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Underground utilities are important assets that provide basic services for society's daily life. They are generally very complex and remain unnoticed until they fail due to any particular reason. The stakeholders involved in the design, construction, and maintenance of utility infrastructure face many problems due to the traditional underground utility management system, resulting in injuries, loss of life, disruptions, project delays, and financial loss. The problem with the traditional system is that it uses 2D drawings and keeps unreliable information or a lack of updated information, which makes it an inefficient utility management system. With the advancement in construction information technology, we can address this effectively by integrating BIM and GIS. In this paper, a novel integrated BIM-GIS framework for underground utility management systems was developed on the basis of IFC to CityGML mapping. It provides an effective underground utility management system that facilitates designers in optimization of the design, assists in the excavator's operator by providing real-time three-dimensional spatial information during the construction process, and acts as an as-built information database for utility facility management. For validation, a real-time project case study indicated that the proposed system can effectively provide comprehensive underground utility information at different project stages. [ABSTRACT FROM AUTHOR]

We report a first principles theoretical investigation of spin polarized quantum transport in Mn2Ga/MgO/Mn2Ga and Mn3Ga/MgO/Mn3Ga magnetic tunneling junctions (MTJs) with the consideration of metal(Mg, Co, Cr) insertion layer effect. By changing the concentration of Mn, our calculation shows a considerable disparity in transport properties: A tunneling magnetoresistance (TMR) ratio of 852% was obtained for Mn2Ga-based MTJs, however, only a 5% TMR ratio for Mn3Ga-based MTJs. In addition, the influence of insertion layer has been considered in our calculation. We found the Co insertion layer can increase the TMR of Mn2Ga-based MTJ to 904%, however, the Cr insertion layer can decrease the TMR by 668%, A negative TMR ratio can be obtained with Mg insertion layer. Our work gives a comprehensive understanding of the influence of different insertion layer in Mn-Ga based MTJs. It is proved that, due to the transmission can be modulated by the interfacial electronic structure of insertion, the magnetoresistance ratio of Mn2Ga/MgO/Mn2Ga MTJ can be improved by inserting Co layer. [ABSTRACT FROM AUTHOR]

The torsional levels of (H2O)3 and (D2O)3 were calculated in a restricted dimensionality (three-dimensional) model with several recently proposed water potentials. Comparison with the experimental data provides a critical test, not only of the pair interactions that have already been probed on the water dimer spectra, but also of the nonadditive three-body contributions to the potential. The purely ab initio CC-pol and HBB potentials that were previously shown to yield very accurate water dimer levels, also reproduce the trimer levels well when supplemented with an appropriate three-body interaction potential. The TTM2.1 potential gives considerably less good agreement with experiment. Also the semiempirical VRT(ASP-W)III potential, fitted to the water dimer vibration-rotation-tunneling levels, gives substantial disagreement with the measured water trimer levels, which shows that the latter probe the potential for geometries other than those probed by the dimer spectrum. Although the three-body nonadditive interactions significantly increase the stability of the water trimer, their effect on the torsional energy barriers and vibration-tunneling frequencies is less significant. [ABSTRACT FROM AUTHOR]

We study the conformational reorganization of formic acid (FA) in solid neon and report the higher-energy cis-FA monomer and one form of the trans-cis FA dimers. They were prepared by selective vibrational excitation of the trans-FA monomer and trans-trans dimer. The proton tunneling decay of cis-FA monomer is surprisingly very fast in solid neon, two orders of magnitude faster than in solid argon. It was also found that the stability of the trans-cis dimer against proton tunneling is enormously enhanced in solid neon compared to the monomer (by a factor of ∼300). These results are discussed in terms of matrix solvation and hydrogen bonding. [ABSTRACT FROM AUTHOR]

This article presents a multifaceted study of the reaction H+C2H6→H2+C2H5 and three of its deuterium-substituted isotopologs. First we present high-level electronic structure calculations by the W1, G3SX, MCG3-MPWB, CBS-APNO, and MC-QCISD/3 methods that lead to a best estimate of the barrier height of 11.8±0.5 kcal/mol. Then we obtain a specific reaction parameter for the MPW density functional in order that it reproduces the best estimate of the barrier height; this yields the MPW54 functional. The MPW54 functional, as well as the MPW60 functional that was previously parametrized for the H+CH4 reaction, is used with canonical variational theory with small-curvature tunneling to calculate the rate constants for all four ethane reactions from 200 to 2000 K. The final MPW54 calculations are based on curvilinear-coordinate generalized-normal-mode analysis along the reaction path, and they include scaled frequencies and an anharmonic C–C bond torsion. They agree with experiment within 31% for 467–826 K except for a 38% deviation at 748 K; the results for the isotopologs are predictions since these rate constants have never been measured. The kinetic isotope effects (KIEs) are analyzed to reveal the contributions from subsets of vibrational partition functions and from tunneling, which conspire to yield a nonmonotonic temperature dependence for one of the KIEs. The stationary points and reaction-path potential of the MPW54 potential-energy surface are then used to parametrize a new kind of analytical potential-energy surface that combines a semiempirical valence bond formalism for the reactive part of the molecule with a standard molecular mechanics force field for the rest; this may be considered to be either an extension of molecular mechanics to treat a reactive potential-energy surface or a new kind of combined quantum-mechanical/molecular mechanical (QM/MM) method in which the QM part is semiempirical valence bond theory; that is, the new potential-energy surface is a combined valence bond molecular mechanics (CVBMM) surface. Rate constants calculated with the CVBMM surface agree with the MPW54 rate constants within 12% for 534–2000 K and within 23% for 200–491 K. The full CVBMM potential-energy surface is now available for use in variety of dynamics calculations, and it provides a prototype for developing CVBMM potential-energy surfaces for other reactions. [ABSTRACT FROM AUTHOR]

