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Application of the Mathieu combined tunnel technique for repairing glans dehiscence after failed hypospadias repair

Asian Journal of Andrology 2022年第3期24卷 311-316页

作者： Qi-Gen Xie Kai Xia Xiang-Ping Li Peng Luo Zuo-Qing Li Cheng Su Chun-Hua Deng Department of Pediatric Surgery First Affiliated HospitalSun Yat-Sen UniversityGuangzhou 510080China Department of Andrology First Affiliated HospitalSun Yat-Sen UniversityGuangzhou 510080China

Repairing glans dehiscence after failed hypospadias repair is challenging for pediatric surgeons.Here,we introduced and evaluated a newly modified Mathieu technique,Mathieu combined tunnel(MCT),which involves multiple custom-designed flaps for the shortage of flap source material after repeated operations;we also constructed a tunnel to avoid the glans incision that may carry new risks of dehiscence.This retrospective study included 26 patients who were consecutively admitted to the First Affiliated Hospital of Sun Yat-Sen University(Guangzhou,China)for glans dehiscence repair after failed hypospadias repair from October 2014 to October 2020;sixteen patients underwent surgery using the MCT(MCT group)and ten patients underwent surgery using the tubularized incised plate(TIP)technique(TIP group).The operative time,blood loss,postoperative complications,normal urethral meatus rate,success rate,and Hypospadias Objective Penile Evaluation(HOPE)score were compared between the two groups.The MCT group achieved an overall satisfactory penile appearance and voiding function,with a higher rate of normal urethral meatus(15/16,93.8%)and a lower rate of glans dehiscence(1/16,6.2%),compared with the TIP group(70.0%and 30.0%,respectively).However,these differences were not statistically significant,possibly because of the limited number of patients(all P>0.05).Mean postoperative HOPE scores were similar in the MCT group(mean±standard deviation:8.83±0.89)and TIP group(8.94±0.57)(P>0.05).No significant differences were found between the two groups in terms of blood loss and success rate,nor in the rates of various complications(e.g.,fistula,urethral stricture,and glans dehiscence).In conclusion,the MCT technique appears to be feasible and reliable for repairing glans dehiscence after failed hypospadias repair.

关键词： failed hypospadias glans dehiscence Mathieu tubularized incised plate(TIP) tunnel

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An analytical model for evaluating the dynamic response of a tunnel embedded in layered foundation soil with different saturations

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 663-681页

作者： Di Honggui Guo Huiji Zhou Shunhua Wang Binglong He Chao Zhang Xiaohui Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China The Technical Center of Shanghai Shentong Metro Group Co. Ltd.Shanghai 201103China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China

This paper proposes an analytical model for evaluating the dynamic response of an underground railway tunnel in layered foundation soil with different saturations.The soil is modeled as layered media,and the circular tunnel lining is modeled as an infinite Flügge cylindrical shell.The separation of variables method is used to solve the motion equation of the shell,and the wave equation of the soil is solved using the Helmholtz decomposition theorem.A dynamic matrix reflecting the wave vectors of soil layers is established using the transfer matrix method.Based on boundary conditions,the tunnel-soil model is coupled using the transformation method of plane wave functions and cylindrical wave functions.The proposed model is validated by comparison with existing tunnel models,and the effects of saturation and the layered properties of soil on the dynamic response of a layered tunnel-soil system is demonstrated via case studies.

关键词： tunnel unsaturated soil saturation transfer matrix method wave function transformation

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CFD simulations of a semi-transverse ventilation system in a long tunnel

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Underground Space 2023年第4期11卷 153-170页

作者： Alireza Dastan Mohammad Rahiminejad Mozhgan Sabz Meisam Abbasi Ali Mokhtari Sasan Sadrizadeh Omid Abouali Department of Mechanical Engineering Faculty of EngineeringUniversity of IsfahanIsfahan 81746-73441Iran School of Mechanical Engineering Shiraz UniversityShiraz 71936-16548Iran Department of Mechanical Engineering University of AlbertaEdmonton T6G 2R3Canada Department of Civil and Architectural Engineering KTH UniversityStockholm 10044Sweden

