Large deformation and failure mechanism analyses of Tangba high slope with a high-intensity and complex excavation process
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摘要
The Tangba high slope is mainly composed of coarse soils and supplies core wall materials for the construction of the Changheba dam. Since the filling intensity of the Changheba dam is high, the Tangba high slope suffers from a high-intensity excavation process, and reinforcement measures are usually not implemented immediately. Moreover, the distribution of useful materials is uneven and insufficient, and the mixing of different soil materials is necessary; thus, multiple simultaneous excavations and secondary excavation are inevitable. In the construction period from 2012 to 2016, large deformations occurred in this area, and one of the largest monitored horizontal deformations whose direction points to the opposite side of the valley even reached more than 8000 mm. According to field investigation, site monitoring and theoretical analysis, the large deformation in the Tangba high slope can be divided into two phases. In the first phase, the excavation construction breaks the original stress equilibrium state; in the second phase, the precipitation infiltration accelerates the deformation. Thus, the excavation construction and precipitation infiltration are the two major factors promoting the deformation, and the high-intensity and complex excavation process is the fundamental cause. Notably, rate of slope deformation significantly accelerated in rainy seasons due to precipitation infiltration; the rate also accelerated in early 2016 due to the high-intensity, complex excavation process. Comprehensively considering the above factors, timely and effective reinforcement measures are essential.
The Tangba high slope is mainly composed of coarse soils and supplies core wall materials for the construction of the Changheba dam. Since the filling intensity of the Changheba dam is high, the Tangba high slope suffers from a high-intensity excavation process, and reinforcement measures are usually not implemented immediately. Moreover, the distribution of useful materials is uneven and insufficient, and the mixing of different soil materials is necessary; thus, multiple simultaneous excavations and secondary excavation are inevitable. In the construction period from 2012 to 2016, large deformations occurred in this area, and one of the largest monitored horizontal deformations whose direction points to the opposite side of the valley even reached more than 8000 mm. According to field investigation, site monitoring and theoretical analysis, the large deformation in the Tangba high slope can be divided into two phases. In the first phase, the excavation construction breaks the original stress equilibrium state; in the second phase, the precipitation infiltration accelerates the deformation. Thus, the excavation construction and precipitation infiltration are the two major factors promoting the deformation, and the high-intensity and complex excavation process is the fundamental cause. Notably, rate of slope deformation significantly accelerated in rainy seasons due to precipitation infiltration; the rate also accelerated in early 2016 due to the high-intensity, complex excavation process. Comprehensively considering the above factors, timely and effective reinforcement measures are essential.
The Tangba high slope is mainly composed of coarse soils and supplies core wall materials for the construction of the Changheba dam. Since the filling intensity of the Changheba dam is high, the Tangba high slope suffers from a high-intensity excavation process, and reinforcement measures are usually not implemented immediately. Moreover, the distribution of useful materials is uneven and insufficient, and the mixing of different soil materials is necessary; thus, multiple simultaneous excavations and secondary excavation are inevitable. In the construction period from 2012 to 2016, large deformations occurred in this area, and one of the largest monitored horizontal deformations whose direction points to the opposite side of the valley even reached more than 8000 mm. According to field investigation, site monitoring and theoretical analysis, the large deformation in the Tangba high slope can be divided into two phases. In the first phase, the excavation construction breaks the original stress equilibrium state; in the second phase, the precipitation infiltration accelerates the deformation. Thus, the excavation construction and precipitation infiltration are the two major factors promoting the deformation, and the high-intensity and complex excavation process is the fundamental cause. Notably, rate of slope deformation significantly accelerated in rainy seasons due to precipitation infiltration; the rate also accelerated in early 2016 due to the high-intensity, complex excavation process. Comprehensively considering the above factors, timely and effective reinforcement measures are essential.
