Discussion: Effect of Bentonite Slurry Pressure on Interface Friction of Pipe Jacking

Pipe jacking is a technique used to construct tunnels by pushing prefabricated pipes through the ground from an entrance shaft to an exit shaft. This technique is referred as microtunneling in U.S. terminology, therefore, in the rest of the text, pipejacking and microtunneling will be used as having the same meaning. Pipe jacking is a more economical alternative to segmental lined tunnels. However, the main limitation of pipe jacking is the jacking distance, which is directly dependent on the friction between the pipe and the soil. Therefore, reducing the friction between the pipe and soil is a critical issue in terms of economy and construction speed. In pipe jacking, in order to reduce the friction between pipe and soil, a bentonite injection is applied. In this paper, a new laboratory test setup was prepared to simulate pipe jacking. The main aim of this test setup was to find the effects of bentonite pressure on the lubrication efficiency, which has not been clarified in the literature yet. In order to verify the test method, results of laboratory tests were compared with measurements of the friction between jacked pipe and soil in several real life projects. The measurements were compared with the coefficient of friction values obtained from three different field measurements conducted in different projects. According to the results, it can be stated that by applying continuous bentonite injection even under very low pressure, an interface can be created between bentonite slurry and a concrete pipe, and this bentonite interface is able to reduce the friction coefficient tremendously to approximately 10% of the sand–concrete pipe interface friction coefficient. But when the injection is not applied continuously, the application of bentonite slurry injection decreases the coefficient of friction to half of that in the case of no bentonite injection

The Effect of Model Uncertainty on the Reliability of Spread Foundations

Risk and Reliability in Geotechnical Engineerin

Case Studies Used in Instruction to Achieve Specific Learning Outcomes: The Case of the Embankments Constructed for the Approach to Limerick Tunnel, Ireland

This paper gives an example of a case study written for instructional purposes, in order to support the achievement of specific learning outcomes which include (i) identifying modes of failure and (ii) selecting appropriate soil parameter types and values. Case writing was based primarily on information from a detailed publicly available article, supplemented with additional input from one author of this article. The case narrative is accompanied by annotated calculations, which follow the general design philosophy of the project. The case focuses on two of the main issues for the geotechnical design of the highway embankments close to the Limerick Tunnel, which are founded on very soft organic fine grained material. First, secondary compression, which is sizeable for this highway project, required surcharging to reduce the rate of long-term settlement. Second, the low undrained shear strength and high compressibility of the foundation material required construction of the embankments in stages, to achieve a degree of consolidation necessary for increased vertical effective stress, increased shear strength and reduced compressibility. This paper includes the case narrative, excerpts from the accompanying calculations, and comments on the instructional decisions involved in the preparation of both

Findings from the 2nd Set of Eurocode 7 Design Examples

Codes and Standard

The feathertop problem in Mitchell grass pastures

Seeds of Aristida latifolia (feathertop grass) in Mitchell grass (Astrebla spp.) pastures are the main cause of vegetable fault in wool from sheep grazing these areas. High stocking rates, particularly when the plants were young, reduced the build up of A. latifolia to only 4 000 plants compared with 35 000 in an adjacent field at low stocking rate. Control of A. latifolia by management strategies, (heavy grazing followed by pasture recovery in the wet season) is recommended

Eurocode 7: Geotechnical Design. Worked examples

This document is a report with worked examples summarizing the general rules, basic design principles and design methods for geotechnical design following Eurocodes. It comprises an overview of Eurocode 7 with focus on the design requirements, actions and design situations, and limit states. Different aspects to be considered for designing shallow foundations, gravity walls, embedded walls and deep foundations are covered in the report. The provisions of Eurocode 7 for ground investigations and testing for geotechnical design, overall stability of and movements in the ground, slopes, hydraulic failure modes and verifications against them are also presented. The Annex contains worked examples to accompany the various chapters of this report. The materials were prepared and presented at the workshop “Eurocode 7: Geotechnical Design” held on 13-14 June 2013 in Dublin, Ireland. The workshop was organized by JRC with the support of DG ENTR and CEN, and in collaboration with CEN/TC250/Sub-Committee 7 and Ireland’s Department of the Environment, Community and Local government. The document is part of the Report Series ‘Support to the implementation, harmonization and further development of the Eurocodes’ prepared by JRC in collaboration with DG ENTR and CEN/TC250 “Structural Eurocodes”.JRC.G.5-European laboratory for structural assessmen

