裂缝对灌溉诱发黄土滑坡的影响——以陕西省泾阳南塬为例
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摘要
泾阳南塬裂缝洞穴很发育,加之当地居民为了提高农业产量一般都采取漫灌方式浇地,这导致了南塬黄土滑坡频繁发生,给当地造成了很大的经济损失,甚至人员伤亡,因此研究裂缝对黄土滑坡的影响有很重要的实际意义。通过现场灌溉试验、地下水位测量和黄土的基本物理力学性质试验,基于非饱和土渗流和强度理论,采用简化Bishop方法,计算黄土斜坡的稳定性。结果表明:南塬塬下在4～5月地下水位最高,平均在地面以下10. 73 m,2015年内变化幅度约为5. 0 m;塬上地下水位埋深约为31. 60 m,年变化幅度较小。农田灌溉水位高出地面约5. 0 cm,历时约100 min。在缝深小于9. 26 m时、距离塬边50 m范围内不灌溉和高的地下水位情况下,裂缝塬边距小于20 m时,泾阳南塬斜坡稳定安全系数随着裂缝塬边距的增加而减小,随着裂缝深度增加而减小;当塬边距大于20 m时,稳定安全系数随着裂缝塬边距和裂缝深度的变化较小,黄土斜坡均处于不稳定状态或者极限平衡状态。得出了保持黄土斜坡稳定时裂缝深度、裂缝位置的临界状态线。当处于状态线以内时,斜坡稳定;否则,不稳定。1976年以前的斜坡稳定性结果验证了以前南塬很少发生滑坡的现象。高的地下水位下,距塬边50 m外灌溉还是不能保证斜坡稳定性。
Because there are many cracks and caves on the southern Jingyang Plateau (SJP) and the local people take flood irrigation in order to increase agricultural production,loess landslides and collapses occur frequently.That cause great economic losses and even casualties. So it is very important to research the influence of the cracks on the loess landslide induced by irrigation. Through the field irrigation test,measurement of the underground water level and indoor physical property tests,the stability of loess slope were studied by the method of simplified Bishop on the basis of the unsaturated soil mechanics theory. The results show that the underground water level of about 10. 73 m below the SJP is the highest in April and May and the changing range is about 5. 0 m in 2015. Underground water level on the SJP is about 31. 60 m below the ground and its change is smaller. The water level of agricultural irrigation is 5. 0 cm about the ground and lasts for about 100 min. In the condition of high underground water level,no irrigation within 50 m to the side of loess plateau and crack depth"h"less than 9. 26 m when the distance between the crack and the slope shoulder (L) is less than 20 m the stability of loess slope (FS) decreases with the increases of L. FS decreases with the increases of h. When L is bigger than 20 m,FS changes small with L and h. The critical state line of maintaining slope stable about crack position and crack depth is obtained. Slope will be stable when the point reflecting the location and depth of crack is inside the critical line,otherwise the slope will be unstable. Through calculating the slope stability in the low underground water level measured in 1976,the results explain why loess landslide in SJP don't occur at that time. Irrigation beyond 50 m is not enough to keep the slope stable and the range of prohibiting irrigation should be increased.
Because there are many cracks and caves on the southern Jingyang Plateau (SJP) and the local people take flood irrigation in order to increase agricultural production,loess landslides and collapses occur frequently.That cause great economic losses and even casualties. So it is very important to research the influence of the cracks on the loess landslide induced by irrigation. Through the field irrigation test,measurement of the underground water level and indoor physical property tests,the stability of loess slope were studied by the method of simplified Bishop on the basis of the unsaturated soil mechanics theory. The results show that the underground water level of about 10. 73 m below the SJP is the highest in April and May and the changing range is about 5. 0 m in 2015. Underground water level on the SJP is about 31. 60 m below the ground and its change is smaller. The water level of agricultural irrigation is 5. 0 cm about the ground and lasts for about 100 min. In the condition of high underground water level,no irrigation within 50 m to the side of loess plateau and crack depth"h"less than 9. 26 m when the distance between the crack and the slope shoulder (L) is less than 20 m the stability of loess slope (FS) decreases with the increases of L. FS decreases with the increases of h. When L is bigger than 20 m,FS changes small with L and h. The critical state line of maintaining slope stable about crack position and crack depth is obtained. Slope will be stable when the point reflecting the location and depth of crack is inside the critical line,otherwise the slope will be unstable. Through calculating the slope stability in the low underground water level measured in 1976,the results explain why loess landslide in SJP don't occur at that time. Irrigation beyond 50 m is not enough to keep the slope stable and the range of prohibiting irrigation should be increased.