A scanning tunneling microscope (STM) is used to study individual Ag doping centers in a monolayer of C60 molecules supported on a thin Al2O3 film grown on the NiAl(110) surface. Vibronic states of the doping centers are observed with differential conductance (dI/dV) spectroscopy. The double-barrier nature of the junction results in bipolar transport: same states participate in charge transport at both bias voltage polarities. Identification of the dI/dV features corresponding to bipolar conduction enables a new mode of vibrational spectroscopy with STM. [ABSTRACT FROM AUTHOR]

Abstract Crosshole ground-penetrating radar (GPR) is a widely used measurement technique to help inspect the structural integrity of man-made underground structures. In a previous paper, we have introduced a Bayesian framework for inversion of crosshole GPR experiments to help back out defects in concrete underground structures. Here, we evaluate the practical usefulness of our inversion framework by application to waveform data from a real-world GPR survey of a diaphragm wall panel with two embedded structure defects. We also use this case study to further refine our methodology by introducing the elements of a two-stage inversion method to help delineate the exact location and shape of small structure defects. Herein, a low-resolution inversion composed of relatively few inversion coefficients (stage-1) is used to determine roughly the presence of structure defects, followed by a second inversion (stage-2) with much enhanced spatial resolution in those areas classified with anomalous or suspicious permittivity values. This two-stage inversion approach uses more wisely CPU-resources by focusing primarily on those areas of the concrete structure that have been classified as anomalies. We investigate the benefits of this two-stage inversion scheme using a synthetic and real-world case study involving waveform data of a diaphragm wall panel measured with crosshole GPR. Our results demonstrate that the proposed two-stage inversion method recovers successfully the location and shape of structure defects, at a computational cost that is considerably lower than the original inversion framework. Highlights • The FDTD-DCT-DREAM (ZS) framework is proved feasible by real-world data. • A two-stage method is used to enhance spatial resolution of inversion result. • The two-stage method reduces computational cost considerably. [ABSTRACT FROM AUTHOR]

The convergence-confinement method (CCM) is a method that has been introduced in tunnel construction that considers the ground response to the advancing tunnel face and the interaction with installed support. One limitation of the CCM is due to the numerically or empirically driven nature of the longitudinal displacement profile and the incomplete consideration of the longitudinal arching effect that occurs during tunnelling operations as part of the face effect. In this paper, the authors address the issue associated with when the CCM is used within squeezing ground conditions at depth. Based on numerical analysis, the authors have proposed a methodology and solution to improving the CCM in order to allow for more accurate results for squeezing ground conditions for three different excavation cases involving various excavation-support increments and distances from the face to the supported front. The tunnelling methods of consideration include: tunnel boring machine, mechanical (conventional), and drill and blast. [ABSTRACT FROM AUTHOR]

It is proposed method of passive cleaning of the excavator working body from adhering soil that practically does not require additional energy. Theoretical studies of the surface temperature effect of the working body on the stickiness of cohesive fine-grained soils of different fractions are made, on the basis of which the calculation is made, and temperature regimes required to prevent adhesion are defined. The proposed design is recommended to be implemented in all types of shovels to improve the operational performance and, as a consequence, reduce the cost of earthworks. [ABSTRACT FROM AUTHOR]

First breakthrough at the Albabstieg Tunnel / Erster Durchschlag am Albabstiegstunnel Last tunnel breakthrough in the Klaus Tunnel Chain / Letzter Tunneldurchschlag in der Tunnelkette Klaus Start for the largest tunnel boring machine in Switzerland / Start für größte Tunnelbohrmaschine der Schweiz Ground breaking at the Pforzheimer Tunnel / Anschlagsfeier für den Pforzheimer Tunnel Marti GmbH and Marti Tunnelbau AG to build second bore of the Perjen Tunnel / Marti GmbH und Marti Tunnelbau AG bauen zweite Röhre des Perjentunnels Fehmarn Belt Tunnel: Femern A/S names preferred bidders / Fehmarnbelt-Tunnel: Femern A/S benennt bevorzugte Bieter Züblin to build part of the Stockholm Bypass / Züblin errichtet Teilstück des 'Stockholm Bypass' Aarau-Zurich rail corridor: direct link with 30 km long tunnel / Bahnkorridor Aarau-Zürich: Direktverbindung mit 30 km langem Tunnel Strabag bundles infrastructure solutions / Strabag bündelt Infrastrukturlösungen 19th Vils construction materials day - Large construction sites in West Austria / 19. Vilser Baustofftag - Großbaustellen in Westösterreich The 2016 ITA Tunnelling Awards / ITA lobt eigenen Tunnelbaupreis aus Call for papers - Themes for the next issues of Geomechanics and Tunnelling / Themen für die nächsten Ausgaben der 'Geomechanics and Tunnelling' [ABSTRACT FROM AUTHOR]