引文
Askarinejad A,Casini F,Bischof P,et al.(2012)Rainfall induced instabilities:a field experiment on a silty sand slope in northern Switzerland.Italian Geotechnical Journal 3:50-71.https://www.scopus.com/record/display.uri?eid=2-s2.0-84874344360&origin=inward
Baum R,Godt J,Savage W(2010)Estimating the timing and location of shallow rainfall-induced landslides using a model for transient,unsaturated infiltration.Journal of Geophysical Research:Earth Surface 115:F03013.https://doi.org/10.1029/2009JF001321
Bittelli M,Valentino R,Salvatorelli F,Pisa PR(2012)Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays.Geomorphology 173-174(9):161-173.https://doi.org/10.1016/j.geomorph.2012.06.006
Bordoni M,Meisina C,Valentino R,et al.(2015)Hydrological factors affecting rainfall-induced shallow landslides:from the field monitoring to a simplified slope stability analysis.Engineering Geology 193:19-37.https://doi.org/10.1016/j.enggeo.2015.04.006
Cascini L,Cuomo S,Pastor M,Sorbino G(2009)Modeling of rainfall-induced shallow landslides of the flow-type.Journal of Geotechnical and Geoenvironmental Engineering 136(1):85-98.https://doi.org/10.1061/(ASCE)GT.1943-5606.0000182
Chen ML,Lv PF,Zhang SL,et al.(2018)Time evolution and spatial accumulation of progressive failure for Xinhua slope in the Dagangshan reservoir,Southwest China.Landslides 15(3):565-580.https://doi.org/10.1007/s10346-018-0946-8
Collins BD,Znidarcic D(2004)Stability analyses of rainfall induced landslides.Journal of Geotechnical and Geoenvironmental Engineering 130(4):362-372.http://doi.org/10.1061/(ASCE)1090-0241(2004)130:4(362)
Corominas J,Moya J(1999)Reconstructing recent landslide activity in relation to rainfall in the Llobregat River basin,Eastern Pyrenees,Spain.Geomorphology 30(1-2):79-93.http://doi.org/10.1016/S0169-555X(99)00046-X
Cruden D,Varnes DJ(1996)Landslide types and processes.Special Report-Transportation Research Board,National Academy of Sciences 247:36-75.https://www.scopus.com/record/display.uri?eid=2-s2.0-7044226255&origin=inward
Duncan JM,Wright SG,Brandon TL(2014)Soil strength and slope stability.Wiley,USA.pp 13-57.https://www.wiley.com/en-cn/Soil+Strength+and+Slope+Stability,+2nd+Edition-p-9781118651650
Ergi nal A,Türke?M,Ertek T,et al.(2008)Geomorphological investigation of the excavation-induced Dündar landslide,BursaTurkey.Geografiska Annaler:Series A,Physical Geography 90(2):109-123.https://doi.org/10.1111/j.1468-0459.2008.00159.x
Fredlund DG,Rahardjo H(1993)Soil mechanics for unsaturated soils.Wiley,USA.pp 9-80.https://doi.org/10.1002/9780470172759
Fredlund DG,Sheng DS,Zhao JZ(2011)Estimation of soil suction from the soil-water characteristic curve.Canadian Geotechnical Journal 48(2):186-198.https://doi.org/10.1139/T10-060
Godt JW,Baum RL,Lu N(2009)Landsliding in partially saturated materials.Geophysical Research Letters 36(2):206-218.https://doi.org/10.1029/2008GL035996
Iverson RM(2000)Landslide triggering by rain infiltration.Water Resources Research 36(7):1897-1910.https://doi.org/10.1029/2000WR900090
Jaedicke C,Eeckhaut MVD,Nadim F,et al.(2014)Identification of landslide hazard and risk‘hotspots’in Europe.Bulletin of Engineering Geology and the Environment 73(2):325-339.https://doi.org/10.1007/s10064-013-0541-0
Klime?J,Rowberry MD,Blah?t J,et al.(2012)The monitoring of slow-moving landslides and assessment of stabilisation measures using an optical-mechanical crack gauge.Landslides 9(3):407-415.https://doi.org/10.1007/s10346-011-0306-4
