[4]SAGASETA C.On the modes of instability of a rigid block on an inclined plane[J].Rock Mechanics and Rock Engineering,1986,19(4):261-266.
[5]ISHIDA T,CHIGIRA M,HIBINO S.Application of the distinct element method for analysis of toppling observed on a fissured slope[J].Rock Mechanics and Rock Engineering,1987,20(4):277-283.
[6]AYDAN,SHIMIZU Y,ICHIKAWA Y.The effective failure modes and stability of slopes in rock mass with two discontinuity sets[J].Rock Mechanics and Rock Engineering,1989,22(3):163-188.
[7]张布荣.倾倒型岩石边坡工程加固的研究[J].土木工程学报,1995,28(5):70-75.(ZHANG Burong.Study on strengthening technique for toppling rock slope[J].China Civil Engineering Journal,1995,28(5):70-75.(in Chinese))
[8]汪小刚,张建红,赵毓芝,等.用离心模型研究岩石边坡的倾倒破坏[J].岩土工程学报,1996,18(5):14-21.(WANG Xiaogang,ZHANG Jianhong,ZHAO Yuzhi,et al.Investigations on mechanism of slope toppling failure by centrifuge model testing[J].Chinese Journal of Geotechnical Engineering,1996,18(5):14-21.(in Chinese))
[9]陈祖煜,张建红,汪小刚.岩石边坡倾倒稳定分析的简化方法[J].岩土工程学报,1996,18(6):92-95.(CHEN Zuyu,ZHANG Jianhong,WANG Xiaogang.A simplified method for stability analysis of rock slopes[J].Chinese Journal of Geotechnical Engineering,1996,18(6):92-95.(in Chinese))
[10]KLICHE C A.Rock slope stability[M].Littleton:Society for Mining,Metallurgy and Exploration,Inc.,1999.
[11]孙东亚,彭一江,王兴珍.DDA数值方法在岩质边坡倾倒破坏分析中的应用[J].岩石力学与工程学报,2002,21(1):39-42.(SUN Dongya,PENG Yijiang,WANG Xingzhen.Application of DDA method to stability analysis of toppling rock slope[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(1):39-42.(in Chinese))
[12]张国新,赵妍,石根华,等.模拟岩石边坡倾倒破坏的数值流形法[J].岩土工程学报,2007,29(6):800-805.(ZHANG Guoxin,ZHAO Yan,SHI Genhua,et al.Toppling failure simulation of rock slopes by numerical manifold method[J].Chinese Journal of Geotechnical Engineering,2007,29(6):800-805.(in Chinese))
[13]王建锋,WILSON H T,崔政权.块状岩体边坡倾倒破坏稳定性分析[J].中国地质灾害与防治学报,2001,12(4):1-8.(WANG Jianfeng,WILSON H T,CUI Zhengquan.Stability analysis of toppling failure of block rock slopes[J].The Chinese Journal of Geological Hazard and Control,2001,12(4):1-8.(in Chinese))
[14]SCAVIA C,BARLA G,BERNAUDO V.Probabilistic stability analysis of block toppling failure in rock slopes[J].International Journal of Rock Mechanics and Mining Sciences,1990,27(6):465-478.
[15]BOBET A.Analytical solutions for toppling failure[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(7):971-980.
[16]SAGASETA C,SáNCHEZ J M,CA IZAL J.A general analytical solution for the required anchor force in rock slopes with toppling failure[J].International Journal of Rock Mechanics and Mining Sciences,2001,38(3):421-435.
[17]LIU C H,JAKSA M B,MEYERS A G.Improved analytical solution for toppling stability analysis of rock slopes[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(8):1361-1372.
[18]LIU C H,JAKSA M B,MEYERS A G.A transfer coefficient method for rock slope toppling[J].Canadian Geotechnical Journal,2009,46(1):1-9.
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