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Despite the widespread use of tunnel junctions in high-efficiency devices (e.g., multijunction solar cells, tunnel field effect transistors, and resonant tunneling diodes), simulating their behavior still remains a challenge. This paper presents a new model to complete that of Karlovsky and simulate an I (V) characteristic of an Esaki tunnel junction. A review of different analytical models of band-to-band tunneling models is first presented. As a complement to previous work on tunnel junction simulation, the transmission coefficient is precisely determined and incorporated, the valley current between the tunneling and drift regimes is included, and calculations of physical parameters are updated. It is found that the model works for a broad range of values of the forward bias. [ABSTRACT FROM AUTHOR]

In this paper, the influence of the foundation configuration (raft or separate footings) on tunnel–soil–framed building interaction is investigated using geotechnical centrifuge testing. Tunnelling-induced soil movements and deformation fields, framed building displacements and structure shear distortions (with associated modification factors) are illustrated. Framed building stiffness and footing bearing capacity are also evaluated experimentally. Results show that the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields, as well as the distribution of soil shear and volumetric strains. In particular, foundation settlements and differential horizontal displacements are larger for separate footings compared to raft foundations. The effects of building width, weight and eccentricity (with respect to the tunnel) on foundation settlements and structural distortions are quantified for separate footings and contrasted against results for raft foundations. The modification factor of the maximum building shear distortion is linked to the relative soil–building shear stiffness; interestingly, for buildings with similar values of relative stiffness, the level of shear distortion within framed buildings is lower for separate footings than rafts. [ABSTRACT FROM AUTHOR]

An acceleration-compensated skin-friction balance based on the floating-head technique was developed to measure skin friction in a hypersonic impulse facility. The balance consisted of measurement and acceleration units, the outputs of which can be coupled using a full-Wheatstone bridge to obtain pure shear output. The working of the balance was tested on a flat plate model exposed to a laminar flow with Mach number, stagnation enthalpy and Reynolds number of 8.2, 0.65 MJ kg−1 and 2.9 × 106 m−1, respectively. The measured wall shear stress agreed reasonably well with that predicted by Reynolds analogy. [ABSTRACT FROM AUTHOR]

As the basic unit of residents' living conditions, the programs and research into public facilities around a community are conducive to people's livelihood and social harmony. In this paper, Dalian, one of the livable cities in China, is selected for this research: (1) due to its unique geographical location and topographic features, the spatial distribution of the quality of living for residents in the main urban area is uneven, communities with residents with a high quality of life in Dalian are distributed in flat and developed areas around the major transportation routes, (2) the urban population of Dalian is increasing every year and community construction remains around the high-quality community that is near the traffic trunk line. Meanwhile, the proportion of the number of high-quality communities is: Xigang>Shahekou>Zhongshan>Ganjingzi; (3) the historical development of coastal cities affects the spatial layout of traffic, functional areas, and population in the region, as well as future planning and development. The types of public facilities in the traditional residential areas are complete and serve the residents. The spatial distribution of residents with a high quality of life is centered around this area, which decreases gradually outward. This paper will make a preliminary small-scale and targeted exploration of the quality of living of residents in the main urban area of Dalian and will combine the experience from the construction of public facilities for social equity in China and abroad to improve the construction of public resource materials that are needed by residents in urban areas, which will provide a foundation for research into improving the urban living quality and spatial equity. [ABSTRACT FROM AUTHOR]

During the early years of the 19th century, narrow‐gauge railways found their way into mines and tunnel projects. Due to economic reasons, these rail‐bound transport systems were successfully used for the transport of personnel, supplies and muck operations. While the worldwide transport logistics developed and changed continuously over the following century, there was limited demand within the tunnelling industry on innovation and improvement for these robust, durable and simple railways. Moreover, rubber‐tired transport systems were introduced to the market and replaced traditional rail equipment on many tunnelling projects. The MTS tunnel Drive 1, originally planned to be 13 km in length and now extended to 30 km, will become the longest single tunnel drive in the world, demonstrating the flexibility of a rail‐bound system. Since the start of the project, various suppliers and manufacturers for rail‐bound equipment and rail track systems have been involved in the development of innovative drive systems, under‐carriages and rail tracks. This article provides an overview of the design, implementation and lessons learned so far. [ABSTRACT FROM AUTHOR]

The deformation mode of loess surrounding rock of anchor under the action of pull-out load and the shear stress distribution law of loess anchor and loess interface under the condition of different lengths anchor are studied by using the laboratory self-made model test chamber and micro anchor pullout instrument. A total of three tests are carried out for the selected test anchor. Three deformation modes of loess surrounding rock under the action of pull-out load are obtained according to the test results. It is proposed that the maximum shear stress of loess anchor under the action of pull-out load appears in the section 25 times the anchor diameter from the anchor head, and the shear stress in the middle and rear part of the anchor body can only be brought into full play when the length-to-diameter ratio of the anchor body is 110 or more. Based on the displacement solution of Mindlin problem, the drawn conclusion is compared with the theoretical solution of shear stress and axial force of loess anchor under the action of pull-out load. The results compared are basically consistent, indicating that the conclusion has strong engineering practice, which can provide technical basis for the design and optimization of the system anchor in the sidewall of loess tunnel. [ABSTRACT FROM AUTHOR]