Kaya A,Alemda?S,Da?S,Gürocak Z(2015)Stability assessment of high-steep cut slope debris on a landslide(Gumushane,NETurkey).Bulletin of Engineering Geology and the Environment75(1):1-11.https://doi.org/10.1007/s10064-015-0753-6
Lainas S,Sabatakakis N,Koukis G(2016)Rainfall thresholds for possible landslide initiation in wildfire-affected areas of Western Greece.Bulletin of Engineering Geology and the Environment75(3):1-14.https://doi.org/10.1007/s10064-015-0762-5
Lee LM,Gofar N,Rahardjo H(2009)A simple model for preliminary evaluation of rainfall-induced slope instability.Engineering Geology 108(3):272-285.https://doi.org/10.1016/j.enggeo.2009.06.011
Lu N,Likos WJ(2006)Suction stress characteristic curve for unsaturated soil.Journal of Geotechnical and Geoenvironmental Engineering 132(2):131-142.https://doi.org/10.1061/(ASCE)1090-0241(2006)132:2(131)
Lu N,Godt J(2008)Infinite slope stability under steady unsaturated seepage conditions.Water Resources Research 44(11):2276-2283.https://doi.org/10.1029/2008WR006976
Margielewski W,Urban J(2003)Crevice-type caves as initial forms of rock landslide development in the flysch carpathians.Geomorphology 54(3):325-338.https://doi.org/10.1016/S0169-555X(02)00375-6
Matsushi Y,Hattanji T,Matsukura Y(2006)Mechanisms of shallow landslides on soil-mantled hillslopes with permeable and impermeable bedrocks in the Boso Peninsula,Japan.Geomorphology 76(1-2):92-108.https://doi.org/10.1016/j.geomorph.2005.10.003
Montrasio L,Valentino R,Corina A,et al.(2014)A prototype system for space-time assessment of rainfall-induced shallow landslides in Italy.Natural Hazards 74(2):1263-1290.https://doi.org/10.1007/s11069-014-1239-8
Quinn PE,Diederichs MS,Rowe RK,Hutchinson DJ(2011)A new model for large landslides in sensitive clay using a fracture mechanics approach.Canadian Geotechnical Journal 48(8):1151-1162.https://doi.org/10.1139/t11-025
Robert DJ(2017)A modified Mohr-Coulomb model to simulate the behavior of pipelines in unsaturated soils.Computers and Geotechnics 91:146-160.https://doi.org/10.1016/j.compgeo.2017.07.004
Schmidt KM,Roering JJ,Stock JD,et al.(2001)The variability of root cohesion as an influence on shallow landslide susceptibility in the Oregon Coast Range.Canadian Geotechnical Journal 38(5):995-1024.https://doi.org/10.1139/cgj-38-5-995
Sorbino G,Nicotera MV(2013)Unsaturated soil mechanics in rainfall-induced flow landslides.Engineering Geology 165(15):105-132.https://doi.org/10.1016/j.enggeo.2012.10.008
Stark TD,Arellano WD,Hillman RP,et al.(2005)Effect of toe excavation on a deep bedrock landslide.Journal of Performance of Constructed Facilities 19(3):244-255.https://doi.org/10.1061/(ASCE)0887-3828(2005)19:3(244)
Su LJ,Xu XQ,Geng XY,Liang SQ(2016)An integrated geophysical approach for investigating hydro-geological characteristics of a debris landslide in the wenchuan earthquake area.Engineering Geology 219(S1):52-63.https://doi.org/10.1016/j.enggeo.2016.11.020
Taga H,Turkmen S,Kacka N(2015)Assessment of stability
problems at southern engineered slopes along Mersin-Tarsus Motorway in turkey.Bulletin of Engineering Geology and the Environment 74(2):379-391.https://doi.org/10.1007/s10064-014-0636-2
