Strength Verification of Stabilised Soil-Cement Columns: A Laboratory Investigation of the Push-In Resistance Test (PIRT)

The Push-In Resistance Test (PIRT) is an in situ means of verifying the strength of stabilised soil columns. A winged penetrometer penetrates the stabilised column and the column strength is estimated from the probing resistance using a bearing capacity factor, N. While N values between 8 and 20 are quoted in the literature, there have been few field tests and no laboratory investigations aimed at investigating the value of N and the factors upon which it depends, thereby limiting international confidence in the method. This paper presents findings from a unique PIRT series conducted at laboratory scale at NUI Galway. The development of appropriate column construction and testing methods is discussed. The results of 11 no. PIRT tests on stabilised columns with unconfined compression strengths (UCS) from 150 kPa to over 800 kPa are reported, as well as those of a complementary cone-only series of tests to assess additional frictional forces acting on the penetrometer. Appropriate corrections to the data for temperature and time-consistency of probing forces and UCS values are discussed. Test results indicate that there is a mild influence of column strength on the N value.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author