bluuebunny/crossref_metadata_2025 huggingface dataset:
Endobiliary radiofrequency ablation combined with bilateral metal stent placement for malignant hilar biliary obstruction
Authors: Inoue Tadahisa , Ibusuki Mayu , Kitano Rena , Kobayashi Yuji , Ohashi Tomohiko , Nakade Yukiomi , Sumida Yoshio , Ito Kiyoaki , Yoneda Masashi
Published: March 2020

Background The effectiveness of endobiliary radiofrequency ablation (RFA) is still uncertain, especially in patients with malignant hilar biliary obstruction (MHBO). We examined the efficacy of endobiliary RFA followed by bilateral self-expandable metal stent (SEMS) placement for unresectable MHBO.

Methods 41 patients met the eligibility criteria for study inclusion. We evaluated the technical success, functional success, and recurrent biliary obstruction (RBO) associated with RFA with bilateral SEMS placement.

Results The technical and functional success rates were both 95.1 % (39/41). The RBO rate was 38.5 % (15/39), and the median time to RBO was 230 days. Stricture length was positively correlated with time to RBO in the multivariate analysis (P = 0.03). The median time to RBO was significantly longer in patients with strictures > 15 mm in length than in those with strictures ≤ 15 mm (314 vs. 156 days; P = 0.02).

Conclusions The present study showed that endobiliary RFA with bilateral SEMS placement achieved good results, but selection of patients with an appropriate stricture length may be needed to obtain a sufficient ablative effect.
Nível de satisfação e dor na retirada de fixador externo em um ambulatório
Authors: Pereira Vitor Luis , Minami Flavio Kazuo , Lima Geraldo Kalif , Spalatti Vitor , Boatto Hilário , Lucarelli Jose
Published: March 2020

Objetivo Quantificar os níveis de satisfação e dor dos pacientes submetidos a retirada ambulatorial de fixadores externos sem anestesia.

Métodos Estudo prospectivo envolvendo 28 pacientes usando fixadores externos submetidos a três questionários associados à Escala Visual Analógica e Numérica da dor durante diferentes etapas da retirada.

Resultados A média de dor prévia à retirada foi de 3,61. Logo após o término do procedimento, encontramos média de 6,68 para a dor mais intensa, e de 2,25 para a dor menos intensa. A variação da dor média foi de 4,43, e a dor após uma semana teve média de 2,03. A lembrança dolorosa da retirada foi menor do que a dor referida imediatamente após a retirada (média de 5,29). A predominância no estudo foi de pacientes do sexo masculino de meia-idade, e 89,3% usavam fixador externo do tipo circular. O principal segmento dos membros envolvido foi a perna, e a maior parte dos pacientes não havia feito uso de fixador externo previamente (71,4%); eles optaram pela retirada ambulatorial por se tratar de opção mais rápida (75%), e para evitar internação hospitalar (25%). O momento de dor mais intensa ocorreu durante a retirada dos pinos de Schanz (60,7%), sendo pior nas extremidades dos membros para 75% dos entrevistados. Uma maioria absoluta de 85,7% mostrou-se satisfeita após a retirada, e 82,1% afirmaram que se submeteriam novamente ao procedimento.

Conclusão A retirada ambulatorial de fixadores externos sem anestesia é uma opção bem tolerada pelos pacientes, tratando-se de um procedimento com bons níveis de aceitabilidade e satisfação.
Perioperative Fracture Risk and Two-Year Survivorship of a Short Tapered Femoral Stem following Direct Anterior Approach Cementless Total Hip Arthroplasty with a Fracture Table
Authors: Andrews Samantha , Harbison Gregory J. , Hasegawa Ian , Unebasami Emily , Nakasone Cass
Published: March 2020

The cementless, tapered wedge, short femoral stem implant is commonly used in direct anterior approach (DAA) total hip arthroplasty (THA). The lack of access and visualization, however, may increase the risk of perioperative fracture and early failure. Therefore, the current study examined perioperative complications and 2-year implant survivorship following DAA THA performed using a fracture table and short, tapered wedge femoral stem. A retrospective analysis was conducted on patients having undergone DAA THA with a cementless, tapered wedge, short femoral stem. Perioperative fractures were noted and survivorship was determined by the incidence of revision surgery within a minimum 2-year follow-up period. A total 366 consecutive patients (441 hips) were identified in the cohort. Four patients (6 hips; 1.4%) were lost to follow-up and three patients died from unrelated causes. Average follow-up time for the remaining 359 patients (435 hips) was 32.9 ± 10.2 months. There were no intraoperative factures but three perioperative fractures within two weeks. Aseptic loosening occurred in one stem at 13 months, resulting in a 99.1% survival rate with a mean survival time of 23.8 ± 0.1 months (95% confidence interval: 23.6–24.0 months). The use of a short, tapered wedge femoral stem and a fracture table for DAA THA resulted in 0.7% periprosthetic fractures and only one aseptic loosening within 2 years. These results suggest that proper femoral exposure with the use of a fracture table and a short, tapered wedge femoral stem does not appear to increase the risk of periprosthetic femoral fracture.
Zero field cooled exchange bias effect in nano-crystalline Mg-ferrite thin film
Authors: Dakua Himadri Roy
Published: March 2020