引文
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7郭晨,许强,魏勇,等.陕西泾阳南塬蒋刘4#滑坡运动堆积特征及流动性成因分析[J].科学技术与工程,2017,17(27):15-25Guo Chen,Xu Qiang,Wei Yong,et al.Analysis of propagation and deposit characteristics and liquidity of Jiangliu 4#landslide in southern Jingyang plateau,Shaanxi Province[J].Science Technology and Engineering,2017,17(27):15-25
8李志强,许强,李姝,等.按主成分分析法研究黄土灌溉区水-岩(土)相互作用[J].科学技术与工程,2017,17(23):161-167Li Zhiqiang,Xu Qiang,Li Shu,et al.Study on water-rock/soil interaction in loess irrigation area based on the principal component analysis[J].Science Technology and Engineering,2017,17(23):161-167
9雷祥义.陕西泾阳南源黄土滑坡灾害与引水灌溉的关系[J].工程地质学报,1994,3(1):56-64Lei Xiangyi.The hazards of loess landslides in the southern tableland of jingyang county,shaanxi and their relationship with the channel water into fields[J].Journal of Engineering Geology,1994,3(1):56-64
10姚海林,游慧杰,范永丰,等.柳家凹黄土滑坡滑动机制研究[J].岩土力学,2013,34(1):182-188Yao Hailin,You Huijie,Fan Yongfeng,et al.Study of sliding mechanism of Liujia'ao loess landslide[J].Rock and Soil Mechanics,2013,34(1):182-188
11武彩霞,戴福初,闵弘,等.台源源顶裂缝对黄土斜坡水文响应的影响[J].吉林大学学报(地球科学版),2011,41(5):1512-1519Wu Caixia,Dai Fuchu,Min Hong,et al.Influence of cracks at the platform on hydrologic response of loess slope[J].Journal of Jilin University(Earth Science Edition),2011,41(5):1512-1519
12周跃峰,龚壁卫,胡波,等.牵引式滑坡演化模式研究[J].岩土工程学报,2014,36(10):1855-1862Zhou Yuefeng,Gong Biwei,Hu Bo,et al.Evolution mode of retrogressive landslide[J].Chinese Journal of Geotechnical Engineering,2014,36(10):1855-1862
13马鹏辉,彭建兵,李同录,等.陕西泾阳“3.8”蒋刘黄土滑坡成因及运动特征分析[J].工程地质学报,2018,26(3):663-672Ma Penghui,Peng Jianbing,Li Tonglu,et al.Forming mechanism and motion characteristics of the“3.8”Jiangliu loess landslide in Jingyang County of Shaanxi Province[J].Journal of Engineering Geology,2018,26(3):663-672
14刘绪洋.坡体形态对黄土边坡稳定性的影响研究[J].工程建设,2018,50(8):49-53Liu Xuyang.Study on influence of slope shape on loess slope stability[J].Engineering Construction,2018,50(8):49-53
15高润德,彭良泉,王钊.雨水入渗作用下非饱和土边坡的稳定性分析[J].人民长江,2001,32(11):25-27Gao Runde,Peng Liangquan,Wang Zhao.Stability analysis of unsaturated soil slope under rainwater infiltration[J].Yangtze River,2001,32(11):25-27
16徐学军,王罗斌,何子杰.坡顶竖向裂缝对边坡稳定性影响的研究[J].人民长江,2009,40(22):46-48Xu Xuejun,Wang Luobin,He Zijie.Study on the influence of top vertical crack on slope stability[J].Yangtze Rive,2009,40(22):46-48
17邓东平,李亮.水力条件下具有张裂缝临河边坡稳定性分析[J].岩石力学与工程学报,2011(9):1835-1847Deng Dongping,Li Liang.Study of stability of slope with tension crack near riverunder hydraulic situation[J].Chinese Journal of Rock.Mechanics and Engineering,2011,30(9):1835-1847
18 Genuchten V.A closed-form equation for predicting the hydraulic conductivity of uns-aturated soils[J].Soil Science Society of America Journal,1980,44(5):892-898
19 Fredlund D G,Xing A,Fredlund M D,et al.The relationship of the unsaturated soil shear strength to the soil-water characteristic curve[J].Canadian Geotechnical Journal,1996,33:440-448
