基于弹性波波速的降雨型滑坡预警系统
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摘要
降雨是诱发滑坡最主要的因素。为减少滑坡灾害造成的人员伤亡和经济损失,滑坡早期预警系统成为了最佳选择之一。根据弹性波传播的基本原理和基于降雨型滑坡变形破坏的特点,提出利用弹性波波速来反映边坡表面土体含水率和位移的变化。开发研制了一套三轴渗流-弹性波测试三轴仪和相关系统。该装置能让水从底部渗入土体,模拟降雨入渗土体的过程,同时能测试弹性波波速。试验过程中同步测试含水率、变形和弹性波波速的变化。还进行了降雨滑坡模型试验。利用三轴弯曲元注水试验和降雨滑坡模型试验,深入分析和研究降雨引起的土体滑坡过程与弹性波波速演化规律,揭示波速与含水率和变形的耦合关系。研究结果表明,弹性波波速随着含水率的增大而缓慢减小,随着变形的增大而急剧减小,临近失稳时,波速骤然减小。根据试验结果对含水率和变形导致弹性波波速减小可能的机制进行了解释,提出弹性波在波速骤然减小时发出滑坡预警。研究结果为滑坡防灾减灾和预测预报提供新的方法和可靠的依据。
Rainfall is the most important factor in triggering the landslide. To reduce the loss of life and property caused by the landslide disaster, the early warning system against landslides becomes one of the best choices. Based on the principle of elastic wave propagation and the characteristics of deformation and failure of rainfall-induced landslides, this paper proposes to use the elastic wave velocity to detect the changes in soil moisture content and displacement on slope surface. The bender elements and ceramic disk, incorporated in a triaxial apparatus, are used to measure the S-wave and P-wave velocities in soils subjected to water infiltration. The device allows water to infiltrate into the soil from the pedestal to simulate the process of rainfall infiltration into the soil. The moisture content, deformation and elastic wave velocity are simultaneously measured during the tests. Besides, the rainfall model tests are carried out. Based on the triaxial model tests, this study reveals the process of rainfall-induced landslides, the evolution of elastic wave velocity, and the coupling relationship among the wave velocity, water content and deformation. The results show that the elastic wave velocity decreases slowly with the increase of water content, but decreases sharply with the increase of deformation, indicating the initiation of the instability. We also interpret possible mechanisms of the reduction of elastic wave velocity caused by water content and deformation. This paper provides a new method and reliable basis for an early warning system for rainfall-induced landslides and slope failures.
Rainfall is the most important factor in triggering the landslide. To reduce the loss of life and property caused by the landslide disaster, the early warning system against landslides becomes one of the best choices. Based on the principle of elastic wave propagation and the characteristics of deformation and failure of rainfall-induced landslides, this paper proposes to use the elastic wave velocity to detect the changes in soil moisture content and displacement on slope surface. The bender elements and ceramic disk, incorporated in a triaxial apparatus, are used to measure the S-wave and P-wave velocities in soils subjected to water infiltration. The device allows water to infiltrate into the soil from the pedestal to simulate the process of rainfall infiltration into the soil. The moisture content, deformation and elastic wave velocity are simultaneously measured during the tests. Besides, the rainfall model tests are carried out. Based on the triaxial model tests, this study reveals the process of rainfall-induced landslides, the evolution of elastic wave velocity, and the coupling relationship among the wave velocity, water content and deformation. The results show that the elastic wave velocity decreases slowly with the increase of water content, but decreases sharply with the increase of deformation, indicating the initiation of the instability. We also interpret possible mechanisms of the reduction of elastic wave velocity caused by water content and deformation. This paper provides a new method and reliable basis for an early warning system for rainfall-induced landslides and slope failures.
引文
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[9] MONTGOMERY D R, DIETRICH W E. A physically based model for the topographic control on shallow landsliding[J]. Water Resources Research, 1994, 30(4):1153-1171.
[10] CROSTA G. Regionalization of rainfall thresholds:an aid to landslide hazard evaluation[J]. Environmental Geology, 1998, 35(2-3):131-145.
[11] CROSTA G B, FRATTINI P. Distributed modelling of shallow landslides triggered by intense rainfall[J].Natural Hazards&Earth System Sciences, 2003,3(1/2):81-93.
[12] IVERSON R M. Landside triggering by rain infiltration[J]. Water Resources Research, 2000, 36(7):1897-1910.
[13] LOLLINO G, ARATTANO M, CUCCUREDDU M. The use of the automatic inclinometric system for landslide early warning:the case of Cabella Ligure(North-Western Italy)[J]. Physics&Chemistry of the Earth(Parts A/B/C), 2002, 27(36):1545-1550.
