A series of centrifuge model tests of geogrid-reinforced slopes with superstructure was conducted under differential settlement condition. The influence of reinforcement placement on the deformation and failure behavior of the slope and superstructure is investigated by considering different numbers of geogrid layers. The response of the slope and superstructure is analyzed based on a full-field displacement measurement via image analysis. The differential settlement induces distinguishable superstructure movement and slope deformation above the subsidence zone. The slope displacement, close to the vertical direction, appears only in a limited zone. An integrated analysis scheme of deformation and failure processes is adopted to reveal the failure mechanism of both the unreinforced and reinforced slopes: a certain level of deformation localization induced by differential settlement results in the local failure, and adversely, the local failure aggravates the deformation localization near it. The geogrid reinforcement mechanism is further clarified as the reduction on the deformation localization of the slope due to geogrid placement. The geogrid reinforcement effect can be comprehensively described with two respects: hooping effect and shielding effect, which illustrates the influence sphere and degree of geogrid reinforcement on restraining the slope deformation. The geogrid reinforcement is proven effective to improve the safety of the slope and superstructure.
Precipitation is an important component of global water and energy transport and a major aspect of climate change. Due to the scarcity of meteorological observations, the precipitation climate over Tibet has been insufficiently documented. In this study, the distribution of precipitation during the rainy season over Tibet from 1980 to 2013 is described on monthly to annual time scales with meteorological observations. Furthermore, four precipitation products are compared to observations over Tibet. These datasets include products derived from the Asian Precipitation-Highly-Resolved Observational Data(APHRO), the Global Precipitation Climatology Centre(GPCC), the University of Delaware(UDel), and the China Meteorological Administration(CMA). The error, relative error, standard deviation, root-mean-square error, correlations and trends between these products for the same period are analyzed with in situ precipitation during the rainy season from May to September. The results indicate that these datasets can broadly capture the temporal and spatial precipitation distribution over Tibet. The precipitation gradually increases from northwest to southeast. The spatial precipitation in GPCC and CMA are similar and positively correlated to observations. Areas with the largest deviations are located in southwestern Tibet along the Himalayas. The APHRO product underestimates, while the UDel, GPCC, and CMA datasets overestimates precipitation on the basis of monthly and inter-annual variation. The biases in GPCC and CMA are smaller than those in APHRO and UDel with a mean relative error lower than 10% during the same periods. The linear trend of precipitation indicates that the increase in precipitation has accelerated extensively during the last 30 years in most regions of Tibet. The CMA generally achieves the best performance of these four precipitation products. Data uncertainty in Tibet might be caused by the low density of stations, complex topography between the grid points and stations, and the interpolation methods, which can also produce an obvious difference between the gridded data and observations. 相似文献
