Geotechnical Engineering Lecture Notes PDF - 2023-2024

Dipartimento di Ingegneria Civile, Università di Salerno Corso di Geotecnica per l'ambiente ed il territorio MODULO II Indagin...

Dipartimento di Ingegneria Civile, Università di Salerno Corso di Geotecnica per l'ambiente ed il territorio MODULO II Indagini e monitoraggi geotecnici convenzionali e innovativi A.A. 2023-2024 Lesson n°1 6 March 2024 Prof. Dario Peduto Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 1 1/20  Introduction to the Course Timetable of classes Wednesday: 8:30 - 10:30 Thursday: 15:30 - 18:30 Course info LESSONS: - frontal lessons on theoretical background and special focus on practical applications; - tutorials focused on the analysis and interpretation of datasets; - «meet the expert» seminars; - field activity; - technical visits. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 2 2/20  Introduction to the Course Course info EXAM: - ORAL EXAM on topics addressed during the course. - Report on the results of Tutorials. DIDACTIC MATERIALS - Notes (slides) from lessons. - Scientific papers, reports provided by the Lecturer. - John Dunnicliff, Geotechnical Instrumentation For Monitoring Field Performance, John Wiley & Sons, 2008 - Italian Technical Standards for Constructions (NTC2018) Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 3 3/20  Indagini e monitoraggi geotecnici convenzionali e innovativi : Index of Contents INVESTIGATIONS AND MONITORING IN GEOTECHNICS Standards, multi-source systems and observational approach to design. Litho-stratigraphic investigations: wells, tunnels, boreholes, open excavations, trenches. Sampling. Monitoring data: characteristics, interpretation and presentation of data. IN-SITU TESTS FOR SOIL MECHANICAL CHARACTERIZATION Tests: SPT, CPT, CPTU, SCPTU, vane-test, pressure gauge, flat dilatometer, seismic dilatometer. GROUNDWATER LEVELS, PORE PRESSURES, HYDRAULIC PROPERTIES OF THE SOILS Open tube piezometers, Casagrande piezometers, piezometric cells, electric and vibrating wire piezometers. Measurements in wells, pumping tests. Lugeon test. Suction measurements in unsaturated soils: tensiometers. Water content measurements: TDR probes. GEOPHYSICAL INVESTIGATIONS Georadar, Down-Hole, Cross-Hole, Sasw, Masw, Magnetometer, ERT tests: principles, techniques of restitution and interpretation; diagnostic applications. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 4 4/20  Indagini e monitoraggi geotecnici convenzionali e innovativi : Index of Contents GIS SYSTEMS AND SATELLITE TECHNIQUES GIS systems for the design of surveys and geotechnical monitoring. Satellite radar interferometry (DInSAR): principles, algorithms, precision/accuracy, data archive, dataset selection, applications to geotechnical problems. LANDSLIDES Characterization. Monitoring of pore pressures and superficial and deep displacements. Multi-source data for risk analysis. SUBSIDENCE Causes, predisposing factors, monitoring of buildings, bridges, embankments. Assessment of the vulnerability of the exposed elements. TUNNELLING Tunnel monitoring with GPR; laserscanner: operation and applications. OPTICAL FIBERS Principles, applications. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 5 5/20  Partnerships Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 6 6/20  Geotechnical Engineering Geotechnical Engineering is part of Civil Engineering and it is aimed at studying the so called geotechnical systems or works. GEOTECHNICAL WORKS works interacting with the ground (foundations, retaining structures, etc) works built in the ground (tunnels, excavations, etc.) works built with the ground (leeves, embankments, dams, etc.) some phenomena occurring in/on the ground (landslides, subsidence, earthquakes, etc.) Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 7 7/20  Geotechnical Engineering Geotechnical Engineering is part of Civil Engineering and it is aimed at studying the so called geotechnical systems or works GEOTECHNICAL WORKS Various and structurally different types or within the same type, different sizes; With the same type and size, different execution techniques (for example, according to the subsoil features and groundwater conditions, etc.). Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 8 8/20  The Role of Monitoring in Geotechnical Engineering OPEN QUESTIONS: WHY A COURSE ON INVESTIGATIONS AND MONITORING IN GEOTECHNICS? WHAT IS THEIR ROLE IN THE DESIGN AND CONTROL OF GEOTECHNICAL SYSTEMS? WHAT DOES “INNOVATIVE” STAND FOR? Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 9 9/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) FRAMEWORK OF THE PROJECT (of a geotechnical work) The design of works and interventions is divided into the following phases: 1. geological characterization and modeling of the site; 2. selection of the type of work or intervention and planning of geotechnical investigations; 3. physical-mechanical characterization of the soils and rocks present in the significant volume and definition of the geotechnical subsoil models; 4. definition of the phases and construction methods; 5. safety and performance checks; 6. planning of control and monitoring activities. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 10 10/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) 6.2.5. USE OF THE OBSERVATIONAL METHOD The design can also use the observational method in cases where, due to the particular complexity of the geological and geotechnical conditions and the importance and commitment of the work, after extensive and in-depth investigations documented reasons of uncertainty still remains that can only be resolved during the execution of the work. In applying this method, the following procedure must be used: - the limits of acceptability of the values ​of some quantities representative of the behavior of the soil-structure complex must be established; - it must be shown that the chosen solution is acceptable in relation to the above limits; - alternative solutions must be provided, consistent with the project, and the related economic costs defined; - an adequate monitoring system must be established during the work, with its related control plans, such as to allow promptly the adoption of one of the alternative solutions provided, if the indicated limits are reached. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 11 11/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) 6.2.6. MONITORING OF THE SOIL-STRUCTURE COMPLEX The monitoring of the soil-structure complex and interventions consists of the installation of appropriate equipment and the measurement of significant physical quantities - such as displacements, stresses, forces and pore pressures - before, during and/or after the construction of the artwork. The purpose of the monitoring is to verify the correspondence between the design hypotheses and the observed behavior and to check the functionality of the products over time. As part of the observational method, monitoring is intended to confirm validity of the design solution adopted or, if not, to identify the most suitable among the other solutions. If scheduled, the monitoring program must be defined and illustrated in the geotechnical report. