Dynamic behavior of pile-supported wharves by slope failure during earthquake via centrifuge tests

The effects of earthquakes on pile-supported wharves include damage to piles by inertial forces acting on the superstructure, and damage caused by horizontal displacement of retaining walls. Piles can also be damaged through kinematic forces generated by slope failure. Such forces are significant but it is difficult to clearly explain pile damage during slope failure since the inertial force of superstructure and the kinematic force by slope failure can occur simultaneously during an earthquake. In this study, dynamic centrifuge model tests were performed to evaluate the effect of the kinematic force of the ground due to slope failure during earthquake on the behavior of a pile-supported wharf structure. Experimental results indicate that the slope failure in the inclined-ground model caused the deck plate acceleration and pile moment to be up to 24% and 31% respectively greater than those in the horizontal-ground model due to the kinematic force of the ground.

Optimisation of geotechnical surveys using a BIM-based geostatistical analysis

PurposeA principle prerequisite for designing and constructing an underground structure is to estimate the subsurface's properties and obtain a realistic picture of stratigraphy. Obtaining direct measure of these values in any location of the built environment is not affordable. Therefore, any evaluation is afflicted with uncertainty, and we need to combine all available measurements, observations and previous knowledge to achieve an informed estimate and quantify the involved uncertainties. This study aims to enhance the geotechnical surveys based on a spatial estimation of subsoil to customised data structures and integrating the ground models into digital design environments.Design/methodology/approachThe present study's objective is to enhance the geotechnical surveys based on a spatial estimation of subsoil to customised data structures and integrating the ground models into digital design environments. A ground model consisting of voxels is developed via Revit-Dynamo to represent spatial uncertainties employing the kriging interpolation method. The local arrangement of new surveys are evaluated to be optimised.FindingsThe visualisation model's computational performance is modified by using an octree structure. The results show that it adapts the structure to be modelled more efficiently. The proposed concept can identify the geological models' risky locations for further geological investigations and reveal an optimised experimental design. The modifications criteria are defined in global and local considerations.Originality/valueIt provides a transparent and repeatable approach to construct a spatial ground model for subsequent experimental or numerical analysis. In the first attempt, the ground model was discretised by a grid of voxels. In general, the required computing time primarily depends on the size of the voxels. This issue is addressed by implementing octree voxels to reduce the computational efforts. This applies especially to the cases that a higher resolution is required. The investigations using a synthetic soil model showed that the developed methodology fulfilled the kriging method's requirements. The effects of variogram parameters, such as the range and the covariance function, were investigated based on some parameter studies. Moreover, a synthetic model is used to demonstrate the optimal experimental design concept. Through the implementation, alternative locations for new boreholes are generated, and their uncertainties are quantified. The impact of the new borehole on the uncertainty measures are quantified based on local and global approaches. For further research to identify the geological models' risky spots, the development of this approach with additional criteria regarding the search neighbourhood and consideration of barriers and trends in real cases (by employing different interpolation methodologies) should be considered.

ChipSats for Planetary Exploration: Dynamics and Aerothermal Modeling of Atmospheric Entry and Dispersion

This paper presents an orbit-to-ground model for the atmospheric entry of ChipSats, gram-scale spacecraft that offer unique advantages over their conventionally larger counterparts. ChipSats may prove particularly useful for in-situ measurements in the upper atmosphere, where spatially and temporally varying phenomena are especially difficult to characterize. Globally distributed ChipSats would enable datasets of unprecedented detail, assuming they could survive. The model presented is used to assess the survival and dispersion of a swarm of ChipSats when deployed over the Earth, Moon, Mars, and Titan. These planetary exploration case studies focus on the Monarch, the newest-generation ChipSat developed at Cornell University, in order to evaluate technology readiness for such missions. A parametric study is then conducted to inform future ChipSat design, highlighting the role of the ballistic coefficient in both peak entry temperature and mission duration.

