Numerical Analysis of Dry Excavation Using a Tie Back Wall Under Static and Dynamic Load
Deep excavations are common in urban areas, nearby existing constructions. The support systems have the main function of preserve the stability and control soil displacements close to the excavation. Settlement control of nearby structures is an essential aspect during design and construction. Settlements prediction is usually made by empirical methods and in some cases also by numerical modeling. The paper presents a numerical modeling of a dry excavation by Plaxis program. The program allows the prediction of stress and deformation behavior of different geotechnical constructions using the Finite Element Method. The excavation has been modeled in five stages, in order to reproduce the construction phases. The numerical modeling was capable to reproduce satisfactorily the horizontal profile of the displacements of the diaphragm wall. In relation to settlements, the shape of the settlement profile was quite similar
GROUND MOVEMENTS CAUSED BY BRACED EXCAVATIONS
The causes and patterns of ground movement associated with braced excavations are examined. Field measurements of displacements for braced cuts in sand and soft to medium clay show a relationship between the deflection of the excavation wall and the ratio of horizontal to vertical movement adjoining the cut. A review of various case histories indicates that soil displacement depends strongly on the construction process. Practices are recommended for promoting a stiff bracing system, excavating beneath the lowest braces, and using berms to restrain ground movement.
Time and Heritage
As a historian studying what can be considered a form of intellectual history, I have slowly come to adopt Michel de Certeau’s observation made at the end of the 1980s that ‘objectifying the past, for the last three centuries, has undoubtedly left unconsidered time within a discipline that has continued to use it as a taxonomic instrument’. To a certain degree, time has become commonplace for the historian who has preserved or instrumentalized it. It is not considered because it is inconceivable, but because we do not think of it or, more simply, we do not think about it. As a historian attempting to pay attention to the time I’m living in, I have thus, like many others, noticed the swift development of the category of the present until it has become obvious that the present is omnipresent. This is what I refer to here as ‘presentism’.