非均质边坡稳定性上限分析评价研究
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摘要
边坡稳定性评价研究是土力学经典问题。为研究非均质边坡稳定性问题,以上限分析法为理论基础,建立非均质边坡分段对数螺旋线破坏机构。应用拟合多项式近似描述对数螺旋线,计算破坏机构外力功率和内能耗散率,应用设计的计算流程进行强度折减循环计算,使边坡逐步过渡至极限平衡状态,确定边坡安全系数。以某露天矿南帮边坡为工程背景,经过反复强度折减,最终确定安全系数,通过变换初值的方式验证计算流程的稳定性,应用严格Morgenstern-Price法验证计算结果的准确性。研究结果表明:该流程性能稳定,不受初始值影响。相比于严格Morgenstern-Price法,二者安全系数计算结果偏差小于5%,可充分满足工程实践要求。同时,上限分析法求得的最危险滑面满足速度分离关系,具有更强的工程参考价值。
Slope stability evaluation is a classic problem for soil mechanics. In order to study the stability of heterogeneous slopes, this paper uses the upper limit analysis method to establish the failure mechanism of segmented logarithmic spiral arcs for heterogeneous slope. Then fitting polynomial is used to approximately describe the logarithmic spiral arcs. External force power and internal energy dissipation power of the failure mechanism can be determined. The calculation process is applied to repeat the strength reduction until the slope gradually transition to the ultimate balance and the slope stability factor can be obtained. Taking the south slope in an open-pit mine as the background, the slope stability factor is determined by the method of repeated strength reduction. The stability of the calculation process is verified by the method of changing initial value, and the accuracy of the calculation result is verified by the method of strict Morgenstern-Price. The results show that the process is stable and is not affected by the initial value. Compared with the strict Morgenstern-Price method, the difference of stability factor calculation results between the two methods is less than 5%. The stability factor calculation results can fully satisfy the requirements of engineering practice. At the same time, the most dangerous slip surface formed by upper limit analysis method can satisfy the speed separation relationship.
Slope stability evaluation is a classic problem for soil mechanics. In order to study the stability of heterogeneous slopes, this paper uses the upper limit analysis method to establish the failure mechanism of segmented logarithmic spiral arcs for heterogeneous slope. Then fitting polynomial is used to approximately describe the logarithmic spiral arcs. External force power and internal energy dissipation power of the failure mechanism can be determined. The calculation process is applied to repeat the strength reduction until the slope gradually transition to the ultimate balance and the slope stability factor can be obtained. Taking the south slope in an open-pit mine as the background, the slope stability factor is determined by the method of repeated strength reduction. The stability of the calculation process is verified by the method of changing initial value, and the accuracy of the calculation result is verified by the method of strict Morgenstern-Price. The results show that the process is stable and is not affected by the initial value. Compared with the strict Morgenstern-Price method, the difference of stability factor calculation results between the two methods is less than 5%. The stability factor calculation results can fully satisfy the requirements of engineering practice. At the same time, the most dangerous slip surface formed by upper limit analysis method can satisfy the speed separation relationship.
引文
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[16]胡卫东,曹文贵,袁青松.基于非线性破坏准则的临坡地基承载力上限分析[J].岩土力学,2017,38(6):1639-1646.HU Wei-dong,CAO Wen-gui,YUAN Qing-song.Upper bound solution for ultimate bearing capacity of ground adjacent to slope based on nonlinear failure criterion[J].Rock and Soil Mechanics,2017,38(6):1639-1646.
[17]王浩然,黄茂松,刘怡林.含软弱夹层边坡的三维稳定性极限分析[J].岩土力学,2013,34(增刊2):156-160.WANG Hao-ran,HUANG Mao-song,LIU Yi-lin.Threedimensional stability analysis of slope with interlayer[J].Rock and Soil Mechanics,2013,34(Supp.2):156-160.
[2]FELLENIUS W.Earth stability calculations assuming friction and cohesion on circular slip surfaces[M].Berlin:Wilhelm Ernst,1927.
[3]BISHOP A W.The use of the slip circle in the stability analysis of slopes[J].Geotechnique,1955,5(1):7-17.
[4]MORGENSTERN N R,PRICE V E.The analysis of the stability of general slip circles[J].Geotechnique,1965,15(1):79-93.
[5]SPENCER E.A method of analysis of the stability of embankments using parallel inter-slice forces[J].Geotechnique,1967,17(1):11-26.
[6]JANBU N.Slope stability computations embankment dam engineering[M].New York:Wiley,1973.
[7]SARMA S K.Stability analysis of embankments and slopes[J].Geotechnique,1973,23(3):423-433.
[8]陈祖煜.土力学经典问题的塑性力学上、下限解[J].岩土工程学报,2002,24(1):1-11.CHEN Zu-yu.Limit analysis for the classic problems of soil mechanics[J].Chinese Journal of Geotechnical Engineering,2002,24(1):1-11.
[9]CHEN W F.Limit analysis and soil plasticity[M].New York:Elsevier Scientific Publishing Co.,1975.
[10]KARAL K.Application of energy method[J].Journal of Geotechnical Engineering,1977,103(5):381-399.
[11]MICHALOWSKI R L.Slope stability analysis:a kinematical approach[J].Geotechnique,1995,45(2):283-293.
[12]DONALD I B,CHEN Z Y.Slope stability analysis by the upper bound approach:Fundamentals and methods[J].Canadian Geotechnical Journal,1997,34(6):853-862.
[13]肖成志,栾茂田,杨庆,等.土工格栅均布加筋土坡稳定性分析的上限解法[J].岩石力学与工程学报,2005,24(增刊1):5076-5080.XIAO Cheng-zhi,LUAN Mao-tian,YANG Qing,et al.Upper bound procedure of limit analysis for stability of soil slope reinforced by uniformly-distributed geogrid[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(Supp.1):5076-5080.
[14]陈祖煜,詹成明,姚海林,等.重力式挡土墙抗滑稳定分析安全判据和标准[J].岩土力学,2016,37(8):2129-2137.CHEN Zu-yu,ZHAN Cheng-ming,YAO Hai-lin,et al.Safety criteria and standards for stability analysis of gravity retaining walls[J].Rock and Soil Mechanics,2016,37(8):2129-2137.
[15]张小艳,张立翔,李泽.基于塑性极限分析上限法理论的土质边坡可靠度分析[J].岩土力学,2018,39(5):1840-1850.ZHANG Xiao-yan,ZHANG Li-xiang,LI Ze.Reliability analysis of soil slope based on upper bound method of limit analysis[J].Rock and Soil Mechanics,2018,39(5):1840-1850.
[16]胡卫东,曹文贵,袁青松.基于非线性破坏准则的临坡地基承载力上限分析[J].岩土力学,2017,38(6):1639-1646.HU Wei-dong,CAO Wen-gui,YUAN Qing-song.Upper bound solution for ultimate bearing capacity of ground adjacent to slope based on nonlinear failure criterion[J].Rock and Soil Mechanics,2017,38(6):1639-1646.
[17]王浩然,黄茂松,刘怡林.含软弱夹层边坡的三维稳定性极限分析[J].岩土力学,2013,34(增刊2):156-160.WANG Hao-ran,HUANG Mao-song,LIU Yi-lin.Threedimensional stability analysis of slope with interlayer[J].Rock and Soil Mechanics,2013,34(Supp.2):156-160.