The Zero Field Cooled (ZFC) Exchange Bias (EB) effect in a single phase nanocrystalline Mg-ferrite thin film, deposited on an amorphous quartz substrate using pulsed laser ablation technique, is reported. The film showed a high ZFC EB shift (HE ∼ 190 Oe) at 5 K. The ZFC EB shift decreased with increasing temperature and disappeared at higher temperatures (T > 70 K). This Mg-ferrite thin film also showed the Conventional Exchange Bias (CEB) effect, but unlike many CEB systems, the film showed a decrease in coercivity (HC) under the Field Cooled measurements. The film also showed the training effect in ZFC measurements, which followed the frozen spin relaxation behavior. The observed exchange bias could be attributed to the pinning effect of the surface spins of frozen glassy states at the interface of large ferrimagnetic grains.
Distributed acoustic sensing for seismic activity monitoring
Authors: Fernández-Ruiz María R. , Soto Marcelo A. , Williams Ethan F. , Martin-Lopez Sonia , Zhan Zhongwen , Gonzalez-Herraez Miguel , Martins Hugo F.
Published: March 2020

Continuous, real-time monitoring of surface seismic activity around the globe is of great interest for acquiring new insight into global tomography analyses and for recognition of seismic patterns leading to potentially hazardous situations. The already-existing telecommunication fiber optic network arises as an ideal solution for this application, owing to its ubiquity and the capacity of optical fibers to perform distributed, highly sensitive monitoring of vibrations at relatively low cost (ultra-high density of point sensors available with minimal deployment of new equipment). This perspective article discusses early approaches on the application of fiber-optic distributed acoustic sensors (DASs) for seismic activity monitoring. The benefits and potential impact of DAS technology in these kinds of applications are here illustrated with new experimental results on teleseism monitoring based on a specific approach: the so-called chirped-pulse DAS. This technology offers promising prospects for the field of seismic tomography due to its appealing properties in terms of simplicity, consistent sensitivity across sensing channels, and robustness. Furthermore, we also report on several signal processing techniques readily applicable to chirped-pulse DAS recordings for extracting relevant seismic information from ambient acoustic noise. The outcome presented here may serve as a foundation for a novel conception for ubiquitous seismic monitoring with minimal investment.
Self-organized networks: Darwinian evolution of dynein rings, stalks, and stalk heads
Authors: Phillips J. C.
Published: March 2020

Cytoskeletons are self-organized networks based on polymerized proteins: actin, tubulin, and driven by motor proteins, such as myosin, kinesin, and dynein. Their positive Darwinian evolution enables them to approach optimized functionality (self-organized criticality). Dynein has three distinct titled subunits, but how these units connect to function as a molecular motor is mysterious. Dynein binds to tubulin through two coiled coil stalks and a stalk head. The energy used to alter the head binding and propel cargo along tubulin is supplied by ATP at a ring 1,500 amino acids away. Here, we show how many details of this extremely distant interaction are explained by water waves quantified by thermodynamic scaling. Water waves have shaped all proteins throughout positive Darwinian evolution, and many aspects of long-range water–protein interactions are universal (described by self-organized criticality). Dynein water waves resembling tsunami produce nearly optimal energy transport over 1,500 amino acids along dynein’s one-dimensional peptide backbone. More specifically, this paper identifies many similarities in the function and evolution of dynein compared to other cytoskeleton proteins such as actin, myosin, and tubulin.
Supplementary pressure comparison from (0.7 to 7) MPa in gas media at gauge mode
Authors: Durgut Y , Yilmaz R , Justice B K , Alotaibi H M , Alanazi N A
Published: March 2020

This report gives the results of a comparison of pressure standards of three National Metrology institutes in the range of 0.7 MPa to 7 MPa. This comparison was piloted by UME and was carried out from February 2017 to March 2019. This work is a part of the GULFMET project and is registered as a supplementary comparison GULFMET.M.P-S1. The transfer standard used was a digital pressure gauge, model 745-1K, serial number 114944, manufactured by Paroscientific Inc, with a resolution of 1 hPa. The reference values have been determined from the weighted mean of the deviations which is a measurement error of the test instrument reported by the participants for each specified pressure.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Calibration model for air quality data
Authors: Duan Luling , Duan Ninggui
Published: March 2020

This article focused on the National Monitoring and control stations and selfbuilt two dust four gas, and the data were analysed, taking into account the humidity, temperature, wind speed, pressure, precipitation of the five meteorological factors, the difference between the two data analysis, and made the establishment of a mathematical model, the self-built Point data was calibrated.
Air Pollution and Environmental Implications in Kano Metropolis Nigeria
Authors: Abdullahi Hashim , Sinniah Gobi Krishna , Siong Ho Chin , Wei Li Rui
Published: March 2020

