0.5:1 grout is used for this, and for the remainder of the grouting.
Assume that the hole takes 16.80 cu t of grout[ 475 litres] in this period.
We pretend that the pressure builds up a little more. This would indicate that the grout is no longer freely escaping into cracks.The grout has filled all the wider ones, and thixotropic stiffening, which can become dominant in thick mixes such as this, has started to influence the situation.The control valve has been wide open since the start of the grouting but there is no need to change it until pressure builds up to the desired maximum pressure (which is not yet).
The return half of the circulation line could have been disconnected from the start of grouting as suggested in the Guide but should now be brought into use.
SUMMARY OF APPLICATION SO FAR - at 1 hour:
Permeability before grouting is more than 100 lugeons (high)
Water:cement ratio = 0.5:1. Pressure builds up to 8 psi [0.5 bars]
Total cement injected so far
You do not need to decide what to do next because the grout is now as thick as it can be. There are no alternatives to just letting the simulation run on to the end of the grouting.
To proceed to the next period in the simulation CLICK HERE.
If you have already worked through the simulation and wish to return to some of the steps again, CLICK HERE.for a list of them, and links.