Deformation properties of diaphragm wall due to deep foundation pit of subway station in Ningbo soft soil
According to the field measured data of a deep foundation pit of subway station of Ningbo rail transit, the paper studies the varieties of deformation rate and cumulative deformation along with excavation time, and estimates the proportion of deformation under different construction phases based on 450 monitoring data of 4 deep foundation pits. The result shows that the main deformation of diaphragm wall due to deep foundation pit of subway station in Ningbo soft soil happens in the third and the forth phases, and these two conditions should be the key point of hierarchical control.
Characteristics of ground surface settlement during excavation
The objective of this paper is to study the characteristics of ground surface settlement during excavation. Ten excavation cases in Taipei with good-quality construction and field observation data are selected to study the characteristics of excavation behavior. The location of maximum lateral wall deflection, magnitude of maximum lateral wall deflection, relationship of maximum lateral wall deflection and maximum ground surface settlement, location of maximum ground surface settlement, and apparent influence range are thus established based on the actual excavation cases. Finally, an empirical formula is proposed to predict the ground surface settlement profile at the center section of an excavation, where the behavior may be characterized by plane-strain conditions. Key words : excavation, surfac settlement, wall deflection, plane strain, empirical formula.
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.