Entering Rock Parameters in Civiltech Shoring Suite

[peelwvu]

Trying to enter rock parameters into Shoring Suite. Entering it as equivalent Clay but not sure if I should give a friction angle and cohesion. The rock is siltstone, compressive strength 1500 ksf, shear strength 2.6 ksf. Is there a rule of thumb that you follow to enter rock and equivalent clay? Or should I just enter the passive pressure by hand?

Thanks

 

[EireChch]

1500ksf is 71MPa compressive strength.

undrained shear strength is half of that , why do you say its only 2.6ksf?

But to try answer your question, you can work our equivialnt mohr coloumb parameters using the Hoek Brown criteria. There is a rock lab app that floats around online that you can use.

You will probably get a phi of 35 deg and c' of 200kPa plus. I pulled these out of thin air, but it equates to a very strong material. Any increase in strength is probably insignificant in terms of your wall design.

 

[peelwvu]

1500ksf is 71MPa compressive strength.

undrained shear strength is half of that , why do you say its only 2.6ksf?

But to try answer your question, you can work our equivialnt mohr coloumb parameters using the Hoek Brown criteria. There is a rock lab app that floats around online that you can use.

You will probably get a phi of 35 deg and c' of 200kPa plus. I pulled these out of thin air, but it equates to a very strong material. Any increase in strength is probably insignificant in terms of your wall design.

We were given those parameters by the engineer who did the preliminary geotech. It's for DOT so I likely can't argue them. Thank you, I'll look for the Rock lab app.