An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China
Chinese Loess Plateau (CLP) has become one of the high-incidence areas of landslide disasters in China, especially at the edge of the tablelands where irrigation has been practiced at a large scale since the 1960s. Heifangtai tableland, located in the CLP in Yongjing County, Gansu Province, has been...
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Wiley
2020-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2020/8850381 |
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| author | Tianfeng Gu Pingping Sun Jiading Wang Herry Lin Yuanjun Xu Jiaxu Kong Bin Sun |
| author_facet | Tianfeng Gu Pingping Sun Jiading Wang Herry Lin Yuanjun Xu Jiaxu Kong Bin Sun |
| author_sort | Tianfeng Gu |
| collection | DOAJ |
| description | Chinese Loess Plateau (CLP) has become one of the high-incidence areas of landslide disasters in China, especially at the edge of the tablelands where irrigation has been practiced at a large scale since the 1960s. Heifangtai tableland, located in the CLP in Yongjing County, Gansu Province, has been selected as a case, where more than 90 slidings occurred in the past three decades. Field monitoring and laboratory tests were conducted to obtain the soil-water characteristic curve, unsaturated soil shear strength, irrigation water infiltration, and the groundwater level change. Based on these results, a three-dimensional numerical model of the slope was established, and the change of seepage field and slope stability before and after irrigation was investigated using simulations and compared with the observed data. The results show that flood irrigation raised the water table, and the increase of soil moisture in the flooded area was more significant than that in the nonirrigated area. The rising speed of the groundwater level was about 0.25 m/yr, with an amplitude of 0.5 m. Near the slope, the hydraulic gradient of the concave slope was steeper than the convex slope. The shear strength of the loess decreased with increasing soil moisture, and the tensile strength was about 15% of the cohesion. Numerical results showed that after three years of continuous flood irrigation at the back of the slope, the slope stability coefficient decreased by 0.12. After irrigation, the potential slip zone slightly expanded. The reason why landslides often occurred at the back of the gully or the landslide was that the water table was shallower on concave slopes and the soil moisture of the concave slopes was more susceptible to irrigation. |
| format | Article |
| id | doaj-art-d985ee506a8146e58835b0e9105fb5f1 |
| institution | Kabale University |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
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| series | Advances in Civil Engineering |
| spelling | doaj-art-d985ee506a8146e58835b0e9105fb5f12025-02-03T01:04:28ZengWileyAdvances in Civil Engineering1687-80861687-80942020-01-01202010.1155/2020/88503818850381An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern ChinaTianfeng Gu0Pingping Sun1Jiading Wang2Herry Lin3Yuanjun Xu4Jiaxu Kong5Bin Sun6State Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi’an, Shaanxi 710069, ChinaXi’an Center of Geological Survey, China Geological Survey, Xi’an, Shaanxi 710054, ChinaState Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi’an, Shaanxi 710069, ChinaDepartment of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, USAState Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi’an, Shaanxi 710069, ChinaState Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi’an, Shaanxi 710069, ChinaState Key Laboratory of Continental Dynamics/Department of Geology, Northwest University, Xi’an, Shaanxi 710069, ChinaChinese Loess Plateau (CLP) has become one of the high-incidence areas of landslide disasters in China, especially at the edge of the tablelands where irrigation has been practiced at a large scale since the 1960s. Heifangtai tableland, located in the CLP in Yongjing County, Gansu Province, has been selected as a case, where more than 90 slidings occurred in the past three decades. Field monitoring and laboratory tests were conducted to obtain the soil-water characteristic curve, unsaturated soil shear strength, irrigation water infiltration, and the groundwater level change. Based on these results, a three-dimensional numerical model of the slope was established, and the change of seepage field and slope stability before and after irrigation was investigated using simulations and compared with the observed data. The results show that flood irrigation raised the water table, and the increase of soil moisture in the flooded area was more significant than that in the nonirrigated area. The rising speed of the groundwater level was about 0.25 m/yr, with an amplitude of 0.5 m. Near the slope, the hydraulic gradient of the concave slope was steeper than the convex slope. The shear strength of the loess decreased with increasing soil moisture, and the tensile strength was about 15% of the cohesion. Numerical results showed that after three years of continuous flood irrigation at the back of the slope, the slope stability coefficient decreased by 0.12. After irrigation, the potential slip zone slightly expanded. The reason why landslides often occurred at the back of the gully or the landslide was that the water table was shallower on concave slopes and the soil moisture of the concave slopes was more susceptible to irrigation.http://dx.doi.org/10.1155/2020/8850381 |
| spellingShingle | Tianfeng Gu Pingping Sun Jiading Wang Herry Lin Yuanjun Xu Jiaxu Kong Bin Sun An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China Advances in Civil Engineering |
| title | An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China |
| title_full | An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China |
| title_fullStr | An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China |
| title_full_unstemmed | An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China |
| title_short | An Experimental and Numerical Study of Landslides Triggered by Agricultural Irrigation in Northwestern China |
| title_sort | experimental and numerical study of landslides triggered by agricultural irrigation in northwestern china |
| url | http://dx.doi.org/10.1155/2020/8850381 |
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