Internal angle of friction for crushed limestone
Internal angle of friction for crushed limestone
(OP)
I read with interest a thread now closed that dates back to July 2010 on a similar subject. I am trying to evaluate the internal angle of friction of crushed limestone as a backfill material (max. particle size of 25mm). I had 30cm x 30cm (1ft x 1ft) direct shear box tests on the material. The angle of internal friction came out pretty high (65 to 80 degrees). We are testing at very low normal stress ( 10 to 50kPa). Due to the Mohr envelope curvature, it is not unexpected to have high angles at such low pressures, but these values seem quite high. Anyone has some experience/feedback? Thanks.





RE: Internal angle of friction for crushed limestone
RE: Internal angle of friction for crushed limestone
RE: Internal angle of friction for crushed limestone
Was there dilation? You may be measuring the dilation angle and friction angle.
RE: Internal angle of friction for crushed limestone
RE: Internal angle of friction for crushed limestone
I had to think about it while running some basic shear box tests the other day.
RE: Internal angle of friction for crushed limestone
RE: Internal angle of friction for crushed limestone
I've used it on various waste products also, with success.
The suggestion then, if results are critical, use more normal force.