In this research, the failure mechanism and anomalous behavior of intact and jointed rock block having a circular tunnel under compression are studied. This was done by monitoring the progressive failure of a rock tunnel subjected to uniaxial loading. The tests were conducted in sandstone blocks and "Acoustic Emission" (AE) technique was used to identify the crack damage and other failure attributes. Three cases have been considered in the research, i.e. tunnel in the intact rock, with horizontal joints, and with vertical joint sets. Images of progressive failure, acoustic signals, and applied loads were simultaneously recorded during the test. The intact block demonstrates continuous crack generation while the block with horizontal joint set shows a stepwise cracking pattern. In the third case where the vertical joints were employed, the deformation was largely roof failure and joint perpendicular extension was dominant. The AE events show that a sudden drop and then a quiet period of seismic "Ib value" could be considered as the precursors to forecast the rockburst hazard. The paper also compares the results of the physical model test with a 2D finite element model. The compared results show good agreement between the physical and numerical models. [ABSTRACT FROM AUTHOR]

Building and urban railway construction are two typical high-risk types of construction in which unsafe behaviors have a considerable impact on the occurrence of accidents. To explore the patterns of unsafe behaviors and promote accident prevention, a comparative analysis is conducted to analyze the behavioral risk chains of accidents for these two construction types in the Chinese construction industry using complex network (CN) theory. First, accident cases are collected from government websites, and unsafe behaviors are extracted and classified according to a summary list of several safety standards and operating procedures. Second, behavioral risk chain networks of accidents (BRCNAs) for the two construction types are established as directed networks. Pajek, a program for visualizing and analyzing large networks, is then used to construct network models. Finally, the topological parameters of the BRCNAs are calculated and compared. The results show that BRCNAs are both scale-free and small-world networks. The characteristics of the building construction BRCNA are related to individual workers, and the characteristics of the urban railway construction BRCNA are related to the working environment and supervisors. However, there are certain unsafe behaviors that play an important role in accidents in both construction types. These findings reveal the variations in interactions among unsafe behaviors that cause accidents in the two construction types to further understand the patterns of unsafe behaviors. This study is of theoretical and practical significance for improving accident causation models and supporting on-site safety management in the construction industry. [ABSTRACT FROM AUTHOR]

In the excavation for underground powerhouse, the blasting vibration leads to dynamic disturbance for construction safety and stability, which means such vibration should be monitored and mitigated. In this paper, the Baihetan Hydropower Station is involved, and the blasting vibration is monitored along either the vertical or the horizontal direction. The monitoring results of the distribution of blasting vibration on the high sidewall shows the vibration velocity at some positions far away from the detonation source is greater than that near the source. Such abnormal elevation amplification phenomenon is different from the distribution of blasting vibration on the slope of open-pit mine. To address this phenomenon, the dynamic finite element simulation is conducted. The comparison between the simulation results and monitoring data validates the proposed solution. Furthermore, the propagation law of blasting vibration velocity of high side wall is proposed, and the local elevation amplification effect of blasting vibration velocity is clarified. Finally, the modified Sadovskii formula is presented, and the reliability and accuracy of the modified formula for the vibration velocity of particles in the direction of elevation are verified and improved through data comparison. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

The presence of squeezing ground conditions often poses significant challenges in predicting tunnel response over time and to the design of an adequate support system to stabilize the tunnel. Many analytical, empirical, observational, and numerical models have been proposed over the years for the design of tunnels in squeezing ground conditions, but they all have some limitations. The study presented in this paper focused on improving the understanding of tunnel squeezing via a unique physical model test that simulated tunnel boring machine (TBM) excavation in squeezing clay-rich rocks. The physical model included a large true-triaxial cell, a miniature TBM, a laboratory-prepared synthetic test specimen having properties similar to natural mudstone, and instrumentations to monitor deformations around the tunnel boundary during and after the excavation. Experiments were conducted at realistic in-situ stress levels to study time-dependent tunnel convergence in three-dimensions. A tunnel was excavated using the miniature TBM in a cubical rock specimen loaded in the true-triaxial cell; then the confining stress was increased in stages to values above the rock unconfined compressive strength. Strain gauges embedded in the rock specimen and a digital borehole caliper monitored tunnel wall deformations with time. The degree of tunnel squeezing was characterized using a classification system based on tunnel radial strain. A model for time-dependent tunnel longitudinal displacement profile (LDP) was proposed using measurements of the tunnel convergence at different times and different stress levels. [ABSTRACT FROM AUTHOR]