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 12 12/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for SLOPE STABILITY 6.3.5. STABILIZATION WORKS The project of stabilization works must include the complete description of the intervention, the influence of the constructive typology on the conditions of stability, the monitoring plan and a significant management and control plan over time of the functionality and effectiveness of the measures taken. In any case, the extent of the improvement of the slope safety conditions as well as the criteria to verify its achievement must be defined. 6.3.6. CHECKS AND MONITORING The monitoring of a slope or a landslide involves different phases that go from the study to the design, to the realization and management of stabilization works and the check of their functionality and durability. It mainly refers to the displacements of surface or deep points on the slope, to the check for any artifacts present and to measure pore pressures, to be carried out with frequency and duration such as to allow defining the periodic and seasonal variations. The control of the effectiveness of stabilization interventions must include the definition of the warning and alarm thresholds and the measures to be taken in the event of their exceedance. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 13 13/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for RETAINING STRUCTURES 6.5.1 GENERAL DESIGN CRITERIA …… The effects deriving from partial loss of effectiveness of particular devices such as surface and deep drainage systems, and anchors must be evaluated. For all these interventions, a detailed monitoring control plan must be prepared in cases where their loss of efficacy can set up risk scenarios. …… 6.6.1. DESIGN CRITERIA FOR ANCHORS An ordinary maintenance program must be defined in the project that may also include subsequent maintenance interventions, adjustment and/or replacement of the anchoring devices. A monitoring plan must also be prepared to verify the behavior of the anchor over time. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 14 14/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for underground construction works 6.7.6. CONTROL AND MONITORING Monitoring must allow verifying the validity of the project forecasts in relation to the behavior of the work during both construction and operational phase, for the period of time indicated in the project. It must be arranged in such a way as to allow evaluating the behavior of the involved soil or rock mass, of the coating structures for each phase of excavation/construction and completed work, as well as the behavior of existing artifacts. In the presence of landslides (potential, dormant or active), monitoring must concern significant quantities (stresses, displacements and pore pressures) and effects on the works to control the phenomenon. In the case of application of the observational method, monitoring must be specifically designed to allow controlling the quantities representative of the behavior of the geotechnical system for the selection of the alternative solutions provided. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 15 15/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for EXCAVATION FRONTS 6.8. WORKS OF LOOSE MATERIALS AND EXCAVATION FRONTS 6.8.5. CHECKS AND MONITORING During construction, control tests must be performed according to a test program commensurate with the type and the importance of the artefact, so as to ensure an adequate number of significant measures. By means of monitoring you have to ascertain that the values of the measured quantities, such as for example displacements and pore pressures, are compatible with the requirements of safety and functionality of the work as well as of the adjacent structures. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 16 16/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for the improvement and reinforcement of soils and rocks 6.9 IMPROVEMENT AND REINFORCEMENT OF SOILS AND ROCKS These rules concern the design, construction and control of soil improvement and reinforcement interventions of rock masses, made for different application purposes. 6.9.2. MONITORING Monitoring is intended to assess the effectiveness of interventions and to verify the compliance of the results obtained with the design hypotheses. It also has the purpose of controlling the behavior over time of the soil-structure complex. Monitoring must be provided in cases where improvement and reinforcement interventions can affect the safety and the functionality of the planned work or surrounding works. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 17 17/20  The Role of Monitoring in Geotechnical Engineering From Italian Technical Standards for Constructions (NTC2018) As for CONSOLIDATION OF EXISTING WORKS 6.10. GEOTECHNICAL CONSOLIDATION OF EXISTING WORKS The rules concern all the technical measures carried out on the soil-structure system to eliminate or mitigate performance defects of an existing work. 6.10.4. CHECKS AND MONITORING The control of the effectiveness of geotechnical consolidation is mandatory when the interventions result in a redistribution of the stresses to soil-structure contact. The controls are performed with different instruments and methods in relation to the importance of the work, the type of defect in the artefact and possible damage to people and things. The monitoring of the consolidation interventions must be foreseen in the project and described in detail - indicating the quantities to be measured, the tools used and the frequency of the measurements - in the case of use of the observational method. The results of the measurements and controls can be a testing element of the individual interventions. Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 18 18/20  The Role of Monitoring in Geotechnical Engineering BACK TO OPEN QUESTIONS: WHY A COURSE ON MONITORING IN GEOTECHNICS? WHAT IS THE ROLE OF MONITORING IN DESIGN AND CONTROL OF GEOTECHNICAL SYSTEMS? WHAT DOES “INNOVATIVE” STAND FOR? Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 19 19/20  The Role of Monitoring in Geotechnical Engineering Innovation……..Innovative techniques Mandolini and Manassero (2011) observe that: “technological evolution is meant as an improvement of something within its own domain (vertical development) whereas technological innovation means something that derives from a transversal process that connects at least two technological domains, causing a sudden change in at least one of them". "Whether we are talking about evolution, or whether we are talking about innovation, in any case it gives rise to better solutions than the previous ones, but with the substantial difference that technological innovation determines something really new, which clearly differs from pre-existing technologies in that it exploits a new principle or radically different from the one hitherto used to respond to one or more needs expressed by the market ". Course of Indagini e monitoraggi geotecnici convenzionali e innovativi – A.A. 2023–2024 – Prof. Dario Peduto - Lesson I, 6 March 2024 20 20/20