Chisel Design for Excavation of Cut-off-wall

[cmorgh]

Hi to All,
The construction of a cut-off-wall in which the panels are excavated by cable-suspended mechanical grabs (about 6 metric tones in weight) is under progress. The panels are filled with plastic concrete, using tremie tube. The texture of the layers to be excavated is, highly weathered conglomerate (being very dense and existing as alluvium which could be classified based on USCS as "GC" with boulder) down to 10 m and fresh cemented conglomerate (actually rock) below that.
For excavation of the both layers, some chisels are designed and used which are not very efficient in accelerating the excavation rate.
My question is:
1- considering the existing situation, layers, accessories and equipment, could the rate of the excavation be well increased using a special-designed chisel?
2- Need your comments for the design of such a chisel.
Please note that I do not mean the conventional chisels used for breaking obstacles in the panel such as boulders. What I am focusing on is the chisel, which loosens the very dense (and rock) textures as outlined above.

Regards
cmorgh

 

[PSlem]

I don't think so. Typically they have a 90* included angle on the ends. Any less and it will dull too fast, same reason drill bits are 110* even though they might drill faster with less angle. As it is when we are doing toes in rock we usually had two welders around the clock gouging off old hardface and putting on new. Best rtecommendation I can give is make sure maintenance is giving you as good an edge as possible and if it's real slow and you think you can lighten up the slurry, do so.

 

[SmokeyBear]

I agree with PSlem on the need for a good an edge as possible. Have you tried increasing the weight of the sinker bar. More weight = more energy at the bit.

 

[cmorgh]

Thanks to PSlem and SmokeyBear,
I have considered sharp-edge chisels, as well as increasing the weight.