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## Computation |

Choose the analysis conditions in the right panel.

In case of bound computation insert the required data in the right panel.

Computation methods

Choose a method to use for the computation: Fellenius, Bishop, Janbu, etc. For further information on the computation methods see also Computation methods.

Back Analysis

Runs the back analysis using the Janbu method. This type of analysis can be performed only for homogenous soils and for generic sliding surfaces assigned by the user. The execution of the computation returns a diagram in which cohesion and internal friction angle are reported such as to provide a safety factor equal to 1.

Perform analysis

Command that performs the calculation of stability with the method chosen by the user.

Recompute

Command that performs the calculation of the safety factor relative to a circular sliding surface already examined. To use this option, proceed as follows:

1. Choose the command Recompute from Computation menu (or click with the mouse on the Recalculate button in the right panel, or right click on the work area and choose Recompute).

2. Insert the coordinates X0, Y0 of the center and the value of the radius of the surface (confirm each inserted value with Enter).

3. Confirming with the Enter key the software performs the computation and shows the safety factor and the geometrical data of the examined surface.

Pilings

When selecting this command a new window opens in which, for each analyzed surface is shown the insertion position of the pile, the horizontal limit load and the segment of the pile on which it is evaluated the reaction of the resistant soil with the formation of a plastic hinge at the point of intersection of the sliding surface with the pile. Obviously, such information is offered by the program only in the case where, in the definition of pilings, has been chosen as a stabilization method the limit load method of Broms or T. Ito & T. Matsui.

Dynamic Analysis

This command performs the computation in dynamic conditions. For the start of the module QSIM it is necessary to perform a first analysis under pseudo-static conditions, and, once found the surface to be examined or that with the lower safety factor found by the program, execute the command.

The opening of a dialog box will allow the user to import a design accelerogram or to generate it using the program.

The command Dynamic analysis starts the computation, scrolling through the calculation accelerogram, and calculates the displacements and the velocity of movement/displacement of the entire potentially instable mass.

Null displacements are associated with conditions of stability even in the presence of an earthquake that generates the considered accelerogram: in essence, the ground acceleration never exceeds the critical acceleration that triggers the movement. On the contrary, high displacements are indicative of the exceeding of mentioned acceleration, and so of unstable masses in the presence of an earthquake. For the theory used in the generation of the accelerogram you can see the help in the QSIM module.

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