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@dgillette "When should I use a hammer" = priceless! :) Does anybody else worry about the structure of questions on this board sometimes? @mnoorzay Mccoy answered your question. Horizontal seismic loads are typically applied in the direction of the slide. As such, they tend to decrease...

Just like everything we do a pseudostatic (or should it be pseudodynamic) analyses are a tool and the key is interpreting the results. Some will tell you that a pseudostatic analysis is a good indicator of potential seismic damage to a structure. A high factor of safety will mean that the...

SlopeW will only be able to model the post earthquake stability of the retaining wall. If you know how the earthquake will affect the soil then you can put post earthquake strengths and pore pressures into the model. However, you will have to do a dynamic analysis to fully understand the...

@ all above... While I can understand your desire to help educate young engineers, it has become clear to me that replying to questions such as the one above may not be the prudent course of action. It worries me that somebody performing slope stability analyses does not understand the...

@rgspringer 1st question) If you are asking this question you are not qualified to do a slope stability analysis. This shows a fundamental lack of understanding in basic geotechnical engineering. Read a text book or ask a senior engineer to explain to you the difference between undrained and...

Since there hasnt been any recent activity, I can only assume that the original poster got what he needed. However, I think this topic is a further example of the disconnect between structural and geotechnical engineering that exists in consulting practice these days. In general these days it...

@ATSE: Geotechnical engineering is not easy. There are no codes which provide definitive absolute parameters for soils. In most cases engineering judgement is required by an experienced professional geotechnical engineer. Given the above, when asking for geotechnical advice, you get what you...

You have to remember that freezing has a capillary effect and that moisture can rise up from the groundwater table. In some cases, frozen samples of soil will have a significantly higher moisture content than samples taken at similar depths in the middle of summer. Hence most road damage...

@CEFDESIGN What part of Victoria are you in exactly? Please give us some idea of the subsurface conditions beneath the house. If you have engaged a geotech then you should have a borehole log with UCS classifications of the subsurface soils. Without knowing where the site is located, here are...

What are you using the correlation for? Is it a critical project? Then I would suggest that this approach is not appropriate and that you should attempt to recover undisturbed samples and do triaxial/shear box testing. Or, Perform oedometer testing and calculate OCR values and use a standard...

dgillette, Yes I mean the EERI book. For the most part the book is just a summary of previous papers on the subject. I do have several issues with it regarding sections on calculating CSR i.e. recommendations for using site specific dynamic response analyses for deep profiles with no...

Just trying to get an idea of what the industry is using at the moment. Boulanger and Idriss (2008) Seed et al (2003) or something new...

The benefit of using the DCP is that the test is usually performed after about a metre and a half of fill placement. The fill is usually placed in accordance with a method specification which is determined at the start of the job by trial runs and nuke testing. The DCP is used for production...

dgillete, AS (Australian Standard) 3798 - Guidelines on Earthworks for Commercial and Residential Developments - Section 7.2, allows for indirect in situ testing methods to assess in place dry density. In direct methods include penetrometer testing as specified in AS 1289.6.3.2 and require...

gadderrao, I am not sure I have ever heard of a penetrograph. Is it like a Dynamic Cone Penetrometer (DCP) or a McIntosh Probe? In Perth, Western Australia, compaction testing for large sand fill projects is usually done with a DCP. Reference penetration values are usually established with...

dgillette, You're right Moss and Seed (2006), thanks for pointing that out. This is turning out to be an interesting discussion. Your point about empirical rd and shake values is spot on. It always makes me feel a little bit awkward writing liquefaction reports and explaining how we did this...

dgillette, Agreed the effect of fines on liquefaction resistance in general is not well understood. Especially non-plastic fines. Part of my issue with the existing CPT charts is there is no seperate factors to account for the effect of compressibility and the effect of fines on the soil. This...

Before I forget one more plus to CPT testing is you don't need to worry about soil disturbance and balancing water pressures in artesian conditions. In soft to firm non-plastic silts and very loose to loose sands beneath the water table getting reliable SPT results is very difficult without...

Hello dgillette, Firstly, I apologise for misspelling your name previously. Any good liquefaction program includes at least a couple of independent in situ assessment methods to assess liquefaction potential. As I understand the current order of confidence in insitu testing to CRR...

In a rapid drawdown condition the dam is in a state of intermediate stability... So generally speaking conservative undrained shear strengths should be adopted for the low permeable materials and contractive granular materials. However, there are some additional factors to consider including...