Doon Revisited

[Anonymous]

Overmod

C'mon guys, you can have a better level of discourse, even if you still have trouble spelling 'liquefaction' after all these posts.

I'll try to remember
Regards, Volker

[Overmod]

I have been holding my tongue about evolving ... discussions ... in this thread.  But I draw the line at folks who don't know how to run the quote function and then comment snarkily about what are basically their own misquotes.  (Thanks, Volker, for trying to answer it objectively.  Hope it does some good.)

This is not quite as pathetic as the comments about sourcing the information for "Do You Live In The Blast Zone", but you can see it from there.

C'mon guys, you can have a better level of discourse, even if you still have trouble spelling 'liquefaction' after all these posts.

[Anonymous]

Somehow you mixed up. What you say is my quote is from dhusman. Here is my complete post again

"dehusman

Volker: Metaphors for what we are talking about. You have a beam that centilevers from a wall. You drop a load on it and the beam shears off and the load falls to the ground. That's a slope failure. You have a beam that centilevers from a wall. You drop a load on it and the beam deforms and bends, the load falls to the ground. That's liquifaction."

 

First, no need to explain the difference between liquifaction and landslide to me. As I said before I'm a civil engineer and that means I learned at least the fundamentals in soil mechanics and geotechnic before specializing in structural design, where these fundamentals are needed too.

 

When you make comparisons you should do it right. A cantilever beam usualy has a stress failure caused by the bending moment not a shear failure. Brackets experience shear failure.

 

dehusman

One is a shear failure, the other is a deformation.

 

Wrong, both are shear failures only with different consequences.

My comment to your post:

In his post dhusman tried to explain to the difference between slope failure and soil liquifaction in terms of structural systems.

Slope failure: http://dkgeo.de/Bild/boeschungsbruch.jpg

It is in German but self-explanatory.

Results of soil liquifaction: https://www.researchgate.net/profile/Sayed_Ahmed11/publication/288515983/figure/fig9/AS:319868416086025@1453273981382/Failure-of-apartment-buildings-by-tilting-in-Niigata-due-to-liquefaction-Source.png

Very simplyfied, how good a soil withstands forces depends on the interlocking of the single grains, their compaction and, in case of cohesive soil, cohesion. One indicator is shear resistance.

When a slope failure occurs, a load on top might lead to shear forces in the soil exceeding the shear resistance. Other reasons can be too steep slope, too high slope, vibration.

With soil liquifaction under special soil and water condition vibrations can lead to a shear resistance reduction to zero. Now the soil reacts like a fluid and e.g. buildings loose the resistance under their foundation.

In both cases we have a shear failure, though with different causes and consequences.

Here is a nice picture how liquifaction can lead to slope failure. Though funny looking it is right: https://slideplayer.com/slide/7951733/25/images/13/IMPORTANT%20CONCEPTS%20INTERNAL%20CAUSES%20OF%20SLOPE%20FAILURE%20Quick%20sand.jpg

I hope that helps. Otherwise ask, please.
Regards, Volker

 

 

[Cotton Belt MP104]

 

Just when I thought NO sane conversation could be made about “Doon”, something came up that is of interest in an engineering sense.  I will have to modify the question to include RAILROAD interest.  Forget about the derailment at Doon (for the moment, or better yet, forever, IMHO)

 Using the same logic quoted/discussed below, if a cantilever bridge is being used as a trestle on a railroad, and a load in the middle of the structure were to exceed the weight limit ……………..liquification is the cause of failure???????????????

As I understand it in physics/materials there is stress, strain, elastic modulus, etcetera.  In the discussion BELOW a statement was made that caused me to wonder and seek explanation.

 

reference:  Partial post of by VOLKER LANDWEHR   Tuesday, July 24, 2018 8:28 AM/ with replies

 

 ………………..MY emphasis is highlighted by bolding text (mrw)

 

Volker: Metaphors for what we are talking about. You have a beam that centilevers from a wall. You drop a load on it and the beam shears off and the load falls to the ground. That's a slope failure...... ( say what ????? that is a Volker quote MRW) You have a beam that centilevers from a wall. You drop a load on it and the beam deforms and bends, the load falls to the ground. That's liquifaction.    (Okay, if you insist, but I fail to see how the word liquefaction can be used since there is NO liquid involved.  All items in the beam scenario are solids..............…albeit “solid ground’ can be made into particulate matter and “act” like a liquid.  But a true solid like steel cannot flow like a liquid unless heated and truly become liquid.The “beam” describe above is surely made of something more “solid” than soil or ballast…..MRW)

 

dehusman

 

First, no need to explain the difference between liquifaction and landslide to me. As I said before I'm a civil engineer and that means I learned at least the fundamentals in soil mechanics and geotechnic before specializing in structural design, where these fundamentals are needed too.

 

When you make comparisons you should do it right. A cantilever beam usualy has a stress failure caused by the bending moment not a shear failure. Brackets experience shear failure.

 

dehusman

 

One is a shear failure, the other is a deformation.

 

VOLKER Wrong, both are shear failures only with different consequences.

 

 

 

COMMENTS, ANYONE?    THANKS   MIKE ENDMRW0725180015