[14] RAMESH M, VASUDEVAN N. The deployment of deep-earth sensor probes for landslide detection[J].Landslides, 2012, 9(4):457-474.
[15] RAMOS-CA?óN A M, PRADA-SARMIENTO L F,TRUJILLO-VELA M G, et al. Linear discriminant analysis to describe the relationship between rainfall and landslides in Bogot??, Colombia[J]. Landslides, 2016,13(4):671-681
[16] UCHIMURA T, TOWHATA I, LAN ANH T, et al. Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface[J].Landslides, 2010, 7(3):351-357.
[17] UCHIMURA T, TOWHATA I, WANG L, et al. Precaution and early warning of surface failure of slopes using tilt sensors[J]. Soils and Foundations, 2015, 55(5):1086-1099.
[18] CHEN Y L, UCHIMURA T, IRFAN M, et al. Detection of water infiltration and deformation of unsaturated soils by elastic wave velocity[J]. Landslides, 2017, 14(5):1715-1730.
[19] CHEN Y L, IRFAN M, UCHIMURA T, et al. Elastic wave velocity monitoring as an emerging technique for rainfall-induced landslide prediction[J]. Landslides,2018, 15(6):1155-1172.
[20] CHEN Y L, IRFAN M, UCHIMURA T, et al.Development of elastic wave velocity threshold for rainfall-induced landslide prediction and early warning[J].Landslides, 2019, 16(5):955-968.
[21] CHEN Y L, IRFAN M, UCHIMURA T, et al. Feasibility of using elastic wave velocity monitoring for early warning of rainfall-induced slope failure[J]. Sensors,2018, 18(4):997.
[22] IRFAN M, UCHIMURA T, CHEN Y L. Effects of soil deformation and saturation on elastic wave velocities in relation to prediction of rain-induced landslides[J].Engineering Geology, 2017, 230:84-94.
[23] JAKY J. Pressure in silos[C]//2nd ICSMFE. London:[s. n.], 1948:103-107.
[24] GALLAGE C, UCHIMURA T. Direct shear testing on unsaturated silty soils to investigate the effects of drying and wetting on shear strength parameters at low suction[J]. Journal of Geotechnical&Geoenvironmental Engineering, 2016, 142(3):04015081.
[25] JOVI?I?V, COOP MR, SIMI?M. Objective criteria for determining Gmax from bender element tests[J].Geotechnique, 1996, 46(2):357-362.
[26] IRFAN M, UCHIMURA T. Helical filter paper technique for uniform distribution of injected moisture in unsaturated triaxial specimens[J]. Soils and Foundations, 2015, 55(4):749-760.
[27] HARDIN B O. Elastic wave velocities in granular soils[J]. Journal of Soil Mechanics and Foundation Division, ASCE, 1963, 95:33-66.
[28] IRFAN M. Elastic wave propagation through unsaturated soils concerning early warning of rain-induced landslides[D]. Tokyo:University of Tokyo, 2014.
[2]黄润秋. 20世纪以来中国的大型滑坡及其发生机制[J].岩石力学与工程学报, 2007, 26(3):433-454.HUANG Run-qiu. Large-scale landslides and their sliding mechanisms in China since the 20th century[J]. Chinese Journal of Rock Mechanics and Engineering, 2007,26(3):433-454.
[3]王发玲,刘才华,龚哲.顺层岩质边坡锚杆支护机制研究[J].岩石力学与工程学报, 2014, 33(7):173-178.WANG Fa-ling, LIU Cai-hua, GONG Zhe. Mechanisms of bolt support for bedding rock slopes[J]. Chinese Journal of Rock Mechanics and Engineering, 2014,33(7):173-178.
[4]陈祖煜,黎康平,李旭,等.重力式挡土墙抗滑稳定容许安全系数取值标准初探[J].岩土力学, 2018, 39(1):1-10.CHEN Zu-yu, LI Kang-ping, LI Xu, et al. A preliminary study of allowable factor of safety in gravity retaining wall stability analysis[J]. Rock and Soil Mechanics,2018, 39(1):1-10.
[5] CHUNG M C, TAN C H, CHEN C H. Local rainfall thresholds for forecasting landslide occurrence:Taipingshan landslide triggered by Typhoon Saola[J].Landslides, 2017, 14(1):19-33.
[6] MONTGOMERY D R, SCHMIDT K M, DIETRICH W E, et al. Instrumental record of debris flow initiation during natural rainfall:implications for modeling slope stability[J]. Journal of Geophysical Research:Earth Surface, 2009, 114:F01031.
