Liquefaction potential assessment of saturated loess

Abstract

Usually, soils with mainly fine grain-sized content, as loess, are considered to have low liquefaction potential. Regardless of this, many researchers have analyzed and presented much field evidence that silty soil (in particular loess) liquefaction occurred under certain conditions. In Bulgaria, the first loess river terrace (T1) within the Danube River lowland areas is covered by low plasticity silty loess with a thickness of 10–12 m. Тhe groundwater level is often located between 5 m and 8 m in depth so that substantial part of loess deposits are saturated and immersed. Meanwhile, that region of North Bulgaria is under the influence of the Vrancea seismic zone in Romania, which is able to generate strong earthquakes with magnitudes M≥7.0. The present paper aims to assess the liquefaction potential of loess in a ground profile representative of the T1 loess river terraces by the so-called simplified procedure based on SPT, which is incorporated in the software code NovoLiq. The safety factor against liquefaction FSL is estimated at the respective depths in one-dimensional model of the ground profile for free-field conditions at varying peak ground accelerations amax. The critical amax, at which liquefaction of loess is possible according to the assumptions of the applied simplified procedure and the requirements of the National Annex of Bulgaria to Eurocode 8, has been established.

Studying the mechanical behavior of loess-cement mixtures and adopting a cement-soil cushion (CSC) as a shallow ground improvement solution for foundations laying on collapsible soils

“…As a summary, the comparative analysis strongly supports the efficacy of both the CSC and DSM methods, highlighting their ability to significantly improve ground foundation performance. These techniques are invaluable assets in geotechnical engineering and construction, particularly in regions susceptible to seismic activity, where they contribute to both structural stability and seismic resistance (Karastanev, Tchakalova, 2021;Minkov et al, 1981).…”

Deterministic Seismic Hazard Analysis to Determine Liquefaction Potential Due to Earthquake

“…Jalil et al [23] studied liquefaction in Palu as the cause of massive mudflows. Karastanev & Tchakalova [24] assessed the liquefaction potential of saturated loess. Uyanik [25] analyzed the soil liquefaction based on soil and earthquake parameters.…”

Influence of geological and hydrogeological settings in assessing the stability of a landslide slope in the Tutrakan area, Northeastern Bulgaria

“…1) покриващи стария релеф от заравнени повърхнини, четвърта, трета и втора надзаливни тераси на р. Дунав. Еоличните седименти са изградени от типичен льос (Minkov, 1968;Philipov, Mikova, 1986;Philipov, 1990;Tchakalova, Karastanev, 2019;Karastanev, Tchakalova, 2021), смесени с алувиалните чакъли, пясъци, глини и склоновите материали. Неогенът е представен от праховопесъчливи глини, глинести варовици и прахов глинест пясък.…”