The multi-function station (MFS) Faido, with track crossovers located symmetrically around the transverse cavern, is accessed through a 2.7 km long access tunnel. The geology encountered in the transverse cavern and the first metres of boring the running tunnels was very different from the forecast. Technical, economic and scheduling considerations demanded the moving of the four crossovers by 600 m to the south. In the drill and blast excavation of the single-track tunnel to the north, deformations of up to 1.3 m occurred in the radius. In addition to the dangers of 'squeezing rock' and 'rock fall', unforecast and serious rock burst also occurred in the east and west running tunnels, which could not have been foreseen. Yielding temporary support measures had to be carried out along a length of 500 m and sometimes massively strengthened. Intensive probing in the form of hammer and core drilling and seismic methods (TSP - Tunnel Seismic Prediction) was carried out during the tunnel drives. The drives were also monitored with intensive rock mechanical measurements. The results of probing, the rock mechanical measurements and the interpretations of the encountered geology all confirmed that the decision was correct to move the MFS. Die Multifunktionsstelle (MFS) Faido mit symmetrisch um die Querkaverne angeordneten Spurwechseln ist mit einem 2,7 km langen Zugangsstollen erschlossen. Die angetroffene Geologie in der Querkaverne und den ersten Metern Vortrieb in den Einspurstrecken wichen massiv von der Prognose ab. Technische, wirtschaftliche und programmliche Gründe erforderten eine Verschiebung der vier Spurwechsel um 600 m nach Süden. Im Sprengvortrieb der Einspurtunnel Richtung Norden stellten sich Deformationen von bis zu 1,3 m im Radius ein. Zu den Gefährdungen 'Druckhaftigkeit' und 'Nachbrüchigkeit' kamen nicht prognostizierte starke Bergschlagphänomene in der Ost- und Weströhre hinzu, die nicht vorhergesagt werden können. Die Ausbruchsicherungsmaßnahmen mussten aufgrund der Bergschlagphänomene auf ca. 500 m Länge nachgiebig ausgeführt und zum Teil massiv verstärkt werden. Die Vortriebe wurden von einer intensiven Vorauserkundung in Form von Schlag- oder Kernbohrungen und mit Seismik (TSP - Tunnel Seismik Prediction) begleitet. Zudem wurden die Vortriebe mit intensiven felsmechanischen Messungen überwacht. Die Erkenntnisse aus den Vorauserkundungen, den felsmechanischen Messungen und den Interpretationen der vorgefundenen Geologie bestätigte die Richtigkeit der Entscheidung, die MFS zu verschieben. [ABSTRACT FROM AUTHOR]

In the process of dimensioning a tunnel lining support an optimized structural system is pursued that can accommodate the inherent uncertainties associated with the geotechnical, hydro-geological, and environmental conditions. Particularly for geotechnics, uncertainty has become a major issue of scientific discussion according to a number of recent publications. At the same time, advanced performance criteria often require probabilistic assessments in order to quantify a structure's safety and reliability or to inform life-cycle engineering decisions. This contribution demonstrates a novel design approach for the design assessment of concrete tunnel linings. The Index for the Capacity Utilization of Linings in Tunnels (CULT-I) introduced herein, facilitates the quantification of reliability of a tunnel lining support, while it aids toward a rationalized, performance-based design optimization with considerations on geotechnical uncertainty. A typical case of a shallow urban tunnel excavated in soft ground using the TBM method is presented, demonstrating the practical application and feasibility of the proposed approach. [ABSTRACT FROM AUTHOR]

The Sedrun section in the middle of the Gotthard Base Tunnel was critical in terms of scheduling and without doubt the section with the most complicated logistics. The article gives an overview of the complex overall construction measures and describes in detail the geotechnical and logistical challenges that had to be overcome. Der Teilabschnitt Sedrun im Zentrum des Gotthard-Basistunnels war zeitlich kritisch und zweifelsohne der logistisch komplizierteste Bauabschnitt, die bautechnischen Anforderungen lagen auf Weltrekordniveau. Der Beitrag gibt eine Übersicht über die komplexe Gesamtbaumaßnahme und beschreibt die zu bewältigenden geotechnischen und baubetrieblichen Herausforderungen im Detail. [ABSTRACT FROM AUTHOR]

Knowledge of the ground condition and its hazards can play an important role in the selection of support and suitable excavation method in underground structures. Water transport tunnel is one of the most important structures with regard to the goal of excavation, special conditions and limitations considered in the design and execution of them. Beheshtabad Water Conveyance Tunnel with 64930 meters length, 6 meters final diameter is the largest water Conveyance tunnel in Iran. Because of high over burden and weak rock in the most of tunnel path, the probable hazardous of the ground condition such as squeezing and rock burst must be studied. Squeezing stands for large timedependent convergence during tunnel excavation. This phenomenon occurs in weak rocks and deep conditions. Besides, the height of overburden in some of the zone tunnel is about 1200 meters. The occurrence of this phenomenon is always together with the instantaneous release of strain energy stored in the rock materials, causing the harm to the personal equipment and the collapse of underground structures. The existence of high thickness overburden in some the zones of this project indicates the high potential of rock burst hazard. In this research, the length of the tunnel has been partitioned into sections using the interpreted geological, geophysical studies and borehole data. After evaluating rock burst and squeezing potential with alternative analytical and experimental methods for each section, the results of different methods were compared with each other. Results predict low to moderate squeezing potential and moderate to high rock burst potential for some panels of the tunnel. [ABSTRACT FROM AUTHOR]

