## slip circle

## slip circle

(OP)

hi.

Is anyone here have any idea how to find radius of slip circle without knowing all the parameter. I only have the information of the bank height which is 23.46m.

I am no specialist in geotech and I have difficulty to solve this. please help. Thank you

Is anyone here have any idea how to find radius of slip circle without knowing all the parameter. I only have the information of the bank height which is 23.46m.

I am no specialist in geotech and I have difficulty to solve this. please help. Thank you

## RE: slip circle

## RE: slip circle

## RE: slip circle

## RE: slip circle

firstly you have to hire a geotech engineer/technician to drill some holes to measure the strength of the soil.

secondly you have to measure the slope angle.

the last step you have to buy the geo-slope software to analyse the stability of your 23.46 bank height.

Finally you will find the critical slip circle.

## RE: slip circle

The lad/lass has a bank height - well, true, that is one parameter. I would hope they know the angle of the slope. LOk is correct in that knowing the soil types and properties is necessary (to a degree which I will explain later). Also the stratigraphy.

First - is the slope of a cohesionless soil? (sand and gravel) - if so, there really isn't a "critical circle" involved as it is an infinite slope problem that will govern to provide the minimum factor of safety. Now if this is an embankment sitting on a soft or firm clay - then there would be a global stability problem - not just the slope itself.

If the soil is cohesive - many years ago, someone wrote a paper that would give you a near/close estimate as to the location of the critical slip surface "focal/centre point" - that point from which the critical radius. The paper I am thinking of was from the mid to late 60s - but Huang (1980) also provided a method - (Huang, Y.H. (1980), Stability charts for effective stress analysis of nonhomogeneous embankments, Transportation Research Record, 749, pp 72-74. you will find this explained in Fang's Foundation Engineering Handbook, 2nd Ed 1991.

So, in essence, there are ways (including many charts) that can be used to find the "critical" surface (or close) of relatively homogenous slopes. Of course, determining the factor of safety is dependent on knowing the properties; complex slopes/stratigrapies notwithstanding.

## RE: slip circle

As BigH states, this analysis can be done using hand calcs and charts, although there is also relatively inexpensive software available these days also (SlopeW is not inexpensive). The software makes the analysis much quicker, but you should understand how the software works before using it, and you will need soil properties, stratigraphy, strength, groundwater conditions, and geometry for the charts or software.

A good, free manual for using chart solutions can be found here:

http://www.vulcanhammer.net/geotechnical/Duncan_19...

## RE: slip circle

## RE: slip circle