Talk:Lateral earth pressure

message: There are quite a few errors on this page. A reference I have (Kramer 1996) has Rankines equation as: Ka= (1-SIN(phi')/(1+SIN(phi') = TAN^2(45-(phi'/2). This page ascribes this to Coulomb (wrong!)
... I cant be bothered writing the rest, but some of the others arent correct either. I'll try and edit myself. Hopefully I wont make too much of a mess.—Preceding unsigned comment added by GeoEng (talk • contribs) 09:25, April 6, 2007
: OK, I've made some changes. More yet to do include adding the references for Caquot & Kerisel, Terzaghi & Peck. "Bells relation" should be moved under "Rankine". More discussion is required for At-rest pressures, compaction pressures etc. A whole section on dynamic earth pressure theory is missing and needs to be added. Usual story... If I have time. Note this page NEEDS figures!!! GeoEng 11:51, 6 April 2007 (UTC)
replies: text: No, I believe you are wrong. Rankine's equation was the larger one; he also presented the simplified version of it with a horizontal backfill. You can see the larger equation in his original work. As for what exactly Coulomb wrote down, I do not know because I have different sources saying different things (see ). The way it is now is fine because it gives a single equation for "Coulomb theory" and does not specify what equation Coulomb originally wrote down. -- Basar (talk · contribs) 21:19, 26 August 2007 (UTC)
replies: text: Additionally, Ka = TAN^2(45-(phi'/2) is valid in both Coulomb and Rankine theory when the appropriate circumstances are met to simplify the equations. -- Basar (talk · contribs) 23:19, 26 August 2007 (UTC)
thread_title: Errors

message: Hello
the compaction soil pressure is missing. Someone might add this chapter.  — Preceding unsigned comment added by 73.8.44.11 (talk) 14:29, 12 May 2020 (UTC)
thread_title:  Discussion 

message: Is it possible for anyone to include in the article how surface surcharges are accounted on Coulomb's wedge analysis? --Mecanismo | Talk 23:05, 23 January 2008 (UTC)
replies: text: Done, in the Coulomb section. Theosch (talk) 22:05, 19 December 2011 (UTC)
thread_title:  Coulomb and surcharge? 

message: The first sentence in the article is: "Lateral earth pressure is the pressure that soil exerts in the horizontal plane." I think this is both confusing and perhaps wrong. "Lateral" means "sideways", i.e. away from the side, presumably in a normal (right-angled) direction. If the side is not vertical, "lateral" is not strictly horizontal.
There is an associated problem with Coulomb's equation for Ka. This correctly includes the term cos(delta+theta) in the part outside the square root. Ka is for the pressure against the wall in the direction of theta, not in the horizontal direction. The coefficient for horizontal active earth pressure is Kah and is the same but without this term cos(delta+theta).
Can any civil engineer here clear this up? It's not easy, as some of the books around also seem muddled or contradictory on this point. My reference (in German) is on pages 95-96 of Prof. Frank's course on soil mechanics: http://homepages.thm.de/~hg8195/Skripte/Boden.pdf (Note that the symbols are slightly different: alpha is used instead of theta.) Theosch (talk) 11:07, 16 November 2011 (UTC)
replies: text: I have investigated this and corrected it. While difference between "lateral" and "horizontal" is mainly semantic and not completely clear, there were one or two factual errors regarding the coefficent K (or Ka). Theosch (talk) 09:00, 1 December 2011 (UTC)
thread_title:  Lateral vs. horizontal 

message: I think the sentence about the OCR profile should be deleted or defined. I have added the definitions for two undefined terms in these equations. The overconsolidation ratio and the effective stress friction angle. Maxeng (talk) 05:57, 10 October 2013 (UTC)
thread_title:  At rest pressure 