20 Vanapalli S K,Fredlund D G,Pufahl D E,et al.Model for the prediction of shear strength with respect to soil suction[J].Canadian Geotechnical Journal,1996,33:379-392
21梁燕,程昌梦,杜鑫,等.晚更新世黄土脱湿-吸湿全过程土水特征曲线研究[J].公路工程,2016,41(4):67-71Liang Yan,Cheng Changmeng,Du Xin,et al.The study of soilwater characteristic curve of Q3 loess in the desorption and absorption process[J].Highway Engineering,2016,41(4):67-71
22何小亮,谢婉丽,丁勇.泾阳南源黄土剪切强度的三轴试验研究[J].工程地质学报,2010,18(增刊):76-80He Xiaoliang,Xie Wanli,Ding Yong.Study on triaxial test of shear strength of loess in southern Jingyang County[J].Journal of Engineering Geology,2010,18(S):76-80
23张宁宁.不同初始应力状态下泾阳黄土平面应变试验研究[D].西安:西北农林科技大学,2014Zhang Ningning.Plane strain test of jingyang loess under the different initial stress state conditions[D].Xi'an:Northwest University of Agriculture and Forestry Technology,2014
24潘春雷.黄土滑坡滑带土工程特性的实验研究[D].西安:长安大学,2008Pan Chunlei.Experimental study on engineering characteristics of loess landslide slip zone[D].Xi'an:Chang'an University,2008
2王家鼎,肖树芳,张倬元.灌溉诱发高速黄土滑坡的运动机理[J].工程地质学报,2001,9(3):241-246Wang Jiading,Xiao Shufang,Zhang Zhuoyuan.The mechanism for movement of irrigation induced highspeed loess landslide[J].Journal of Engineering Geology,2001,9(3):241-246
3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):1493-1499Jin Yanli,Dai Fuchu.The mechanism of irrigation-induced landslides of loess[J].Chinese Journal of Geotechnical Engineering,2007,29(10):1493-1499
4许领,戴福初,邝国麟,等.台缘裂缝发育特征、成因机制及其对黄土滑坡的意义[J].地质论评,2009,55(1):85-90Xu Ling,Dai Fuchu,Kuang Guolin,et al.Characteristics and forming mechanisms of the plateau-edge cracks and their significance to loess landslides[J].Geological Review,2009,55(1):85-90
5许领,戴福初.泾阳南塬黄土滑坡特征参数统计分析[J].水文地质工程地质,2008,5:28-32Xu Ling,Dai Fuchu.Statistical analysis of the characteristic parameters of loess landslides at the South Jingyang Plateau[J].Hydrogeology and Engineering Geology,2008,5:28-32
6孔庆,刘小军,白俊杰.练家沟黄土斜坡失稳机制及稳定性评价[J].公路,2017(10):5-10Kong Qing,Liu Xiaojun,Bai Junjie.Sliding formation mechanism of lianjiagou loess landslide and stability evaluation[J].Highway,2017(10):5-10
7郭晨,许强,魏勇,等.陕西泾阳南塬蒋刘4#滑坡运动堆积特征及流动性成因分析[J].科学技术与工程,2017,17(27):15-25Guo Chen,Xu Qiang,Wei Yong,et al.Analysis of propagation and deposit characteristics and liquidity of Jiangliu 4#landslide in southern Jingyang plateau,Shaanxi Province[J].Science Technology and Engineering,2017,17(27):15-25
8李志强,许强,李姝,等.按主成分分析法研究黄土灌溉区水-岩(土)相互作用[J].科学技术与工程,2017,17(23):161-167Li Zhiqiang,Xu Qiang,Li Shu,et al.Study on water-rock/soil interaction in loess irrigation area based on the principal component analysis[J].Science Technology and Engineering,2017,17(23):161-167
9雷祥义.陕西泾阳南源黄土滑坡灾害与引水灌溉的关系[J].工程地质学报,1994,3(1):56-64Lei Xiangyi.The hazards of loess landslides in the southern tableland of jingyang county,shaanxi and their relationship with the channel water into fields[J].Journal of Engineering Geology,1994,3(1):56-64
10姚海林,游慧杰,范永丰,等.柳家凹黄土滑坡滑动机制研究[J].岩土力学,2013,34(1):182-188Yao Hailin,You Huijie,Fan Yongfeng,et al.Study of sliding mechanism of Liujia'ao loess landslide[J].Rock and Soil Mechanics,2013,34(1):182-188