Rapid growth and the urban development of Chinese megacity in recent decades have led to land utilization challenges and the need for over-track buildings above metro depots that are part of the subway systems in these cities. Frequent subway operations into and out of the depots, which generate excessive vibration that transmits into the over-track buildings, can have adverse effects on the buildings' occupants in terms of feelable vibration and noise. An efficient modeling procedure is presented for estimating vibration levels within the buildings before construction to determine whether vibration mitigation is required. Models were developed and validated based on vibration measurements in low-rise and high-rise buildings over a metro depot in Shenzhen, China. Impedance models were developed that characterize vibration transmission through the primary support columns or load-bearing walls into the building floors. Inputs to the model are vibration levels at the buildings' foundation where the model estimates the transmission through individual support structures to the upper floors. Vibration estimates at different elevations within the building were compared with the measured levels during train pass-bys under the buildings with good agreement. Based on axial wave transmission impedances for column or load-bearing wall segments and simple impedance expressions for building floors, the closed-form analytical impedance model is an efficient and cost-effective tool for estimating floor vibration before construction. [ABSTRACT FROM AUTHOR]

(001)-oriented FeAlSi polycrystalline thin films with a flat surface and B2-ordered structure were grown on thermally oxidized SiO2 substrates using MgO buffer layers. The FeAlSi thin films composition-adjusted to the Sendust alloy exhibited a low coercivity (Hc) after the annealing process. We utilized these films as bottom electrodes of magnetic tunnel junctions (MTJs) and characterized their tunnel magnetoresistance (TMR) effect. The TMR effect was 35.9% at room temperature. In addition, the TMR ratio increased to 51.0% when a thin CoFeB layer was inserted into the FeAlSi/MgO interface, without degrading the small switching field of the FeAlSi electrode. These MTJs with a small switching field and relatively high TMR ratio using the FeAlSi electrode are promising for highly sensitive MTJ-based magnetic sensor devices. [ABSTRACT FROM AUTHOR]

Copyright of Direito da Cidade is the property of Editora da Universidade do Estado do Rio de Janeiro (EdUERJ) 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.)

The LA3M Laboratory of Aix Marseille University (France), in cooperation with the Institute of Archaeology and Ethnography of the Armenian Academy, represented on the ground by the Regional Museum of Shirak, has carried out, from 2009 to 2016, an archaeological survey of the early Christian and medieval site of Yereruyk. The project was aimed at a multidisciplinary approach of the complex, combining armenology, history of art and architecture, building archaeology, classic archaeology, archaeological anthropology, and geo-archaeology. One of the purposes was to better understand the reasons why such a large ensemble had been established in a space now deprived, at the northwestern tip of the country. The complex includes the vestiges of several buildings, among which an early Christian basilica, a vaulted construction which served perhaps as a mausoleum, the remains of a "false rampart", and of a series of parallel walls corresponding, at a certain period, to a dam, two underground halls, and numerous fragments of sculpted stones. A special attention was paid to the basilica and to the cemetery, where twenty-seven tombs were studied in detail. Another objective was to try to clarify the absolute and relative dating of the main buildings, as well as the function of many of them, which was still unclear. The mission also sought to specify the relationship which must have existed around the year one thousand between the religious complex and the medieval capital Ani, from which it is only some kilometers away. [ABSTRACT FROM AUTHOR]

In the present study, a physical model test was used to investigate the cracking characteristics of the surrounding rocks of hydraulic tunnels under high geothermal conditions. Based on similarity theory, a similar material was developed to simulate the intact and hard rocks in thermo-hydro-mechanical (THM) coupling fields; this material was used to cast a large-scale model tunnel. A new loading system, including a temperature loading system and a water pressure loading system, was designed to improve upon conventional laboratory hydraulic tunnel testing and provide a means of better understanding the fracture behavior of solid media. An acoustic emission (AE) monitoring system, thermocouples and osmometers were used to reveal the real-time evolution of the temperature field, seepage pressure field and crack propagation. The test results showed that compared to a hydraulic tunnel without high geotemperature, the critical internal water pressure of the hydraulic tunnel under high geothermal conditions decreased significantly. After the initiation of main cracks was induced by hydraulic fracturing, due to THM coupling, a certain number of secondary cracks initiated and developed between the main cracks. In this process, the trend of the secondary crack tip deviated from the radial direction, resulting in a more developed and complicated evolution of cracks (including main cracks and secondary cracks). This was different from the cracking behavior of surrounding rocks without a high geothermal gradient, in which only a few main cracks due to hydraulic fracturing were observed. An obvious multifield THM coupling effect was observed under high-geotemperature conditions, and cracks propagated and damage increased in the surrounding rocks in a discontinuous and step-like manner. The number and source locations of the cracks recorded by the AE monitoring system were in good agreement with the evolution of the temperature field and seepage pressure field. In addition, FLAC3D numerical simulations based on the thermo-hydro-mechanics and damage (THMD) model revealed that high geotemperatures and in situ stresses significantly influenced on the cracking mode of the surrounding rocks of hydraulic tunnels under high geotemperatures. The results obtained in this study provide a better understanding of the cracking characteristics of the surrounding rocks of hydraulic tunnels under high geothermal conditions and are useful for the design of hydraulic tunnels. [ABSTRACT FROM AUTHOR]

