Impulse waves in reservoirs, lakes, bays and oceans may be generated by landslides. The resulting impulse waves can propagate and cause disaster to the downstream. Some studies are carried out to investigate such phenomenon but most of them were based on either experimental observations or empirical/semiempirical relationships in simulating the waves generated by landslides. Therefore, the fundamental mechanism of such hazard is not got fully understood (complex motions of landslides with arbitrary geometry and interactions of fluid with landslides or shorelines). In addition, the effects of landslide-induced waves on downstream structures are rarely reported. Therefore, it appears necessary that the coupling numerical model is developed to simulate landslide-induced waves and to investigate generated wave characteristics. Furthermore, their effects on downstream structures should be investigated for mitigating hazard, such as the estimations of wave run-up, rundown and wave overtopping. This thesis presents the numerical modeling of landslide-induced waves and their effects on the downstream structures based on the computational fluid dynamics (CFD) package FLUENT. As there is no existing module to simulate water waves, the redevelopment of FLUENT by the user defined function (UDF) is necessary. For the problem of landslide-induced wave, two simplified numerical models are developed, including piston-type model and inlet boundary-type model. These two numerical models can rapidly assess the landslide-induced waves but be appropriate for the simple cases, such as a vertical wall moving horizontally or slump-type landslide whose particle velocities and free surface displacements at the inlet boundary are known. In order to expand the available range of numerical modeling, the block models aiming for rockslide are developed to investigate landslide-induced waves. Four categories of landslides are considered, such as horizontal landslide, vertical landslide, subaerial landslide and submarine landslide. Except of horizontal landslide, the coupled block model is employed to investigate water waves generated by vertical, subaerial and submarine landslides. The coupling is based on an iterative procedure enforcing the principle of the dynamic equilibrium of the fluid, the slide and their interfaces, and the interaction between landslide and fluid are considered. The wave characteristics generated by above-mentioned different types of landslides are investigated and discussed. For their effects of landslide-induced wave on downstream structures, the focuses of numerical modeling are the run-up and rundown of waves generated by subaerial and submarine landslides and wave overtopping on the downstream structures. The detailed numerical modeling illustrates that the present models can predict fairly well landslide-induced waves and their effects on downstream structures. The results of parametric study indicate that slide volume and impact Froude number ( v / gh ) play important roles on generated wave characteristics. The wave characteristics, propagation distance and geometric characteristics of seaward structural wall (slope and crest freeboard) are major factors in determining the characteristics of wave run-up, rundown and overtopping. Several useful prediction relationships are provided. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Η εργασία αυτή έγινε στα πλαίσια του Μεταπτυχιακού Προγράμματος Σπουδών «Εφαρμοσμένη και Περιβαλλοντική Γεωλογία» του Τμήματος Γεωλογίας του Πανεπιστημίου Πατρών και έχει ως σκοπό την διερεύνηση και στατιστική επεξεργασία των βροχομετρικών δεδομένων για την περιοχή της Βόρειας Πελοποννήσου προκειμένου να γίνει ανάλυση και συσχέτιση τους με τις κατολισθήσεις της περιοχής. Η περιοχή μελέτης περιλαμβάνει τους Νομούς Αχαΐας και Κορινθίας. Πρόκειται για μια περιοχή που δέχεται σχετικά μεγάλα ποσοστά βροχόπτωσης και στην οποία έχει παρατηρηθεί σημαντικός αριθμός κατολισθήσεων. Γίνεται συστηματική καταγραφή, επεξεργασία και αξιολόγηση των διαθέσιμων βροχομετρικών δεδομένων από μετεωρολογικούς σταθμούς που υπάρχουν στις περιοχές αυτές για την εκτίμηση των μέσων ετήσιων τιμών και στη συνέχεια γίνεται εκτίμηση της χωρικής κατανομής αυτών. Η συγκριτική θεώρηση του αριθμού των κατολισθήσεων που έγιναν την αντίστοιχη περίοδο δείχνει ότι υπάρχει μια ποιοτική συσχέτιση με τις βροχοπτώσεις. Σκοπός της παρούσας εργασίας είναι να αποτελέσει την βάση για την ποιοτική έκφραση μιας τυπικής σχέσης στα πλαίσια περαιτέρω και συστηματικότερης διερεύνησης του φαινόμενου. / This project has been carried out in the framework of the Postgraduate studies of ‘’Applied and Environmental Geology’’ of the Geology Department of the University of Patras. Its aim is the examination and statistic processing of the rainfall data in the region of North Peloponnisos, so that they will be analyzed and related to the landslides of the area. The study area includes Achaia and Korinthia. Its an area with relatively great amount of rainfall and in which a large number of landslides has been observed. The available rainfall data taken from several weather stations have been methodical recorded, processed and evaluated, so that the mid-annual rates can be estimated and afterwards there has been an evaluation of their space allocation. The comparative consideration of the number of landslides taken place in the respective period shows a qualitative relation to the rainfalls. The aim of the present project is to become the basic of the qualitative expression of the typical relation in the framework of an even more systematic examination of these observations.