The study employed both quantitative and experimental approaches, CO and CO2 was sensed and recorded with the aid of Carbon Monoxide Analyzer and Handheld GPS. Four hundred (400) structured questionnaires was administered and Volumetric traffic count was conducted along seven (7) major junctions across the study area. E. View 8 was adopted for the analysis. Carbon Sensing results depict that Fagge local government area recorded the highest out door CO of 012Ppm. On the other hand, Gwale local government is the top indoor carbon emitters with10Ppm. The field survey indicates that types of land uses, densities and nature of socio-economic activities significantly affect both CO and CO2 in the metropolis. It indicates that Tarauni local Dangi Junction’s average daily carbon sensed records is the highest with exactly 19.5 Ppm. Fagge, Dala and Gwale local governments areas precisely record the same of 14 Ppm. The quantitative air quality indicators demonstrate that, the coefficient of determination (R2) reveals that relatively 84% of the changes in the dependent variable (DV) environmental impact was fully captured in the study and therefore changes within the explanatory variables have significant environmental impacts. Traffic count result shows that, Nasarawa local governemnt maintains the most traffic flow with 18957 vehicles records within the study days and the study indicates that interaction of traffic flow in the metropolis significantly increases the air pollution. Recommendation is drawn from the identified issues.
Optimization of the degradation conditions of swine wastewater and microbial community structure analysis in immobilized microbial technology
Authors: Wang Ying , Sun Xuefei , Chang Yuge , Quan Yue , Jin Mingji
Published: March 2020

In this paper, the treatment characteristics of immobilized microbial technology on swine wastewater under different operating conditions were investigated, so as to optimize the operating conditions of the system. At the same time, the microorganism community structure in the optimal condition was analyzed by high throughput sequencing technology. As a results, the optimal conditions for the degradation of TN in swine wastewater by immobilized microorganism were the filling rate of 25%, HRT of 27.5h and C/N of 5.48. In this case, the actual value of the TN removal rate was 74.81%. With the operation of the system, the abundance and diversity of the microbial community in the system are decreased, while the diversity and abundance of the microbial community in the denitrification tank are generally higher than that in the nitrification tank. Proteobacteria and Bacteroidetes are the dominant bacterial phylum, Hydrogenophaga are the dominant bacterial genus. The function of microbial community in the system is mainly "Metabolism".
Study on the Secondary Pollution of Building Fire Water Storage and Domestic Water
Authors: Duan Chunyi , Chen Hong
Published: March 2020

In order to solve the maintenance and management problems of the fire water tank in the fire water supply system, the problem of how to prevent the secondary pollution of domestic water by using the water source for fire storage water and domestic water is discussed. The countermeasures and the concept of intrinsic safety using shared fire-fighting water tanks are proposed, and it is clear that fire-fighting pools (boxes) need to strengthen water quality and the intrinsic safety of the pools. The innovative construction of the fire water tank system architecture is conducive to improving the reliability of fire water supply for buildings.
Discussion on water saving technology of building water supply and drainage
Authors: Zhao Li , Li Yong , Zhang Miao , Qin Faming
Published: March 2020

According to the present situation of building water supply and drainage, water saving technology of building water supply and drainage is analyzed, and the effective utilization of water resources is realized. Water saving technology mainly includes the reasonable limit water pressure point, to avoid pressure flow; improve water supply system and reduce the invalid water; using water-saving water distribution equipment, sanitary ware; promote the use of high quality pipeline and valve; improve the status of the fire pool construction and development and promote the regeneration of water and rainwater utilization technology.
Practical application of domestic sewage in a new compound biological filter
Authors: Gao Hua , Ma Chennan
Published: March 2020

The application of a new composite biofilter with a batch-type mud membrane composite biofilter (CSBF) series deep treatment filter (EBF) combination in urban domestic sewage was studied. The results of 20-day operation data show that the new filter process has good removal effect on COD, NH3-N, TN and TP. The average removal rate of COD during operation is 94.63%, the average removal rate of NH3-N is 99.02%, and the average removal rate of TN is 77.89%. The average removal rate of TP is 97.99%, and each index is stable to the first-class A standard of GB8978-1996, in which COD, NH3-N and TP can reach the surface water class IV standard.
The design of coal mine water disasters prevention and control assistance decision system
Authors: Xu Jiangtao , Sun Chengyong
Published: March 2020

According to actual situation of coal mine water disasters and the expert system research survey, the author has proposed the overall structure of the assistance decision system. The author has established the coal mine water disasters assistance decision platform based on dot NET soft. We has realized the formulation of determination and the preventing and controlling measure of the flood of old hole, roof, floor by using dot Net soft and the CLIPS computer language, combining with database platform established the expert knowledge library and the inference library; has solved the time and the spatial disposition question of the most superior sparse water volume by using the methods of finite element and the linear programming; Moreover aims at these questions of the note thick liquid, searching and draining water, the setup of waterproof rock seam, the forecast of water inflow volume, we has produced the correlation computational methods result and the operation craft.
Towards understanding the stabilization process in vermicomposting of excess sludge under copper oxide nanoparticles stress using PARAFAC analysis of fluorescence spectra
Authors: Wang Yong , Ma Liang , Xu Chenglin , Zhao Yue , Zhu Linxu , Chen Junru , Mu Hui , Guo Weilin , Zhao Chunhui
Published: March 2020

