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 ::to  the use of ""analyze"" is more to do with my English skill. I will correct that. ""measure"" is more correct I believe. Thank you for pointing out. I know a boring machine measures the soil strength as SPT N-value. From the SPT article a sledgehammer weights 63.5kg so I believe like in Japan, the US counts the number of blows in the interval of 1m and wash out soil with water and start pounding the hammer again, repeating. I believe this is what you mean by ""SPT run in borehole created by a boring machine"".  
 You said ""if there is a weak layer in the interval over which the SPT is run, it will show up in the test results."" So i believe what you saying is that if there are several soil layers within an interval of 1m, the result shows the differences?; even though they only report one SPT N-value for each interval?? Actually I happen to have a SPT N-value report on my side right now, and the graph shows only one N-value for each interval. I hope I understand your ""inteval"" correctly. Correct me if I am wrong. At least that is how it is done in Japan. I'd like to know very much how the difference in the soil strength among different soil layers in the interval shown?? Educate me. 
 Secondly, I am very willing to discuss with you. I will take back my writing or correct it by myself if i find them wrong. So please respect it and do not delete my writings. I have never deleted your writings. 
 Thirdly, you made a PWRI source link as a reference for your writing. In the talk page you specifically said you cannot read Japanese. I have read it, and although it is about SPT problems associated with weak layers as a title says, the content is quite different from your writing. Have you actually read it??? 
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