The catastrophic consequences associated with landslides necessitate predictions of these hazards to be made with as much certainty as possible. However, the often complex nature of these events make predictions highly challenging. In this thesis, a number of hypotheses related to the triggering mechanisms and subsequent consequences of landslides in a loose-granular soil were investigated. The investigation was conducted using small-scale geotechnical centrifuge models, and a new flume facility developed to examine landslide behavior in a reduced-scale model. The first hypothesis explored in this research was that static liquefaction might preferentially occur in the saturated granular soil located at the base of the landslide rather than the well-drained inclined portion of the slope. Using a geotechnical centrifuge model, it was found that a small initial toe failure did act as a monotonic loading trigger to shear the loose contractile saturated sand at the base of the slope and caused liquefaction to occur. The second hypothesis investigated whether the consequences of a landslide triggered under elevated groundwater antecedent conditions are higher than scenarios under drier antecedent conditions. Results from five centrifuge models subjected to different antecedent groundwater conditions show that higher groundwater conditions can result in landslides with velocities about three times higher and travel distances eight times higher than low antecedent conditions. The third hypothesis investigated the influence of slope inclination on landslide consequences. Seven geotechnical centrifuge models were built and tested, comparing the consequences of landslides triggered in 20° and 30° sloped models with different groundwater conditions. The results of these tests found that the influence of slope angle on the mobility consequences of a triggered landslide are highly dependent on the antecedent groundwater conditions. The most significant case was under high groundwater conditions, where the shallower 20° slope travelled twice the distance and speed of the steeper 30° slope. A new flume facility was developed to examine landslide behaviour in a reduced-scale model, and a direct comparison was made to one of the centrifuge models from the research. The comparison demonstrated the challenges associated with using reduced-scale models to study suction-dominated problems such as hydraulically-induced landslides in loose granular soils. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2014-04-29 16:45:11.335

Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract and vita. Includes bibliographical references (leaves 449-468).

Thesis (M. Sc.)--University of Hong Kong, 2005.

Στην εργασία αυτή γίνεται η περιγραφή, των κατολισθητικών φαινομένων που λαμβάνουν χώρα στον ελλαδικό χώρο. Έμφαση δίνεται κυρίως στη δυτική Ελλάδα όπου παρατηρούνται οι σημαντικότερες κατολισθήσεις στη χώρα μας που αφορούν κατά βάση ολισθήσεις εδαφών και μαλακών βράχων. Προκύπτουν τόσο λόγω της φύσης των γεωλογικών σχηματισμών της περιοχής, όσο και των τεκτονικών διεργασιών. Επίσης, παρουσιάζεται η μελέτη που πραγματοποιήθηκε στην περιοχή του Λαμπιρίου Αχαΐας. Μια περιοχή όπου παρατηρούνται ολισθήσεις εδαφών (άμμοι, ψαμμίτες, κροκκαλοπαγή) και έχουν οδηγήσει σε αστοχία την παλαιά εθνική οδό. Στην εργασία αυτή παρουσιάζονται τα γεωτεχνικά προβλήματα της συγκεκριμένης ολίσθησης. Επίσης παρουσιάζονται οι εργασίες που έγιναν για τη σύνταξη της γεωτεχνικής μελέτης για την επίλυση του προβλήματος, τόσο στο πεδίο (δειγματοληπτική γεώτρηση, επί τόπου δοκιμές), όσο και στο εργαστήριο (δοκιμές φυσικών-μηχανικών ιδιοτήτων). Τέλος, στην εργασία αυτή παρουσιάζονται τα αναγκαία μέτρα για την προστασία και την εξυγίανση της περιοχής της μελέτης. Τα μέτρα αυτά έχουν προταθεί ήδη και αναμένεται η εκτέλεση των εργασιών. / -