In this study, fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was employed to trace the behaviour of dissolved organic matter during vermicomposting of excess sludge under four dosages (0, 400, 800, 1600 mg/kg-TSS) of copper oxide nanoparticles (CuO NPs) stress. Determination of dissolved organic carbon (DOC) and total content of organic carbon (TOC), available nitrogen and available phosphorous indicated the presence of CuO NPs decrease the sludge stabilization by vermicomposting, but the organics degradation efficiency was not significantly inhibited with the increase of CuO NPs concentration. Fluorescence spectra results of dissolved organic matter (DOM) during the four groups of vermicomposting indicated CuO NPs led to the reduce of humic acid-like materials in vermicomposting. The positive relationship of protein-like component 1 and negative relationship of humic-like component 2 with CuO NPs concentrations in the substrates reflected by PARAFAC analysis suggested CuO NPs inhibit transformation of humic-like maters during the vermicomposting.
Research on Pollution Control of Solid Waste in China
Authors: Liu Qi
Published: March 2020

Solid waste is some solid and semi-solidified waste objects produced in production and other activities in our lives, typical of which are industry, agricultural, life and dangerous solid waste. Due to the restrictions on conditions and objects themselves, some objects cannot be used in production and will become waste in mankind activities, so the existence of solid waste is unavoidable. Therefore, it is impossible to stop the production of solid waste. However, it cannot be abandoned either. Instead, it is necessary to carry out proper disposal to effectively prevent secondary pollution.
The Ecological Risk Assessment of PPCPs Based on Different Endpoints in Urban Rivers from The Pearl River
Authors: Zhu Guanyu , Su Yan , Zhang Yang , Han Jingcheng , Wu Xiaofeng , Gao Yinliang
Published: March 2020

With rapid development of the cities along the Pearl River, the ecological system of urban rivers is being threatened by pharmaceuticals and personal care products (PPCPs). In this study, the distribution of four common PPCPs triclocarban, diclofenac, ibuprofen and triclosan was summarized from literatures and the ecological risk of the PPCPs in surface water of urban rivers from the Pearl River was evaluated based on six different endpoints. Among these PPCPs, ibuprofen was the most predominant compound with the highest concentration of 1417 ng/L, and triclocarban had the lowest PNECs of 2.4 ng/L derived from reproduction toxic data. Additionally, PNECs of diclofenac and triclocarban derived from reproduction toxic data were lower than those derived from other effects, while the PNECs of ibuprofen and triclosan derived from biochemical toxic data (endocrine disruption effect) were lower than those derived from other effects. All the PPCPs exhibited high risk on certain effects, especially for triclocarban exhibited high ecological risk on cellular, growth, mortality and reproduction of aquatic life. The results demonstrated that triclocarban, diclofenac, ibuprofen and triclosan had adverse effects on aquatic life in the Pearl River and actions needed to be taken for PPCPs, especially for triclocarban.
Discussion on Treatment Technology of Overflowing Waste Gas in Silicone Desulfurization Regeneration Tank
Authors: Deng Jianguo , Zhou Junbo , Gao Liping , Zhang Yongle , Niu Yongsheng
Published: March 2020

During the process of removing the sulfur-containing gas in the semi-aqueous gas by using the rubber desulfurization process, a large amount of exhaust gas overflows from the top of the rubber desulfurization regeneration tank, which has a heavy odor. After testing, the exhaust gas contains a large amount of carbonyl sulfur (COS), ethanethiol (CH3CH2SH), volatile phenols and other volatile organic gases (VOCs), which has a certain toxicity, volatile and complex chemical composition, causing harm to the surrounding and operators. However, there is no stable, single, and effective exhaust gas treatment for the exhaust gas overflowing from the tannin desulfurization regeneration tank. Characteristics of the exhaust gas generated during the production process of the semi-water gas desulfurization and oxidation regeneration tank is studied in this paper. After process designed, debugged, optimized, and inspected repeatedly, the method of “washing absorption + condensation removal of water + filter + fan + activated carbon adsorption” is proposed. When the exhaust gas outlet concentration is 542mg/m3, the gas outlet concentration is 58.1mg/m3 and the processing system efficiency achieve 89.28% after debugged stably, which has reached the local environmental protection emission limit (120mg/m3).
Variability in PM2.5 and meteorological effects on their mass concentrations over Fuzhou, China during 2014-2016
Authors: Li Junyi , Huang Yulin , Sun Danmei , Xu Zhixin , Lan Yuxiang , Chen Ye , Dong Jianwen
Published: March 2020

Simultaneous measurements of mass concentrations of PM2.5 along with other co-existence pollutants viz., SO2, CO, NO2 and O3, were studied with hourly datasets and the data of meteorological conditions were measured per 3 hours from 1st Sep 2014 to 30th Sep 2016 at Fuzhou city, China. The concentration of PM2.5 is 28.42 ± 14.75 in the study period. Meanwhile, the seasonal ratio of PM2.5 was also analysed, with the maximal value as 0.61 in winter, 0.52 in spring, 0.49 in autumn and 0.44 in summer. This implied that fine particulate reaches the maximal value in winter and the minimum value in summer. The correlation coefficient between concentrations of PM2.5 and SO2, CO, NO2, and O3 concentrations were 0.64, 0.52, 0.53 and 0.67. There existed negative correlation between PM2.5 and T (– 0.27), HCC (– 0.13), WS (– 0.16), VIS (– 0.46), DT (-0.31) and RF (-0.10). Subsequently, the impacts of typhoons on the mass concentrations of PM2.5 during September 10th 2016 to September 16th 2016 were analyzed during which the mass concentration of PM2.5 decreased at a large extent and the fine particulates have more prominent changes during the typhoon period compared with coarse particulates.
Numerical simulation of toxic gas diffusion in confined space
Authors: Yue Yicen
Published: March 2020

