Shear strength of Rock

[darogers]

I'm designing a soldier beam wall with embedment in rock. The job provisions did not include shear strength of rock, so I am assuming 4 ksf, which I know is a conservative value but my embedments are reasonable. My only issue is referencing this for the reviewer. Does anyone have a textbook or reference that contains a table of typical shear strengths of soil/rock. I just need something to prove that my assumption is conservative.

Thanks,

Dan

 

[civilperson]

3000 psi concrete has more than 15 ksf shear strength.

 

[GeoPaveTraffic]

Try back calculating the rock strength based on presumptive bearing pressures on rock based on your local building code.

 

[fattdad]

My master's thesis pertains to the strength and behavoir of rock. I have a pdf of it posted on my web server. But it's currently down. When it comes back up, I'll post a link. You may find something helpful.

f-d

¡papá gordo ain’t no madre flaca!

 

[VoyageofDiscovery]

Try Hoek-Brown criterion

HTH

 

[fattdad]

the long-awaited link:

http://home.comcast.net/~fatt-dad/thesis.pdf

Hope you enjoy!

f-d

¡papá gordo ain’t no madre flaca!

 

[cap4000]

I just finished a soldier pile project using 4ksf. Based on the rock cores taken prior to blasting it was much higher. RQDs was in the 80's and 90's. After the blasting was done the diabase bluestone trap rock turned out to be very fractured and seamy. I normally use the cohesion strength as a residual rock shear strength. See the Rock Foundations Book by ASCE publication #16 on pg 117 for some typical cohesion values. What type of rock do you have?? I would add a min. of 25% to your number for unseen site conditions.

 

[mudman54]

hoek & bray's rock slope engineering textbook give a plot of cohesion vs friction angle in figure 43; it all depends on how the rock discontinuities intersect your pile socket. since you didn't tell us anything about the rock type or where it is, i like geopave's answer about using some percentage of the local building code bearing pressure.