The old city centers of many major cities represent a great challenge from a constructive point of view since the foundations of the buildings consist of an aggregation of previous constructions. This endorses thorough monitoring activities during any underground construction. The capabilities of the persistent scatterer interferometry (PSI) can be exploited to cope with these monitoring needs. However, the old city centers represent a very challenging urban scenario since the rooftops are usually filled with air conditioning systems and due to the fact that the streets are usually crowded. This work assesses the applicability of the PSI technique under this challenging scenario. Moreover, it proposes a set of novel classification indexes that allow an objective assessment of the building's health and the impact derived from any activity. They can be applied in deformation monitoring and risk evaluation in urban areas. The applicability of the technique and the proposed indexes is validated in the monitoring of underground construction works in the old city center of Madrid comparing the results against on-ground measurements and identifying the potential and the limitation of the technique. [ABSTRACT FROM AUTHOR]

Curved metro lines currently account for a significant proportion of total route mileage. However, the existing prediction model of environmental vibration only considered the vibration induced by trains running in a straight tunnel. In the present study, a numerical model was proposed to predict the environmental vibration induced by trains running in a curved tunnel. The model was divided into two parts: a train-track coupled model and a tunnel-soil-building finite element model. In the first part, a novel three-dimensional train-curved track coupled model was established and solved in the frequency domain based on the periodic theory. Both vertical and horizontal train loads were calculated by this model. Then, an in situ measurement was performed in the curved tunnel of an operating metro line, and the tunnel vibration responses were obtained and used to calibrate the train-track model. Finally, a case study was selected from Beijing metro line 16, where it is needed to predict and evaluate the environmental impact of vibration from a curved metro line being planned for construction beneath an office building. A three-dimensional tunnel-soil-building finite element model was built, and the building vibrations in vertical and horizontal directions were predicted. The results show that the floor vibrations have peak values of approximately 5.29 and 27.8 Hz, which are exacerbated by the building local mode and the spacing of the rail supports. Below the third floor, the vertical vibration response exceeded the vibration control limit recommended by Chinese national standards. Track solutions for vibration control must be implemented to mitigate the environmental vibrations. [ABSTRACT FROM AUTHOR]

This study presents performance of the solar tunnel dryer for drying of peach samples. The solar tunnel dryer consists of a flat plate solar collector, a drying tunnel, a solar cell module and a small axial fan. It has been constructed at the Department of Agricultural Machinery and Technologies Engineering at Isparta University of Applied Sciences. During the drying process, solar irradiation, drying air temperature, relative humidity, and air velocity were measured constantly in different parts of the dryer. At same time, mass loss of the peach samples was measured during the drying period at one-hour interval. In this study, the color measurements fresh and dried products were determined at the beginning and end of experiment. The fresh peach samples were sorted, graded, washed by tap water and then sliced manually as half-moon without peeling before pretreatment. Sun drying behavior of sliced peach samples pretreated with 1% sodium metabisulfit, 1% ascorbic acid and non-pretreated was investigated. The drying characteristic curves were evaluated against ten mathematical models. Results showed that the Midilli et al. model was found to be the best descriptive model for solar tunnel drying of thin layer peach. [ABSTRACT FROM AUTHOR]

With the large-scale development of urban underground space, foundation pit engineering has become one of the important geotechnical engineering topics in urban construction. In this paper, the effects of foundation pit excavation and precipitation on adjacent buildings are studied in detail. The main research work includes the following aspects: summarizing and analyzing the soil consolidation theory, foundation pit excavation, and precipitation process; the influencing factors of the adjacent soil layer displacement; the influence mechanism and influence types of foundation pit excavation and precipitation on adjacent buildings. The finite element model considering the whole process of foundation pit excavation is established, and the variation law of the upper layer displacement around the foundation pit is analyzed. The deformation law of the retaining structure, the calculation results of precipitation and nonprecipitation, and different excavation methods will be analyzed and compared. The calculation results show that the displacement of the soil layer around the foundation pit is also different between different excavation methods. As the distance between the foundation pits increases, the lateral displacement of the underground continuous wall near the frame structure gradually decreases. The distance from the foundation pit wall is 30 m. The maximum value of the lateral shift is reduced by 4.7% compared with 5 m. The foundation pit is studied, as well as the law of internal force variation of adjacent buildings caused by digging and precipitation, and checking the safety and adaptability of structural members. The calculation results show that a large additional internal force will be generated on the bottom floor of the adjacent building, and some structural members will be damaged by the bearing capacity. [ABSTRACT FROM AUTHOR]