With the ruling of the Austrian federal administrative court in May 2015, all necessary permits have now been issued for the construction of the Semmering Base Tunnel. The project is one of the most reviewed projects in Austria, and as the other authorities had done previously, the federal administrative court once again confirmed the environmental acceptability of the project. Until the judgement of the constitutional high court with the revocation of the construction permit (served on 10 February 2014), all necessary preliminary works had been carried out on schedule and within budget since 2012. The preliminary works started in the Fröschnitzgraben in January 2014 could however only be continued with limitations on the basis of official notifications issued without preliminary investigation. No construction could take place at the landfill site due to the lack of a decision under the waste management law. Only after the ruling by the federal administrative court could the construction works be resumed at full pace. Works started soon after in the Gloggnitz tunnel section in Lower Austria on 1 July 2015. Construction works for the third and final tunnel section, Grautschenhof , were officially tendered on 2 September 2015. By 2016, all tunnel construction contracts should be continuously under construction. Für den Bau des Semmering-Basistunnels liegen nach der erfolgten Entscheidung des Bundesverwaltungsgerichts im Mai 2015 nun alle erforderlichen Genehmigungen vor. Das Projekt ist eines der meistgeprüften Projekte Österreichs, und wie schon die anderen Behörden zuvor, hat auch das Bundesverwaltungsgericht erneut die Umweltverträglichkeit des Projekts bestätigt. Bis zum Urteil des Verwaltungsgerichthofs mit der Aufhebung des Baubescheids (Zustellung 10. Februar 2014) konnten alle erforderlichen Vorarbeiten seit 2012 im Zeit- und Kostenrahmen umgesetzt werden. Die im Fröschnitzgraben im Januar 2014 begonnen Vorarbeiten konnten jedoch nur eingeschränkt auf Basis von Mandatsbescheiden fortgeführt werden. In der Deponie konnte wegen des Fehlens des AWG-Bescheids gar nicht gebaut werden. Erst mit Vorliegen der Entscheidung durch das Bundesverwaltungsgericht konnten die Bauarbeiten wieder volle Fahrt aufnehmen. Der Baubeginn des niederösterreichischen Tunnelabschnitts Gloggnitz erfolgte bereits am 1. Juli 2015. Die Bauarbeiten des dritten und letzten Tunnelabschnitts Grautschenhof wurden am 2. September 2015 öffentlich ausgeschrieben. Ab Frühjahr 2016 sind voraussichtlich alle Tunnelbaulose durchgängig in Bau. [ABSTRACT FROM AUTHOR]

Underground in Doha in the Guinness Book of Records: 21 TBMs working at the same time / U-Bahn in Doha im Guiness Buch der Rekorde: 21 TBM gleichzeitig im Einsatz Online Monitoring during the Driving of the Emscher Sewer Tunnel / Online-Monitoring beim Vortrieb des Abwasserkanals Emscher Ventilation of the Gotthard Base Tunnel during the Equipment Phase / Belüftung des Gotthard-Basistunnels während der Ausrüstungsphase [ABSTRACT FROM AUTHOR]

Security of metro tunnels is extremely important, but the influence of new underground construction on existing tunnels has become more and more important. To control the existing tunnel deformation induced by an adjacent excavation, a novel construction method for excavations crossing above underlying tunnels, referred to as the divided alternate excavation method (DAEM), is presented in this paper. In this method, several dividing walls are constructed to divide the overlying excavation into small independent pits. During construction, several small pits are excavated at intervals simultaneously, and the remaining soil in other pits can resist the tunnel heave. After the underground structures of these pits are constructed, soil is backfilled onto their roof to decrease the rebound of the existing tunnels, and the remaining small pits can then be constructed. The proposed construction method is applied in the case of tunnel excavation above running metro tunnels. Field data reveal that the novel method has advantages in controlling deformation of the underlying metro tunnels. [ABSTRACT FROM AUTHOR]

The management of the ventilation system is crucial to deal with efficiency, health and safety issues in an underground environment. This paper presents the design of a geographic information system – also known as GIS – capable to store, manipulate and extract results from the data collected regarding the ventilation features of an underground mine. The GIS can also be adapted to other types of underground infrastructures or include any additional parameter required. A database of these parameters, in a case study, has been created taking into account two conditions: The changeable layout of the ventilation system during the evolution of the mine and the location of the control points, so the information can be analysed with the GIS in many different ways and purposes. Therefore, the system can control the underground conditions in the long term and evaluate any change applied to the ventilation circuit. The study has given insight of the most sensitive parts of a mine in terms of gases, temperature, air velocity and airflow – either from the principal or auxiliary ventilation circuit – finding a relationship among the airflow quantity, gases concentration and effective temperature. [ABSTRACT FROM AUTHOR]

For a better understanding of risk management and the optimization of risk mitigation, a multiphase risk-management method is proposed in which the assessment of risks is divided into two phases: the initial risk phase and the secondary risk phase. The initial risk phase is used for risk evaluation at the beginning of a project and can be quantified by the combination of probability and loss. If the initial risk is not acceptable, risk-mitigation measures are evaluated and the most appropriate measure will be adopted. The secondary risk phase involves identifying risks after implementing the selected mitigation measures for the initial risk, and the mitigation costs are also included. Obviously, the secondary risk must be lower than the initial risk. The task of a tunnel engineer is to select mitigation measures that result in the lowest secondary risk. During project execution, environmental factors may change, and deviations from the original design assumptions may take place. These phenomena have a knock-on effect on the risk profile, and a timely reevaluation of the risk scenario becomes necessary. Therefore, it is further proposed that the two-phase risk-evaluation process be extended to infinite phases. The novelty of the proposed method is characterized by its combination of a dynamic risk-management system and a timely reassessment of new risks, and the continuous tracking of risks until they are negligible. Finally, a relevant example of risk management using the proposed method is illustrated, in which the most appropriate and economical risk management was achieved, and the established objectives of the construction quality and timeline were ensured. This multiphase risk-management approach can be applied to tunnel engineering as well as other engineering fields. [ABSTRACT FROM AUTHOR]

