Insight into Some Aspects of Pipe Jacking Techniques during Long Distance Installations in Municipal Engineering

ICPTT 2011 ◽  
2011 ◽  
Author(s):  
Zhuanyun Yang
Author(s):  
Rui P. Chaves ◽  
Michael T. Putnam

This book is about one of the most intriguing features of human communication systems: the fact that words which go together in meaning can occur arbitrarily far away from each other. The kind of long-distance dependency that this volume is concerned with has been the subject of intense linguistic and psycholinguistic research for the last half century, and offers a unique insight into the nature of grammatical structures and their interaction with cognition. The constructions in which these unbounded dependencies arise are difficult to model and come with a rather puzzling array of constraints which have defied characterization and a proper explanation. For example, there are filler-gap dependencies in which the filler phrase is a plural phrase formed from the combination of each of the extracted phrases, and there are filler-gap constructions in which the filler phrase itself contains a gap that is linked to another filler phrase. What is more, different types of filler-gap dependency can compound, in the same sentence. Conversely, not all kinds of filler-gap dependencies are equally licit; some are robustly ruled out by the grammar whereas others have a less clear status because they have graded acceptability and can be made to improve in ideal contexts and conditions. This work provides a detailed survey of these linguistic phenomena and extant accounts, while also incorporating new experimental evidence to shed light on why the phenomena are the way they are and what important research on this topic lies ahead.


The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 564-573 ◽  
Author(s):  
Hans Slabbekoorn ◽  
Jacintha Ellers ◽  
Thomas B. Smith

Abstract Animal vocalizations used for long-distance communication are shaped by acoustic properties of the environment. Studies of the relationship between signal design and sound transmission typically focus on habitat-induced limitations due to signal attenuation and degradation. However, signal design may not entirely be explained by habitat limitations, but rather by beneficial consequences of reverberations. Narrow-frequency bandwidth notes (NFB notes) are pure notes that change little in frequency, and are typical for many bird species living in dense tropical forests. In contrast to frequency-modulated notes, we show that reverberations lead to a longer and louder signal after transmission for NFB notes. Furthermore, playback experiments to territorial males of an African passerine indicated that longer notes led to a stronger behavioral response. These results suggest that reverberations may benefit signal efficiency depending on the signal design, and add new insight into the selection pressures imposed on acoustic signals by the environment. Canto de Aves y Transmisión de Sonido: Beneficios de las Reverberaciones Resumen. Las vocalizaciones utilizadas por animales para la comunicación a larga distancia están condicionadas por las propiedades acústicas del entorno. Los estudios sobre la relación entre el diseño de las señales y la transmisión del sonido suelen centrarse en los límites impuestos por el hábitat debido a la atenuación y degradación de la señal. Sin embargo, es posible que el diseño de la señal no esté regido exclusivamente por las limitaciones del habitat, sino por las consecuencias beneficiosas de las reverberaciones. Las notas de frecuencia de banda estrecha (notas NFB) son notas puras que cambian poco de frecuencia y son típicas de varias especies que habitan bosques tropicales densos. Al contrario que en las notas de frecuencia modulada, mostramos que las reverberaciones alargan y aumentan la señal de las notas NFB. Asimismo, experimentos de playback con machos territoriales de un paseriforme africano indican que las notas más largas provocan una mayor respuesta. Estos resultados sugieren que las reverberaciones pueden mejorar la eficiencia de la señal, dependiendo del diseño de la misma, y añaden un nuevo componente a nuestro conocimiento sobre las presiones selectivas impuestas por el entorno sobre las señales acústicas.


2011 ◽  
Vol 51 (2) ◽  
pp. 746
Author(s):  
Irina Borissova ◽  
Gabriel Nelson

In 2008–9, under the Offshore Energy Security Program, Geoscience Australia (GA) acquired 650 km of seismic data, more than 3,000 km of gravity and magnetic data, and, dredge samples in the southern Carnarvon Basin. This area comprises the Paleozoic Bernier Platform and southern part of the Mesozoic Exmouth Sub-basin. The new seismic and potential field data provide a new insight into the structure and sediment thickness of the deepwater southernmost part of the Exmouth Sub-basin. Mesozoic depocentres correspond to a linear gravity low, in water depths between 1,000–2,000 m and contain between 2–3 sec (TWT) of sediments. They form a string of en-echelon northeast-southwest oriented depressions bounded by shallow-dipping faults. Seismic data indicates that these depocentres extend south to at least 24°S, where they become more shallow and overprinted by volcanics. Potential plays in this part of the Exmouth Sub-basin may include fluvio-deltaic Triassic sandstone and Lower–Middle Jurassic claystone source rocks sealed by the regional Early Cretaceous Muderong shale. On the adjoining Bernier Platform, minor oil shows in the Silurian and Devonian intervals at Pendock–1a indicate the presence of a Paleozoic petroleum system. Ordovician fluvio-deltaic sandstones sealed by the Silurian age marine shales, Devonian reef complexes and Miocene inversion anticlines are identified as potential plays. Long-distance migration may contribute to the formation of additional plays close to the boundary between the two provinces. With a range of both Mesozoic and Paleozoic plays, this under-explored region may have a significant hydrocarbon potential.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xian Yang ◽  
Yang Liu ◽  
Chao Yang