This study mainly investigated the variation law and mechanical mechanism of surrounding earth pressure and deformation of an existing tunnel, caused by dewatering, foundation excavation, building loading, and groundwater recovery. According to different dewatering schemes, two modes were established: nonisolated dewatering unloading-loading mode and isolated dewatering unloading-loading mode. Through large-scale similar materials model test, the variation law of deformation and surrounding earth pressure of adjacent tunnel under complex unloading-loading conditions was preliminarily revealed. Based on the size of the prototype project, the test results were further verified by the numerical simulation. The mechanical mechanism of tunnel deformation in different construction stages was analyzed after the comparative study. The results show that the tunnel structure deformation, vertical and horizontal displacement, and torsion occur in the process of building construction. In the nonisolated dewatering unloading-loading mode, the decrease or rise of the groundwater level significantly reduces (maximum 27.85%) or increases (maximum 35.19%) the surrounding earth pressure of the tunnel. The decrease or increase of the horizontal total stress was much greater than that of the vertical total stress, which leads to the deformation of tunnel structure. The vertical displacement of the tunnel is generally settlement, which mainly occurs in the stage of dewatering and building loading, accounting for 83.21%–100.00% and 25.11%–40.34% of the total settlement, respectively. In the stage of foundation pit excavation and groundwater recovery, the tunnel rises. In the horizontal direction, the tunnel moves towards the foundation pit, mainly in the excavation stage, accounting for 82.77%–86.30% of the maximum value. Due to the uneven change of displacement field and stress field of soil outside the foundation pit, the tunnel torsion occurs. In the isolated dewatering unloading-Loading mode, the change of groundwater has little effect on the tunnel. In the stage of excavation and construction load, the variation law of tunnel surrounding earth pressure and deformation is similar in the two modes. [ABSTRACT FROM AUTHOR]

Building S1 is a 12-storey office development site that is situated within London, north of King's Cross Station. The site directly overlies twin Thameslink rail. The construction activities include: ~3 m of surface excavation; insertion of piles either side of – and between – the tunnels; subsequent loading of the piles; and excavation of a 1-storey deep basement adjacent to the tunnels. The tunnels have live monitoring equipment installed around the lining. The aim of this project is to use the live monitoring data to produce a back-analysed finite element model that accurately predicts the tunnel displacement recorded. The latter is compared with the model of the stages of construction covered by the monitoring. The subsequent stages are modelled in order to have a holistic idea of the behaviour of the site. The model uses the assumptions involved with 2D plane strain, along with assuming homogenous and isotropic geotechnical units. Additionally, the London Clay is modelled with the hardening soil with small strain constitutive model (HSS). Sensitivity analyses show that the small strain parameters of HSS for the London Clay had the most significant effect on tunnel displacement compared with the strength, stiffness and permeability. [ABSTRACT FROM AUTHOR]

Based on the experience and technology summary of immersed tunnel construction of HZMB island and tunnel project and its further innovation, we proposed and introduced a paralleled -flow -line -prefabrication factory method for concrete type monolithic element of immersed tunnel, and quantitatively analyzed its advantages as compared to conventional factory method, which lies in shorter construction period, less land occupation and optimized workload. With the increase of the length of immersed tunnel and the number of tube elements, its advantages become more obvious. [ABSTRACT FROM AUTHOR]

In geotechnical engineering, modeling geo-structures is challenging, particularly in cases where the interaction between the structures and soil or rock is complex. Most well-known commercial modeling software is based on homogenous and isotropic materials. However, soil and rock are often modeled in heterogeneous and anisotropic media because of the inherent anisotropy of sedimentary rock masses and their stratified structure. In recent decades, coupled hydro-mechanical (HM) interactions in isotropic porous media have been studied; however, the behavior of transversely isotropic porous media is rarely considered. In addition, it is difficult for commercial software such as Plaxis and Flac3D to express complex rock formation where the anisotropy of the material and the associated cracks and fractures could be assembled into a single model. In this study, a finite element implementation using Differential Equation Analysis Library (DEAL.II), an open-source library of finite element codes, was developed to model the fully coupled HM behavior of transversely isotropic porous media. The proposed implementation can be applied to both isotropic and transversely isotropic porous media based on Biot's theory. The developed code can be used to model poroelastic media with (1) equations of linear elasticity for the solid matrix and (2) diffusion equations for fluid flow based on mass and linear-momentum conservation laws. We verified the performance and accuracy of the code through two examples, i.e., Mandel's problem with a compared analytical solution and a tunnel excavation process with the Flac3D software. On the basis of these numerical applications, we present the code to model the behavior of various geo-structures such as tunnels and pile–soil interactions with anisotropic materials. [ABSTRACT FROM AUTHOR]

