Unconfined Compressive Strength of Rock

[Usmi09]

how to determine C and θ of rock by UCS by Formula or stress strain curve.

 

[L0k]

Hi Usmi
I have read a paper written by Hoek & Bray regarding your query, but I could not recover the title.
My understanding there is a curve for each rock, then the c & θ is depending on its overburden pressure.

 

[Usmi09]

Thank you for your reply to this thread.
I have came to know to determine C = 0.145*Cu ( cu is UCS value ) but i was unable to get the right reference. and for θ as well.