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This thesis investigates the WCSPH model by considering fluid entry and exit, and integrates the WCSPH method into a new, novel, particle-based Bluff Morphology Model (BMM). Using the BMM, this thesis investigates the stability, collapse and equilibrium position of soft coastal bluffs (cliffs). Fluid and floating object interaction using a novel adaptation of the WCSPH method is investigated by incorporating a floating object model. In particular, this thesis examines the water impact, hydrodynamic forces, fluid motions, and movement of objects in the conventional case studies of object entry and exit from still water. A two-dimensional wedge drop analysis was examined, and the hydrodynamic forces show acceptable agreement with published experimental and numerical results. Simulations for water entry and exit of a buoyant and neutral density cylinder compares well with the previous experimental, numerical and empirical studies. These results provide a good foundation to evaluate the accuracy and stability of WCSPH for modelling complex flows, and therefore offers a platform for the use of WCSPH in a Bluff Morphology Model. The BMM combines a multiple wedge displacement method with an adapted Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method. At first the wedge method is applied to compute the stability of the bluff. Once the critical failure mechanism of the bluff slope has been identified, if the Factor of Safety for the mechanism is less than 1, the adapted WCSPH method is used to predict the failure movement and residual shape of the slope. The model is validated against benchmark test cases of bluff stability for purely frictional, purely cohesive, and mixed strength bluff materials including 2D static water tables. The model predictions give a good correlation with the expected values, with medium resolution models producing errors of typically less than 2.0%. In addition, the prediction of lateral movement of a surveyed cliff and the dynamic collapse of a vertical bluff are computed, and compare well with published literature. This model is further extended to then investigate the effect of two dimensional seepage on the stability and collapse of soil slopes and levees. To incorporate the seepage in the model, Darcy’s Law is applied to the interactions among neighbouring soil particles and ghost particles are introduced along the enclosed soil boundary to ensure that no fluid crosses the boundary. The contribution of partially saturated soils and matric suction, as well as the change in hydraulic conductivity due to seepage, are predicted well by this model. The predicted time evolution of slope stability and seepage induced collapse are in reasonable agreement with the experimental results for homogeneous frictional sand and multiple layered cohesive soils. Rapid drawdown over a sand soil is also investigated, and the location and time of the levee collapse occurrence are captured well. A toe erosion model is incorporated within the numerical model, and the location and quantity of erosion caused by lateral seepage is well predicted. The interplay of erosion, seepage and slope instability is examined.

This research has developed a methodology for high precision monitoring of coastal chalk sea cliffs using both terrestrial and unmanned aerial vehicle (UAV) digital photogrammetry. Two contrasting study sites of similar geology at Brighton Marina and Telscombe enabled a comparative assessment of cliff behaviour, for an engineered cliff with toe protection and cliff face stabilisation versus a natural cliff subject to active toe erosion respectively. The site at Brighton Marina was monitored between November 2014 and March 2017, during this period no rockfall was detected above the surface change threshold of 0.07 m. For the Telscombe site, monitored between August 2016 and July 2017, volumetric estimations of rockfalls populated a rockfall inventory. Frequency-magnitude analysis of the monthly inventories demonstrated negative power law scaling over seven orders of magnitude with 10,085 mass wasting events and a total volumetric flux of 3,889.35 m3. Statistically significant correlations were found, for the first time, between significant wave height (Hs) and the power law scaling coefficients, β and s with R2 values of 0.4971 and 0.5793 respectively. The model was an accurate predictor of erosion evidenced by the R2 of 0.9981 between the model predictions and observations over the data collection period. A Monte Carlo simulation of potential erosion scenarios between 2020 and 2089 was established using these relationships based on Hs probabilities and sea level forecasts derived from the UKCP09 medium emission climate model (A1B) to assess the impact of future climate change on cliff recession. For the most likely cliff recession scenario the model predicts an approximate 6% increase in recession between the current and future (UKCP09 medium emission scenario) conditions from 20.45 m to 21.76 m. The model also estimates the probability of recession breaching the A259 coastal road by 2089, this revealed an increase from 0.0778 to 0.1056 due to the influence of future climate. The photogrammetric models were also used to characterise the Newhaven Chalk cliffs and through kinematic analysis found wedge failure to be the most likely mechanism of failure, with 39.97% of mapped intersections favourable to this mode. A limit equilibrium analysis of the observed conjugate joint sets within the defended section of cliffs between Brighton Marina and Telscombe was undertaken to assess the risk of any future failure to infrastructure. This revealed that the coastal road would not be at immediate threat (breach) due to any of the modelled wedge failures occurring, however measures would need to be put in place to maintain the road in its current location were any of these failures to occur. A probabilistic recession model using current industry best practice, in the absence of a rockfall inventory, was used to predict future recession for the defended section of cliffs. Within identified ‘pinch-points' where the distance between the road and cliff edge was less than 10 m the probability of recession reaching the road over the next 100 years did not exceed 0.0014. A comparison between approaches identified the benefits of the scientific method presented in this research. The outputs of this research offer a new approach for the collection and processing of coastal monitoring data which ultimately drives the prediction of future coastal cliff recession and facilitates effective planning and mitigation.

This thesis examines the pre and post failure deformation behaviour of landslides in cut, fill and natural soil slopes, and of the deformation behaviour of embankment dams. The deformation behaviour of landslides and embankment dams have been analysed from a database of case studies from a number of classes of slope (and dam) and material type. The database included some 450 landslides in cuts, fills and natural slopes, and some 170 embankment dams. For landslides in soil slopes, methods and guidelines have been developed for use in the analysis, evaluation and prediction of the pre and post failure deformation behaviour. They take into consideration the factors influencing and the mechanics controlling the deformation behaviour for the classes of slope and material types, which are different for pre and post failure. Pre-failure deformations are largely controlled by the effective stress conditions within the slope, changes in the boundary conditions and the response of the soil to those changes in boundary conditions. Whether the soil, under the effective stress conditions imposed within the slope, is contractive (and saturated or near saturated) or dilative on shearing, has a significant influence on the pre failure deformation behaviour. The post failure deformation behaviour is strongly influenced by the mechanics of failure (including whether the soil is contractive or dilative on shearing), the source area slope angle, the downslope geometry, the orientation of the surface of rupture, the material properties and slide volume. Guidelines are presented for prediction of 'rapid' and 'slow' post failure velocity. For embankment dams, methods and guidelines have been developed for evaluation and prediction of the deformation behaviour during and post construction for selected embankment types. They take into consideration the influence of material type and placement methods, material strength and compressibility properties, embankment zoning geometry, embankment height, and reservoir operation, amongst other factors. Guidelines have been developed to assist in the identification of 'abnormal' deformation behaviour, which can be related to internal deformations or a marginal stability condition and the onset to failure.

Thesis (M.A.)--University of Hong Kong, 1972. / Mimeographed.

published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

No description available.

No description available.

Thesis (M.S.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 102-106). Also available on the World Wide Web.

Thesis (Ph. D.)--University of New South Wales, 2003. / Also available online.