This paper corrected the long-term misunderstanding of the land utilization efficiency concept. The Undesirable-Window-DEA model, Dagum Gini coefficient, and spatial panel autoregressive model with fixed effect were used to explore the spatial heterogeneity and influencing factors of urban construction land utilization efficiency in China from 2004 to 2016. The results show the following: (1) China's overall utilization of urban construction land is still at a low level. It decreased first and then rose, with a "flat V-shaped" evolution pattern. (2) During the study period, the Gini coefficient of urban construction land utilization efficiency for all provinces decreased first, then rose, and decreased again. The utilization efficiency Gini coefficients within provincial grouping were eastern region (0.063), central region (0.101), and western region (0.128). The Gini coefficients within provincial grouping were central versus western (0.121), eastern versus western (0.161), and eastern versus central (0.168). For the contribution to overall inequality of land utilization efficiency, the inequality within groups contributes the most (57.57%), and the inequality between groups accounts for about 25.62%. The overall efficiency is improved, with an evolution pattern of "difference narrowed–differences expanded–difference narrowed." (3) "economic development," "industrial structure," "research development investment," and "land urbanization level" have significantly positive effect on urban construction land utilization efficiency, while other factors have a negative effect, including "urbanization level of population," "urban population density," "cultivated field resources level," "government influence level," "land urbanization level," and "financial dependence level." This study could provide theoretical support for the implementation of cross-provincial/regional urban construction land quotes reallocation and differential construction land management policies. [ABSTRACT FROM AUTHOR]

The results of numerical and field studies of deformations of the foundations of buildings and structures in the zone of underground construction influence during the implementation of protective measures are presented. Methods for predicting additional settlement of buildings in the surrounding development, taking into account the technology of protective measures, have been developed. Recommendations on the selection of protective measures for buildings of different statuses and technical condition categories are proposed. [ABSTRACT FROM AUTHOR]

Copyright of ESTOA: Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca is the property of ESTOA Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca 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.)

A deep foundation pit in a station of the Hangzhou subway is adjacent to new high-rise residential buildings on the north side and to the Evergrande foundation pit being excavated on the south side. This work considers the excavation of the foundation pit in the subway station as the research subject, focuses on the difference of the deformation and Earth pressure between the north side and the south side of the foundation pit under these special working conditions through the analysis of the measured data, and compares it with an ordinary foundation pit. Analyzing the measured data reveals that the horizontal displacement of the retaining wall and the ground settlement are far larger on the north side than on the south side, and both often exceed the deformation alarm value; the deformation of the ordinary foundation pit is between the deformation of the overloaded (north) side and that of the unloaded (south) side of the foundation pit. Moreover, the maximum rate of the horizontal creep of the soil and the maximum rate of the creep caused by the ground settlement on the north side of the foundation pit are larger than those on the south side of the foundation pit; the maximum rate of the horizontal creep of the ordinary foundation pit is between the two. The active Earth pressure on the pit wall on the north side is higher than that on the south side of the foundation pit, and because of the surrounding unloading, passive Earth pressure is generated at the bottom of the pit wall on the south side of the foundation pit, which causes it to shift to the outside of the foundation pit. The settlement of the surrounding high-rise buildings and the settlement of the columns are all within the range of the alarm values; also, the buildings settle evenly. Due to the excavation and unloading on the south side of the foundation pit, the uplift of the columns is not considerable. [ABSTRACT FROM AUTHOR]

Based on the blasting engineering of the subway tunnel, the overall dynamic response of the 28-story frame-shear-wall structure is studied by field test and numerical analysis. Field test is the blasting vibration monitoring and operational mode analysis (OMA). OMA used Ibrahim Time Domain method to extract the modal frequencies, the modal damping ratio of the structure, provided the basis for further analysis of the vibration response laws. The structure is simplified into a mass-spring-damper model. Based on the modal parameters extracted from the AVT, fixed the stiffness matrix and the damping matrix of the mass-spring-damper model, and set up the dynamic differential equation. So the modal parameters and frequency-response-functions of the building bending vibration can be calculated. SIMULINK dynamic simulation model was established based on the dynamic differential equation of the mass-spring-damper model. Based on the blasting vibration velocity signal, the overall vibration response law of high-rise buildings under tunnel blasting seismic is analyzed. The following conclusions are drawn: 1. Under the blasting vibration of the subway tunnel, the vibration response velocity of high-rise buildings presents: vertical vibration is the largest, lengthways vibration velocity is the second, and transverse vibration velocity is the smallest. However, the vertical vibration velocity peak and tangential vibration velocity peak at the higher floors is not much different. 2. On the higher floors, the velocity peaks fluctuated with floor increasing, and fluctuation is interrelated with the dominant mode. The peak value of vibration velocities distribution shows this correlation; 3, To simplify the high-rise building to be the mass-spring-damper model and set up the mathematical model of dynamic reaction. Then, the Simulink simulation model was established for simulation calculation. This method can adequately predict the response of the structure under blasting vibration. [ABSTRACT FROM AUTHOR]

