Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimati...Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.展开更多
A colluvial landslide in a debris flow valley is a typical phenomena and is easily influenced by rainfall. The direct destructiveness of this kind of landslide is small, however, if failure occurs the resulting blocki...A colluvial landslide in a debris flow valley is a typical phenomena and is easily influenced by rainfall. The direct destructiveness of this kind of landslide is small, however, if failure occurs the resulting blocking of the channel may lead to a series of magnified secondary hazards. For this reason it is important to investigate the potential response of this type of landslide to rainfall. In the present paper, the Goulingping landslide, one of the colluvial landslides in the Goulingping valley in the middle of the Bailong River catchment in Gansu Province, China, was chosen for the study. Electrical Resistivity Tomography(ERT), Terrestrial Laser Scanning(TLS), together with traditional monitoring methods, were used to monitor changes in water content and the deformation of the landslide caused by rainfall. ERT was used to detect changes in soil water content induced by rainfall. The most significant findings were as follows:(1) the water content in the centralupper part(0~41 m) of the landslide was greaterthan in the central-front part(41~84 m) and(2) there was a relatively high resistivity zone at depth within the sliding zone. The deformation characteristics at the surface of the landslide were monitored by TLS and the results revealed that rainstorms caused three types of deformation and failure:(1) gully erosion at the slope surface;(2) shallow sliding failure;(3) and slope foot erosion. Subsequent monitoring of continuous changes in pore-water pressure, soil pressure and displacement(using traditional methods) indicated that long duration light rainfall(average 2.22 mm/d) caused the entire landslide to enter a state of creeping deformation at the beginning of the rainy season. Shear-induced dilation occurred for the fast sliding(30.09 mm/d) during the critical failure sub-phase(EF). Pore-water pressure in the sliding zone was affected by rainfall. In addition, the sliding L1 parts of the landslide exerted a discontinuous pressure on the L2 part. Through the monitoring and analysis, we conclude that this kind of landslide may have large deformation at the beginning and the late of the rainy season.展开更多
基金Supported by Tianjin Land Subsidence Controlling Office(No.kJ/095).
文摘Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.
基金funded by International S&T Cooperation Program of China (ISTCP) (Grant No. 2013DFE23030)the Fundamental Research Funds for the Central Universities (Grant No. lzujbky-2014-273 and lzujbky-2015-133)
文摘A colluvial landslide in a debris flow valley is a typical phenomena and is easily influenced by rainfall. The direct destructiveness of this kind of landslide is small, however, if failure occurs the resulting blocking of the channel may lead to a series of magnified secondary hazards. For this reason it is important to investigate the potential response of this type of landslide to rainfall. In the present paper, the Goulingping landslide, one of the colluvial landslides in the Goulingping valley in the middle of the Bailong River catchment in Gansu Province, China, was chosen for the study. Electrical Resistivity Tomography(ERT), Terrestrial Laser Scanning(TLS), together with traditional monitoring methods, were used to monitor changes in water content and the deformation of the landslide caused by rainfall. ERT was used to detect changes in soil water content induced by rainfall. The most significant findings were as follows:(1) the water content in the centralupper part(0~41 m) of the landslide was greaterthan in the central-front part(41~84 m) and(2) there was a relatively high resistivity zone at depth within the sliding zone. The deformation characteristics at the surface of the landslide were monitored by TLS and the results revealed that rainstorms caused three types of deformation and failure:(1) gully erosion at the slope surface;(2) shallow sliding failure;(3) and slope foot erosion. Subsequent monitoring of continuous changes in pore-water pressure, soil pressure and displacement(using traditional methods) indicated that long duration light rainfall(average 2.22 mm/d) caused the entire landslide to enter a state of creeping deformation at the beginning of the rainy season. Shear-induced dilation occurred for the fast sliding(30.09 mm/d) during the critical failure sub-phase(EF). Pore-water pressure in the sliding zone was affected by rainfall. In addition, the sliding L1 parts of the landslide exerted a discontinuous pressure on the L2 part. Through the monitoring and analysis, we conclude that this kind of landslide may have large deformation at the beginning and the late of the rainy season.
