My mind has become so lazy in calculations that I always use a spreadsheet, even when simply adding figures.
My answer consequently is that I use the automatic pi() function when needed.
I've been using the approximate solutions from Gazetas you cite and the rigorous solutions from Pais & Kausel. The hypothesis is that the foundation is rigid but it is shown that a nonrigid foundation is an acceptable approximation.
What happens in the presence of a rock mass which is not...
That's exactly the same thing I do, I examine visually the graphical output of all critical surfaces within the lower FOS range and decide which ones are realistic and which ones look more like a potential result of surface erosion rather than of a potential sliding surface.
My attention was caught by the 'rotational stiffness' since it is rarely considered. The stiffness of bedrock (which bedrock?) is usually very large in translational stiffness, so much so that to all practical purposes we can assume a fixed constraint (especially if the bedrock exhibits few...
I myself do not waste time at all with anomalous values. If a parameter goes outside the known range, from literature or professional practice, I simply discard it as garbage, unless extensively justified with valid technical reasonings.
I'm utterly horrified that the university guys cited by...
It also depends on the software. I've been working mainly with a FEM-based software. The procedure is to discretize piles in finite-length cylinders. The reaction of each cylinder is modeled by 3 Winkler springs, horizontal, torsional and vertical (all applied to the lateral surface). The Base...
My first impression is the same as your impression, that is the report appears to state the obvious since if the soil stress exceeds the shear capacity, a rupture or shear plane is formed which will compromise the stability of the foundation.
Those loads act in a very short time span so the undrained condition should be used. Please note that, in analogy to the drained condition, probably we should not use peak Cu (also defined Su), but rather the remolded Cu, sometimes called Cu,r. the remolded quantity is often calculated by an...
This is a slope in a statistically homogeneous soil with a small scale of fluctuation (SOF) of its strength (described by Su or phi, according to the soil type and rupture model used). The elementary soil volumes are small and the light ones represent smaller strength whereas the darker ones...
Just about that, if we simplify considering a single statistically homogeneous layer, if each CPT is considered a random sampling/§resampling through the layer, then after conversion for example from Qc to Su in your example we would have 10 values of Su average, and one corresponding values of...
AS stated above, phi_cs, which is phi at the critical state (also called phi_cv or constant volume)for prevalently sandy soil, is usually 30° or above.
There is a discussion on this topic almost 10 years old....
https://www.eng-tips.com/viewthread.cfm?qid=348077
This thread has been inspired by the practical issues posed in this other thread: https://www.eng-tips.com/viewthread.cfm?qid=493211
The issue was basically that Pf, or Pof = Probability of failure, sometimes, or often, seems to be high in relation to the FS, the minimum Factor of safety of the...
I do agree with Eirechch as above.
Also, If you can extrapolate safely to 30 m of depth, then you should also have reliable numbers for Vs of each rock, by reliable I mean citing sources.
In my experience, a weathered shale may have a 400 m/s cautious Vs, whereas a hard shale may have from 600...
I don't know if you guys agree but I believe that the concept of passive pressure can also be modeled by Winkler-like springs (for example, the p-y model in piles) so in such models a horizontal modulus of subgrade reaction with relevant units (pressure/length) may be envisaged. In this case...
Right, if there is a level issue, I too would insist on engineering a super-stiff fill on the soil side and on designing an adequately stiff foundation. And maybe I would recommend a daily prayer on top of it...
In my experience, engineers who design structures have no suitable means/software to work out a rigorous solution. They might try, with higher than average advanced software, to split the foundations into separate entities (slabs, usually) each with its own seismic stress. I should enquire if...
I've come across this issue quite a few times, there has even been a discussion on it about 20 years ago. There may be a couple of significant cases.
1= building on rock AND on soft, compressible soil. In this instance a proper solution is not easy, what has been experienced here is a slab...
During the early years of my career, I used to work with a foundation company, specialized in drilled piles.
There would be no problem whatsoever to drill a large diameter bored pile thru the saturated ground, by use of steel casing or light 'to waste' casing or drilling mud. And further down...
I've been pondering about the apparently high probabilities of failures related to FoS's.
One reason might be the wrong choice of the representative distribution: sample distribution or distribution of the average value of data?
I'm going to open a new thread about it.