message: Countless discussions on the subject of the earth pressure K factor, as well as some 28 million entries in Google under 'Earth pressure' permit the conclusion that there are no globally accepted and faultless teaching on earth pressure. Even the numerous entries posted by many users in an attempt to reduce the error rate of conventional earth pressure calculations have obviously not been successful.
In order to throw light on discrepancies found in present teachings and the specified calculation procedures, I have prepared a detailed 'Study on Earth Pressure' and published it under www.earth-pressure.com.'''
The study reveals serious misinterpretations in the basics of current earth pressure teachings, all of which have been adopted in the European guidelines for earth pressure calculations (EC7, DIN 1054 and 4085).
The question remains: How can dyke & dam failures, landslides, and building collapses be prevented, if the dimensioning of restraining elements is based on incorrect calculation basics?
Similarly, the question arises: How can experts find the real cause of the collapse of the Historic Archive in Cologne, or the landslide in Nachterstedt –both in 2009 – if their investigations are based on the faulty basics of current earth pressure teachings or the European calculation guidelines?
The result of my studies is a modern "Earth Pressure Theory" based on Coulomb's classical earth pressure theory, pure basic physics, and natural soil characteristics.
Although it seems presumptuous, it is likely that the new findings will cause most of the 28 million contributions on the subject of earth pressure to become meaningless.
The study shows that:
•	Current earth pressure calculations are based on empiric soil characteristics, and neither follow Coulomb's classical earth pressure theory, nor the generally accepted rules of physics.
•	In a soil body at rest, current teachings only see vertical stresses in the material, similar to that in rock. Consequently, in order to mobilize the earth resistance of the soil behind a rigid wall, current teachings require a parallel shift, or a rotation of the head point or the base of the wall.
This approach is wrong, simply because the soil behind a rigid wall obviously also generates horizontal stresses against the wall, whereby the magnitude of the stresses depends on the nature of the soil and its characteristics.
•	Current teachings state that soil density is not the only condition for equilibrium in the soil. To compensate for this deficit, various limits are introduced, to which different earth pressure factors (K, Ka, K0, Kp) are assigned.
Because equilibrium in the earth mantle is demonstrably maintained by earth forces, the earth pressure calculations require neither the introduction of limits, nor the use of earth pressure factors to equalize stresses.
•	Equal for all soil types, the current teachings fix the thrust height of the earth pressure force at 1/3 of the wall height, and see the force direction influenced by wall friction and/or soil cohesion.
Hereby, the current teachings evidently fail to see that different soils also create different inclination angles, which lead to different thrust heights against the restraining wall, depending on the physical conditions of the earth force. Consequently, a fixed thrust height for the earth pressure forces is false.
•	The study under www.earth-pressure.com also describes other misinterpretations in current calculation specifications in detail.
The findings of this study provide good reason for the professional world to discuss the misinterpretations in the basics of current earth pressure teachings and the calculation guidelines. In my opinion, the current teachings can no longer claim to represent the present state of the art.
Norbert Giesler — Preceding unsigned comment added by 178.201.171.126 (talk • contribs) 12:38, 28 July 2015‎
:Mr. Giesler - the building codes you reference may be using lateral earth pressure theory incorrectly, but most of what I understand from your post is that the building codes (EN7/DIN4085, etc) are wrong, not that lateral earth pressure theory as a whole, or the use of K-factors within it, is wrong. Therefore, any changes to articles on Wikipedia would be most appropriate on articles about those particular building codes, if such articles exist. Argyriou (talk) 15:27, 22 July 2015 (UTC)
replies: text: Please don't remove other people's comments as you did to my comment above, which I have restored. Argyriou (talk) 00:57, 29 July 2015 (UTC)
thread_title:  Incorrect assumptions for the K factor 

message: The symbols defined in the table should be referenced to a diagram. They are not at all clear to someone who is not familiar with the field (I am a mechanical engineer, so if they are not clear to me, the layperson is at a severe disadvantage) · · · Peter (Southwood) (talk): 05:56, 23 May 2018 (UTC)
thread_title:  Symbol definitions unclear