Holdfast Training Services Trial Blog

I’ve been told to oversee the use of a Menard test to validate the formation of some substitution concrete that was poured in almost submerged conditions.  I.e water was being chased out of the 30m x 15m x 2m excavation by the concrete. Testing came about as the regulatory body was not best pleased about the whole thing.
Menard tests give a horizontal total stress to allow the eventual shear strength to be calculated. The picture is of the Menard assembly that is placed down the hole and expanded with gas and water in two separate membranes to give a pressure. This is repeated at different depths, normally from deepest to shallowest. 
Issues are as follows:

1. They are struggling to keep the hole open to get the required membrane Volume for the test to be valid. About 60cm3.

2. They are trialling the use of a polymer in varying quantities (pure bore I think) But the polymer is too viscous and the pump pressure is getting too high. Possibly due to the trial area being on rock that is better than the siltstone which the real test was specified for. 

3. The whole thing is becoming time critical as it is the second go we have had at it.

Could an SPT test give a similar result? Or is it too crude?

The use of Menard was a method specification given by the principal contractor geotechnical engineer. So the risk is ours. 

Any thoughts would be appreciated.