A modified method for estimating the permeability of clayey soils based on piezocone sounding results

A modified method for estimating the permeability of clayey deposits in the horizontal direction (kh) based on piezocone sounding (uCPT) results was proposed. Most of the currently available methods relate the value of kh with the Δu/σꞌv0 ratio (∆u is the measured excess pore pressure from uCPT at the shoulder of the cone, and σ’v0 is the initial vertical effective stress at the measurement location). However, it has been understood that the effect of the overconsolidation ratio (OCR) on the Δu/σꞌv0 ratio is more significant than that on the value of kh. As a result, for an overconsolidated deposit, there is no suitable method for estimating the value of kh based on uCPT results. Based on the results of laboratory model uCPT, an empirical equation for considering the effect of the OCR on Δu/σꞌv0 and then kh corresponding to the yield vertical effective stress (σvmax) and initial vertical effective stress (σv0) for OCR > 1.0 is established. The modified method for kh corresponding to σvmax requires two parameters: OCR and a model parameter (α). In addition, for kh corresponding to σv0, two more soil parameters are needed: the swelling index (Cs) and the initial void ratio (e0). The methods for estimating these parameters are also proposed. Finally, the modified method was applied to three field case histories to show its usefulness.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