Geomorphological Assessment of the Viability of the Landforms in the Khalekan Valley Basin for Human Uses

The study aims to evaluating the landform in the khalakan basin and its to preparing appropriate model for the capacity of the lands by using remote sensing (RS) technology and geographic information system (GIS) by depending on function of (Wighted-Overlay) which can be considered as one of the significant function of GIS. And in order to achieve the aim of the study, eight layers have been extracted for preparing appropriate ground model. according to the importance of each layer which is used to determine the ability and they are: (geological formations, slope, splash erosion, soil, plant cover (NDVI), elevation and lineaments, geomorphological unit) layers which can be considered as the result of Intrusive and extrusive processes. After the processes of Overlaying, the study successfully produced a general map for the appropriateness ground which categorized the area into three levels of appropriateness: the level of high appropriateness with area of(9.34Km), the level of mid appropriateness with area of (70.34Km) and the level with no appropriateness with area of (4.957Km.

A Methodology for Estimating the Position of the Engineering Bedrock for Offshore Wind Farm Seismic Demand in Taiwan

Taiwan lies in the circum-Pacific earthquake zone. The seabed soil of offshore wind farms in Taiwan is mainly composed of loose silty sand and soft, low-plasticity clay. The seismic demand for offshore wind turbines has been given by the local code. Ground-motion analysis is required to consider the site effects of the soil liquefaction potential evaluation and the foundation design of offshore wind turbines. However, the depth of the engineering bedrock for ground motion analysis is not presented in the local code. In this study, we develop a three-dimensional ground model of an offshore wind farm in the Changhua area, through use of collected in situ borehole and PS (P wave (compression) and S (shear) wave velocities) logging test data. The engineering bedrock is the sediment at the depth where the average shear wave velocity of soil within 30 m, Vsd30, is larger than 360 m/s. In this ground model, the shear wave velocity of each type of soil is quantified using the seismic empirical formulation developed in this study. The results indicate that the engineering bedrock lies at least 49.5–83 m beneath the seabed at the Changhua offshore wind farm. Based on these findings, it is recommended that drilling more than 100 m below the seabed be done to obtain shear wave velocity data for a ground response analysis of the seismic force assessment of offshore wind farm foundation designs.

Geological structures beneath the River Thames in London: findings from the Thames Tideway Tunnel investigations

The Thames Tideway Tunnel is 25 km long and extends west – east through central London, beneath the River Thames for most of its route. A detailed preconstruction ground model has been assembled, using data from borehole and river-borne seismic reflection survey investigations. The two data sets have together delineated several significant geological structures along the route.The investigations have led to an improved understanding of the morphology of some structures, such as the Greenwich Fault, London Bridge Fault Zone, Millwall Anticline and Greenwich-Plaistow Syncline, which were only generally indicated during preliminary desk studies. Other structures, such as the Putney-Hammersmith Fault Zone, Chelsea Embankment Fault Zone and Lambeth Anticline, are entirely new discoveries.Most of the structures described here have characteristics compatible with strike-slip displacement and, although this has been previously widely suspected, this paper presents new evidence towards this. When intersected by the tunnel during its construction phase, they have imposed significant changes in geological strata, leading to changes in the performance of tunnelling plant or creating adverse ground conditions. Their early identification by the ground model has assisted engineering design and planning, for the benefit of construction cost efficiency and, importantly, Health and Safety of underground personnel.Thematic collection: This article is part of the Geology of London and its implications for ground engineering collection available at: https://www.lyellcollection.org/cc/london-basin

Interlude: Context and Common Ground

An influential alternative account of context that likewise models context as a body of information that changes with an evolving discourse is Stalnakerian common ground model. On this model, however, the context is projected from a body of information mutually accepted by the interlocutors for the purposes of a conversation—a common ground. While the context constantly changes, these changes simply reflect the agents’ rational and cooperative response to manifest evidence. Might one attempt to assimilate the kinds of effects on prominence simply to such rational responses to manifest evidence? Might we then do without the rich discourse structure posited in this chapter? It is argued here that this account would be empirically inadequate, failing to capture the special status linguistic conventions have when weighed against our overall evidence.