Underground storage schemes are gaining importance in India, as all over the world. Such storage schemes involve the excavation of large underground caverns, connecting tunnels and various types of shafts. This example provides storage for more than 1.3 mill. metric tons of crude oil stored in unlined caverns 20 m wide, 30 m high and up to 820 m long. The scheme also includes three 110 m deep product intake shafts, two 90 m deep product extraction shafts and about 2,600 m of tunnels. The total volume, excavated by drill and blast method, is about 2 mill. m3 and rock support is provided by post-grouted rock bolts and steel fibre reinforced shotcrete. The product is confined on the principle of a groundwater curtain system, essentially employing ground water pressure gradients to contain the crude oil within the unlined rock cavern complex. Excavation works on the project commenced in the middle of 2008 and, after some delays, were finally completed in February 2014. This paper focuses on the risk management practices employed for this project. The paper 'Rock mass behaviour of weathered, jointed and faulted Khondalite - Examples from the underground crude oil storage caverns, Visakhapatnam, India' by Sigl, Millen and Höfer-Öllinger that refers to the actual situation will be published in issue 3-2014 of Geomechanics and Tunnelling. [ABSTRACT FROM AUTHOR]

The Rohtang Tunnel has been advancing into the Himalaya Mountains in the northern state of Himachal Pradesh since autumn 2010. After the completion of almost 50 % of the alignment, it is time for an intermediate report. The article will intentionally not only describe technical matters but also describe the local aspects of tunnelling in India. Im Himalaja-Gebirge im nordindischen Bundesstaat Himachal Pradesh wird seit Herbst 2010 der Rohtang-Tunnel in den Berg getrieben. Nach fast 50 % der Strecke ist es Zeit für eine Zwischenbilanz. Der Beitrag will dabei bewusst nicht nur auf die Technik eingehen, sondern gemäß dem Thema Indien auch die lokalen Aspekte beleuchten. [ABSTRACT FROM AUTHOR]

The Garner and Coffman method was developed to design a proposed underground facility based on an allowable settlement profile; the method may also be used to characterize an unknown underground facility based on an observed surface settlement profile. The method uses both static methods and 2-D finite element analyses to relate the characteristics of the ground surface settlement profile to the underground facility (depth, diameter, and number of tunnels). The calibration and validation of the Garner and Coffman method, as obtained by using tunnel segment data from historical tunneling projects (Bangkok, London, Taipei, Singapore, and Heinenoord), are presented. Specifically, the method was calibrated using settlement profiles and facility characteristics from 15 tunnel segments and validated using settlement profiles from 16 additional tunnel segments. A numerical relationship (developed during this research project) was then used during the validation of the model to predict facility characteristics for the 'unknown' underground structures. The predicted depth and diameter for each of the 'unknown' underground structures were within ten percent of the actual diameter and actual depth of the underground structure, as obtained from the literature. For all 16 validation tunnel segments, the tunnel location was predicted within one tunnel diameter of the actual facility centerline. [ABSTRACT FROM AUTHOR]

In order to study the space-time development characteristics and strata movement pattern in opencast coal mining, an earthwork volume computation model is proposed to determine the geometric dimensions of the outer dumps. Meanwhile, a dynamic 3D model is put forward in an attempt to record strata movement data in different states and regions. The results indicate that a 'displacement circle' takes shape around the areas where coal mining and dumping has been practiced. Furthermore, the circle would enlarge with increasing excavation depth and loading height. The scope of influence in end slope is linearly related to the excavation depth. In non-working slope region, surface strata movement follows a stable pattern and is not relevant to the excavation depth in any way. When it comes to the working slope, however, the way how the strata move is determined by the place where the stope has been advanced to and when it is pushed forward to the border, its surface strata moving resembles that in non-working slope. The heavy load in outer dumps brings about obvious subsidence displacement. In the rear and on the left side of the dump, surface rock movement rules are consistent with one another. [ABSTRACT FROM AUTHOR]

Numerous infrastructures including national roads, tunnels, etc. in Sichuan Province were damaged to various extents in China's Wenchuan earthquake in 2008. The Shaohuoping road tunnel, near the epicentre of the earthquake, was the typical damaged one. The damage modes of different parts of the Shaohuoping tunnel were summarised based on the spot investigation data. It was found that various damages involving cracking and spalling of concrete lining were observed on different parts of the tunnel. The earthquake damages of critical positions, portal section and body portion, were simulated and analysed by finite element numerical model proposed in this paper. Influences of vertical motion on seismic responses of the tunnel were also studied by means of the finite element simulation. The simulation responses were compared with the spot investigations of earthquake structural damages to different parts of the tunnel. The comparisons showed a good agreement, which indicated that, the damage mechanism of the tunnel can be predicted reliably by the proposed finite element model. Furthermore, the results show that the damage of different parts of the tunnel is mainly controlled by horizontal ground motions, but the tunnel may suffer more damages with the effect of the vertical motion. [ABSTRACT FROM PUBLISHER]

Results of investigations of the properties of gravelly soils in the beds of foundations and underground structures in Alamty are presented. [ABSTRACT FROM AUTHOR]

