反倾软硬互层岩体边坡地震响应的数值模拟研究
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摘要
反倾软硬岩体互层边坡是公路建设中经常遇到的一类边坡,在不利条件下有失稳破坏的可能,特别是在坡脚受到扰动、降雨、地震等作用时。以"5.12"地震期间都汶公路(都江堰—汶川)上一处边坡的地震响应为例,采用离散元UDEC软件对其进行模拟,系统研究了其地震响应的变形破坏机制。研究结果表明,地震作用下,软弱岩层挤压变形强烈,有向外剪出的趋势。同时,在地震波反复拉张作用下,软弱岩层位置容易开裂,成为坡体变形破坏的优势拉裂区域。地震波加速度、速度随高程变化放大显著,在坡体表部位移量随高程增高而逐渐增大。就整体而言,岩体内部的节理裂隙进一步张开,并产生了一些新的裂隙,弯曲倾倒有加剧的趋势;而坡表覆盖层普遍具有表部拉张开裂和掉块现象,特别是在地形几何形态突变处,破坏更为显著。
A kind of anti-dumping rock slope interbedded by hard and soft layers are often encountered in highway construction.In adverse conditions,the stability of the slope may be lost,especially under certain conditions such as disturbed slope toe and effect of rainfall and earthquake,etc.This paper takes the earthquake response of Shawozi slope during the 5.12 Wenchuan earthquake as an example,which is located in Duwen road(Dujiangyan-Wenchuan).The discrete element software UDEC is used to simulate and systematically study the seismic response of deformation and failure mechanism.The results show that,under the earthquake,the soft and weak rock is squeezed and cut out from the slope with strong deformation.At the same time,in soft rock locations,it is easy to crack under the repeated tensile influence of seismic waves,and become the advantage area of deformation and failure of the slope.The amplification coefficient of acceleration and speed changes significantly with elevation.The displacement in the slope gradually increases with increasing elevation.On the whole,the joints and fissures inside the bend-dumping rock mass further open,and a number of new cracks are produced so that there is an increasing trend in dumping bent.The phenomena generally appear in the slope cover-layer including the tensile cracking and block dropping,especially at the mutation position of terrain geometry,and the damage extent is more significant.
A kind of anti-dumping rock slope interbedded by hard and soft layers are often encountered in highway construction.In adverse conditions,the stability of the slope may be lost,especially under certain conditions such as disturbed slope toe and effect of rainfall and earthquake,etc.This paper takes the earthquake response of Shawozi slope during the 5.12 Wenchuan earthquake as an example,which is located in Duwen road(Dujiangyan-Wenchuan).The discrete element software UDEC is used to simulate and systematically study the seismic response of deformation and failure mechanism.The results show that,under the earthquake,the soft and weak rock is squeezed and cut out from the slope with strong deformation.At the same time,in soft rock locations,it is easy to crack under the repeated tensile influence of seismic waves,and become the advantage area of deformation and failure of the slope.The amplification coefficient of acceleration and speed changes significantly with elevation.The displacement in the slope gradually increases with increasing elevation.On the whole,the joints and fissures inside the bend-dumping rock mass further open,and a number of new cracks are produced so that there is an increasing trend in dumping bent.The phenomena generally appear in the slope cover-layer including the tensile cracking and block dropping,especially at the mutation position of terrain geometry,and the damage extent is more significant.
引文
[1]黄润秋.汶川地震地质灾害研究[M].北京:科学出版社,2009.[HUANG R Q.Large-scale landslidesinduced by the Wenchuan earthquake[M].Beijing:Science Press,2009.(in Chinese)]
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[7]袁仁茂,谭锡斌,陈桂华,等.地震破裂带特殊部位大型滑坡及其基于构造地貌发生模型的机制解释:以东河口抛射型滑坡为例[J].地学前缘,2010(5):243-253.[YANG R M,TAN X B,CHEN GH,et al.Huge landslides occurred at the specialplaces of the coseismic rupture and their mechanismexplanation based on the formation model of tectonic-geomorphology:A case study of Donghekou ejectionlands[J].Earth Science Frontiers,2010(5):243-253.(in Chinese)]
[8]崔芳鹏,胡瑞林,殷跃平,等.纵横波时差耦合作用的斜坡崩滑效应离散元分析——以北川唐家山滑坡为例[J].岩石力学与工程学报,2010,29(2):319-327.[CUI F P,HU R L,YIN Y P,et al.Discrete element analysis of collapsing and slidingresponse of slope triggered by time difference couplingeffects of P and S seismic waves—taking Tangjiashanlandslide in Beichuan County for example[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):319-327.(in Chinese)]
