Prediction of Ground Settlement Induced by Slurry Shield Tunnelling in Granular Soils
TL;DR: Doi et al. as discussed by the authors studied the ground surface settlement caused by the Greater Cairo Metro Line 3 - Phase-1 tunneling project, which was constructed by a slurry shield tunnel boring machine (TBM).
Abstract: Underground structures play an important role in achieving the requirements of rapid urban development such as tunnels, parking garages, facilities, etc. To achieve what is needed, new transportation methods have been proposed to solve traffic congestion problems by using of high-speed railway and subway tunnels. One of the issues in urban spaces due to tunnel excavation is considerable surface settlements that also induce problems for surface structures. There are a variety of published relationships concerned with field measurements and theoretical approaches to evaluating the amount of the maximum surface settlement value due to tunneling. This paper studies the ground surface settlement caused by the Greater Cairo Metro – Line 3 - Phase-1. This project was constructed by a slurry shield Tunnel Boring Machine (TBM). Therefore, this work consists of two parts. The first part presents the details of the project and monitoring results field and laboratory geotechnical investigations in order to determine the soil properties. The second part is to the comparison between the field measurements and theoretical approaches for surface settlement due to tunneling construction. At the end of the works, the results show that the more convenient methods which approach the field measurements, and the major transverse settlement occurs within the area about 2.6 times the diameter of the tunnel excavation. Doi: 10.28991/cej-2020-03091617 Full Text: PDF
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Journal Article•
TL;DR: In this article, hydrated lime (HL) is used as an active filler in bitumens, which can have a much more substantial effect on the bitumen than inert fillers, and the level of interaction between HL and bitumen is bitumen dependent.
Abstract: Hydrated lime (HL) is an active filler in some bitumens. Rheological models demonstrate that HL interacts with certain bitumens to develop an adsorbed (interactive) layer around the HL particles. The volume of this layer can be substantial, causing HL to have a much more substantial effect on the bitumen than inert fillers. The level of interaction between HL and bitumen is bitumen dependent. This interaction causes HL to strongly affect high-temperature rheology in certain bitumens, but it has less of an effect in others. The low-temperature stiffening effects of HL are less prominent, and a significant level of fracture toughening (at low temperatures) occurs through the addition of HL. The active nature of HL with certain bitumens is further verified by nuclear magnetic resonance. HL is considered a multifunctional additive with potential benefits to the binder and to the mixture that include resistance to deformation, low-temperature fracture toughening, and increased resistance to age hardening. HL may be competitive with some polymer additives.
107 citations
Journal Article•
TL;DR: A perspective on three scientific translational gaps is presented here: (i) making policy decisions within the context of scientific uncertainty, (ii) the role of alternative assessments in selecting safer commercial materials, and (iii) the translation of scientific evidence into disease prevention as mentioned in this paper.
Abstract: Mesothelioma, a malignant cancer of the pleura, is almost exclusively associated with asbestos exposure.1 What will it take to eradicate this highly preventable cancer? Despite the scientific consensus that exposure to asbestos fibres causes deadly diseases, we continue to use asbestos in products designed ostensibly to improve quality of life. For example, asbestos is still used in automobile brake-linings, and in the chloralkali industry that produces chlorine for disinfecting water worldwide.2 Toxic asbestos remains the main material for some plastics and in domestic building products – especially in corrugated roof materials for housing in developing countries.
Regional disparities persist in translating scientific knowledge of asbestos risks to policy for preventing cancers and other diseases. Most cases of mesothelioma are now found in countries producing asbestos and in developing countries using the products, where scientific knowledge of asbestos toxicity seems to have been lost in translation.3 It is in these countries, where affected populations are less likely to have access to prompt diagnosis, health care or litigation, that we will observe the next wave of mesothelioma cases.3 A perspective on three scientific translational gaps is presented here: (i) making policy decisions within the context of scientific uncertainty, (ii) the role of alternative assessments in selecting safer commercial materials, and (iii) the translation of scientific evidence into disease prevention.
