灌溉淋滤对原状黄土物理力学性质的影响
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摘要
甘肃黑方台地区因农业灌溉诱发了大量黄土滑坡,给当地群众生命财产安全构成了严重威胁。为探究灌溉诱发黄土滑坡的形成机理,以灌溉淋滤为出发点,对比分析了原状黄土在长期灌溉条件下物质组成、物理性质的变化规律,通过室内三轴试验研究了灌溉淋滤对原状黄土静态液化特性的影响。结果表明:长期灌溉造成原状黄土中可溶盐含量的大幅降低,胶结弱化,粗颗粒分散,黏粒增多,塑性指数增大,同时灌溉过程中发生的湿陷引起黄土干密度增大、孔隙比减小;淋滤前后饱和黄土均表现出强烈的应变软化特性,具有静态液化特征;与未淋滤黄土相比,淋滤后黄土脆性破坏特征有所减弱,表现为峰值应变增大、超孔隙水压力减小和稳态线上移。
Agricultural irrigation in Heifangtai area of Gansu has induced a large number of landslides,which threaten the safety of the local residents.In order to investigate the mechanism of the irrigation-induced loess landslide,the variations of material composition and physical properties of undisturbed loess caused by long-term irrigation were analyzed;laboratory triaxial tests were performed to further study the effects of irrigation leaching on static liquefaction characteristics inherent in undisturbed loess.The results show that long-term irrigation leaching results in the decrease of contents of soluble salt in undisturbed loess,weakening in the cementation,the dispersion of coarse particles and the increase of clay particle and plasticity index;meanwhile,the wetting collapse in the process of irrigation causes the increase of dry density and the decrease of void ratio;all saturated loess before and after leaching are characterized by static liquefaction in isotropically consolidated undrained compression testing;compared with loess without leaching,the loess leached is characterized by smaller brittleness with the increase of peak strain,the decrease of excess pore water pressure and the upward of steady state line.
Agricultural irrigation in Heifangtai area of Gansu has induced a large number of landslides,which threaten the safety of the local residents.In order to investigate the mechanism of the irrigation-induced loess landslide,the variations of material composition and physical properties of undisturbed loess caused by long-term irrigation were analyzed;laboratory triaxial tests were performed to further study the effects of irrigation leaching on static liquefaction characteristics inherent in undisturbed loess.The results show that long-term irrigation leaching results in the decrease of contents of soluble salt in undisturbed loess,weakening in the cementation,the dispersion of coarse particles and the increase of clay particle and plasticity index;meanwhile,the wetting collapse in the process of irrigation causes the increase of dry density and the decrease of void ratio;all saturated loess before and after leaching are characterized by static liquefaction in isotropically consolidated undrained compression testing;compared with loess without leaching,the loess leached is characterized by smaller brittleness with the increase of peak strain,the decrease of excess pore water pressure and the upward of steady state line.
引文
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[22]李骅锦,许强,何雨森,等.甘肃黑方台滑坡滑距参数的BP神经网络模型[J].水文地质工程地质,2016,43(4):141-146,152.LI Hua-jin,XU Qiang,HE Yu-sen,et al.BP Neural Network Model for Analyzing the Impact Factors of the Travel Distance of the Heifangtai Landslide in Gansu[J].Hydrogeology and Engineering Geology,2016,43(4):141-146,152.
[23]周飞,许强,巨袁臻,等.黑方台黄土斜坡变形破坏机理研究[J].水文地质工程地质,2017,44(1):157-163.ZHOU Fei,XU Qiang,JU Yuan-zhen,et al.A Study of the Deformation and Failure Mechanism of the Heifangtai Loess Slope[J].Hydrogeology and Engineering Geology,2017,44(1):157-163.
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[2]赵尚学,李鸿琏,马东涛.盐锅峡库区黄土台缘滑坡研究[J].水土保持通报,1995,15(1):19-22,58.ZHAO Shang-xue,LI Hong-lian,MA Dong-tao.Study on the Landslides at the Edge of Loess Terrace in Yanguoxia Reservior Region[J].Bulletin of Soil and Water Conservation,1995,15(1):19-22,58.