Comprehensive sediment budgets are compiled for a series of pocket shingle beaches in West Dorset backed by massive soft cliffs that degrade in a rapid and complex manner. Studies involve the identification and quantification of sediment (primarily shingle) inputs, transfers, storage and outputs within terrestrial and marine subsystem components. Results are unified within budget and flow models and applied to tackle questions of coastal evolution and management. Research involved mapping and sampling of the ground forming materials in terms of their beach forming potential. Cliff landsliding and recession are analysed using comparisons of historical maps, aerial photos and documentary evidence. A method of quantifying the release, throughput and supply to the beaches of various sediment grades from the eroding cliffs is presented. The volumes and types of sediment at the beach and in the inshore zone are investigated by various profile, intertidal, and offshore surveys. Detailed sampling and sediment analysis of the beaches is undertaken to elucidate beach drift and for attrition assessments through comparisons with cliff inputs. Shingle tracing experiments using aluminium tracers are conducted to study transport and sorting at two contrasting sites over a full spectrum of wave energy conditions. Validated littoral drift volumes and original wave power relationships are developed. Information is compiled to produce budget models for the main beaches. Complex long established links are demonstrated between eroding cliff sources and the shingle beaches that they supply. Chesil Beach is identified as the ultimate shingle sink suggesting that it is not entirely a product of the Holocene transgression as often envisioned, but a component of a Lyme Bay process system and open periodically to inputs of shingle from the west. Adverse impacts arising from various human interventions are highlighted using the models.

The Appalachian Mountains in eastern Tennessee are known for landslides, and landslides are reported to cause millions of dollars of damage. To aid in the estimation of future susceptibility, geographic information systems was used to perform a logistic regression, to identify landslides in eastern Tennessee. Landslide model results validated using Kold cross validation. The model results suggest that the environmental variables slope, soil, landcover/vegetation, and distance to roads were significant factors related to landslide susceptibility. The susceptibility map showed that 86.8% of urban areas in eastern Tennessee were at highest susceptibility for landslides, possibly due to lower amounts of landcover. By overlaying past landslides on landslide susceptibility for accuracy, areas with high landslide susceptibility were found in areas along main highways and interstates. This model is a first step in using GIS to increase the awareness of landslide susceptibility in the regions and may ultimately lead to better preparation.

The section of this report devoted to the control of slides serves to illustrate the more typical situation of a movement, that is not subject to a theoretical analysis. The great majority of slides that occur in natural ground pass through complex soil stratifications that do not permit the simplifying assumptions needed for the various methods of mathematical and graphical analysis, In these cases, the procedures for the control and stabilization of the moving material depend exclusively on the characteristics of the particular location, Each slide is a separate problem whose solution is not necessarily similar to any other. The control section of this report has presented a summary of the various methods for the field control of slides that may he used, The choice of the applicable method is made only after extensive study of the nature of the particular slide, The more common control procedures have been illustrated by reference to the case histories of actual slides that have been successfully controlled. / Master of Science

Submarine landslides, commonly triggered by earthquakes, significantly affect tsunami wave heights. Subaerial landslides can also generate tsunamis (if the land flows into a body of water) and may be catastrophic in nature, causing human casualties and direct property damage. This work focuses on landslides associated with shear band that develops beneath the slipping mass. Accordingly, we consider a landslide as a dynamic process when a shear band emerges along the potential failure surface. Within this band, the shear strength decreases due to the softening behaviour of the particulate material. Material above the band moves downwards, causing the band to propagate dynamically. This already produces a landslide velocity before the slide reaches the post-failure stage and begins separating from the substrata and generating tsunami. However, existing models of tsunamigenic landslides assume zero initial slide velocity. Previous analyses of the catastrophic shear band propagation in slopes of normally- and over-consolidated sediments have shown that a relatively short initial failure zone is sufficient to cause a full-scale landslide. For the shear band to propagate, the energy produced in the body by an incremental propagation of the shear band must exceed the energy required for the propagation. This consideration separates the shear band growth into progressive (stable) and catastrophic (dynamic) stages and treats the band growth as a true physical process rather than an instantaneously appearing discontinuity. This work considers a dynamic shear band problem formulated within the framework of the Palmer and Rice’s [1973] approach. We obtain the exact, closed-form solution for the shear band and landslide velocities as well as for the spatial and temporal distributions of strain and material velocity. This solution assesses when the slide fails due to the limiting condition near the propagating tip of the shear band. We also obtain a simple asymptotic solution, which is compared to the exact solution. In the case of submerged slopes, the obtained solutions are used in landslide and tsunami height analyses. Our results suggest that the conventional static approach to the slope stability analysis leads to a significant underestimation of the slide size (volume). In most cases, the volumes of catastrophic slides are roughly twice the volumes of progressive slides. For submerged slides, this dynamic effect further manifests itself in increasing the tsunami magnitude compared to the static case.