Review of Studies on Retaining Wall's Behavior on Dynamic / Seismic Condition
Current theories, experimental investigations and numerical findings for retaining walls subject to dynamic excitations are reviewed. Brief features of each method, and experimental and numerical methods are introduced and compared. Tables are listed after each section for a clear and brief view of methods in a categorized manner. Conclusive comments plus current concerns and future expectations of this area are made at last. This review aims at shedding light on the development and concepts of different researches in dynamic retaining wall design and analysis.
Effect of Counterforts and Buttresses on Retaining Wall using Finite Element Analysis
Retaining walls are used with tying with more than one wall at perpendicular joints to retain liquids, water storage and materials storages such as dyke walls and tanks. Retaining walls excessively used in culverts and as well as in the bridges i.e., construction of abutments, wing walls supposed to resist soil pressures, applied perpendicular to the axis of the walls. Due to in-sufficient land and based on the present construction scenario followed in the construction of retaining structures, the wall height is often increased, thereby increasing the cost of construction of sub structure. The values of the bending moment at the base increases due to the increase in the height of the wall resulting in higher sections which is uneconomical. The need of having safe and economical section shall be achieved by transforming the structural system of retaining wall i.e., by introducing supports to the vertical wall thus decreasing the thickness of stem. The design of rigid retaining wall either Cantilever or Counterfort or Buttress retaining wall is based on pressure exerted by the retaining material, wall slope, height, ease of construction and stability. When the retaining wall height is more than 8 m, the selection of extra supports i.e., either counterforts or buttresses is based upon the designer’s experience. By conducting comparative study on resisting forces for varying heights, the behaviour of these supports on retaining wall can be depicted. The depiction of forces can be achieved by running an analysis in STAAD.pro with preliminary dimensions and soil parameters respectively. Resisting forces from counterfort and buttress supports on retaining wall are equal when the height is in between 9 m to 24 m but buttress support has shown less resisting forces when the height is less than 9 m.
Archaeological Survey of Dangoyama Kofun by 3DGPR
We presented a three-dimensional ground penetrating radar (3DGPR) system for the archeological investigation in a harsh site, where we have to deal with many trees and/or great topographic variations. This system consists of a commercial GPR system with a laser positioning system. With this system, we can move the GPR antenna freely, on which a positioning detector can record accurate position for each GPR data trace. We applied our 3DGPR system at Dangoyama Kofun, a burial mound, in Fukushima prefecture, Japan. A lot of trees and bushes covered the survey area and cannot be cut. We acquired six datasets in two days in this area. We successfully imaged the boundary between the original surface of the burial mound and the covering soil clearly at about 0.3 m depth around the mound. Furthermore, we found some strong reflections appeared at 0.8 m depth in the top area of the mound, which can be from the artificial parts of the burial mound. The results would greatly aid the following archaeological excavation. In addition, we compared the non-interpolated depth slice with interpolated depth slice at same position and demonstrated that the interpolation process on threedimensional GPR data may introduce some artifacts which might mislead our interpretation.