In the present work,a semi-transverse ventilation system in a long tunnel with a length of 4.9 km,as a complex case study,is numer-ically studied by performing a set of three-dimensional steady incompressible computational fluid dynamics(CFD)simulations.The ven-tilation system consisted of a ceiling duct connected to two axial fans at the ending portals,and a series of jet fans in the main tunnel for supporting airflow in the desired direction.To focus on what can and cannot be achieved in commissioning tests,the ventilation system’s performance in various scenarios is numerically evaluated with two different tunnel states;empty tunnel and complete traffic congestion with 1176 stationary vehicles–which is almost impossible to evaluate during a commissioning test.By considering two hypothetical loca-tions for the extraction zone from the main tunnel(in a distance of 450 and 1000 m from one portal),it is shown that the required number of jet fans in a traffic condition drops from 57 for the first extraction location to 43(25%decrease)when the ventilation system extracts from the second zone.We show that if only the close axial fan to the extraction zone is activated,the required number of jet fans reduces by 56%and 72%for the first and second extraction locations,respectively.This finding can provide a cheaper and easier controlling scenario for emergency ventilation.

关键词： CFD Semi-transverse ventilation tunnel Ceiling duct Traffic

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Numerical prediction of ground vibrations induced by LPG boiling liquid expansion vapour explosion(BLEVE)inside a road tunnel

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Underground Space 2023年第5期12卷 44-64页

作者： Ruishan Cheng Wensu Chen Hong Hao Jingde Li Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityBentley 6102Australia Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou 510006China

Accidental boiling liquid expansion vapour explosions(BLEVEs)caused by the bursting of liquified petroleum gas(LPG)tank inside a tunnel can induce vibrations of its surrounding geological media and threaten the stability of adjacent tunnels and structures.Therefore,it is essential to understand the characteristics of vibrations induced by LPG BLEVEs inside the tunnel for the safety design of its adjacent structures.Owing to the difficulty in effectively predicting the LPG BLEVE loads,the current practice usually employs equivalent methods,e.g.,the TNT-equivalency method,in LPG BLEVE load predictions for structural response analysis,which may lead to inaccurate response predictions.This study compares ground vibrations induced by a BLEVE inside an arched road tunnel with those induced by its equivalent TNT explosion via high-fidelity numerical simulations.The results demonstrate that the frequency of BLEVEinduced vibrations is lower than that induced by the TNT explosion at the same scaled distance.The intensity of LPG BLEVE-induced vibrations at relatively small-scaled distances is lower than that of TNT explosion-induced vibrations at the same scaled distance,but becomes higher after a certain scaled distance because of the relatively low attenuation rate.In addition,parametric analysis is conducted to evaluate the effects of various factors on the characteristics of LPG BLEVE-induced ground vibrations.It is found that the surrounding rock type,the rock porosity,and the cover depth of the tunnel have more significant influences than the concrete grade of the tunnel lining.The recommendation for the tunnel design is also given based on the intensity and frequency characteristics of BLEVE-induced vibrations.

关键词： tunnel BLEVE TNT explosion Vibration intensity Vibration frequency

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A Fast Approach for Predicting Aerodynamic Noise Sources of High-Speed Train Running in tunnel

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Computer Modeling in Engineering & Sciences 2022年第3期130卷 1371-1386页

作者： Deng Qin Tian Li Honglin Wang Jizhong Yang Yao Jiang Jiye Zhang Haiquan Bi State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu610031China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu610031China China Railway Eryuan Engineering Group Co. Ltd.Chengdu610031China

The aerodynamic noise of high-speed trains passing through a tunnel has gradually become an important issue.Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues.In this paper,two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains.These are the static method combined with non-reflective boundary conditions and the dynamic mesh method combined with adaptive mesh.The fluctuating pressure,flow field and aerodynamic noise source are numerically simulated using the abovemethods.The results showthat the fluctuating pressure,flow field structure and noise source characteristics obtained using different methods,are basically consistent.Compared to the dynamic mesh method,the pressure,vortex size and noise source radiation intensity,obtained by the static method,are larger.The differences are in the tail car and its wake.The two calculation methods show that the spectral characteristics of the surface noise source are consistent.The maximum difference in the sound pressure level is 1.9 dBA.The static method is more efficient and more suitable for engineering applications.

