Probit Analysis of Landslide Dam Stability in Italy

Author(s):  
Kenneth H. Tiedemann
2021 ◽  
Vol 9 ◽  
Author(s):  
Hongchao Zheng ◽  
Zhenming Shi ◽  
Danyi Shen ◽  
Ming Peng ◽  
Kevin J. Hanley ◽  
...  

Numerous landslide dams have been induced in recent years as a result of frequent earthquakes and extreme climate hazards. Landslide dams present serious threats to lives and properties downstream due to potentially breaching floods from the impounded lakes. To investigate the factors influencing the stability of landslide dams, a large database has been established based on an in-depth investigation of 1,737 landslide dam cases. The effects of triggers, dam materials, and geomorphic characteristics of landslide dams on dam stability are comprehensively analyzed. Various evaluation indexes of landslide dam stability are assessed based on this database, and stability evaluation can be further improved by considering the dam materials. Stability analyses of aftershocks, surges, and artificial engineering measures on landslide dams are summarized. Overtopping and seepage failures are the most common failure modes of landslide dams. The failure processes and mechanisms of landslide dams caused by overtopping and seepage are reviewed from the perspective of model experiments and numerical analyses. Finally, the research gaps are highlighted, and pathways to achieve a more complete understanding of landslide dam stability are suggested. This comprehensive review of the recent advances in stability and failure mechanisms of landslide dams can serve as a key reference for stability prediction and emergency risk mitigation.


2021 ◽  
Author(s):  
Xi Xiong ◽  
Tatsunori Matsumoto ◽  
Zhenming Shi ◽  
Feng Zhang

Abstract Landslide dams (LDs) usually form from natural debris materials and exhibit heterogeneous strata along both the depth and run-out directions. In addition, an LD usually has a weaker structure than that of undisturbed ground and is more vulnerable to seepage loading. Considering that the surface layer of naturally packed LD materials is generally in an unsaturated state, it is undoubtedly important to investigate the stability of the unsaturated debris materials in the heterogeneous strata of LDs. In this paper, a systematic flume test program was first conducted, in which the Tangjiashan LD was carefully referenced for model design. Three water level rising rates and two stratal arrangements were considered in the flume tests. Then, soil-water-air coupled finite element analyses were conducted to simulate the flume tests, and all the material parameters of the LD materials were carefully determined based on the results of the element tests. A comparison of the test and calculated results shows the possibility of using the proposed numerical method to estimate the occurrence of dam breaching and the risk of LD failure. Moreover, the hydraulic/mechanical behaviors of the LD materials and the heterogeneous strata of the LD were very important to the stability of the Tangjiashan LD. Finally, from an engineering viewpoint, the possibility of utilizing a naturally formed LD and thus not destroying it when it forms is also discussed, e.g., dam breaching risk can be reduced by excavation of a drainage tunnel, and the dam stability can be carefully estimated based on accurate geological data.


Author(s):  
E. K. Rakhmatullin ◽  
O. D. Sklyarov

The article presents the results of a study of the "Bisolbi" drug toxicity (powder of light ash color, poorly soluble in water). When it is mixed with water it forms a suspension of particles that settle rapidly. Values of acute drug toxicity were determined on rats. We studied groups of six animals of the same sex, as well as similar control ones. The "Bisolbi" drug was injected to white rats intragastrically, males weighing 310 ... 320 g in doses of 2500 and 2740 mg / kg. Each dose was used in six animals; distilled water (3 ml) was used for the controls. The LD50 was calculated by the probit analysis method proposed by Litchfield and Wilcoxon modified by Z. Roth. When administered orally, an atraumatic metal probe was immersed in the stomach. Within 14 days monitored the overall health status and behavior of animals, the manifestation or absence of symptoms of intoxication; noted the features of feed and water ingestion, assessed the condition of the coat, physiological functions. Then groups of experimental rats were euthanized and pathomorphologically examined. We studied the effect of "Bisolbi" with repeated introduction and on not purebred dogs. Two groups of 3-4 years of age were completed with an average initial body weight of 13.63 ... 15.11 kg. Before use, the additive was thoroughly mixed with feed. The drug was injected during 31 days at a dose of 0.5 g / kg. Dogs of the control group (three) were fed wheat flour. After 15 and 31 days in laboratory animals in order to characterize the general condition in the blood, the amount of protein, urea, glucose, creatinine, cholesterol were determined. Based on studies it was found that the drug daily application by animals, is low toxic and safe, does not provoke the development of pathological reactions. According to the Hodge and Sterner classification "Bisolbi" can be attributed to the 6th class of toxicity - relatively harmless. Accordingto GOST 12.1.007-76 LD50 of the drug is more than 151 mg / kg, but less than 5000 mg / kg it is the 3rd hazard class (moderately hazardous).


Author(s):  
Shoki TAKAYAMA ◽  
Hiroki HOSHIYAMA ◽  
Shusuke MIYATA ◽  
Masamitsu FUJIMOTO ◽  
Yoshifumi SATOFUKA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaiheng Hu ◽  
Chaohua Wu ◽  
Li Wei ◽  
Xiaopeng Zhang ◽  
Qiyuan Zhang ◽  
...  

AbstractLandslide dam outburst floods have a significant impact on landform evolution in high mountainous areas. Historic landslide dams on the Yigong River, southeastern Tibet, generated two outburst superfloods > 105 m3/s in 1902 and 2000 AD. One of the slackwater deposits, which was newly found immediately downstream of the historic dams, has been dated to 7 ka BP. The one-dimensional backwater stepwise method gives an estimate of 225,000 m3/s for the peak flow related to the paleo-stage indicator of 7 ka BP. The recurrence of at least three large landslide dam impoundments and super-outburst floods at the exit of Yigong Lake during the Holocene greatly changed the morphology of the Yigong River. More than 0.26 billion m3 of sediment has been aggraded in the dammed lake while the landslide sediment doubles the channel slope behind the dam. Repeated landslide damming may be a persistent source of outburst floods and impede the upstream migration of river knickpoints in the southeastern margin of Tibet.


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