# Main Results

## Consistency of the Experimental Loads

The following values of F_{el-maxBB} were measured: 31.78; 29.61; 37.69 kN (mean value: F_{el-max BB} = 33.03 kN). Thus, calculations lead to: F_{pre}__{cracking} = 39.63 kN and F_{creep} = 19.81 kN.

A comparative study was carried out to check if these loading rates are consistent with what could be observed in a tunnel project. To do so, structural analysis using Navier’s solution and a yield line analysis were carried out on the slab used in the creep test. They led to mean bending moments of M_{pre-cracking} = 6.10 kN m/m and M_{creep} = 3.06 kN m/m. Then, these results were compared to those of a finite element model corresponding to the detailed design of a 2D-section of the Saint-Beat Tunnel with a layer of 10 cm of FRSC and steel arches spaced at 1.5 m intervals. The corresponding geological model is mostly composed of limestone (RMR IV according to the AFTES classification) modeled with a Mohr-Coulomb constitutive law, the parameters of which are у = 26 kN/m^{3}, c = 150 kPa, u = 35°, E = 1 GPa and *t* = 0.3. The medium depth of the tunnel is about 120 m and the deconfinement rate is estimated at 20 % (k = 0.80). After de-homogenisation, the results in terms of designed bending moment in the sprayed concrete layer ranged between 1 and 7 kN m/m, with a mean value of 4 kN m/m. Consequently, the loading rates considered in the Asquapro research programme are consistent with what can be observed in a tunnel project in a surrounding limestone rock with a low value of deconfinement. More detailed analyses are on-going.

Table 4 Duration of the pre-cracking phase

RSC |
Type of reinforcement |
Pre-cracking duration for specimens |
||

A |
B |
C |
||

BF01 |
Polymeric fibres |
7 min |
4 min |
4.5 min |

BF02 |
Steel fibres |
- |
- |
- |

BF03 |
Polymeric fibres |
7 days |
75 days |
- |

BF04 |
Steel fibres |
6 min |
- |
- |

BF05 |
Polymeric fibres |
25 min |
2 min |
1.5 min |

BF06 |
Amorphous metallic fibres |
- |
- |
- |

WWM |
Welded wire mesh |
- |
- |
40 days |

- means: the whole test

^{a}This is a prototype fibre, not on the market