Analysis of chemo-mechanical behavior of silty soil under long-term immersion in saline reservoir water

2020 ◽  
Vol 80 (1) ◽  
pp. 627-640
Author(s):  
Chunye Ying ◽  
Xinli Hu ◽  
Chang Zhou ◽  
Sumi Siddiqua ◽  
Gehad Mohamed Hossam Makeen ◽  
...  
2021 ◽  
Vol 13 (2) ◽  
pp. 224
Author(s):  
Xin Liang ◽  
Lei Gui ◽  
Wei Wang ◽  
Juan Du ◽  
Fei Ma ◽  
...  

Since the impoundment of the Three Gorges Reservoir (TGR) in June 2003, the fluctuation of the reservoir water level coupled with rainfall has resulted in more than 2500 landslides in this region. Among these instability problems, most colluvial landslides exhibit slow-moving patterns and pose a significant threat to local people and channel navigation. Advanced monitoring techniques are therefore implemented to investigate landslide deformation and provide insights for the subsequent countermeasures. In this study, the development pattern of a large colluvial landslide, locally named the Ganjingzi landslide, is analyzed on the basis of long-term monitoring. To understand the kinematic characteristics of the landslide, an integrated analysis based on real-time and multi-source monitoring, including the global navigation satellite system (GNSS), crackmeters, inclinometers, and piezometers, was conducted. The results indicate that the Ganjingzi landslide exhibits a time-variable response to the reservoir water fluctuation and rainfall. According to the supplement of community-based monitoring, the evolution of the landslide consists of three stages, namely the stable stage before reservoir impoundment, the initial movement stage of retrogressive failure, and the shallow movement stage with stepwise acceleration. The latter two stages are sensitive to the drawdown of reservoir water level and rainfall infiltration, respectively. All of the monitoring approaches used in this study are significant for understanding the time-variable pattern of colluvial landslides and are essential for landslide mechanism analysis and early warning for risk mitigation.


Author(s):  
Peizhao Chen ◽  
Shibin Tang ◽  
Xin Liang ◽  
Yongjun Zhang ◽  
Chunan Tang

2005 ◽  
Vol 278 (1-2) ◽  
pp. 315-325 ◽  
Author(s):  
B. Ludwig ◽  
M. Helfrich ◽  
H. Flessa
Keyword(s):  

2021 ◽  
Vol 8 ◽  
Author(s):  
Ghita Kadri ◽  
Loubna Bahije ◽  
Saloua Berrada

Background: The implant-supported removable partial denture appears to be an interesting alternative for cases where the implant-supported fixed prosthesis is contraindicated whether it is for medical, local, or financial reasons. The objective of this systematic review is to evaluate the biological and mechanical behavior of the implant under a removable partial denture.Methods: A literature search was conducted on the following databases: Pubmed [Medline], Science Direct, and Cochrane Library. Research was limited to publications in English and French during the period from 01/1/2007 to 27/03/2020.Results: Of the 334 citations initially identified, 22 articles met our inclusion criteria, assessing the implant survival rate, patient satisfaction, and the occurrence of implant and prosthetic complications. As well as the evaluation of the stress distribution on the three support surfaces of this prosthesis. Finally, the evaluation of implant localization. The results showed a high rate of implant survival, the occurrence of some prosthetic complications. Stable and acceptable bone resorption over the long term. Better stress distribution at the implant and the bone.Conclusion: The biological and mechanical behavior of the implant under this type of prosthesis appears to be viable in the short, medium, and long term. Although this association between implantology and partial prosthesis seems promising, additional studies are needed to spread this practice still reserved for some specific cases.


2018 ◽  
Vol 23 (5) ◽  
pp. 841-848 ◽  
Author(s):  
William Bonino Rauen ◽  
Ana Camila Ferraresi ◽  
Leila Maranho ◽  
Edinalva Oliveira ◽  
Rudhy Costa ◽  
...  

ABSTRACT The Passaúna catchment is part of the Upper Iguaçu watershed and includes a water supply reservoir for over 500,000 inhabitants of Curitiba metropolitan region. The aim of this study was to establish the state of reservoir water quality, and whether it has undergone any recent medium- and long-term variations. A physical-chemical-biological assessment was undertaken using nine indicators and three indexes: Water Quality Index (WQI), Trophic State Index (TSI) and Shannon-Weaver Index (H’) for macroinvertebrate diversity. Compliance with the prescribed quality standards for the water body was verified using frequency curves. Two WQI calculation approaches were contrasted to test for conditions of partial data unavailability. Temporal trends in key parameters were assessed using Spearman’s rank correlation coefficient. WQI results from 1991-2014 indicated that the water quality may be classified as good and improved in the final decade of such period, while most TSI results were in the oligotrophic/mesotrophic range, but with no significant temporal trend. The biodiversity result of H’=1.6 obtained with data acquired in 2014 indicated a moderately degraded ecosystem that is typically associated with flow regulation and a degree of water quality impairment. Such a multi-indicator integrated physical-chemical-biological monitoring approach comprised a robust framework for assessments of medium-long term aquatic health.


Author(s):  
Norman L. Hecht ◽  
Hongsang Rho ◽  
Nora R. Osborne ◽  
Dale E. McCullum ◽  
Steven M. Goodrich

This paper presents the results of a long term program initiated in December of 1984 to investigate the effects of environment (temperature, atmosphere, and stress) on the mechanical behavior of eight Si3N4 and three SiC ceramics being considered for heat engine applications. Microstructure, chemistry, and physical properties were determined. The mechanical behavior of these materials was investigated from room temperature to 1400°C by employing tests for flexural and tensile strength, dynamic, static and cyclic fatigue, and fracture toughness. The results obtained from these evaluations showed that the thermal mechanical behavior was quite varied, depending on the composition and processing methods employed. Batch to batch differences were also found to cause variances in the property values measured. Insights gained from this work about the failure mechanisms and potential service life are also discussed.


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