关键词： High-speed train tunnel numerical calculation method aerodynamic noise source flow field

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Empirical approach for reliability evaluation of tunnel excavation stability using the Q rock mass classification system

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Underground Space 2022年第5期7卷 862-881页

作者： Hui Lu Marte Gutierrez Eunhye Kim McMillen Jacobs Associates Walnut CreekCAUSA Department of Civil and Environmental Engineering Colorado School of MinesGoldenCOUSA Federal Energy Regulatory Commission San FranciscoCAUSA

The critical strain concept has been widely used in analytical or numerical approaches to evaluate the stability of underground excavations.Analytical,empirical,and numerical procedures are usually used to determine the critical strain values.This paper presents a reliability assessment procedure for evaluating excavation stability using the empirical approach based on the rock mass classification Q and the first order reliability method(FORM).In contrast to deterministic critical strain values,a probabilistic critical strain,which considers uncertainties in rock mass parameters,was incorporated in a limit state function for reliability analysis.Using the rock mass classification Q,the empirically estimated tunnel stain was included in the limit state function.The critical strain and estimated tunnel strain were probabilistically characterized based on the rock mass classification Q-derived rock mass properties.Monte Carlo simulations were also conducted for comparing the reliability analysis results with those derived from the FORM algorithm.A highway tunnel case study was used to demonstrate the reliability assessment procedure.The effects of the input ground parameter correlations,probability distributions,and coefficients of variation on tunnel reliability were investigated.Results show that uncorrelated and normally distributed input parameters(intact rock strength and elastic modulus)have generated more conservative reliability.The reliability analysis results also show that the tunnel had relatively high reliability(reliability index of 2.78 and probability of failure of 0.27%),indicating the tunnel is not expected to experience instability after excavation.The tunnel excavation stability was assessed using analytical and numerical approaches for comparison.The results were consistent with the reliability analysis using the FORM algorithm’s Q-based empirical method.

关键词： Reliability analysis tunnel Critical strain Rock mass classification Q First order reliability method

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Face stability analysis of large shield-driven tunnel in rock-soil interface composite formations

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Underground Space 2022年第6期7卷 1021-1035页

作者： Xiaobin Ding Kang Li Yuxuan Xie Shuzhuo Liu School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510641China Guangdong Provincial Key Laboratory of Modern Civil Engineering Technology South China Institute of Geotechnical EngineeringGuangzhou 510650China

A new 3D log-spiral model(LS-M model)is proposed to determine the minimal support pressure on the tunnel face of a large shielddriven tunnel in rock-soil interface(RSI)composite formations.In the proposed LS-M model,we define the RSI angle ω and use a new approach to calculate the equivalent tunnel face area,which provides a collapse zone with more realistic geometry than the traditional wedge model.And it has acceptable accuracy with simpler implementation than limit equilibrium analysis.Comparing with previous studies and 3D numerical analysis,it indicates that:(i)the LS-M results agree well with others in full-soil formations on the variation patterns of minimum support pressure and stability coefficients N_(c) and N_(γ);(ii)the critical RSI angle ω_(cr),which is predominantly influenced by soil cohesion,increases with the soil property values;(iii)the limit support pressure starts to increase with ω only when ω>ω_(cr);(iv)the peak support pressure occurs at lower C/D with a lower ω;(v)ω can only affect stability coefficients N_(c) and N_(γ) when ω and the friction angle are relatively small,while N_(s) is substantially influenced by RSI angle ω.

关键词： tunnel Stability Limit support pressure RSI composite formations 3D failure mechanism

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Construction strategies for a NATM tunnel in Sao Paulo, Brazil, in residual soil

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Underground Space 2022年第1期7卷 1-18页

作者： Osvaldo P.M.Vitali Tarcisio B.Celestino Antonio Bobet Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907USA Sao Carlos School of Engineering University of Sao PauloSao CarlosSP 13566Brazil

Due to the fast growth of urban areas worldwide,the demand for tunnels in developed areas is increasing.The design and construc-tion of those tunnels are complex because of their shallow depths and their interaction with existing aboveground and buried structures,which results in rather limited allowable ground deformations induced by the tunnel excavation and support.In tropical regions,residual porous soils near the surface are common.Those soils are highly deformable;thus,tunneling may induce large ground deformations that may damage nearby structures.The new Austrian tunneling method(NATM)and the sprayed concrete lining(SCL)technique are being widely employed in several big cities in tropical regions,but little research has been conducted to assess the induced ground deformations in residual soils,common in tropical areas.This paper provides insight into this issue.A well-documented metro tunnel in Sa˜o Paulo,Brazil,in a residual red porous clay,was analyzed using 3D finite element method(FEM).The behavior of the residual red porous clay was approximated by an advanced constitutive soil model calibrated with triaxial tests on intact samples extracted at the site.Predictions of the tunnel deformations during construction matched the field data.The calibrated model was then used to explore the tunnel per-formance under different construction strategies.The influence of partial face excavation,unsupported span length,support stiffness and pipe roof umbrella were assessed.The numerical results showed that partial face excavation was effective to reduce ground deformations ahead of the face of the tunnel and to improve face stability;however,the settlements behind the face increased because of the delay in closing the primary lining.The installation of a stiffer liner closer to the face reduced the ground deformations significantly.The pipe roof umbrella was the most effective technique to reduce the ground deformations around the tunnel;however,the numerical results did not consider deformations that could be ind

