Assessing the influence of the slotted tube on modulus calculations, from theory to field tests
Assessing the influence of the slotted tube on modulus calculations, from theory to field tests
In the current French practice, the use of a 44 mm probe inserted inside a slotted tube is very common and tends to extend beyond the initial scope of use, whether it is by driving the tube into loose soils or inserting the tube in a prebored borehole. Besides the obvious effects of driving the tube on the soil, the mere presence of the slotted tube influences the way the probe applies pressure and volume change on the cavity. To take this into account, Hansbo (1990) has proposed a formula to derive the Ménard modulus that accounts for the tubes thickness, which is now used in EN ISO 22476-4 standard.
In this paper we examine the influence of the slotted tube on the expansion of the cavity from a theoretical standpoint and the expected effects on the derived modulus. We then confront this analysis with the field results obtained at the Messanges test site during ARSCOP works, where comparative Ménard pressuremeter tests were carried out in medium dense to dense sands, with 60 mm probes with a flexible cover alongside 44 mm probes inside a slotted tube, both performed in prebored boreholes.
Marjorie Gregoire; A. Finiasz; Catherine Jacquard; Michel Rispal
8th International Symposium on Pressuremeters (ISP2025)
Site Characterization and parameter determination
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