When the pipe jacking technology is applied in expansive formation, the soil around the pipe will easily absorb water from the slurry and expand to wrap up the pipe, producing an excessive pipe jacking force. A water-based slurry formula suitable for pipe jacking in expansive soil layer was proposed in this paper. Firstly, the key design points of pipe jacking slurry in expansive soil were put forward. Secondly, plant glue, potassium humate, Na-CMC, and graphite powder were chosen as treating agents to improve the slurry performance. The effect of addition levels of different treating agents on the funnel viscosity, filter loss, expansion ratio, friction coefficient and water dissociation rate of the slurry were tested. Thirdly, based on the results of single-factor tests, a water-based slurry formula suitable for pipe jacking in expansive soil was obtained. Finally, the slurry formula was applied in a practical pipe jacking project in expansive formation, and the jacking force was controlled well in the whole jacking process. The new water-based slurry is cheap and practical and has no pollution to environment. Furthermore, a simple and practical calculating method of the pipe jacking force was presented. The comparison of the calculated and measured pipe jacking force shows that the simple calculating method can estimate the jacking force well. Improving slurry performance to reduce jacking force in pipe jacking and predicting pipe jacking force accurately can help reducing the investment for counterforce wall and jacking system in pipe jacking engineering.


2015 ◽  
Vol 743 ◽  
pp. 121-130
Author(s):  
Yan Feng Bai ◽  
Gang Wang ◽  
Zhi Yan Zhou

Pipe-jacking method has been widely used in municipal engineering for its relatively simpler equipment and lower environment impacts. Since intact sections were used in traditional pipes, their application is restrained by transportation when the diameter is too large. A split prefabricated pipe-jacking structure design method is proposed in this paper. The traditional intact pipe section is split into several segments for assembling in the construction site, which can solve the transportation and stocking problem.


2013 ◽  
Vol 639-640 ◽  
pp. 247-250
Author(s):  
Shao Tang Liu ◽  
Guo Rong Pan ◽  
Hui Feng Zhang

The paper discusses guide survey system in long distance curved pipe jacking, presents a three-dimensional datum transformation model to determine the orientation of jacking pipe,The unitary principle and the new navigating method are introduced and the methods accuracy and variance are analyzed. The intelligence guide system is carried through easily associate with total station. The mathematical model, the operation principle, the hardware realization of extra long pipe jacking automatic guidance are introduced. Practice shows that all the reference points are used more efficiently in the new model than in the general model, and the surveying and navigating system gets enormous time-saving against conventional methods


2018 ◽  
Vol 16 (2) ◽  
pp. 125-144 ◽  
Author(s):  
A.C. Christie ◽  
A. Haour

AbstractThe lost caravan of Ma’den Ijafen, Mauritania, with its cargo of cowries and brass, is widely discussed in African archaeology, providing significant insight into the nature of long-distance trade in the medieval period. While the brass bars recovered by Théodore Monod during his expedition to the site in 1962 have received considerable attention, the cowrie shells described in his comprehensive publication of the assemblage in 1969 have received much less coverage. This issue was addressed during a recent visit to the Institut Fondamental d’Afrique Noire (IFAN) in Dakar, Senegal in May 2017, when the authors re-examined the shells as part of a wider project which also involved archaeological and environmental surveys in the Maldives, the oft-assumed source of these shells. Examinations of natural history collections of cowries, ethnographic interviews in the Maldives, and environmental surveys in East Africa were also carried out. Drawing on insights from these surveys, we systematically compared the Ma’den Ijafen cowrie assemblage to three others from the Maldives, focussing on four criteria: species composition and diversity, shell size and evidence of modifications. This analysis enabled us to shed new light on the nature of the Ma’den Ijafen cowries and their wider significance to understanding the role of the shells in West African trade networks.


2021 ◽  
Vol 11 (1) ◽  
pp. 56-72
Author(s):  
Lauren Reiss

This ethnographic study uses a phenomenological approach to better understand how Appalachian Trail (AT) and Long Trail (LT) thru-hikers create meaning and make sense of their experiences while hiking. Drawing on participant observation and in-depth interviews with 13 hikers, I analyze hikers’ initial reasons for hiking, their reflections while on the trail, and the impacts thru-hiking had on their self-concepts and social lives. Key findings demonstrate how life on the trail contrasts with hikers’ everyday lives in society and thus suggest ways that their experiences on the AT/LT may give insight into nature, community life, personal change, and the process of personal reflection. In particular, this study suggests that long-distance hiking builds personal skills and confidence. Further, this research uses a phenomenological approach as well as the concepts of liminality and communitas to analyze the creation of an alternative trail subculture and new personal identities on the trail, including trail families. 


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