The International Labour Organization’s Asbestos Convention, designed to protect workers from the well-known hazards of asbestos exposure, entered into force on 16 June 1989. Yet, nearly twenty-five years later, only 35 countries, 19% of 184 that are eligible, have formally ratified the Convention.2 In contrast, 154 countries (83% of those eligible) are Parties to the 1998 Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and Pesticides in International Trade.4 However, attempts to include chrysotile asbestos – the most common form used – in Annex III of the Rotterdam Convention have failed repeatedly, most recently at the sixth Conference of Parties due to resistance from seven countries, most of whom continue to produce, use, and export asbestos on a large scale (Fig. 1). The minority objection prevailed despite powerful testimony from the representative of the World Health Organization (WHO) that chrysotile and all forms of asbestos are carcinogenic to humans.6 Moreover, given the widespread use of chrysotile in domestic building products, it is impossible to safeguard hazardous exposures in occupational settings or to prevent environmental contamination that threatens the general population. Opposition to the proposal to regulate chrysotile asbestos under the Rotterdam Convention highlights three major gaps in the translation of scientific evidence to global disease prevention policy.
Fig. 1
Asbestos producers and consumers, 35 countries, 2011
The first gap concerns making policy decisions within the context of scientific uncertainty. For example, the representative of one country claimed that there are insufficient scientific data to support listing asbestos under the Rotterdam Convention. This objection reflects a lack of understanding of the complexities of the scientific process and the inherent variability of factors that contribute to the relationship between toxic exposures and disease outcomes. There are small differences in the findings of observational studies of the effects of asbestos exposure. These are the result of complex interactions between asbestos exposure and genetic, environmental and social factors. Published research in this field includes studies contributed by laboratories that may have a conflict of interest with the asbestos industry.7 This complicates any assessment of the scientific evidence. In practice, a combination of different categories of evidence are used to reach policy decisions that protect the most vulnerable people.8 The proposed requirement of informed consent for the use of chrysotile is based on consistent and reliable evidence from numerous empirical and mechanistic studies conducted by independent scientists.
The second gap is the role of alternatives assessments in the selection of safer materials used in consumer products. For example, at least two representatives of countries opposing the international regulation of chrysotile asbestos claim that alternative materials have not been sufficiently researched to compare the risks to human health and the environment. Also, claims have been made that technical assistance is lacking for countries wishing to phase out asbestos use and replace it with safer alternatives. The scientific methods developed to address this issue – including materials’ life cycle assessment and functional equivalence – struggle with making comparisons across very different characteristics and potential health and environmental impacts. The assessment methods also have to compare a range of plausible disease endpoints. Whereas a particular material used in a consumer product may be linked to respiratory diseases, proposed alternatives may be linked to reproductive health effects, cognitive deficits or to cancers.9 Although there are legitimate scientific issues to be resolved with alternative assessments, they do not amount, in the case of asbestos, to reasons for stalling policy procedures that simply require informed consent. Inclusion of asbestos under the Rotterdam Convention would increase the pace of research to discover safer alternative materials and their adoption by key industries.
The third gap in the efficient translation of scientific evidence to disease prevention policy is the need to acknowledge trade-offs between public health, industrial development, economic advancement, employment and political autonomy. Representatives of countries opposing the listing of asbestos under the Rotterdam Convention acknowledge that this inclusion would not imply a ban on production, but argue that it would have a negative impact on international trade and contribute to unemployment. Without political consensus, regulations may be ineffective as detractors identify and use loopholes and backdoor trading to circumvent international policy. This has been the case, for example, with toxic electronic waste and the Basel Convention for controlling transboundary movements and disposal of hazardous wastes.10,11 Yet, forward-thinking countries manage to withstand pressure to protect economic interests at the expense of public health. This is exemplified by the implementation of California’s landmark safer consumer products regulations after five years of contemplation and debate surrounding these trade-offs.12
It is possible to eradicate mesothelioma, but we must work harder to bridge the gaps between scientific knowledge and policy decisions that should protect people.
16 citations
TL;DR: A series of numerical simulations have been established to investigate the effects of tunnel construction of the Greater Cairo Metro Line 3-Phase-1 on adjacent pile cap foundations of Garage El-Attaba building as mentioned in this paper.
