The 2015 catastrophic landslide in a 110-m-high waste dump in Shenzhen is recognized as one of the largest landfill failure worldwide. An earlier comprehensive field investigation revealed that the dominant component of the fill was completely decomposed granite (CDG), and the dumping operation was accompanied by a rise of the groundwater level. In this paper, the complex stress paths for the initially unsaturated fill materials being subjected to both rapid filling and wetting were investigated. A simplified method was proposed for estimating the gain of undrained shear strength under the complex stress paths. Soil samples were taken from the site to a laboratory to measure the undrained shear strength and validate the estimation method. Total stress-based stability analyses were carried out to calculate the factor of safety of the dump at failure. The triggering mechanism of the landslide is clarified as follows: The gain of shear strength with the surcharge loading for the wet layer in the lower part of the waste dump was limited by a build-up of excess pore-water pressure. The gain of shear strength for the relatively dry fill material was attenuated with the rise of groundwater level. When the shear strength was not enough to resist the increasing slip force with the surcharge loading, a deep-seated translational failure took place in the lower wet layer of the waste dump. The proposed method for analyses of undrained strength and slope stability are proven to be applicable to the waste-dumping operation with rapid filling and rising groundwater level.
A statistic analysis has been conducted of the climatological features of Northwest Pacific typhoons over the past 50 years based on historical record from 1949 to 1996. The objects of study include theannual variation, distribution by season and intensity, and category of motion. Additional investigation is made ofhow the typhoon varies in terms of the geographic location of generation and the relationship between the intensity and the source area. It is revealed that most of the strong typhoons originate over waters east of 125°E with the strongest group coming from the Mariana Is. Besides, distribution of landing typhoons is given with respect toseason and latitude. Statistics of central pressure at the point of landfall suggests that typhoons making landfallson the provinces of Zhejiang and Fujian are less frequent than in south China but have relatively high intensity. 相似文献