Nonhyperbolicity, as characterized by the coexistence of Kolmogorov-Arnold-Moser (KAM) tori and chaos in the phase space, is generic in classical Hamiltonian systems. An open but fundamental question in physics concerns the relativistic quantum manifestations of nonhyperbolic dynamics. We choose the mushroom billiard that has been mathematically proven to be nonhyperbolic, and study the resonant tunneling dynamics of a massless Dirac fermion. We find that the tunneling rate as a function of the energy exhibits a striking "clustering" phenomenon, where the majority of the values of the rate concentrate on a narrow region, as a result of the chaos component in the classical phase space. Relatively few values of the tunneling rate, however, spread outside the clustering region due to the integrable component. Resonant tunneling of electrons in nonhyperbolic chaotic graphene systems exhibits a similar behavior. To understand these numerical results, we develop a theoretical framework by combining analytic solutions of the Dirac equation in certain integrable domains and physical intuitions gained from current understanding of the quantum manifestations of chaos. In particular, we employ a theoretical formalism based on the concept of self-energies to calculate the tunneling rate and analytically solve the Dirac equation in one dimension as well as in two dimensions for a circular-ring-type of tunneling systems exhibiting integrable dynamics in the classical limit. Because relatively few and distinct classical periodic orbits are present in the integrable component, the corresponding relativistic quantum states can have drastically different behaviors, leading to a wide spread in the values of the tunneling rate in the energy-rate plane. In contrast, the chaotic component has embedded within itself an infinite number of unstable periodic orbits, which provide far more quantum states for tunneling. Due to the nature of chaos, these states are characteristically similar, leading to clustering of the values of the tunneling rate in a narrow band. The appealing characteristic of our work is a demonstration and physical understanding of the "mixed" role played by chaos and regular dynamics in shaping relativistic quantum tunneling dynamics. [ABSTRACT FROM AUTHOR]

Zur Erweiterung der Einsatzbereiche von Erddruckschilden auf gemischtkörnige Lockergesteine mit geringem Feinanteil sowie auf grobkörnige Böden hat sich die Konditionierung des abgebauten Materials mit Schäumen, Polymeren und Feinstoffsuspensionen als effektiv erwiesen. Auf diese Weise können die Eigenschaften des Stützmediums in der Abbaukammer eines Erddruckschilds so verändert werden, dass z.B. die Fließfähigkeit sowie die Durchlässigkeit günstig beeinflusst werden. Bisherige Veröffentlichungen zu den Einsatzgrenzen von Erddruckschilden, insbesondere in grobkörnigen Böden, sind vielfach durch die empirische Auswertung von Baustellenerfahrungen geprägt. In den hier vorgestellten Untersuchungen erfolgte dagegen eine breite und systematische Variation von Kornverteilungen grob- und gemischtkörniger Böden, die mit Schäumen, Polymeren sowie Feinstoffsuspensionen konditioniert wurden. Die Laboruntersuchungen mit den konditionierten Böden betrafen insbesondere die Kriterien der Verarbeitbarkeit und der Wasserdurchlässigkeit. Unter Berücksichtigung praxisnaher Vorgaben für diese Kriterien konnte ein modifiziertes Kornverteilungsdiagramm für die Einsatzbereiche von Erddruckschilden entwickelt werden. Extended Application Ranges of EPB-Shields. Soil conditioning for Earth-Pressure-Balance shield tunnelling with foams, polymers or high density slurries has proven to be an effective measure to extend the application ranges of EPB-Shields towards mixed-grained soils with a low content of fines and coarse-grained soils. By conditioning, the properties of the support medium in the excavation chamber, which mainly consists of the excavated ground, can be changed in order to positively influence i.e. its deformability and permeability. Acknowledging existing results of research on EPB conditioning a new investigation programme was developed, which aimed at a broad and systematic variation of coarse soil types as well as conditioning agents. Based on the results of the laboratory research, a chart for the application ranges for EPB-Shields using various conditioning agents was developed, which shows some significant differences to the existing empirical charts that by large are based on job site experience. [ABSTRACT FROM AUTHOR]

We report the transport properties of a dual MgO barrier magnetic tunnel junction (DMTJ) where a FeNiSiB layer was inserted in a CoFeB free layer. Upon post-deposition annealing at 330 °C, the tunneling magnetoresistance (TMR) ratio of the DMTJ with a hybrid CoFeB/FeNiSiB/CoFeB free layer reached 195% which is higher than the TMR ratio of 121% from the DMTJ with the single CoFeB free layer. The bias voltage dependence profile was more symmetric for the hybrid case. Boron depth profiling result suggests that the FeNiSiB layer dragged boron atoms more to it rather than letting them diffuse toward CoFeB/MgO interfaces, resulting in improved MTJ performances. [ABSTRACT FROM AUTHOR]

An efficient transport infrastructure, connected to the European transport network contributes to economic competitiveness, facilitates integration into the European economy and the realization of new domestic activities. The current situation of the national transport system is characterized by a reduced number of highways. [ABSTRACT FROM AUTHOR]

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The article explains the interaction of the overall system of ground, TBM and segment lining based on recent experience of projects using TBMs with active face support in Austria and abroad. The alternating dependencies and their consequences for tunnel construction are discussed in more detail. Of particular interest is the influence of the support medium and how it functions at the face and the tunnel side walls. The interaction of support pressure, thrust force and the centre of gravity of the TBM and its effect on steering behaviour are also considered. The effects of the compression of the segment tube by the TBM (prestress) are considered in relation to the improvement of the bedding and the problem of floating. Der Beitrag beleuchtet die Interaktion des Gesamtsystems 'Untergrund - Tunnelvortriebsmaschine - Tübbingausbau' basierend auf aktuellen Erfahrungen zuletzt realisierter Projekte im In- und Ausland bei TVM-Einsätzen mit aktiver Ortsbruststützung. Dabei wird insbesondere auf die wechselweisen Abhängigkeiten und deren Auswirkungen auf die Tunnelherstellung eingegangen. Ein Schwerpunkt liegt beim Einfluss des Stützmediums und der zugehörigen Wirkungsweise an der Ortsbrust und der Tunnellaibung. Berücksichtigung findet die Wechselwirkung von Stützdruck, Vortriebskraft und der Schwerpunktlage der TVM auf deren Steuerverhalten. Die Auswirkung des Zusammendrückens der Tübbingröhre durch die TVM (Vorspannung) wird in Bezug auf die Bettungsverbesserung und die Problematik des Aufschwimmens betrachtet. [ABSTRACT FROM AUTHOR]