In this paper, the numerical simulation method is used to study the gas diffusion in a limited space under the scene of poisonous gas attack or leakage. Based on the STAR-CCM + software, the toxic gas diffusion process in a limited enclosed space under specific flow field conditions was simulated and analyzed, and the effects of different wind speeds on the diffusion law and concentration field distribution were studied.
Environmental Behavior of Petroleum in Soil and its Harmfulness Analysis
Authors: Hu Mengxue
Published: March 2020

The environmental behavior of rock and oil pollutants in soil has always been the focus of environmental protection research. In this paper, the sources, hazards and existing states of the stone oil pollutants in the soil are briefly introduced, and their migration, adsorption and degradation behaviors in the soil, as well as their behavior characteristics and influencing factors are also introduced. It is of great significance to protect the ecological environment and promote the sustainable development of petroleum industry to fully understand the environmental behavior of stone and oil pollutants in soil.
Analysis on dynamic change of vegetation coverage in coastal wetland of Yellow River delta
Authors: Jin Kangkang , Fan Jinshan , Zhao Xuan , Zhang Peng
Published: March 2020

How to efficiently use multi-source remote sensing images to extract the coastal wetland vegetation landscape information of the Yellow River Delta, and provide scientific basis for wetland protection, utilization and ecological restoration, is of great significance. In this paper, the vegetation coverage of Landsat TM/OLI remote sensing images from 1984 to 2018 is dynamically monitored, and the remote sensing images are analyzed using NDVI and pixel dichotomous models. The conclusions are as follows: From 1984 to 2018, the coverage of vegetation in the northern part of the Yellow River Delta is relatively low, and the coverage of vegetation in the south due to agricultural development is high; Over the past 30 years, the vegetation coverage area of the Yellow River Delta has shown an overall upward trend, and the area of low vegetation coverage areas has declined significantly, decreasing by 19.64% from 1984 to 2018. For the study of the Yellow River Delta coastal wetland, the methods used include the NDVI and pixel dichotomy model, and the results obtained are consistent with the facts, which can help the local ecological protection or soil and water conservation.
Effect of Acid Rain Pollution on Durability of Reinforced Concrete Structures
Authors: Yong Ding
Published: March 2020

In order to solve the problem of insufficient accuracy and effectiveness of the current analysis model of the durability of reinforced concrete, the corrosion process of concrete by acid rain and the corrosion process of steel bars by acid rain are analyzed; based on the acid rain corrosion process, the structure of reinforced concrete composite beams under acid rain erosion Carbonization depth of medium concrete; Corrosion depth of reinforced concrete composite beam structure was obtained by carbonization depth; Durability index was calculated by carbonization depth and corrosion depth. It is suitable for analysis of the influence of acid rain pollution on the durability of reinforced concrete composite beam structures.
Marine Pollution of Ship Domestic Waste and Countermeasures
Authors: Zhang Rongjun
Published: March 2020

Ocean is the natural environment for human survival and development. The exploitation and utilization of marine resources is one of the main methods to solve the pressures of the world's population, resources and environment. Moreover, the development of marine resources put forwards an important problem for mankind to prevent marine pollution, the various domestic waste produced by various ships in the ocean is one of the important sources of marine pollution. Therefore, preventing marine pollution caused by ship domestic waste, studying and formulating reasonable antipollution countermeasures, which has great practical significance for maintaining the sustainable development of the marine environment. For this reason, this paper analyzes the marine pollution caused by marine domestic waste, and proposes a waste recovery ship based on trimaran technology for recycling ship domestic waste.
Application of FCTEM60-1 Instrument in Invert Rebar Testing for Highway Tunnel
Authors: Liu Qiuzhuo , Wang Yao
Published: March 2020

The invert of a highway tunnel is the foundation for the entire tunnel structure. Its quality has a direct influence on the stability of tunnel structure. However, in practice the tunnel invert has various defects for a variety of reasons. FCTEM60-1 instrument is able to rapidly cut off the current using constant voltage clamping technique, thus significantly reducing the shallow dead-zone effect of transient electromagnetic (TEM). In this study the instrument is applied to testing invert rebar execution in a highway tunnel. The study result shows FCTEM60-1 instrument successfully detected the invert rebar, demonstrating its feasibility and reference value to tunnel quality test.
Numerical Modeling of the Strata Deformation During Tunnel Excavation Based on Discrete Element Method
Authors: Cao Peng , Wu Mengjun , Fang Lin , Chen Shouchao
Published: March 2020