11武彩霞,戴福初,闵弘,等.台源源顶裂缝对黄土斜坡水文响应的影响[J].吉林大学学报(地球科学版),2011,41(5):1512-1519Wu Caixia,Dai Fuchu,Min Hong,et al.Influence of cracks at the platform on hydrologic response of loess slope[J].Journal of Jilin University(Earth Science Edition),2011,41(5):1512-1519
12周跃峰,龚壁卫,胡波,等.牵引式滑坡演化模式研究[J].岩土工程学报,2014,36(10):1855-1862Zhou Yuefeng,Gong Biwei,Hu Bo,et al.Evolution mode of retrogressive landslide[J].Chinese Journal of Geotechnical Engineering,2014,36(10):1855-1862
13马鹏辉,彭建兵,李同录,等.陕西泾阳“3.8”蒋刘黄土滑坡成因及运动特征分析[J].工程地质学报,2018,26(3):663-672Ma Penghui,Peng Jianbing,Li Tonglu,et al.Forming mechanism and motion characteristics of the“3.8”Jiangliu loess landslide in Jingyang County of Shaanxi Province[J].Journal of Engineering Geology,2018,26(3):663-672
14刘绪洋.坡体形态对黄土边坡稳定性的影响研究[J].工程建设,2018,50(8):49-53Liu Xuyang.Study on influence of slope shape on loess slope stability[J].Engineering Construction,2018,50(8):49-53
15高润德,彭良泉,王钊.雨水入渗作用下非饱和土边坡的稳定性分析[J].人民长江,2001,32(11):25-27Gao Runde,Peng Liangquan,Wang Zhao.Stability analysis of unsaturated soil slope under rainwater infiltration[J].Yangtze River,2001,32(11):25-27
16徐学军,王罗斌,何子杰.坡顶竖向裂缝对边坡稳定性影响的研究[J].人民长江,2009,40(22):46-48Xu Xuejun,Wang Luobin,He Zijie.Study on the influence of top vertical crack on slope stability[J].Yangtze Rive,2009,40(22):46-48
17邓东平,李亮.水力条件下具有张裂缝临河边坡稳定性分析[J].岩石力学与工程学报,2011(9):1835-1847Deng Dongping,Li Liang.Study of stability of slope with tension crack near riverunder hydraulic situation[J].Chinese Journal of Rock.Mechanics and Engineering,2011,30(9):1835-1847
18 Genuchten V.A closed-form equation for predicting the hydraulic conductivity of uns-aturated soils[J].Soil Science Society of America Journal,1980,44(5):892-898
19 Fredlund D G,Xing A,Fredlund M D,et al.The relationship of the unsaturated soil shear strength to the soil-water characteristic curve[J].Canadian Geotechnical Journal,1996,33:440-448
20 Vanapalli S K,Fredlund D G,Pufahl D E,et al.Model for the prediction of shear strength with respect to soil suction[J].Canadian Geotechnical Journal,1996,33:379-392
21梁燕,程昌梦,杜鑫,等.晚更新世黄土脱湿-吸湿全过程土水特征曲线研究[J].公路工程,2016,41(4):67-71Liang Yan,Cheng Changmeng,Du Xin,et al.The study of soilwater characteristic curve of Q3 loess in the desorption and absorption process[J].Highway Engineering,2016,41(4):67-71
22何小亮,谢婉丽,丁勇.泾阳南源黄土剪切强度的三轴试验研究[J].工程地质学报,2010,18(增刊):76-80He Xiaoliang,Xie Wanli,Ding Yong.Study on triaxial test of shear strength of loess in southern Jingyang County[J].Journal of Engineering Geology,2010,18(S):76-80
23张宁宁.不同初始应力状态下泾阳黄土平面应变试验研究[D].西安:西北农林科技大学,2014Zhang Ningning.Plane strain test of jingyang loess under the different initial stress state conditions[D].Xi'an:Northwest University of Agriculture and Forestry Technology,2014
24潘春雷.黄土滑坡滑带土工程特性的实验研究[D].西安:长安大学,2008Pan Chunlei.Experimental study on engineering characteristics of loess landslide slip zone[D].Xi'an:Chang'an University,2008