GGU-RETAIN: "Embedment depth via:" group box (Analyse)¶
In the "Embedment depth via" group box of the start dialog box of the "System/Analyse" menu item you can define the method of calculation for the embedment depth. If you prefer to use another than the default method to determine the embedment depth, use the "Select method" button. The following dialog box opens:
If you select one of the options using fixed section lengths "Fixed section length" appears in the start dialog box instead of the degree of fixity; you must enter the value, you require.
You can choose between Blum's method or the subgrade reaction modulus method for the calculation. For soldier pile walls and bored soldier pile walls you also have the option of calculating according to the p-y method.
Where a bedded toe is used, the subgrade reaction can be reduced using the partial factor gamma(Ep) by activating the check box. The reduction can be made using characteristic values to DIN 1054, GL. (47) and (48). If the "Reduce subgrade with gamma(Ep)" check box is not activated, the subgrade reaction can be taken into consideration in accordance with the EAB, R 102.
Using soldier pile walls or bored soldier pile walls the "Subgrade on continuous wall" check box appears additionally. If the check box is deactivated, the subgrade will be adopted for the girder width.
The check box applies to the analysis with a bedded toe and defines the width on which the modulus of subgrade reaction ks acts below the excavation base. With a as the girder spacing and b as the girder width:
| Check box activated (default) | Check box deactivated | |
|---|---|---|
| Subgrade acts on | the continuous wall, i.e. on the girder spacing a per girder | the girder width b only |
| Subgrade stiffness per girder and metre of depth | ks · a | ks · b |
The subgrade stiffness therefore differs by the factor a/b. With a girder spacing of 3.0 m and a girder width of 0.3 m, the subgrade is 10 times softer when the check box is deactivated. The wall then deforms considerably more, and the calculated embedment depth may increase.
The passive earth pressure that limits the subgrade reaction does not depend on the check box: per girder, both settings give the same values. How it is determined (passive earth pressure in front of the individual girder or on the continuous wall, the smaller value governs) is described under Passive earth pressure. Only the reference width of the passive earth pressure stresses in the output differs:
- Check box activated: per 1 m of wall length.
- Check box deactivated: per girder width. In addition, each line is marked: (*) means "Three-dimensional passive ep is governing", (+) means "Passive ep on continuous wall is governing".
In the results, the sum of the passive earth pressure Eph,k is given per girder in kN in both cases.