[7] ANGELI M G, PASUTO A, SILVANO S. A critical review of landslide monitoring experiences[J].Engineering Geology, 2000, 55(3):133-147
[8]贺可强,郭栋,张朋,等.降雨型滑坡垂直位移方向率及其位移监测预警判据研究[J].岩土力学, 2017,38(12):3649-3659.HE Ke-qiang, GUO Dong, ZHANG Peng, et al. The direction ratio of vertical displacement for rainfall-induced landslides and its early warning criterion[J]. Rock and Soil Mechanics, 2017, 38(12):3649-3659.
[9] MONTGOMERY D R, DIETRICH W E. A physically based model for the topographic control on shallow landsliding[J]. Water Resources Research, 1994, 30(4):1153-1171.
[10] CROSTA G. Regionalization of rainfall thresholds:an aid to landslide hazard evaluation[J]. Environmental Geology, 1998, 35(2-3):131-145.
[11] CROSTA G B, FRATTINI P. Distributed modelling of shallow landslides triggered by intense rainfall[J].Natural Hazards&Earth System Sciences, 2003,3(1/2):81-93.
[12] IVERSON R M. Landside triggering by rain infiltration[J]. Water Resources Research, 2000, 36(7):1897-1910.
[13] LOLLINO G, ARATTANO M, CUCCUREDDU M. The use of the automatic inclinometric system for landslide early warning:the case of Cabella Ligure(North-Western Italy)[J]. Physics&Chemistry of the Earth(Parts A/B/C), 2002, 27(36):1545-1550.
[14] RAMESH M, VASUDEVAN N. The deployment of deep-earth sensor probes for landslide detection[J].Landslides, 2012, 9(4):457-474.
[15] RAMOS-CA?óN A M, PRADA-SARMIENTO L F,TRUJILLO-VELA M G, et al. Linear discriminant analysis to describe the relationship between rainfall and landslides in Bogot??, Colombia[J]. Landslides, 2016,13(4):671-681
[16] UCHIMURA T, TOWHATA I, LAN ANH T, et al. Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface[J].Landslides, 2010, 7(3):351-357.
[17] UCHIMURA T, TOWHATA I, WANG L, et al. Precaution and early warning of surface failure of slopes using tilt sensors[J]. Soils and Foundations, 2015, 55(5):1086-1099.
[18] CHEN Y L, UCHIMURA T, IRFAN M, et al. Detection of water infiltration and deformation of unsaturated soils by elastic wave velocity[J]. Landslides, 2017, 14(5):1715-1730.
[19] CHEN Y L, IRFAN M, UCHIMURA T, et al. Elastic wave velocity monitoring as an emerging technique for rainfall-induced landslide prediction[J]. Landslides,2018, 15(6):1155-1172.
[20] CHEN Y L, IRFAN M, UCHIMURA T, et al.Development of elastic wave velocity threshold for rainfall-induced landslide prediction and early warning[J].Landslides, 2019, 16(5):955-968.
[21] CHEN Y L, IRFAN M, UCHIMURA T, et al. Feasibility of using elastic wave velocity monitoring for early warning of rainfall-induced slope failure[J]. Sensors,2018, 18(4):997.
[22] IRFAN M, UCHIMURA T, CHEN Y L. Effects of soil deformation and saturation on elastic wave velocities in relation to prediction of rain-induced landslides[J].Engineering Geology, 2017, 230:84-94.
[23] JAKY J. Pressure in silos[C]//2nd ICSMFE. London:[s. n.], 1948:103-107.
[24] GALLAGE C, UCHIMURA T. Direct shear testing on unsaturated silty soils to investigate the effects of drying and wetting on shear strength parameters at low suction[J]. Journal of Geotechnical&Geoenvironmental Engineering, 2016, 142(3):04015081.
[25] JOVI?I?V, COOP MR, SIMI?M. Objective criteria for determining Gmax from bender element tests[J].Geotechnique, 1996, 46(2):357-362.
[26] IRFAN M, UCHIMURA T. Helical filter paper technique for uniform distribution of injected moisture in unsaturated triaxial specimens[J]. Soils and Foundations, 2015, 55(4):749-760.
[27] HARDIN B O. Elastic wave velocities in granular soils[J]. Journal of Soil Mechanics and Foundation Division, ASCE, 1963, 95:33-66.
[28] IRFAN M. Elastic wave propagation through unsaturated soils concerning early warning of rain-induced landslides[D]. Tokyo:University of Tokyo, 2014.