A New Prediction Model for Slope Stability Analysis

The instability of river bank can result in considerable human and land losses. The Po river is the most important in Italy, characterized by main banks of significant and constantly increasing height. This study presents multilayer perceptron of artificial neural network (ANN) to construct prediction models for the stability analysis of river banks along the Po River, under various river and groundwater boundary conditions. For this aim, a number of networks of threshold logic unit are tested using different combinations of the input parameters. Factor of safety (FS), as an index of slope stability, is formulated in terms of several influencing geometrical and geotechnical parameters. In order to obtain a comprehensive geotechnical database, several cone penetration tests from the study site have been interpreted. The proposed models are developed upon stability analyses using finite element code over different representative sections of river embankments. For the validity verification, the ANN models are employed to predict the FS values of a part of the database beyond the calibration data domain. The results indicate that the proposed ANN models are effective tools for evaluating the slope stability. The ANN models notably outperform the derived multiple linear regression models

Rapporto 2013 sullo stato della ricerca scientifica all’Università di Trieste

Università degli Studi di Trieste Commissione per la Valutazione della ricerca "Rapporto 2013 sullo stato della ricerca scientifica all’Università di Trieste. Primo esercizio di valutazione delle pubblicazioni scientifiche 2008-2011", Trieste, EUT Edizioni Università di Trieste, 201

Numerical and Experimental Investigation into the Effect of Retention Properties of Partially Saturated Soil for the Stability Analysis of River Embankments

Stability assessment for river embankment represents a fundamental issue in safety assessment towards geo-hazard; several topical issues are involved with this study. Primary, unsaturated soil conditions are experienced during the entire lifetime of these structure; transient analysis are often required in regards to time-variability of external conditions; uncertainties related to soil hydraulic, mechanical and retention parameters are intrinsic for this problem, as well as those related to the knowledge of initial conditions. To overcome these problems, several simplified hypothesis are usually adopted both for the design and assessment of embankments. With the purpose to comprehensively deal with main part of the involved geotechnical issues, numerical and experimental investigations has been performed for the stability analysis of river embankments. The effect of retention properties of partially saturated soils on the hydraulic and stability conditions have been investigated, accounting for hydrometric water-level time-variability; numerical studies have been performed with increasing level of sophistication, using different mathematical methodologies for probabilistic numerical analysis. Various experimental studies and site monitoring data are presented, sharing the purpose of investigating retention properties for partially saturated soils. In its entirety, the final purpose of this study is to analyse the assessment process of riverbanks stability towards global instability mechanism triggered by variable hydraulic boundary conditions. Indications and suggestions, which can eventually be referenced for similar problems or implemented in the standard engineering practice, are provided; the use of site monitoring is justified to improve present flood early-warning system able to define in continuous progressive alert level combining measured and forecasted data with numerical probabilistic analysis results