Priorities and Principles for Investment in Aquaculture Research by NSW Department of Primary Industries

This review examined the characteristics of the main aquaculture industries in NSW with respect to current impediments to growth, market development and future opportunities. Within this context, it examined the nature, funding and impacts of the NSW Department of Primary Industries’ current and proposed investments in aquaculture R&D and industry development, as well as its alignment with DPI and industry priorities.aquaculture, research evaluation, public good, Agribusiness, Livestock Production/Industries, Research and Development/Tech Change/Emerging Technologies, Q160,

OMIP contribution to CMIP6: experimental and diagnostic protocol for the physical component of the Ocean Model Intercomparison Project

The Ocean Model Intercomparison Project (OMIP) is an endorsed project in the Coupled Model Intercomparison Project Phase 6 (CMIP6). OMIP addresses CMIP6 science questions, investigating the origins and consequences of systematic model biases. It does so by providing a framework for evaluating (including assessment of systematic biases), understanding, and improving ocean, sea-ice, tracer, and biogeochemical components of climate and earth system models contributing to CMIP6. Among the WCRP Grand Challenges in climate science (GCs), OMIP primarily contributes to the regional sea level change and near-term (climate/decadal) prediction GCs. OMIP provides (a) an experimental protocol for global ocean/sea-ice models run with a prescribed atmospheric forcing; and (b) a protocol for ocean diagnostics to be saved as part of CMIP6. We focus here on the physical component of OMIP, with a companion paper (Orr et al., 2016) detailing methods for the inert chemistry and interactive biogeochemistry. The physical portion of the OMIP experimental protocol follows the interannual Coordinated Ocean-ice Reference Experiments (CORE-II). Since 2009, CORE-I (Normal Year Forcing) and CORE-II (Interannual Forcing) have become the standard methods to evaluate global ocean/sea-ice simulations and to examine mechanisms for forced ocean climate variability. The OMIP diagnostic protocol is relevant for any ocean model component of CMIP6, including the DECK (Diagnostic, Evaluation and Characterization of Klima experiments), historical simulations, FAFMIP (Flux Anomaly Forced MIP), C4MIP (Coupled Carbon Cycle Climate MIP), DAMIP (Detection and Attribution MIP), DCPP (Decadal Climate Prediction Project), ScenarioMIP, HighResMIP (High Resolution MIP), as well as the ocean/sea-ice OMIP simulations

Network Topologies and Dynamics Leading to Endotoxin Tolerance and Priming in Innate Immune Cells

The innate immune system, acting as the first line of host defense, senses and adapts to foreign challenges through complex intracellular and intercellular signaling networks. Endotoxin tolerance and priming elicited by macrophages are classic examples of the complex adaptation of innate immune cells. Upon repetitive exposures to different doses of bacterial endotoxin (lipopolysaccharide) or other stimulants, macrophages show either suppressed or augmented inflammatory responses compared to a single exposure to the stimulant. Endotoxin tolerance and priming are critically involved in both immune homeostasis and the pathogenesis of diverse inflammatory diseases. However, the underlying molecular mechanisms are not well understood. By means of a computational search through the parameter space of a coarse-grained three-node network with a two-stage Metropolis sampling approach, we enumerated all the network topologies that can generate priming or tolerance. We discovered three major mechanisms for priming (pathway synergy, suppressor deactivation, activator induction) and one for tolerance (inhibitor persistence). These results not only explain existing experimental observations, but also reveal intriguing test scenarios for future experimental studies to clarify mechanisms of endotoxin priming and tolerance.Comment: 15 pages, 8 figures, submitte

Memories of a Dying Industry: Sense and Identity in a British Paper Mill

Frogmore paper mill is a kind of time machine that allows historians of technology and the senses to study mechanized paper-making as it was done one hundred years ago. Before the introduction of instrumentation and automatic process control paper-making depended profoundly on the embodied skills of the workers. This paper will focus on the sensory knowledge and skills required for monitoring and controlling old machinery. Investigating skills-in-use will help to unravel the close link between sensing and acting to keep a continuous production process stable and running. Paper-makers would shift intuitively between different senses and sensory modes of monitoring and diagnosing sensory tell-tales to balance the production process. The importance of sensory knowledge and embodied skills also shaped paper-makers’ self-perception and professional ethos. The paper will examine the impact of new process control technology on the crucial role of sensory skills for the paper-makers’ individual and collective identities