Tohari A,Nishigaki M,Komatsu M(2007)Laboratory rainfallinduced slope failure with moisture content measurement.Journal of Geotechnical and Geoenvironmental Engineering133(5):575-587.https://doi.org/10.1061/(ASCE)1090-0241(2007)133:5(575)
Tsai TL,Chen HF(2010)Effects of degree of saturation on shallow landslides triggered by rainfall.Environmental Earth Sciences59(6):1285-1295.https://doi.org/10.1007/s12665-009-0116-3
Wang HL,Xu WY,Cai M,et al.(2017)Gas permeability and porosity evolution of a porous sandstone under repeated loading and unloading conditions.Rock Mechanics and Rock Engineering50(6):1-13.https://doi.org/10.1007/s00603-017-1215-1
Xu X,Dai ZH(2017)Numerical implementation of a modified Mohr-Coulomb model and its application in slope stability analysis.Journal of Modern Transportation 25(1):40-51.https://doi.org/10.1007/s40534-017-0123-0
Youssef AM,Pourghasemi HR,El-Haddad BA,Dhahry BK(2016)Landslide susceptibility maps using different probabilistic and bivariate statistical models and comparison of their performance at Wadi Itwad Basin,Asir Region,Saudi Arabia.Bulletin of Engineering Geology and the Environment 75(1):1-25.https://doi.org/10.1007/s10064-015-0734-9
Zhou JW,Cui P,Yang XG(2013)Dynamic process analysis for the initiation and movement of the Donghekou landslide-debris flow triggered by the Wenchuan earthquake.Journal of Asian Earth Sciences 76:70-84.https://doi.org/10.1016/j.jseaes.2013.08.007
Zhou JW,Cui P,Hao MH(2016)Comprehensive analyses of the initiation and entrainment processes of the 2000 Yigong catastrophic landslide in Tibet,China.Landslides 13(1):39-54.https://doi.org/10.1007/s10346-014-0553-2
Zizioli D,Meisina C,Valentino R,Montrasio L(2013)Comparison between different approaches to modeling shallow landslide susceptibility:a case history in Oltrepo Pavese,Northern Italy.Natural Hazards and Earth System Sciences 13(3):559-573.https://doi.org/10.5194/nhess-13-559-2013
Baum R,Godt J,Savage W(2010)Estimating the timing and location of shallow rainfall-induced landslides using a model for transient,unsaturated infiltration.Journal of Geophysical Research:Earth Surface 115:F03013.https://doi.org/10.1029/2009JF001321
Bittelli M,Valentino R,Salvatorelli F,Pisa PR(2012)Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays.Geomorphology 173-174(9):161-173.https://doi.org/10.1016/j.geomorph.2012.06.006
Bordoni M,Meisina C,Valentino R,et al.(2015)Hydrological factors affecting rainfall-induced shallow landslides:from the field monitoring to a simplified slope stability analysis.Engineering Geology 193:19-37.https://doi.org/10.1016/j.enggeo.2015.04.006
Cascini L,Cuomo S,Pastor M,Sorbino G(2009)Modeling of rainfall-induced shallow landslides of the flow-type.Journal of Geotechnical and Geoenvironmental Engineering 136(1):85-98.https://doi.org/10.1061/(ASCE)GT.1943-5606.0000182
Chen ML,Lv PF,Zhang SL,et al.(2018)Time evolution and spatial accumulation of progressive failure for Xinhua slope in the Dagangshan reservoir,Southwest China.Landslides 15(3):565-580.https://doi.org/10.1007/s10346-018-0946-8
Collins BD,Znidarcic D(2004)Stability analyses of rainfall induced landslides.Journal of Geotechnical and Geoenvironmental Engineering 130(4):362-372.http://doi.org/10.1061/(ASCE)1090-0241(2004)130:4(362)
Corominas J,Moya J(1999)Reconstructing recent landslide activity in relation to rainfall in the Llobregat River basin,Eastern Pyrenees,Spain.Geomorphology 30(1-2):79-93.http://doi.org/10.1016/S0169-555X(99)00046-X
