scholarly journals Influence of Utility Tunnel on the Lower Part of the Existing Double-Track Shield Tunnel in Loess Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Min Yang ◽  
Hongru Li ◽  
Ning Li ◽  
Shun Yang

The interaction between the double-track shield tunnel and the integrated pipe gallery is complex, and there is still a lack of systematic research. Based on the numerical simulation of the Xi’an case, this paper studies the influence of the construction of the integrated pipe gallery on the deformation characteristics of the existing double-line subway tunnels with different buried depths and clear distances and finds the safe buried depth and clear distance of the tunnel. The results indicated that, in the loess area, the maximum deformation of the existing subway has a linear and inverse relationship with the buried depth and spacing, respectively. Increasing the buried depth can reduce the impact of the upper construction disturbance more than increasing the clear distance ratio. Moreove, under the design conditions of constructing a utility tunnel by the open-cut method, when the buried depth of the tunnel is 4.5 D and the spacing is greater than 4.5 D, or the buried depth is 5.0 D and the spacing is greater than 2.5 D, the combination of subway tunnels can meet the deformation control standards.

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chunquan Dai ◽  
Mengying Yang ◽  
Quanlei Wang ◽  
Tingzhi Yang ◽  
Kun Jiang

With the development of urban rail transit, subway lines are becoming more and more denser, the departure time interval is short, and the probability of subway trains meeting is high. The impact of vibration caused by double-line subway meeting on the surrounding environment cannot be ignored. Taking the typical cross-section of a single-circle double-track subway tunnel as an example, a single running scenario and three typical meeting scenarios, namely, 4 s meeting, 6 s meeting, and 8 s meeting scenarios were considered, and a track-tunnel-foundation three-dimensional ABAQUS finite element model was established. The dynamic response of monitoring points at different distances between the center of the track bed and the center line of the track was analyzed. Results showed that due to the consistent load action period, the center acceleration of the track bed increases significantly during the meeting, the main frequency of vibration and the peak value of the 1/3 octave spectrum were increased by about 5 Hz, and the vibration level at the dominant frequency was increased by about 7 dB. The center displacement of the track bed and the peak compressive strain increased significantly under the 4 s meeting and 6 s meeting working scenarios; while the 8 s meeting and 4 s single running scenarios were basically the same, only the action time was doubled. The dynamic response of the 4 working scenarios decreases with the increase of distance, and the attenuation rate gradually decreases and has gradually stabilized within 15–19 m above the vault.


2021 ◽  
Vol 23 (1) ◽  
pp. 73-84
Author(s):  
Davut Akca ◽  
Cassandre Dion Larivière ◽  
Joseph Eastwood

Substantial resources have been dedicated to designing and implementing training courses that focus on enhancing the interviewing skills of police officers. Laboratory research studies and real-world assessments of the effectiveness of interview training courses, however, have found notably mixed results. In this article, empirical studies ( N = 30) that have assessed the effectiveness of police interview and interrogation training courses were systematically reviewed. We found a wide variation in terms of the type, length, and content of the training courses, the performance criteria used to assess the training effectiveness, and the impact of the training courses on interviewing performance. Overall, the studies found that basic interviewing skills can be developed to a certain level through even short evidence-based training courses. More cognitively demanding skills, such as question selection and meaningful rapport-building, showed less of an improvement post training. The courses that included multiple training sessions showed the most consistent impact on interviewing behavior. This review also indicated a need for more systematic research on training effectiveness with more uniform and longer-term measures of effectiveness. Our findings should help guide future research on this specific topic and inform the training strategies of law enforcement and other investigatory organizations.


2021 ◽  
Vol 13 (11) ◽  
pp. 6503
Author(s):  
Yu Peng ◽  
Hubert Hirwa ◽  
Qiuying Zhang ◽  
Guoqin Wang ◽  
Fadong Li

Given the impact of COVID-19 and the desert locust plague, the Ethiopian food security issue has once again received widespread attention. Its food crisis requires comprehensive and systematic research to achieve the United Nations Sustainable Development Goal of zero hunger. This review discusses the current situation and the causes of food security in Ethiopia. We focus on the challenges in the food security assessment field. The article lists seven typical causes of food insecurity and three roots of food security in Ethiopia. Long-term food security assessment and a comprehensive understanding and manageability for food security causes are considered as the main existing research challenges. Climate-resilient management, water management, and long-term ecosystem network monitoring and data mining are suggested as potential roadmap for future research.


2011 ◽  
Vol 71-78 ◽  
pp. 32-36 ◽  
Author(s):  
Xin Jiang Wei ◽  
Jie Hong ◽  
Gang Wei

Considering the interaction of building-soil-tunnel, the grillage beams foundation frame building vertical crossed by Double-O-Tube (DOT) shield tunnel was simulated by 3D MIDAS/ GTS software, and the impact of construction on the building was analyzed. The results show that: the ground settlement trough caused by DOT shield tunnel can be fitted by peck formula; during the passage of the shield tunneling through the building, the settlement of the building increased and settlement trough was wilder; the settlement was stable and had a little rebound when shield machine already passed the building; with the increase of driving distance, the first principal stress P1 increased and then was stable; with the increase of L, the shape of foundation settlement curve changed, and the maximum differential settlement between columns increased but was small.