[3]范立民,岳明,冉广庆.泾河南岸崩岸型滑坡的发育规律[J].中国煤田地质,2004,16(5):33-35,42.FAN Li-min,YUE Ming,RAN Guang-qing.Development Pattern of Slumping Bank Type Landslides at the South Bank of Jinghe,Shaanxi Province[J].Coal Geology of China,2004,16(5):33-35,42.
[4]李文,龙建辉,李同录,等.陕西泾阳南塬黄土滑坡滑带土残余剪切强度特性[J].地球科学与环境学报,2012,34(4):95-101.LI Wen,LONG Jian-hui,LI Tong-lu,et al.Residual Shear Strength Characteristics of Landslide Soil in Loess Landslide of Jingyang Southern Highland,Shaanxi[J].Journal of Earth Sciences and Environment,2012,34(4):95-101.
[5]胡炜,朱立峰,张茂省,等.灌溉引起的黄土工程地质性质变化[J].地质通报,2013,32(6):875-880.HU Wei,ZHU Li-feng,ZHANG Mao-sheng,et al.The Changes of Engineering Geological Properties of Loess Caused by Irrigation[J].Geological Bulletin of China,2013,32(6):875-880.
[6]张茂省,朱立峰,胡炜,等.灌溉引起的地质环境变化与黄土地质灾害:以甘肃黑方台灌区为例[M].北京:科学出版社,2016.ZHANG Mao-sheng,ZHU Li-feng,HU Wei,et al.The Changes of the Geological Environment and the Geological Disaster of Loess by Irrigation:A Case Study of Heifangtai Irrigation Area,Gansu Province[M].Beijing:Science Press,2016.
[7]张茂省,李同录.黄土滑坡诱发因素及其形成机理研究[J].工程地质学报,2011,19(4):530-540.ZHANG Mao-sheng,LI Tong-lu.Triggering Factors and Forming Mechanism of Loess Landslides[J].Journal of Engineering Geology,2011,19(4):530-540.
[8]习羽,李同录,邢鲜丽.灌渠渗漏诱发的黄土滑坡泥流触发机理分析[J].地球科学与环境学报,2017,39(1):135-142.XI Yu,LI Tong-lu,XING Xian-li.Analysis of the Triggering Mechanism of a Loess Flowslide Induced by Water Canal Leakage[J].Journal of Earth Sciences and Environment,2017,39(1):135-142.
[9]王家鼎.高速黄土滑坡的一种机理:饱和黄土蠕动液化[J].地质论评,1992,38(6):532-539.WANG Jia-ding.A Mechanism of High-speed Loess Landslides:Saturated Loess Creeping Liquefaction[J].Geological Review,1992,38(6):532-539.
[10]赵春宏,戴福初.深圳某填土滑坡破坏机理研究[J].中国地质灾害与防治学报,2007,18(2):1-8.ZHAO Chun-hong,DAI Fu-chu.Study on Failure Mechanism of a Fill Slope in Shenzhen[J].The Chinese Journal of Geological Hazard and Control,2007,18(2):1-8.
[11]金艳丽,戴福初.灌溉诱发黄土滑坡机理研究[J].岩土工程学报,2007,29(10):1493-1499.JIN Yan-li,DAI Fu-chu.The Mechanism of Irrigation-induced Landslides of Loess[J].Chinese Journal of Geotechnical Engineering,2007,29(10):1493-1499.
[12]金艳丽,戴福初.饱和黄土的静态液化特性试验研究[J].岩土力学,2008,29(12):3293-3298.JIN Yan-li,DAI Fu-chu.Experimental Investigation of Static Liquefaction of Saturated Loess[J].Rock and Soil Mechanics,2008,29(12):3293-3298.
[13]武彩霞,许领,戴福初,等.黑方台黄土泥流滑坡及发生机制研究[J].岩土力学,2011,32(6):1767-1773.WU Cai-xia,XU Ling,DAI Fu-chu,et al.Topographic Features and Initiation of Earth Flows on Heifangtai Loess Plateau[J].Rock and Soil Mechanics,2011,32(6):1767-1773.
