STS

CDD Win is a programme specifically developed by STS for the stability calculation of general slopes according to the methods of Bell, Bishop, Jambu , Morgestern-Price, Sarma and Spencer.‎ The programme also verifies the slope according to several theories at the same time, thus enabling comparative analysis of the results.‎ It is also possible to perform a dynamic slope calculation.‎ For this purpose, a new input phase was specially created for importing natural accelerograms according to different formats: SIMQ, REXEL or EXCEL with tags.‎ This new phase is also equipped with a procedure for generating spectro-compatible synthetic accelerograms, which are, however, only to be used for testing and/or study purposes, since the NTC explicitly prohibits the use of artificial accelerograms for professional purposes.‎ Simplified dynamic analysis, also known as seismic analysis using the displacement method, is provided for by current Italian regulations and allows the displacements that a slope may undergo under seismic action to be determined.‎ The simplified dynamic analysis also makes it possible to calculate the time-history of the slope, considering the mass in potential landslide as a rigid body sliding along a circular surface, subjected to a design accelerogram.‎ The determination of the safety coefficient is conducted either for polygonal or circular sliding surfaces for three known points, set by the designer, or among a series of possible circular failure surfaces.‎ In the latter case, once the grid of centres has been defined, which may have a completely generic position, the programme automatically generates all the circular sliding surfaces tangent to a segment or passing through a predetermined point.‎