Excavating a tunnel in a deep and saturated ground affects the short- and long-term hydro-mechanical (H-M) response in the ground surrounding the opening. However, the interactions between transient pore pressure behavior and the corresponding deformation and stresses in the ground ahead of and behind the tunnel face are still not well understood. This paper investigates the transient H-M response of excavating a tunnel in a deep and saturated ground using a two-dimensional axisymmetric coupled model in the computer code Fast Lagrangian Analysis of Continua (FLAC). The tunnel was advanced in a stepwise excavation procedure consisting of undrained excavation and drained consolidation until the final tunnel face was reached. The final excavated face was then left to consolidate toward the steady-state condition. The main results of the paper are as follows: (1) when simulating a tunnel excavation in deep saturated ground using the convergence-confinement method, the unloading factors should be nonlinear and should consists of the mechanical unloading factor in the form of excavation force and the hydraulic unloading factor in the form of excavation pore pressure. These two unloading factors are necessary because the induced H-M response near the tunnel face is a rather transient response instead of an initial or final response. Moreover, it is observed that the pore pressure dissipation is not linear either with time or with distance to the tunnel face, (2) a relationship between the unloading factors and the distance to the tunnel face should then be established. This relationship is vital because it will provide the timing for tunnel support installation, and (3) the extrusion and the convergence of the advance core could be related through the proposed equations capturing the linear relationships between the face extrusion and its convergence as well as between the core extrusion and its pre-convergence. Through these relationships, the tunnel engineer may be able to estimate the magnitude of the deformation ahead of the face, which will subsequently allow control of the deformation behind the face. [ABSTRACT FROM AUTHOR]

In Southeast China, the presence of boulders significantly threatens subway construction projects. Undetected boulders could negatively impact the efficiency and safety of subway construction methods that use shield and tunnel-boring machines. Therefore, boulder detection is a necessary step before construction begins. Recently, the cross-hole electrical resistivity tomography (ERT) method has gained attention as a potential boulder-detection approach in subway construction projects. However, in this method, the detection effect of each electrode configuration still needs to be assessed. In this study, a full-scale physical model test was conducted to determine the optimal electrode configuration for the cross-hole ERT method. Additionally, a sensitivity analysis of three types of electrode configurations, namely, bipole-bipole, dipole-dipole, and pole-tripole, was conducted. The results showed that the detection ability of the bipole-bipole electrode configuration was satisfactory, with very good boulder-detection resolution and sensitivity. Conversely, the resolution of the dipole-dipole electrode configuration, with relatively low signal strength, decreased as boulder distribution became more complex. Although the pole-tripole electrode configuration showed acceptable resolution, the boulder-detection results had many artifacts. Thus, the full-scale physical model test was conducted to thoroughly investigate the cross-hole ERT electrode configurations and determine the influence of boulder distribution on the measurements, with a view on achieving a more efficient application of this method in the field. [ABSTRACT FROM AUTHOR]

For months we have been locked out of Junkspace. So, who's complaining? Confined to domestic spaces, #stayhome has given many of us a forced opportunity to rethink the type of spaces that are not only functional and useful, but that make us feel comfortable. Our own residential arena may have felt restrictive and even – for some – oppressive at times, but who would say that they truly missed their daily passage through the endlessly stale air of check-in desks, departure gates, and duty frees at the airport; the epic journeys through low ceiling corridors and passageways of railway terminals and subway stations; and the blinding hallucinatory proliferation of brands and franchises in malls...? [ABSTRACT FROM AUTHOR]

Accurate prediction of the stability of rock surrounding a tunnel is important in order to prevent from rock collapse or reduce the hazard to personnel and traffic caused by such incidents. In our study, a KNN algorithm based on grouped center vector is proposed, which reduces the complexity of calculation, thus improving the prediction performance of the algorithm. Then, the improved KNN algorithm was applied to the surrounding rock stability prediction of a high-speed railway tunnel, which, to our knowledge, forms the first application thereof for the prediction of surrounding rock stability. Extensive experimental results show that our proposed prediction model achieves high prediction performance in this regard. Finally, a laboratory experiment of a tunnel is conducted to evaluate whether the tunnel surrounding rock is stable or not. The experimental results matched the prediction results obtained by our proposed prediction model, which further demonstrates its effectiveness. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new three‐directional isolator and a new prediction model for base isolation method of buildings to improve the comfort of occupants under subway‐induced environmental vibration. The mechanical properties of the isolator were tested in a laboratory. The results indicated that the stiffness values can satisfy the isolation requirements for environmental vibrations by increasing the thickness of rubber layers, and the sliding bottom is beneficial for protecting the new isolator from instability failures under earthquakes. The suppression effectiveness of the new isolator for three‐directional subway‐induced environmental vibrations was then investigated via field experiments with a full‐scale building. Further, the tri‐axial comfort of occupants inside the building is enhanced significantly. Finally, using the measured data from the field experiments as an input, the new prediction model was proven to be effective for evaluating the vertical vibration levels of the base‐isolated building. As the new prediction model only includes a few of the most influential floor slabs, the modeling workload and computational cost of the prediction analysis are eased. Therefore, the new isolator and the prediction model are beneficial for improving the service performances of the base isolation method, especially for the buildings near subway transportation and in seismic areas. [ABSTRACT FROM AUTHOR]