Cruden D,Varnes DJ(1996)Landslide types and processes.Special Report-Transportation Research Board,National Academy of Sciences 247:36-75.https://www.scopus.com/record/display.uri?eid=2-s2.0-7044226255&origin=inward
Duncan JM,Wright SG,Brandon TL(2014)Soil strength and slope stability.Wiley,USA.pp 13-57.https://www.wiley.com/en-cn/Soil+Strength+and+Slope+Stability,+2nd+Edition-p-9781118651650
Ergi nal A,Türke?M,Ertek T,et al.(2008)Geomorphological investigation of the excavation-induced Dündar landslide,BursaTurkey.Geografiska Annaler:Series A,Physical Geography 90(2):109-123.https://doi.org/10.1111/j.1468-0459.2008.00159.x
Fredlund DG,Rahardjo H(1993)Soil mechanics for unsaturated soils.Wiley,USA.pp 9-80.https://doi.org/10.1002/9780470172759
Fredlund DG,Sheng DS,Zhao JZ(2011)Estimation of soil suction from the soil-water characteristic curve.Canadian Geotechnical Journal 48(2):186-198.https://doi.org/10.1139/T10-060
Godt JW,Baum RL,Lu N(2009)Landsliding in partially saturated materials.Geophysical Research Letters 36(2):206-218.https://doi.org/10.1029/2008GL035996
Iverson RM(2000)Landslide triggering by rain infiltration.Water Resources Research 36(7):1897-1910.https://doi.org/10.1029/2000WR900090
Jaedicke C,Eeckhaut MVD,Nadim F,et al.(2014)Identification of landslide hazard and risk‘hotspots’in Europe.Bulletin of Engineering Geology and the Environment 73(2):325-339.https://doi.org/10.1007/s10064-013-0541-0
Klime?J,Rowberry MD,Blah?t J,et al.(2012)The monitoring of slow-moving landslides and assessment of stabilisation measures using an optical-mechanical crack gauge.Landslides 9(3):407-415.https://doi.org/10.1007/s10346-011-0306-4
Kaya A,Alemda?S,Da?S,Gürocak Z(2015)Stability assessment of high-steep cut slope debris on a landslide(Gumushane,NETurkey).Bulletin of Engineering Geology and the Environment75(1):1-11.https://doi.org/10.1007/s10064-015-0753-6
Lainas S,Sabatakakis N,Koukis G(2016)Rainfall thresholds for possible landslide initiation in wildfire-affected areas of Western Greece.Bulletin of Engineering Geology and the Environment75(3):1-14.https://doi.org/10.1007/s10064-015-0762-5
Lee LM,Gofar N,Rahardjo H(2009)A simple model for preliminary evaluation of rainfall-induced slope instability.Engineering Geology 108(3):272-285.https://doi.org/10.1016/j.enggeo.2009.06.011
Lu N,Likos WJ(2006)Suction stress characteristic curve for unsaturated soil.Journal of Geotechnical and Geoenvironmental Engineering 132(2):131-142.https://doi.org/10.1061/(ASCE)1090-0241(2006)132:2(131)
Lu N,Godt J(2008)Infinite slope stability under steady unsaturated seepage conditions.Water Resources Research 44(11):2276-2283.https://doi.org/10.1029/2008WR006976
Margielewski W,Urban J(2003)Crevice-type caves as initial forms of rock landslide development in the flysch carpathians.Geomorphology 54(3):325-338.https://doi.org/10.1016/S0169-555X(02)00375-6
Matsushi Y,Hattanji T,Matsukura Y(2006)Mechanisms of shallow landslides on soil-mantled hillslopes with permeable and impermeable bedrocks in the Boso Peninsula,Japan.Geomorphology 76(1-2):92-108.https://doi.org/10.1016/j.geomorph.2005.10.003
Montrasio L,Valentino R,Corina A,et al.(2014)A prototype system for space-time assessment of rainfall-induced shallow landslides in Italy.Natural Hazards 74(2):1263-1290.https://doi.org/10.1007/s11069-014-1239-8