关键词： tunnel NATM Residual soil FEM 3D face effects Ground deformation Face stability

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Visualization and digitization of model tunnel deformation via transparent soil testing technique

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Underground Space 2022年第4期7卷 564-576页

作者： Wengang Zhang Haiyi Zhong Yuzhou Xiang Daifeng Wu Zhikai Zeng Yanmei Zhang Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China School of Civil Engineering Chongqing UniversityChongqing 400045China Chongqing City Construction Investment(Group)Co. Ltd.Chongqing400023China College of Aerospace Engineering Chongqing UniversityChongqing 400044China

With the increasing demand for transportation infrastructure,the construction of urban tunnel systems linking different areas is indispensable.The deformation and the failure process during a tunnel excavation are essential concerns for geotechnical engineers.However,few studies have systematically investigated the effect of the ground loss ratio on tunnel deformation and the inequality between the ground loss ratio and the volume of the settlement trough.An experimental study using the transparent soil testing technique is performed herein for better visualization and digitization purposes.The three dimensional vertical and horizontal deformation patterns of a single tunnel are investigated for both the surface and the stratum right below considering different ground loss ratios.The relationship among the empirical constant of the settlement trough width,buried depth,depth-diameter ratio,and ground loss ratio is presented.

关键词： Transparent soil tunnel Model test Settlement Horizontal displacement

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Geothermal anomalies in the Xianshuihe area: Implications for tunnel construction along the Sichuan-Tibet Railway, China

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地下水科学与工程:英文版 2023年第3期11卷 237-248页

作者： Feng Liu Wei Zhang Gui-ling Wang Shuai-chao Wei Chen Yue Guang-zheng Jiang Yu-zhong Liao Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological ScienceShijiazhuang 050061China China University of Geosciences(Beijing) Beijing 100083China Technology Innovation Center of Geothermal&Hot Dry Rock Exploration and Development Ministry of Natural ResourcesShijiazhuang 050061China Chengdu University of Technology Chengdu 610059China

This study presents a comprehensively analysis of geothermal characteristics in the Xianshuihe geothermal area along the Sichuan-Tibet Railway,using temperature logging,temperature monitoring and thermal conductivity measurement,and regional geothermal geological survey data.The research focuses on the geothermal background,geothermal field,and their potential impact on the surrounding tunnels.The investigation reveals that the average heat flow value in the study area is approximately 73.0 mW/m^(2),significantly higher than the average terrestrial heat flow in China's Mainland(62.5 mW/m^(2)).This high terrestrial heat flow signifies a distinct thermal background in the area.In addition,geothermal anomalies in the area are found to be closely associated with the distribution of hot springs along NW faults,indicating a strong control by the Xianshuihe fault zone.The study concludes that the region's favorable conditions for geothermal resources are attributed to the combination of high terrestrial heatflow background and water-conducting faults.However,these conditions also pose a potential threat of heat damage to the tunnels along the Sichuan-Tibet Railway.To evaluate the risk,the research takes into account the terrestrial heat flow,thermal conductivity of the tunnel surrounding rocks,characteristics of the regional constant temperature layer,as well as the distribution of hot springs and faults.The analysis specifically focuses on the thermal damage risk of Kangding 1# tunnel and 2# tunnel passing through the study area.Based on the findings,it is determined that Kangding 1# tunnel and 2# tunnel have relatively low risk of heat damage,as they have avoided most of the high temperature anomaly areas.However,several sections of the tunnels do traverse zones with low to medium temperatures,where surface rock temperatures can reach up to 45℃.Therefore,these regions should not be neglected during the construction and operation of the tunnel project,and mitigation measures may be necessary to address the potential he

关键词： Xianshuihe geothermal zone Terrestrial heat flow Hot spring tunnel Heat damage

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