2014 ◽  
Vol 915-916 ◽  
pp. 108-113
Author(s):  
Wei Kai Zong

Shield construction will cause surface subsidence, and the presence of underground structures above the tunnel has an impact on surface subsidence. Based on this, with the engineering of undercross shield tunnel construction on railway station as background, used numerical simulation method to analyze the effect of surface subsidence of underground passage, and studied the influence of depth and width of underpasses on ground movement induced. The results show that: The impact of the underground passage to the wire surface subsidence caused by the shield cannot be ignored. Surface subsidence caused by double shield will be decreased because of the existence of the underground passage, and that related to the channel depth and width. The greater the depth of underground channel, the greater the surface subsidence; greater the underground channel width, the smaller surface subsidence. Meanwhile, the surface subsidence trough width and the largest settlement scope unrelated to the depth of underground tunnels but the underground channel width, and increases with the increasing of the underpass width.


2021 ◽  
Author(s):  
Наталия Александровна Иванова

Актуальность исследования для экономики усиливается такими явлениями, как влияние мирового финансового кризиса, усложнение отраслевой и территориальной структуры производства, усиление интеграции всех сфер общественной жизни, возрастание значения экологических, социальных и политических факторов развития общества, повышение трансакционных издержек принятия решений в сфере управления. Изучение литературы о территориях дает основание определить понятие региональной системы России как элемент, подсистему некоторой иерархической системы, в роли которой выступает национальная экономика. Процессы глобализации коренным образом изменяют роль регионов в национальной экономике. Регион постепенно становится не только отдельным экономическим агентом, но также вступает в мировые конкурентные процессы. Положение территориально-организованных систем оказывается зависимым не только от макроэкономических условий или возможностей самих регионов, но также от расстановки конкурентных сил, механизмов взаимодействия регионов с другими субъектами. В этой связи возникает необходимость системных исследований с целью выработки комплекса мер, которые будут способствовать повышению конкурентоспособности экономики в целом, ее регионов в частности. Существующий инструментарий региональной экономики является уже недостаточным для анализа такого рода проблем, а традиционный конкурентный анализ не рассматривает регионы в качестве субъектов конкуренции. Требуется расширение и применение новых теоретических подходов к анализу региональных экономических систем и эффективности их развития, формированию целостной концепции развития территориальной организации хозяйства, что обусловило актуальность данного исследования. The relevance of the study for the economy is enhanced by such phenomena as the impact of the global financial crisis, the complication of the sectoral and territorial structure of production, the strengthening of integration of all spheres of public life, the increasing importance of environmental, social and political factors in the development of society, the increase in transaction costs of decision-making in the field of management. The study of the literature on territories gives grounds to define the concept of the regional system of Russia as an element, a subsystem of some hierarchical system, in the role of which the national economy acts. The processes of globalization are fundamentally changing the role of regions in the national economy. The region is gradually becoming not only a separate economic agent, but also enters into global competitive processes. The position of geographically organized systems turns out to depend not only on the macroeconomic conditions or the capabilities of the regions themselves, but also on the alignment of competitive forces, the mechanisms of interaction of regions with other entities. In this regard, there is a need for systematic research in order to develop a set of measures that will contribute to improving the competitiveness of the economy as a whole, its regions in particular. The existing tools of the regional economy are no longer sufficient to analyze such problems, and traditional competitive analysis does not consider regions as subjects of competition. It requires the expansion and application of new theoretical approaches to the analysis of regional economic systems and the effectiveness of their development, the formation of an integral concept of the development of the territorial organization of the economy, which determined the relevance of this study.


Trains scheduling is an important problem in railway transportation. Many companies use fixed train timetabling to handle this problem. Train delays can affect the pre-defined timetables and postpone destination arrival times. Besides, delay propagation may affect other trains and degrade the performance of a railway network. An optimal timetable minimizes the total propagated delays in a network. In this paper, we propose a new approach to compute the expected propagated delays in a railway network. As the main contribution of the work, we use Discrete-time Markov chains to model a railway network with a fixed timetable and use probabilistic model checking to approximate the expected delays and the probability of reaching destinations with a desired delay. We use PRISM model checker to apply our approach for analyzing the impact of different train scheduling in double line tracks.


Author(s):  
Grandon Gill

Aim/Purpose: Labeling a journal as “predatory” can do great damage to the journal and the individuals that have contributed to it. This paper considers whether the predatory classification has outlived its usefulness and what might replace it. Background: With the advent of open access publishing, the term “predatory” has increasingly been used to identify academic journals, conferences, and publishers whose practices are driven by profit or self-interest rather than the advancement of science. Absent clear standards for determining what is predatory and what is not, concerns have been raised about the misuse of the label. Methodology: Mixed methods: A brief review of the literature, some illustrative case studies, and conceptual analysis. Contribution: The paper provides recommendations for reducing the impact of illegitimate journals. Findings: Current predatory classifications are being assigned with little or no systematic research and virtually no accountability. The predatory/not predatory distinction does not accommodate alternative journal missions. Recommendations for Researchers: The distinction between legitimate and illegitimate journals requires consideration of each journal’s mission. To serve as a useful guide, a process akin to that used for accrediting institutions needs to be put in place. Impact on Society: Avoiding unnecessary damage to the careers of researchers starting out. Future Research: Refining the initial classification scheme proposed in the paper.


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