scholarly journals Bank Protection Structures along the Brahmaputra-Jamuna River, a Study of Flow Slides

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2588 ◽  
Author(s):  
Maarten van der Wal
Keyword(s):  
Slope Failure ◽  
Research Question ◽  
Failure Mechanisms ◽  
Flood Plain ◽  
Design Guidelines ◽  
Test Facility ◽  
Training Structures ◽  
Bank Protection ◽  
Flow Slides ◽  
River Training

The planform of the Brahmaputra-Jamuna River followed its natural path in Bangladesh until the construction of bank protection works started to save Sirajganj from bank erosion since the 1930s. Several so-called hardpoints such as groynes and revetments were constructed in the period 1980–2015 and the Jamuna Multipurpose Bridge was opened in 1998. The Brahmaputra Right Embankment and other projects had saved the western flood plain from inundation during monsoon floods. These river training works experienced severe damage by geotechnical failures, mostly flow slides. A flow slide is an underwater slope failure because of liquefaction or a breaching process in the subsoil or a combination of both. The design of most of these training works did not consider the risk of damage by flow slides. All descriptions of the observed damages show that scour phenomena in the channel close to a river training work are a cause of flow slides, besides pore water outflow. The research question was: how can the design of river training works be improved to reduce the risk of damage by flow slides? The main part of the investigation was focussed on reducing local scour holes near river training works. The most promising results are river training works with gentle bank slopes, permeable groynes, bed protections in dredged trenches with gentle side slopes, and methods to increase locally the bearing capacity of the subsoil. It is recommended to increase the knowledge of the failure mechanisms in the Brahmaputra-Jamuna River by improved monitoring in the field, the setup of a database with descriptions of all observed flow slides and the circumstances in which they occur. In addition to these recommendations, a field test facility is proposed to verify the knowledge of the failure mechanisms in that river. These activities will optimise the design of new river training structures with a very low risk of damages by flow slides and geotechnical instabilities and they will contribute to an improvement of the current design guidelines for river training structures.

Performance of alternative methods of bank protection

1992 ◽  
Vol 19 (6) ◽  
pp. 1049-1061 ◽  
Author(s):  
P. F. Doyle
Keyword(s):  
Bank Erosion ◽  
Alternative Methods ◽  
Channel Stability ◽  
Severe Attack ◽  
Gravel Bed ◽  
Training Structures ◽  
Bank Protection ◽  
River Training ◽  
Riprap Protection ◽  
Large Floods

The durability of several common bank protection methods used as less expensive or environmentally acceptable alternatives to toe-trenched angular rock riprap has been documented during the 1980s at seven typical bank erosion sites in British Columbia. Since the sites were uncontrolled examples of actual river training works in operation, natural events hindered a precise comparison of each scheme with toe-trenched angular rock riprap protection. However, of the four alternatives investigated – gravel dykes, tree revetments, riprap with toe apron, and semi-round riprap – all but semi-round riprap performed less than satisfactorily over the years of observation. Documentation of performance is sufficient to conclude that on steep gravel-bed rivers, gravel dykes do not endure; tree revetments require constant maintenance and will not endure large floods, unless extremely well-constructed; toe aprons are not as reliable as toe trenches for the same volume of rock; and well-placed, large semi-round rock performs well under moderately severe attack. Key words: erosion, bank protection, channel stability, river training structures, gravel-bed.

Slope Failure Mechanisms due to Seepage: Three-Dimensional Soil Block Experiments

2008 ◽  
Author(s):  
Maria Chu-Agor ◽  
Rachel M Cancienne ◽  
Garey A Fox ◽  
Glenn V Wilson
Keyword(s):  
Slope Failure ◽  
Failure Mechanisms ◽  
Three Dimensional ◽  
Soil Block

Comparing Segmentation Approaches for Learning-Aware Wireframe Generation on Human Model

2020 ◽  
Author(s):  
Jida Huang ◽  
Tsz-Ho Kwok
Keyword(s):  
Human Body ◽  
Research Question ◽  
Automatic Segmentation ◽  
Design Guidelines ◽  
Learning Performance ◽  
Human Model ◽  
Human Body Model ◽  
Segmentation Methods ◽  
Definition Of ◽  
Semantic Parameters

Abstract Wireframe has been proved very useful for learning human body from semantic parameters. However, the definition of the wireframe is highly dependent on the anthropological experiences of experts in previous works. Hence it is usually not easy to obtain a well-defined wireframe for a new set of human models in the available database. To overcome such difficulty, an automated wireframe generation method would be very helpful in relieving the need for manual anthropometric definition. In order to find such an automated wireframe designing method, a natural way is using automatic segmentation methods to divide the human body model into small mesh patches. Nevertheless, different segmentation approaches could have various segmented patches, thus resulting in various wireframes. How these wireframes affect human body learning performance? In this paper, we attempt to answer this research question by comparing different segmentation methods. Different wireframes are generated with the mesh segmentation methods, and then we use these wireframes as an intermediate agent to learn the relationship between the human body mesh models and the semantic parameters. We compared the reconstruction accuracy with different generated wireframe sets and summarized several meaningful design guidelines for developing an automatic wireframe-aware segmentation method for human body learning.

Laboratory Facility for Testing Road Iron work Installations

1998 ◽  
Vol 1624 (1) ◽  
pp. 237-245 ◽  
Author(s):  
S. F. Brown ◽  
C. J. Brown
Keyword(s):  
Laboratory Test ◽  
Urban Areas ◽  
Failure Mechanisms ◽  
Test Facility ◽  
Bedding Material ◽  
Premature Failure ◽  
The United Kingdom ◽  
Laboratory Facility ◽  
High Incidence ◽  
Iron Work

The term “road ironwork” is used to refer to covers that are placed over manholes, drainage gullies, water valves, and the like. Such ironwork can be found in virtually all highways, especially in urban areas. Highway engineers have to deal with a high incidence of premature failure in these installations, the total costs of which are estimated to be £207 million (U.S. $338 million 1998) per year in the United Kingdom alone. These failures are generally characterized by gradual deterioration of the surrounding asphalt surfacing, associated with failure of the bedding material that supports the ironwork frame. The reasons for this high incidence of failure were investigated in a research project involving the construction of a full-scale laboratory test facility to simulate field conditions. This paper contains a description of the development of this apparatus. The results recorded from the apparatus were later used to identify the failure mechanisms that develop within road ironwork installations.

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