The construction of transportation infrastructure is transferring from ground to underground, which could evacuate the urban traffic and is also the future trend of the expansion of our cities. The cobble stratum brings about many technical problems in the underground engineering. Based on the calibration test and macroscopic mechanical characteristic curve, the microscopic calculation parameters of particle flow code simulation used for cobble strata in Urumchi were determined. According to establishing the numerical model of pebble tunnels using double-side-drift method, both the ground deformation and force chain evolution were analyzed for the tunnels using subsurface excavation method. This manuscript presented the differentiation of influence on ground deformation in cobble stratum under different excavation stages, the influence extent was ranked as follows, upper bench > double-side-drift > lower bench; the result of numerical simulation test was compared with the field monitoring data, proving that it is reasonable to adopt the particle flow code to simulate the excavation of pebble tunnels, and the research result could be provided for reference for the similar engineering.
Reinforcement Analysis of Bifurcated Highway Tunnels with Large Section of Different Surrounding Rock Grades in Tiger Leaping Gorge
Authors: Zhou Dong , Ding Wenqi , Xie Dongwu , Chen Shuwang
Published: March 2020

In order to analyse the reinforcement effect of tunnels with different surrounding rock grades in Tiger Leaping Gorge, a three-dimensional tunnel model was established. The effects of surrounding rock parameters and bolt supporting on the displacement and tension strain disturbance zone of surrounding rock were explored. The numerical results of tension strain and displacement show that the improvement of surrounding rock stability is limited by reinforcement measures, and the change of tension strain disturbance zone is also small when the rock is intact. However, when the surrounding rock is relatively fragmented, the range of tension-strain disturbance zone and displacement of the cave are very large. After strengthening, the range of tension-strain disturbance zone is reduced by 61.5%. Comparing the displacement of vault and arch waist, it can be seen that the displacement of cave in grade V surrounding rock is larger, the vertical displacement of vault is 3.5 times higher than that of grade IV surrounding rock, and the horizontal displacement of large section in arch waist is 58.63 mm, and it has great influence on the stability of tunnel. The displacement value of vault and arch waist reinforced in grade V rock is similar to that of tunnel without reinforcement in grade IV rock.
Seismic and sealant behaviour of segmental joint gaskets in shallow immersed tunnel
Authors: Wu Weifeng , Ding Wenqi , Ge Shiping , Lu Xingbang , Zhao Tianchi
Published: March 2020

Joint gaskets of the immersed tunnel are critical for the seismic safety of the immersed tunnel. In this study, a rigorous numerical model of rubber gaskets is conducted and validated against experimental results. Then, the model is used to estimate the mechanical and water tightness behaviour of three types of gaskets. Finally, a coupled nonlinear soil-structure interaction beam-mass-spring model is developed. The joints are simulated with the nonlinear hyperelastic elements following obtained load-deformation of three gaskets. The hydrostatic installation is modeled properly, then the seismic excitation is fired on bedrock. Finally, the results are discussed in the aspects of joint deformation and water tightness during the seismic loading.
Study on Section Selection of Super Large Oil Storage Tunnel Based on Strength Reduction Method
Authors: Xiang Liang , Wang Fei , Kong Chao , Zou Zaiyan , Zhang Huijian
Published: March 2020

To study the section selection of super large oil storage tunnel could help make full use of underground space and arrange tunnels reasonably. The stability of tunnel with three different section (horseshoe section, circular section, elliptic arch section) was studied using the strength reduction method by finite difference element software. The FoS evolution with depth was discussed and the limiting failure state of tunnel were observed with the depth. The results indicated that the stability of different section are basically the same, because of the surrounding rock conditions are good. Cost and space utilization can be the main factors in the section selection.
Study on deformation law of double-line shield tunnel obliquely crossing underneath existing municipal tunnel
Authors: Qi Xingxin , Qiu Wenge , Gao Ganggang , Zhou Zhenghao , Deng Zhiheng , Zhao Hailin , Wan Shifu , Huang Qiming
Published: March 2020

This paper mainly relies on the project of Hangzhou Metro Line 5 obliquely crossing underneath Zijingang Road Tunnel. The paper analyzes the influence of the shield position on the vertical displacement and torsion of the existing tunnel. Grouting pressure and stratum reinforcement conditions are also considered. And find the law of the influence of various construction technical parameters on deformation under different excavation stages. Then give corresponding advice for the project and provide guidance and reference for similar projects in the future.
Three-dimension numerical analysis of large-span bridges’ pile foundation adjacent to an existing tunnel
Authors: Sun Keguo , Xiao Zhifei , Liu Xu , Hong Yiqin , Hou Zonghao
Published: March 2020

In the process of urban transportation construction, it is inevitable that the new bridges will be adjacent to the existing tunnels. According to the spatial relationship between the new bridge and the existing tunnel, a three-dimension finite differential model of the pile-tunnel interaction is established by a numerical simulation method. The influence of the upper load of the new bridge on the adjacent tunnel is simulated, with the results of the numerical simulation method and the Boussinesq method are compared. It is found that the results of numerical simulation are verified by the Boussinesq method, with the deviation less than 10%. Moreover, the horizontal deformation of the tunnel is central-symmetrically distributed, and the symmetrical point of the horizontal deformation and the position of maximum vertical deformation are both near the midpoint of the two cushion caps. Besides, the deformation of the tunnel is mainly vertical. Last but not least, the influence of the construction and operation of the pile foundation of the bridge on the rails in the existing tunnel meets the control criteria. Therefore, the methods of analysis and parameters in this paper can provide a reference for similar projects.
Study on the Characteristics of Flow Field and Gas Migration in Gas Tunnels
Authors: Cao Zhengmao , Liu Xiao
Published: March 2020