[14]邴慧,武俊杰,邓津.黄土状盐渍土洗盐前后物理力学性质的变化[J].冰川冻土,2011,33(4):796-800.BING Hui,WU Jun-jie,DENG Jin.Variations of Physical and Mechanical Properties of Saline Loess Before and After Desalting[J].Journal of Glaciology and Geocryology,2011,33(4):796-800.
[15]WEN B P,HE L.Influence of Lixiviation by Irrigation Water on Residual Shear Strength of Weathered Red Mudstone in Northwest China:Implication for Its Role in Landslides’Reactivation[J].Engineering Geology,2012,151:56-63.
[16]何蕾,文宝萍.灌溉溶滤对西北地区红层风化泥岩不排水抗剪强度的影响[J].水文地质工程地质,2014,41(3):47-52.HE Lei,WEN Bao-ping.Effect of Lixiviation by Irrigation Water on Undrained Shear Strength of Weathered Red Mudstone in Northwest China[J].Hydrogeology and Engineering Geology,2014,41(3):47-52.
[17]卢雪清.盐分变化对黄土强度特性影响的试验研究[D].杨凌:西北农林科技大学,2012.LU Xue-qing.Study on the Effect of Salinity Changes on Strength Character of Loess[D].Yangling:Northwest A&F University,2012.
[18]ZHANG F Y,WANG G H,KAMAI T,et al.Undrained Shear Behavior of Loess Saturated with Different Concentrations of Sodium Chloride Solution[J].Engineering Geology,2013,155:69-79.
[19]许强,彭大雷,亓星,等.2015年4.29甘肃黑方台党川2#滑坡基本特征与成因机理研究[J].工程地质学报,2016,24(2):167-180.XU Qiang,PENG Da-lei,QI Xing,et al.Dangchuan2#Landslide of April 29,2015in Heifangtai Area of Gansu Province:Characteristices and Failure Mechanism[J].Journal of Engineering Geology,2016,24(2):167-180.
[20]亓星,许强,彭大雷,等.地下水诱发渐进后退式黄土滑坡成因机理研究:以甘肃黑方台灌溉型黄土滑坡为例[J].工程地质学报,2017,25(1):147-153.QI Xing,XU Qiang,PENG Da-lei,et al.Mechanism of Gradual Retreat Loess Landslide Caused by Groundwater:A Case Study of the Irrigation Loess Landslide in Heifangtai,Gansu Province[J].Journal of Engineering Geology,2017,25(1):147-153.
[21]曹从伍,许强,彭大雷,等.基于物理模拟实验的黑方台黄土滑坡破坏机理研究[J].水文地质工程地质,2016,43(4):72-77.CAO Cong-wu,XU Qiang,PENG Da-lei,et al.Research on the Failure Mechanism of the Heifangtai Loess Landslides Based on the Physical Simulation Experiments[J].Hydrogeology and Engineering Geology,2016,43(4):72-77.
[22]李骅锦,许强,何雨森,等.甘肃黑方台滑坡滑距参数的BP神经网络模型[J].水文地质工程地质,2016,43(4):141-146,152.LI Hua-jin,XU Qiang,HE Yu-sen,et al.BP Neural Network Model for Analyzing the Impact Factors of the Travel Distance of the Heifangtai Landslide in Gansu[J].Hydrogeology and Engineering Geology,2016,43(4):141-146,152.
[23]周飞,许强,巨袁臻,等.黑方台黄土斜坡变形破坏机理研究[J].水文地质工程地质,2017,44(1):157-163.ZHOU Fei,XU Qiang,JU Yuan-zhen,et al.A Study of the Deformation and Failure Mechanism of the Heifangtai Loess Slope[J].Hydrogeology and Engineering Geology,2017,44(1):157-163.
[24]谷天峰,朱立峰,胡炜,等.灌溉引起地下水位上升对斜坡稳定性的影响:以甘肃黑方台为例[J].现代地质,2015,29(2):408-413.GU Tian-feng,ZHU Li-feng,HU Wei,et al.Effect on Slope Stability due to Groundwater Rising Caused by Irrigation:A Case Study of Heifang Platform in Gansu,China[J].Geoscience,2015,29(2):408-413.
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