This article uses Cronkhite's definition of communication to examine the relationship between Abarkouhi homes and three forms of human communication—(1) human–human, (2) human–nature, and (3) human–place—that take place in the "home" as symbolic actions. We assumed first that it is the sense of belonging that causes the stability of life in Abarkouhi houses. We use the definitions of "home" offered by phenomenologists to present our theoretical synthesis based on two concepts of place and communication. The article will discuss the ethnographic methodology of the study and the ethnographic interviews conducted with the residents about Abarkouh's historic context, including the analysis of a number of photos. After collecting the interview data, we combined them with the data gathered by direct observations. Some of the findings indicate that the current residents of Abarkouh are old men and women who are probably the last generation of people living in the historic city. Therefore, the sense of belonging to "home" and the level of adaptation to new ways of life and new communicative actions within the old homes are not such that they contribute to the durability of life in the old houses and to keeping the future generations eager enough to continue living in this historic context. Along with the introduction of new technology and a modern way of life, many of the communicative actions resulting from living in these homes have disappeared, and nothing has replaced them. We believe that the historic context of the city, including its various home types and typical places, is in danger of disappearing. [ABSTRACT FROM AUTHOR]

Over the past three decades, China has experienced rapid economic growth along with a rapid increase in urbanization and living standards, leading to a boom in infrastructure demand. A large part of China's newly constructed infrastructure is through urban construction; thus, cities have become a major source of material consumption and carbon emissions. Understanding the relationship between material consumption, carbon emissions, and the economic growth of cities is key to ensuring that the construction of infrastructure satisfies the needs for both economic development and dematerialization. In this study, we first accounted for material consumption and the carbon emissions of infrastructure construction of 34 cities in Northeast China and characterized spatial and temporal changes from 2010–2017. The material use and carbon emissions of infrastructure construction declined by 34.6% and 30.2% during this period. Specifically, material consumption decreased from 305.2 million tonnes to 199.6 million tonnes, and carbon emissions decreased from 77.7 million tonnes to 54.3 million tonnes. Furthermore, we used a decoupling indicator to evaluate the decoupling of material consumption or carbon emissions from GDP in these cities. We found that most cities have achieved the absolute decoupling of material consumption and carbon emissions from GDP over the study period. Finally, we proposed several policy recommendations for promoting the sustainable development of the infrastructure of cities. To ensure that cities realize low-carbon urbanization, policymakers need to promote modular buildings and low-emission construction materials. This paper also serves as a practical reference for the improvement of relevant materials and carbon emissions management strategies for other developing regions. [ABSTRACT FROM AUTHOR]

Suppose α and R are disjoint simple closed curves in the boundary of a genus two handlebody H such that H [ R ] (i.e. a 2-handle addition along R) embeds in S 3 as the exterior of a hyperbolic knot k (thus, k is a tunnel-number-one knot), and α is Seifert in H (i.e. a 2-handle addition H [ α ] is a Seifert-fibered space) and not the meridian of H [ R ]. Then for a slope γ of k represented by α , γ -Dehn surgery k (γ) is a Seifert-fibered space. Such a construction of Seifert-fibered Dehn surgeries generalizes that of Seifert-fibered Dehn surgeries arising from primtive/Seifert positions of a knot, which was introduced in [J. Dean, Small Seifert-fibered Dehn surgery on hyperbolic knots, Algebr. Geom. Topol. 3 (2003) 435–472.]. In this paper, we show that there exists a meridional curve m of k (or H [ R ]) in ∂ H such that α intersects m transversely in exactly one point. It follows that such a construction of a Seifert-fibered Dehn surgery k (γ) can arise from a primitive/Seifert position of k with γ its surface-slope. This result supports partially the two conjectures: (1) any Seifert-fibered surgery on a hyperbolic knot in S 3 is integral, and (2) any Seifert-fibered surgery on a hyperbolic tunnel-number-one knot arises from a primitive/Seifert position whose surface slope corresponds to the surgery slope. [ABSTRACT FROM AUTHOR]

The drill and blast method is one of the most widely used techniques for excavation of tunnels in rock masses. The most worrying issue in this method is unfavorable damage induced by blast impact into the surrounding rock mass. The blast-induced damaged zone has a possible influence on the tunnel stability. Therefore, the damage in the rock mass should be minimized as much as possible, or if it is inevitable, the design of the tunnel should be performed based on an accurate analysis considering the damaged zone. In this paper, a theoretical and practical method is presented for the ground reaction curve of a circular tunnel excavated in an elastic strain-softening Mohr–Coulomb rock mass considering the blast-induced damaged zone. A cylindrical damaged zone with decreased strength and deformability parameters is taken into account. The results for a typical tunnel obtained using the proposed solution are compared with other well-known analytical methods. It is observed that the proposed approximate solution converges to the exact solution if the stress increments are sufficiently small. The influence of the strain-softening behavior on the results is examined through the establishment of stresses and displacement distributions and ground reaction curves and the discussion for the extent of the plastic zone. The results show that the influence of the damaged zone with reduced properties on the tunnel convergence is significant. [ABSTRACT FROM AUTHOR]

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Copyright of Tunel is the property of Ceska Tunelarska Asociace ITA-AITES, z.s 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.)