A modified method for estimating permeability of clayey deposits in the horizontal direction (kh) based on piezocone sounding (uCPT) results is proposed. Most of the currently available methods relate the value of kh with the Δu/[Formula: see text] ratio (Δu is the measured excess pore pressure from uCPT at the shoulder of the cone and [Formula: see text] 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/[Formula: see text] 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/[Formula: see text] and then kh corresponding to the yield vertical effective stress ([Formula: see text]) and initial vertical effective stress ([Formula: see text]) for OCR > 1.0 is established. The modified method for kh corresponding to [Formula: see text] requires two parameters: OCR and a model parameter (α). In addition, for kh corresponding to [Formula: see text], 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 is applied to three field case histories to show its usefulness.

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Along the zone of interaction between land and water, there are continually changes due to dynamic interaction of water and land, so lots of problems occur such as Erosion, flooding, etc. Therefore riverbank and flood protection structures have become useful in the past decades. The National Road NR.01B is built along the mountainous area below the road is a river which flow parallel to the road alignment in soft shale area. There are 4 different stations which were investigated at KM90+600, KM 92+125, KM 92+212.5 and KM92+512.5. Unusually heavy monsoon rains, exacerbated by tropical storms, have caused widespread flooding in more than 60 per cent of the Lao PDR from late June through August. The monsoon rains continued since, and the country endured almost continuous heavy rainfall for some ten weeks. The forensic solution for erosion along the National Road is to use geosynthetic for improving the stability of the erosion protection structures. PLAXIS FEM 2D analysis was utilized to predict factor of safety for each station in case of low water and high water level. In each station of erosion protection structure used same soil parameter due to the same locations. The Slide Software was utilized to predict the value of factor of safety using Bishop, Janbu and Spencer methods in both cases of water level for each flood and erosion protection structure by using the same soil and support parameters which was used in PLAXIS FEM 2D Software. Moreover, comparing the best station between each erosion protection structures were carried out. Furthermore, comparing the results from PLAXIS FEM 2D and Slide Software, the result from PLAXIS 2D seems to have higher accuracy.