Quinn PE,Diederichs MS,Rowe RK,Hutchinson DJ(2011)A new model for large landslides in sensitive clay using a fracture mechanics approach.Canadian Geotechnical Journal 48(8):1151-1162.https://doi.org/10.1139/t11-025
Robert DJ(2017)A modified Mohr-Coulomb model to simulate the behavior of pipelines in unsaturated soils.Computers and Geotechnics 91:146-160.https://doi.org/10.1016/j.compgeo.2017.07.004
Schmidt KM,Roering JJ,Stock JD,et al.(2001)The variability of root cohesion as an influence on shallow landslide susceptibility in the Oregon Coast Range.Canadian Geotechnical Journal 38(5):995-1024.https://doi.org/10.1139/cgj-38-5-995
Sorbino G,Nicotera MV(2013)Unsaturated soil mechanics in rainfall-induced flow landslides.Engineering Geology 165(15):105-132.https://doi.org/10.1016/j.enggeo.2012.10.008
Stark TD,Arellano WD,Hillman RP,et al.(2005)Effect of toe excavation on a deep bedrock landslide.Journal of Performance of Constructed Facilities 19(3):244-255.https://doi.org/10.1061/(ASCE)0887-3828(2005)19:3(244)
Su LJ,Xu XQ,Geng XY,Liang SQ(2016)An integrated geophysical approach for investigating hydro-geological characteristics of a debris landslide in the wenchuan earthquake area.Engineering Geology 219(S1):52-63.https://doi.org/10.1016/j.enggeo.2016.11.020
Taga H,Turkmen S,Kacka N(2015)Assessment of stability
problems at southern engineered slopes along Mersin-Tarsus Motorway in turkey.Bulletin of Engineering Geology and the Environment 74(2):379-391.https://doi.org/10.1007/s10064-014-0636-2
Tohari A,Nishigaki M,Komatsu M(2007)Laboratory rainfallinduced slope failure with moisture content measurement.Journal of Geotechnical and Geoenvironmental Engineering133(5):575-587.https://doi.org/10.1061/(ASCE)1090-0241(2007)133:5(575)
Tsai TL,Chen HF(2010)Effects of degree of saturation on shallow landslides triggered by rainfall.Environmental Earth Sciences59(6):1285-1295.https://doi.org/10.1007/s12665-009-0116-3
Wang HL,Xu WY,Cai M,et al.(2017)Gas permeability and porosity evolution of a porous sandstone under repeated loading and unloading conditions.Rock Mechanics and Rock Engineering50(6):1-13.https://doi.org/10.1007/s00603-017-1215-1
Xu X,Dai ZH(2017)Numerical implementation of a modified Mohr-Coulomb model and its application in slope stability analysis.Journal of Modern Transportation 25(1):40-51.https://doi.org/10.1007/s40534-017-0123-0
Youssef AM,Pourghasemi HR,El-Haddad BA,Dhahry BK(2016)Landslide susceptibility maps using different probabilistic and bivariate statistical models and comparison of their performance at Wadi Itwad Basin,Asir Region,Saudi Arabia.Bulletin of Engineering Geology and the Environment 75(1):1-25.https://doi.org/10.1007/s10064-015-0734-9
Zhou JW,Cui P,Yang XG(2013)Dynamic process analysis for the initiation and movement of the Donghekou landslide-debris flow triggered by the Wenchuan earthquake.Journal of Asian Earth Sciences 76:70-84.https://doi.org/10.1016/j.jseaes.2013.08.007
Zhou JW,Cui P,Hao MH(2016)Comprehensive analyses of the initiation and entrainment processes of the 2000 Yigong catastrophic landslide in Tibet,China.Landslides 13(1):39-54.https://doi.org/10.1007/s10346-014-0553-2
Zizioli D,Meisina C,Valentino R,Montrasio L(2013)Comparison between different approaches to modeling shallow landslide susceptibility:a case history in Oltrepo Pavese,Northern Italy.Natural Hazards and Earth System Sciences 13(3):559-573.https://doi.org/10.5194/nhess-13-559-2013