Abstract: Day by day the call to solve traffic congestion problems is increasing. Subway tunnels and high-speed railway are commonly used for transportation. Therefore, tunnel construction induces soil movement, which in turn affects the stability and integrity of adjacent existing buildings. A series of numerical simulations have been established to investigate the effects of tunnel construction of the Greater Cairo Metro–Line 3-Phase-1 on adjacent pile cap foundations of Garage El-Attaba building. Many parameters have been investigated such as tunnel diameter and the distance between pile and tunnel at different tunnel axis and deep and shallow tunnel. After thorough analysis of the results’ simulation, it was found that the tunneling induces additional axial forces and bending moment as well as increasing axial settlement and lateral deflection. Moreover, the results obtained from the parametric study for the shallow and deep tunnel show that the tunnel depth has a much significant effect on piles responses. Finally, the tunnel diameter has an impact on pile responses as well as the pile cap foundation influenced by the tunnel when the tunnel is in very close vicinity of the pile, and its effect is modest to negligible if located far away from the buildings.
11 citations
Book•
13 Jun 2013
TL;DR: In this article, the authors explored the use of engineering economic analysis to determine the most efficient way to meet transportation infrastructure needs and how to ensure the availability of transportation infrastructure funding in the United States.
Abstract: This book focuses on meeting funding needs for transportation infrastructure in the United States. Two main ideas are explored, the use of engineering economic analysis to determine the most efficient way to meet funding needs and how to ensure the availability of funding. Topics include: banking formulae for use in alternatives analysis; the use of project costs and benefits in economic analysis; the history of transportation financing; the use of bonds; and potential solutions for transportation funding in the future.
10 citations
Book•
01 Jan 1989
TL;DR: In this article, the authors present a symposium sponsored by the Geotechnical Engineering Division (GE Division) on the application of geotechnics in the field of road networks.
Abstract: Proceedings of a symposium sponsored by the Geotechnical Engineering Division. Geotechnical Special Publication No. 23.
10 citations
References
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TL;DR: In this article, the number of physical constants necessary to determine the properties of the soil is derived along with the general equations for the prediction of settlements and stresses in three-dimensional problems.
Abstract: The settlement of soils under load is caused by a phenomenon called consolidation, whose mechanism is known to be in many cases identical with the process of squeezing water out of an elasticporous medium. The mathematical physical consequences of this viewpoint are established in the present paper. The number of physical constants necessary to determine the properties of the soil is derived along with the general equations for the prediction of settlements and stresses in three‐dimensional problems. Simple applications are treated as examples. The operational calculus is shown to be a powerful method of solution of consolidation problems.
8,253 citations
TL;DR: In this article, a constitutive model based on an internal variable-formulation of plasticity theory for the non-linear analysis of concrete is presented, which uses a new yield criterion which matches experimental data quite well and it accounts for both elastic and plastic stiffness degradations effects.
3,080 citations
TL;DR: In this paper, a new plastic-damage model for concrete subjected to cyclic loading is developed using the concepts of fracture-energy-based damage and stiffness degradation in continuum damage mechanics.
Abstract: A new plastic-damage model for concrete subjected to cyclic loading is developed using the concepts of fracture-energy-based damage and stiffness degradation in continuum damage mechanics. Two damage variables, one for tensile damage and the other for compressive damage, and a yield function with multiple-hardening variables are introduced to account for different damage states. The uniaxial strength functions are factored into two parts, corresponding to the effective stress and the degradation of elastic stiffness. The constitutive relations for elastoplastic responses are decoupled from the degradation damage response, which provides advantages in the numerical implementation. In the present model, the strength function for the effective stress is used to control the evolution of the yield surface, so that calibration with experimental results is convenient. A simple and thermodynamically consistent scalar degradation model is introduced to simulate the effect of damage on elastic stiffness and its recovery during crack opening and closing. The performance of the plastic-damage model is demonstrated with several numerical examples of simulating monotonically and cyclically loaded concrete specimens.
2,825 citations
Book•
01 Jan 1968
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
2,573 citations
"Prediction of Ground Settlement Ind..." refers methods in this paper
...As shown in the summary at the end of this section, and based on SPT-N value, the Young’s modulus, 𝐸 for sandy soil layers are estimated using theoretical equations by Webb (1969); Bowles (1982) and Denver (1982) [25-27]....
[...]
...As shown in the summary at the end of this section, and based on SPT-N value, the Young’s modulus, E for sandy soil layers are estimated using theoretical equations by Webb (1969); Bowles (1982) and Denver (1982) [25-27]....
[...]