Nails and anchors¶
The Anchors section defines the nail (the cemented passive bar) and how it is laid out on the slope. You can start from a commercial catalog or enter the parameters manually.
Nail catalog¶
The Nail catalog field lists the available catalogs; selecting one reveals the Nail type field with the list of bars in that catalog, each with its own diameter. The default catalog collects bar and anchor systems for nailed mesh, in two families:
- GEWI — solid threaded bar, B500B steel.
- TITAN — hollow self-drilling bar, with outer and inner diameter, designed for loose soils or fractured rock where conventional drilling is difficult.
Choosing a nail from the catalog, SRS automatically fills the bar diameter φ_b, the yield strength f_yk and the bar type (later shown in the report). You can still correct the values manually after selecting.
Selecting -- Manual parameters -- in the Nail catalog field leaves all fields freely editable: use it for bars not in the catalog, or to check a solution already defined elsewhere.
Bar and drilling parameters¶
| Symbol | Parameter | Unit |
|---|---|---|
| — | Bar type (free description, e.g. B500) | — |
| I.18 φ_b | Bar diameter | mm |
| I.19 f_yk | Bar yield strength | N/mm² |
| I.17 D_f | Drilling diameter | mm |
| I.16 L_a | Anchor length | m |
| I.15 β | Anchor inclination from horizontal | ° |
Layout on the slope¶
| Symbol | Parameter | Unit |
|---|---|---|
| I.13 i_y | Vertical grid spacing | m |
| I.14 i_x | Horizontal grid spacing | m |
A tighter grid (smaller i_x, i_y) increases the number of anchors per
100 m² but reduces the tension required from each, because every nail
restrains a smaller overburden wedge (V = i_x · i_y · S). See
Design checks.
Layout scheme¶
In plan the anchors are arranged on a grid with spacing i_x (horizontal) and i_y (along the slope), either staggered (diamond pattern, left) or on a rectangular grid (right):
Grouting mortar¶
| Symbol | Parameter | Unit |
|---|---|---|
| I.20 R_ck (NTC) / f_ck (Eurocode) | Mortar compressive strength | N/mm² |
| I.21 η₁ | Bond coefficient | — |
| I.22 N_prof | Number of geotechnical investigation profiles | — |
With design code NTC 2018 enter the cubic strength R_ck; with Eurocode the field becomes f_ck (cylindrical strength, already direct — no 0.83 conversion). The η₁ coefficient is 1.00 for good bar-mortar bond or 0.70 for poor bond (less favourable casting conditions). N_prof (1 to "≥ 5") is the number of geotechnical investigation verticals available in the area: the more there are, the lower the reduction coefficient ξ_a4 applied to the bulb pull-out resistance (see Design checks).
Design code and partial factors¶
The Design code field, at the top of the Professional Data and Project section, selects the set of partial factors used in every check:
| Design code | γ_s (steel) | γ_Rap (anchors) | γ_Q1 static | γ_Q1 seismic | γ_c (mortar) | R_ck→f_ck |
|---|---|---|---|---|---|---|
| Eurocode 7/8 (EN 1997 + EN 1998, DA1-C2) | 1.15 | 1.10 | 1.5 | 1.0 | 1.5 | 1.0 |
| NTC 2018 | 1.15 | 1.20 | 1.5 | 1.0 | 1.5 | 0.83 |
| User | customisable | customisable | customisable | customisable | customisable | customisable |
Selecting User shows a panel with the six coefficients, all editable: use it for codes other than NTC 2018 and Eurocode, or for sensitivity studies.
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