In order to improve the ventilation efficiency and gas dilution effect in the gas tunnel, the main source and formation mechanism of the gas in the tunnel were analyzed, and the hydrodynamic calculation model is established for the gas tunnel ventilation with the auxiliary vertical shaft. The k-ε two-equation turbulence model was used to simulate the ventilation effect under different wind velocity, the flow field distribution characteristics and gas migration regularity under the auxiliary ventilation conditions were obtained. The results indicate that the internal space of the tunnel can be divided into different zones in the longitudinal direction according to the distribution characteristics of the flow field in the tunnel. The distribution of gas concentration in the tunnel is closely related to the flow field characteristics of each zone. The ventilation of the gas tunnel must meet both the requirements of the gas concentration dilution and the cross section wind velocity. When the cross section wind velocity is greater than 0.5m/s, the airflow reaches full turbulence state in tunnel. There is obvious effect on eliminating accumulation of gas at the top of the tunnel by the cross section wind velocity controlling. Under the condition of cross-section wind velocity is 0.5∼1.0m/s, the methane zone is prone to accumulate at the top of the tunnel, which can be diluted when the cross-section wind velocity is greater than 1.0m/s.
Monitoring Study on Dust Diffusion in High Altitude Tunnel under Drilling and Muck Removal Conditions
Authors: Nima Zhuoma , Hu Xuebing , Chen Jianzhong , Yuan Ye
Published: March 2020

In the high altitude area, the air density and the air pressure are low. In this paper, combined with a high altitude tunnel engineering in Tibet, the dust concentration during the drilling and muck removal was monitored, and tunnel dust diffusion situation was analyzed. The result shows that the dust concentration on the middle line of tunnel is higher than the dust concentration at the tunnel side. The dust concentration near the tunnel face is the highest. In the longitudinal direction, the change rule of the total dust and respirable dust concentration, are totally the same. With the increase of distance from tunnel face, dust concentration declines rapidly, then gradually become stable. The dust diffusion rule in the process of muck removal is basically similar to that of drilling process, but the dust concentration is larger, and the concentration of respirable dust accounts for a higher proportion than that in the drilling operation.
Study on influence partition of tunneling adjacent to multi-storey building in upper-soft and lower-hard stratum
Authors: Rui Zhu , Yujie Yang , xiaoyu Niu , Huijian Zhang , Hongbo Guo , Wenge Qiu
Published: March 2020

Based on several examples relating to tunneling near the multi-storey building in Qingdao Jiaozhou bay tunnel connecting engineering, the study on influence partition of tunneling adjacent to multi-storey building has been conducted by the finite element strength reduction method. The safety factor of 2.0 was defined as the boundary of the strong to weak influence zone, and the peak safety factor was considered as the boundary of weak to none influence zone. Based on the distribution of safety factors in three cases with relative scale of 2, 1, 1/2, and considering the convenience use on site, a influence partition map of tunneling to the existing multi-storey building in upper-soft and lower-hard stratum has been proposed.
The numerical analysis of the cross passage of large diameter shield tunnel beneath the river
Authors: Chen Biguang
Published: March 2020

The construction of the cross passages of twin shield tunnel is confronted with high uncertainty and huge risk. Ground freezing method is widely used for passages excavation in sandy ground condition when the tunnel is under the water. Earlier studies usually concerned the effectiveness of the freezing program, such as the space between the the freezing pipes or the temperature variation in the frozen soil. In this paper, the structure force of the cross passage of a large diameter shield tunnel beneath the river is discussed. A 3-dimensional numerical method is described to calculate the stress of the frozen soil and the internal force of the cross passage lining. The critical situations in construction and operation phases and the key mechanical parts are recognized. The safety of the design scheme is checked.
Study on Traffic Organization around Pivotal Tunnel Entrance/Exit
Authors: Jiang Xinghong , Li Ke , Cui Xiangyang
Published: March 2020

With increasing pressure on above ground space and surface traffic, more and more cities choose to construct underground transportation junction to speed up traffic and improve travel efficiency. This paper covers survey and VISSIM simulation of vehicles at the entrance and exit of an in-progress tunnel at Zengjiayan, Chongqing. The results show: during construction of the pivotal tunnel, the entry of trucks to the construction area near the “left-in left-out” entrance and exit will significantly affect traffic on the artery where the tunnel is located; the flow line scheme under which trucks change lanes in advance at the entrance to the construction area is optimal. In addition to optimization of entrance and exit points, traffic organization around the tunnel during construction should be optimized to mitigate traffic pressure on the artery where the tunnel is located.
ShenZhong Passage (Island-Tunnel) Project – Refined Exploration Technology and Management
Authors: Liu Jian , Xia Fengyong
Published: March 2020