Embedded retaining walls for 1·8 km of cut-and-cover tunnels and earth-retaining structures were redesigned during the construction period to optimise construction methods and temporary propping. The design approach included many of the developments now recommended in Ciria report C580, and the paper summarises the experience gained on this contract. The site team made detailed observations of the performance of all 14 structures during construction, and this paper gives an overall summary of the wall movements and prop loads that were measured. The walls were surcharged, and none of the props was preloaded. Despite this, the maximum movements were within those estimated from published correlations. Wall movements were time dependent, and occurred at rates of up to 0·2 mm/day. Prop loads were generally about 40% of the values obtained from moderately conservative calculations. Reducing the prop stiffness assumed in calculations improves agreement, and measurements are reported that provide a basis for closer appraisal of this aspect in future designs. [ABSTRACT FROM AUTHOR]

A common practice in the USA for excavation support system design is to assume that the complete support system is 'wished in place'. This implies that the construction of the in situ wall component and the installation of the supports do not cause any movements or changes in the in situ stress state. However, the installation can cause appreciable changes in the in situ soil stress conditions, which result in significant movements in the surrounding ground. This paper presents the results of efforts to evaluate the factors that influence movements associated with excavation support wall installation, using a series of three-dimensional finite-element models. These analyses demonstrated that soil responses and the processes that produce them are three-dimensional in nature. Thus it can be concluded that fully three-dimensional analyses are required to provide insight into these complex relationships. [ABSTRACT FROM AUTHOR]

Rigid-flexible-pile composite foundations are a newly developed method for resisting vertical load in deep soft soil. Flexible piles are used to strengthen shallow soft soil, and rigid piles are used to reduce settlement of the foundation. A cushion below the foundation caps is used to redistribute and adjust stresses on the piles and subsoil. The soft soil can also share part of the applied load in the foundation system. This enables the rigid-flexible-pile composite foundation to resist much larger load with less settlement. This paper examines the performance of such a foundation under vertical load. The results show that the stress and load-sharing ratio of the two kinds of pile and subsoil varies with the applied loading, but most of the applied load is shared by the rigid and flexible piles. Settlement of the composite foundation is controlled well, and can satisfy the performance requirements of buildings on deep soft soil. [ABSTRACT FROM AUTHOR]

Copyright of Annals of 'Constantin Brancusi' University of Targu-Jiu. Engineering Series / Analele Universităţii Constantin Brâncuşi din Târgu-Jiu. Seria Inginerie is the property of Universitatea Constantin Brancusi din Targu-Jiu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As far as the bifurcated tunnel of underground engineering is concerned, it is usually used in the water conveyance system. Due to the complexity of underground rock masses and concrete lining, researches on mechanical characteristic and stability of the bifurcation tunnel have attracted more and more attention in the geotechnical field. In order to understand bifurcated tunnel in detail, three-dimensional (3D) numerical method is applied to solve the above key subjects by simulating a practical project. Furthermore, sub-model technology is applied to analyze the intersection position, corresponding deformation and stress results in the practical condition. Meanwhile, 3D excavation and support calculation under four conditions have been simulated based on 3D self-compiled code and Ansys software. In addition, the paper plays emphasis on the stress, displacement analysis considering different stress releasing ratio instead of rheological analysis, and the results corresponding with the fact indicate the feasibility of 3D elasto–visco–plastic code. [ABSTRACT FROM AUTHOR]

The present study analyses radio propagation at the 400 MHz frequency band inside road and railway tunnels. It proposes, on the basis of field measurements, a path loss model consisting of four segments, namely: the free space segment, the high path loss segment, the waveguide segment and, in the furthest region, the free space propagation segment. Free space propagation is characteristic in a region close to an antenna. In the next region, the near region, only a few reflected rays reach the receiver resulting in high path loss. Further away, in the far region, the waveguide effect occurs because of a set of waves reflected from the tunnel walls resulting in low path loss. In the extreme far region, the waveguide effect vanishes because of attenuation of reflected rays. The points separating the individual segments are analytically defined. Model applicability and accuracy are checked by calculating the mean error and standard deviation. The results indicate reasonable agreement between measurements and the model. This four-slope path loss channel model can be applied for rapid and simple coverage prediction of direct mode operation in TETRA systems. [ABSTRACT FROM AUTHOR]

The paper presents constitutive hereditary-type equations describing nonlinear behavior of a prestressed medium (salt rock mass) exposed to loading (tunnel construction). It is proposed to solve the related boundary value problem by using Newton’s quadrature method. The offered approach is illustrated with analyzing stress-strain state of salt rocks in the vicinity of a circular section tunnel. [ABSTRACT FROM AUTHOR]

This article shows an example about the behavior of metallic structures used in underground constructions. The article shows some results that were obtain in order to see what efforts appear in a metallic maintenance that it is used in a gallery from Livezeni Mine, Romania. [ABSTRACT FROM AUTHOR]

Abstract: Large scale and intensive metro construction through dense urban area increases sharply the impaction on risk control and environment protection. Three typical cases of shield crossing building above ground (SCBA), shield crossing tunnel from above (SCTA) and shield crossing tunnel from below (SCTB) are studied, respectively, based on field measurements and site investigations of actual projects in Shanghai soft ground. The risks of shield crossing sensitive buildings and subways, ground movement prediction and its control regulations, the settings of shield driving parameters such as earth pressure, driving speed, postures and grouting are demonstrated and summarized in detail. It is proposed that stringent stipulations on controlling ground volume loss (GVL) ratio (GVLR) and strengthened monitoring measures are necessary and substantial for eliminating/reducing potential construction risks. It is urgently decisive to improve the performance of shield machine and to make it more flexible for counteracting complications of geology and environment, as refer to the present status of shields in Shanghai, most of them being overused or out of date. [Copyright &y& Elsevier]