[9]胡聿贤.地震工程学[M].北京:地震出版社,1988.[HU Y X.Earthquake Engineering[M].Beijing:Seismological Publishing House,1988.(inChinese)]
[10]胡光韬.滑坡动力学[M].北京:地质出版社,1995.[HU G T.Dynamics of landslides[M].Beijing:Geological Publishing House,1995.(inChinese)]
[11]徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624-632.[XU G X,YAOL K,GAO Z N,et al.Largescale shaking table modeltest study of dynamic characteristics and dynamicresponse of slope[J].Chinese Journal of RockMechanics and Engineering,2008,27(3):624-632.(in Chinese)]
[12]王来贵,刘成,赵娜,等.动力作用下岩体工程累积破坏研究[J].渤海大学学报:自然科学版,2007,28(1):1-5.[WANG L G,LIU C,ZHAO N,et al.Research on accumulat ive dest ruction of rock massaffected by dynamic[J].Journal of Bohai University:Natural Science Edition,2007,28(1):1-5.(inChinese)]
[13]陈玲玲,陈敏中,钱胜国.岩质陡高边坡地震动力稳定分析[J].长江科学院院报,2004,21(1):33-35.[CHEN L L,CHEN M Z,QIAN S G.Stabilityanalysis of high-steep rocky slope under earthquakeloads[J].Journal of Yangtze River ScientificResearch Institute,2004,21(1):33-35.(inChinese)]
[2]许强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探[J].工程地质学报,2008,16(6):721-729.[XU Q,HUANG R Q.Kineticscharateristics of large landslides triggered by May 12thWenchuan earthquake[J].Journal of EngineeringGeology,2008,16(6):721-729.(in Chinese)]
[3]许强.汶川大地震诱发地质灾害主要类型与特征研究[J].地质灾害与环境保护,2009,20(2):86-93.[XU Q.Main types and characteristics of the geo-hazards triggered by the Wenchuan earthquake[J].Journal of Geological Hazards and EnvironmentPreservation,2009,20(2):86-93.(in Chinese)]
[4]黄润秋.汶川8.0级地震触发崩滑灾害机制及其地质力学模式[J].岩石力学与工程学报,2009,28(6):1239-1249.[HUANG R Q.Mechanism andgeomechanical modes of landslide hazards triggered byWenchuan 8.0 earthquake[J].Chinese Journal ofRock Mechanics and Engineering,2009,28(6):1239-1249.(in Chinese)]
[5]殷跃平.汶川八级地震地质灾害研究[J].工程地质学报,2008,16(4):433-444.[YIN Y P.Reserches on the Geohazards Triggered by WenchuanEarthquake,Sichuan[J].Journal of EngineeringGeology,2008,16(4):433-444.(in Chinese)]
[6]殷跃平.汶川八级地震滑坡特征分析[J].工程地质学报,2009,17(1):29-38.[YIN Y P.Featuresof Landslides Triggered by the Wenchuan Earthquake[J].Journal of Engineering Geology,2009,17(1):29-38.(in Chinese)]
[7]袁仁茂,谭锡斌,陈桂华,等.地震破裂带特殊部位大型滑坡及其基于构造地貌发生模型的机制解释:以东河口抛射型滑坡为例[J].地学前缘,2010(5):243-253.[YANG R M,TAN X B,CHEN GH,et al.Huge landslides occurred at the specialplaces of the coseismic rupture and their mechanismexplanation based on the formation model of tectonic-geomorphology:A case study of Donghekou ejectionlands[J].Earth Science Frontiers,2010(5):243-253.(in Chinese)]
[8]崔芳鹏,胡瑞林,殷跃平,等.纵横波时差耦合作用的斜坡崩滑效应离散元分析——以北川唐家山滑坡为例[J].岩石力学与工程学报,2010,29(2):319-327.[CUI F P,HU R L,YIN Y P,et al.Discrete element analysis of collapsing and slidingresponse of slope triggered by time difference couplingeffects of P and S seismic waves—taking Tangjiashanlandslide in Beichuan County for example[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):319-327.(in Chinese)]
[9]胡聿贤.地震工程学[M].北京:地震出版社,1988.[HU Y X.Earthquake Engineering[M].Beijing:Seismological Publishing House,1988.(inChinese)]
[10]胡光韬.滑坡动力学[M].北京:地质出版社,1995.[HU G T.Dynamics of landslides[M].Beijing:Geological Publishing House,1995.(inChinese)]
[11]徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624-632.[XU G X,YAOL K,GAO Z N,et al.Largescale shaking table modeltest study of dynamic characteristics and dynamicresponse of slope[J].Chinese Journal of RockMechanics and Engineering,2008,27(3):624-632.(in Chinese)]
[12]王来贵,刘成,赵娜,等.动力作用下岩体工程累积破坏研究[J].渤海大学学报:自然科学版,2007,28(1):1-5.[WANG L G,LIU C,ZHAO N,et al.Research on accumulat ive dest ruction of rock massaffected by dynamic[J].Journal of Bohai University:Natural Science Edition,2007,28(1):1-5.(inChinese)]
[13]陈玲玲,陈敏中,钱胜国.岩质陡高边坡地震动力稳定分析[J].长江科学院院报,2004,21(1):33-35.[CHEN L L,CHEN M Z,QIAN S G.Stabilityanalysis of high-steep rocky slope under earthquakeloads[J].Journal of Yangtze River ScientificResearch Institute,2004,21(1):33-35.(inChinese)]
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