For Shen-zhong Link project with two islands and a tunnel, the survey process is in full compliance with international standards. The large-scale survey equipment with international advanced level (offshore power head drilling platform, support drilling platform) is used to carry out survey operations and tests in accordance with international standards, so as to minimize the disturbance to the undisturbed samples. Various in-situ test and indoor test methods are used to carry out all-round and multiple means for rock and soil layers. The results of the investigation are better than that of the conventional investigation and have been verified in the implementation of the island and tunnel project. Experience of this survey is helpful to promote the fine geological survey in China.
Summary of the Development of New Technologies for Submarine Immersed Tunnel Foundation Reinforcement and Settlement Control
Authors: Fu Bai-yong , Chen Wei-le , Xu Guo-ping , Song Shen-you , Xia Feng-yong
Published: March 2020

Based on the immersed tunnel foundation improvement modeling and analysis of data through investigations and researches on immersed tunnel diseases at home and abroad, this paper proposes that the adverse loads and poor geology are main causes inducing settlement and diseases. On top of the review on technical innovations in typical immersed tunnel foundation improvement abroad, the innovation and advancement of immersed tunnel foundation improvement of Hong Kong-Zhuhai-Macao Bridge Project is introduced with emphasis and these technical innovations mainly comprise the technology of double-layer bed with both rigidity and flexibility, the technology of SCP(Sand Compaction Piles) plus surcharge loading in ground improvement, the settlement computation method based on CPTU of rebounding and recompression and determination of settlement control criteria and others new development. Furthermore, through analysis the corresponding foundation improvement countermeasures are provided in this paper to meet such construction challenges faced in the immersed tunnel foundation improvement of Shenzhong Link and those challenges are super-wide width varied immersed tunnel element, soft soil ground of sand pit, weathered rock softening in water, sandy soil liquefaction, intense siltation. Finally, as the State key study and development program, it is pointed out that the technical study on diseases inducing mechanism and corresponding pro-active prevention and control of submarine immersed tunnel founded on poor ground conditions shall be carried out based on the full consideration of interactive actions between the structure and its foundation and the technical route and main study contents are further proposed for reference of relevant technical professionals.
Analysis on Application Effect of Prestressed Anchor Cable in Large Span Tunnel
Authors: Li Ke , Jiang Xinghong
Published: March 2020

Safety is the top priority during the construction process, the construction risk increases sharply with the increase of section size. Bifurcated tunnel structure is adopted in the entrance portal section of Bibanpo tunnel. The span of transition section reaches 25.79m (type A) and 22.11mm (type B), To ensure safety, a new support method of pre-stressed anchor was used. during the construction, we monitored the structure stress of primary support, and the tension stress of pre-stressed anchor cable, and we get that: the pre-stressed anchor cable on hence can support quickly, prevent plastic zone from deepening, decrease the load of primary support structure, especially the load of shaped steel. Through engineering practice, it can be concluded that pre-stressed anchor is an effective active support method. The successful application experience in Bibanpo tunnel is of great significance for similar projects.
Study on Deformation of Shallow Buried Underground Pipe Gallery
Authors: Xie Junfei , Huang Nenghao , Feng Jiajia , Zhang Gen
Published: March 2020

The underground pipe gallery is a symbol of modernization and intensification of urban construction. Domestic research on the deformation of underground pipe gallery started late and has not yet formed a unified standard. Based on the deformation requirements and deformation control standard of the internal pipeline of the pipe gallery, the longitudinal deformation control standard of the integrated pipe gallery is preliminarily established. The main conclusions are as follows: Based on the deformation requirements of the underground pipe gallery, the equation for calculating the allowable value of the longitudinal radius of curvature of the pipe gallery is proposed. Comparing the safety standards of various types of inlet pipelines, the longitudinal deformation allowable value of the pipe gallery is given. At the same time, the influence of surface load on the deformation of pipeline gallery is analyzed by theoretical analysis and model test, and the theoretical and experimental results are compared. The results indicate that theoretical calculation features accuracy and practicality.
Research on Assessment of Highway Tunnel Operating Safety
Authors: Chen Siyang , Xia Yangyuyu , Ma Fei , Liao Haomiao
Published: March 2020

The operating safety of highway tunnels is governed by a complex system of people-vehicle-tunnel-environment and influenced by many factors. Its assessment is complex and unique to the specific tunnel. In this paper we discuss the assessment of the operating safety of highway tunnels from three aspects of rating, risk evaluation and resiliency, and propose the concept of operating safety resiliency of highway tunnels. We also summarize prior research in these aspects and analyze advantages and disadvantages of each assessment method.
Web Crawler Based Study on Traffic Accident Data Acquisition for Operating Tunnels
Authors: Liao Zhipeng , Ding Hao , Xia Yangyuyu , Ma Fei
Published: March 2020

With constant development of tunnels, traffic accidents in the tunnels continue to rise. To control and manage tunnels and reduce traffic accidents. Based on Web crawler technology, this paper, based on Web crawler technology, covers research on traffic accident information characteristics for operating tunnels and Web crawler mechanism to establish a PySpider-based Web platform for real-time acquisition of traffic accident data for operating tunnels. This platform can fetch valid traffic accident data URL for operating tunnels from designated websites and to extract, analyze and store traffic accident feature data, thereby managing and controlling traffic risks existing in an operating tunnel, reducing traffic accidents and safeguarding people’s properties.