In this paper, we study the thermal properties of the inner horizon of a Kerr-Newman black hole. By adopting Damour-Ruffini method and the thin film model which is developed on the base of brick wall model suggested by ’t Hooft, we calculate the temperature and the entropy of the inner horizon of a Kerr-Newman black hole. We conclude that the temperature of inner horizon is positive and the entropy of the inner horizon is proportional to the area of the inner horizon. The cut-off factor is same as it in calculation of the entropy of the outer horizon, 90 β. In addition, we write the integral and differential Bekenstein-Smarr formula as the parameters of the inner horizon. Then, we discuss that if the contribution of the inner horizon is taken into account to the total entropy of the black hole, the Nernst theorem can be satisfied. At last, We calculate the tunneling rate of the outer horizon Γ+ and the inner horizon Γ−. The total tunneling rate Γ should be the product of the rates of the outer and inner horizon, Γ=Γ+⋅Γ−. We find that the total tunneling rate is in agreement with the Parikh’s standard result, Γ→exp (Δ S BH), and there is no information loss. [ABSTRACT FROM AUTHOR]

Abstract: Most of the rocks surrounding deep underground construction consists of cracked rock. The deformation of the surroundings is complicated, and not only involves slipping, but also involves re-fracturing. Available results in conventional uniaxial and triaxial experiments of rock samples can be used to analyze deformations of supports and surrounding rocks on underground constructions, but they cannot reflect the evolution of the re-fracture processes and the mechanical characteristics of the cracked surrounding rock mass. The purpose of this paper is to study deformations and re-fracture characteristics of surrounding rock mass in deep underground engineering. First, deformations and cracking characteristics of intact rock samples are analyzed on the basis of uniaxial and triaxial experiments. The lateral constraint testing method is then applied to study deformation and re-fracturing characteristics of cracked rock mass. The lateral constraint test provides different lateral stiffness to the cracked rock samples and causes different failure modes in the cracked rock samples. Conditions for re-fracturing have been derived and validated through the lateral constraint tests, which can be used to study load capacities and stabilities of surrounding rock in deep underground engineering under structural constraints formed by different supports. [Copyright &y& Elsevier]

Abstract: The Q-system is one of the most applied classification tool in modern tunnelling. After an exact evaluation of the parameters the rock support can be determined via the “Q-support chart”. In an already finished tunnel, mainly driven through limestone, the Q-system was tested under difficult geological conditions (shale–marl). Scope of the appraisal was a comparison of the support suggested by the “Q-support chart” with the real performed support after the NATM, regarding partly massive damages. This article is a contribution referring to the last publication on the topic “fitness of various engineering design tools” from [Palmstrom, A., Stille, H., 2007. Ground behaviour and rock engineering tools for underground excavations. Tunnelling and Underground Space Technology 22, 363–376]. [Copyright &y& Elsevier]

The concept of sustainable development is receiving much attention throughout the global community. The concept embraces the traditional paradigm of infrastructure development and is expanding to a wider range of implications from social and environmental impacts caused by infrastructure development. Enhancement of sustainability is generally summarized using a triple bottom line approach of (i) minimizing environmental impact, (ii) maximizing economical benefit, and (iii) minimizing adverse social-cultural impact. Sustainability assessment should consider complications and interrelationships of all sustainability aspects throughout the entire life cycle. This paper presents a methodological development for a sustainability assessment modeling framework aimed at underground infrastructure construction projects. The modeling framework is based on assessing multiple proposed design alternatives and eliciting the most sustainable alternative through multiple assessment processes and a decision making process. [ABSTRACT FROM AUTHOR]

Abstract: Misalignment and breakthrough errors have been a threat for tunnelers for 2500 years, and they still represent a problem that has been studied in detail on the occasion of certain rather recent major tunnels. From these analyses precise formulae permitting to compute the uncertainties in tunnel alignment and the breakthrough error have been proposed. Since these formulae are complex, require geodetic details and do not permit direct estimation of the order of magnitude of these errors, the latter have remained an obscure point for non-specialists. In this paper we explain why such errors occur and, based on the theory of error propagation and numerical approximation techniques, we derive certain simple formulae which permit to predict the magnitude of errors in tunnel alignment and in breakthrough in three dimensions. These formulae are for simple horizontal tunnels, constrained by geodetic observations at one portal and indicate that errors broadly follow a cantilever-type pattern. In addition, hints on how these formulae can be easily extended to all other cases of curved, inclined, etc. tunnels are provided. In the case, however, of complex tunnels (for instance double tunnels connected with transversal segments) errors are smaller for their propagation is controlled by redundant observations. [Copyright &y& Elsevier]

Abstract: This study deals with the analytical solutions for the thrust and moment in the lining of a circular tunnel due to seismic-induced ovaling deformation. The discrepancy among the existing solutions in the thrust and moment for no-slip interface condition is investigated. New analytical solutions are developed by considering the relations between displacements and interaction forces at the soil-lining interface and including the slippage effect at the soil-lining interface using a spring-type flexibility coefficient. The comparison among the solutions in the thrust and moment is discussed. The effects of flexibility coefficient and deformation ratio are investigated. [Copyright &y& Elsevier]