48
Geotechnics
REGGIO DI CALABRIA
Overview
Date/time interval
Syllabus
Course Objectives
The course aims at providing the fundamental understanding of theoretical and practical aspects concerning modeling of soil slopes and slope stability (natural, artificial and cut slopes). The knowledge and skills acquired in the course concern: a) geotechnical modeling of the slope; b) evaluation of the safety conditions of slope according to limit equilibrium (LE) analysis and Italian Building Code; c) design methods adopted in the engineering practice and criteria for stabilization of slopes; d) instrumentation and field monitoring of slope stability (movements and pore water pressures); e) Excavations. executive techniques, risks, and types of supporting works of the excavation fronts; f) safety analysis of diaphragm walls and ground anchors in accordance with current national code
Course Prerequisites
Basic knowledge of soil mechanics and geotechnical engineering are required.
Teaching Methods
The course is divided into: a) lessons on all the topics of the course with an active interaction with the students; b) Exercises and practical applications related to the safety analysis of slopes even by using computer programs (SEEP/W, SLOPE/W)
Assessment Methods
The exam consists of an oral exam aimed at verifying the acquired knowledge and application skills. The objective of the oral exam will be to verify the learning ability, the level of knowledge and understanding of the course contents, as well as to evaluate the communication skills. The ability to apply knowledge in the context of real application problems, with particular reference to the stability analysis of the natural and artificial slopes, trenching and excavation safety, will be verified through the exercises delivered by the student. The final grade in 30-point scale will be assigned on the basis of the following elements:
-30 - 30 cum laude”: complete, in-depth and critical knowledge of the topics, excellent language skills, complete and original interpretative ability, full ability to autonomously apply knowledge to solve the proposed problems;
-“26 – 29”: complete and in-depth knowledge of the topics, high language skills, complete and effective interpretative ability, capability to autonomously apply knowledge to solve the proposed problems;
-“24 – 25”: knowledge of the topics with a good level of learning, good language skills, correct and confident interpretative ability, ability to correctly apply most of the knowledge to solve the proposed problems;
-“21 – 23”: adequate knowledge of the topics, but lack of mastery of the same, satisfactory language skills, correct interpretative ability, limited ability to autonomously apply the knowledge to solve the proposed problems;
-“18 – 20”: basic knowledge of the main topics, basic knowledge of technical language, sufficient interpretative ability, ability to apply the basic knowledge acquired;
-“Insufficient”: does not have acceptable knowledge of the topics covered during the course.
Texts
Suggested books
• Course materials prepared by the teacher
• Analisi di stabilità dei pendii. I metodi dell'equilibrio limite I metodi dell'equilibrio limite. Farulla C. Airò (2001), Hevelius Editore, Benevento.
• Meccanismi di deformazione e rottura dei pendii. Picarelli L. (2000), Hevelius Editore, Benevento.
• Lancellotta ‐ “Geotecnica” ‐ Zanichelli.
In depth books
The stability of slopes. Bromhead E.N. (1986). Surrey Univ. Press, London.
• Slope stability. Engineer Manual EM 1110-2-1902 (2003). US Army Corps of Engineers, Engineering and Design.
• Geotechnical Engineering of the Stability of Natural Slopes, and Cuts and Fills in Soil- Keynote Lecture (2000). Fell R., Hungr O., Leroueil S.and Riemer W., pp.100.
Italian Building Code : NTC 18– –D.M. 17 Gennaio 2018.
Contents
The main topics provided for in the course, based on the objectives to be achieved are:
SLOPE STABILITY: INTRODUCTION. 1. SLOPE CLASSIFICATION SYSTEMS. Types of slope: natural and artificial slopes. Landslide classification and definitions. Landslide activity. Causes of slope failures. 2. GEOTECHNICAL ASPECTS OF SLOPE MODELING. Shear strength of soils. Geotechnical characterization of soil for slope stability analysis. 3. METHODS FOR SLOPE STABILITY ANALYSIS. Theoretical basis of limit equilibrium (LE) analysis. Method of slices: basic assumptions. Infinite slope derivation : dry slope, wet slope, with seepage. Bishop’s method, Janbu’s method. Morgenstern-Price method, Spencer’s method.. Accuracy and reliability of LE methods. Three-dimensional analysis. 4. SAFETY ANALYSIS ACCORDING TO ITALIAN BUILDING CODE (NTC18). Safety levels and critical slip surface. Natural and artificial slopes, embankment and cuts. 5. STRAIN AND FAILURE MECHANISMS OF NATURAL/ARTIFICIAL SLOPES. Formation and propagation of shear failure surface. Strain-softening and progressive failure; re-activated and first-time failures. Criteria for selecting shear strength parameters in slope stability analysis: considerations on drainage and slope type. 6. SLOPE STABILIZATION METHODS. Design and analysis of slope stabilization methods: an overview. 7. SLOPE MONITORING SYSTEMS. Monitoring pore water pressures by piezometers and slope movements (depth, rate, directions) by inclinometers.
EXCAVATIOPNS. INTRODUCTION. Shallow and deep excavations; general issues, support systems. Excavations below ground water level; dewatering systems. Excavation methods. 1. FAILURES MECHANISMS OF TRENCH EXCAVATIONS. Bulging of the vertical face of the trench excavation: critical height of unsupported trenches, influence of cohesion and tension cracks. Heaving or sqeezing of cohesive soil: stability factor-based analysis. Hydraulic failure mechanisms of soil piping and excavation bottom uplifting 2. MOVEMENTS INDUCED I BY EXCAVATIONS ON ADJACENT GROUND. Diaphragm wall displacement and associated ground movement.3. LATERAL EARTH PRESSURE OF SOIL. Active and passive earth coefficients. Displacement-dependence of lateral earth pressure of soil. Influence of soil cohesion and friction, and drainage conditions. 4. TEMPORARY PROPPED WALLS: trench wall support systems; earth pressure distribution on sheets piles and compressive loads on props. 5. DIAPHRAGM WALLS. Construction techniques; cantilever and anchored walls; soldier piles; ultimate and serviceability limit states design criteria. Ground anchors: construction techniques; pull out behavior and sliding resistance; design criteria. 6. GEOTECHNICAL DESIGN OF DIAPHRAGM WALLS AND PROPPED WALLS: standard requirements of current Italian Code; soil parameters selection and evaluation.