HDPE管内衬盾构隧道复合式衬砌结构极限承载力试验研究

为研究采用HDPE双壁缠绕管作为内衬的盾构隧道复合衬砌结构的破坏机理,依托桃浦污水处理厂初期雨水调蓄工程涉铁段排水隧道工程,开展整环足尺试验研究,得到如下结论:(1)复合衬砌结构破坏过程经历协调变形阶段和各自承载阶段,弹性极限点为顶底部纵缝处界面的剥离脱开,各纵缝及管片本体相继发生破坏,纵缝处填充层混凝土发生拉剪或压剪破坏;(2)复合衬砌结构的薄弱位置为各纵缝处的界面及填充层混凝土,其中顶部和腰部纵缝处最为薄弱;(3)复合衬砌结构不同位置纵缝处的界面破坏和填充层破坏形态均源自于纵缝转动变形导致刚度差异引起的界面应力和填充层应力突变。

HDPE管与拉索接触相对长度对索力的影响

为了准确测量平行钢绞线拉索内部接触情况对索力的影响,对其截面特性及索力力学关系进行分析,研究内部接触的不同影响机理。施工中为避免钢绞线的锈蚀,采取在拉索上套HDPE管的防护措施,对此进行试验验证。实验结果显示,HDPE管的自重是拉索的重要影响因素,当HDPE管与拉索接触时,拉索振动行为表现出整体性及独立性,导致各部分振动发生耦合,耦合振动具有一致性,为通过振动频率法测量总索力提供了理论基础,但在非接触区域测得的频率并非拉索的真实频率,因此对于非常规的平行钢绞线拉索,当HDPE管与拉索索股的接触耦合不完好时,测得的频率误差超出规范要求且不能忽视。应用修正公式计算索力,可满足工程需求,提高索力的计算精度。

海洋环境下漂浮光伏电站浮体HDPE材料的抗疲劳性能与优化策略

研究旨在深入探讨高密度聚乙烯(HDPE)材料在海洋环境下应用于漂浮光伏电站浮体的抗疲劳性能。通过试验研究、理论分析和案例研究,探讨了海洋环境因素对漂浮光伏电站浮体HDPE材料疲劳性能的影响,并提出了改进策略。研究发现,在海洋环境中,改良的HDPE材料在漂浮光伏浮体中表现出优越的抗疲劳特性。使用高效的光屏蔽剂、光吸收助剂和合金混合物作为物理保护,同时使用持久的高低温抗氧化剂、聚合物抗紫外线稳定剂、抗疲劳剂和紫外线活化增韧系统,可以增强HDPE材料的抗老化和加工性能。改良的HDPE材料在海洋环境中的漂浮光伏电站浮体的耐久性和稳定性得到了提升。

HDPE装置不锈钢管线腐蚀原因与防护措施

文中针对HDPE装置的不锈钢管线发生腐蚀的原因进行分析,对腐蚀部位液体进行分析,确定Cl-腐蚀,同时由于HDPE装置工艺特点,腐蚀还造成干燥机加热蒸汽管泄漏、水冷器泄漏等问题,为此提出防止Cl-腐蚀的防范措施,包括设计上选用更加耐腐蚀的金属材料、生产重加强泄漏管理、使用无机防腐涂料等,经实际应用效果好,保证HDPE装置稳定生产。

Numerical Simulation of the Seismic Response of a Horizontal Storage Tank Based on a SPH-FEM Coupling Method

A coupled numerical calculation method combining smooth particle hydrodynamics(SPH)and the finite element method(FEM)was implemented to investigate the seismic response of horizontal storage tanks.Anumericalmodel of a horizontal storage tank featuring a free liquid surface under seismic action was constructed using the SPH–FEM coupling method.The stored liquid was discretized using SPH particles,while the tank and supports were discretized using the FEM.The interaction between the stored liquid and the tank was simulated by using the meshless particle contact method.Then,the numerical simulation results were compared and analyzed against seismic simulation shaking table test data to validate the method.Subsequently,a series of numerical models,considering different liquid storage volumes and seismic effects,were constructed to obtain time history data of base shear and top center displacement,which revealed the seismic performance of horizontal storage tanks.Numerical simulation results and experimental data showed good agreement,with an error rate of less than 18.85%.And this conformity signifies the rationality of the SPH-FEM coupling method.The base shear and top center displacement values obtained by the coupled SPH-FEM method were only 53.3% to 69.1% of those calculated by the equivalent mass method employed in the current code.As the stored liquid volume increased,the seismic response of the horizontal storage tank exhibited a gradual upward trend,with the seismic response increasing from 73% to 388% for every 35% increase in stored liquid volume.The maximum von Mises stress of the tank and the supports remained below the steel yield strength during the earthquake.The coupled SPH-FEM method holds certain advantages in studying the seismic problems of tanks with complex structural forms,particularly due to the representation of the flow field distribution during earthquakes by involving reservoir fluid participation.

Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RMPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAM) was studied in detail.PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process.The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s.The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system,and further compared to those of steel and aluminum projectiles.Significantly different from the conical cavity formed by the inert metal projectile,the cavity formed by the RMP appeared as an ellipsoid with a conical front.The RMPs were demonstrated to enhance the radial growth velocity of cavity,the global HRAM pressure amplitude and the front panel damage,indicating the enhanced HRAM and structural damage behavior.Furthermore,combining the impact-induced fragmentation and deflagration characteristics,the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed.The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis.Finally,the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed.It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior.

大型蒸发池HDPE土工膜施工工艺及质量控制

结合伊拉克南部拉塔维油田巴士拉天然气轻烃回收处理厂项目实例,介绍了大型蒸发池高密度聚乙烯(HDPE)土工膜的施工工艺和质量控制措施;阐述蒸发池HDPE土工膜的施工工艺和质量管理过程,以确保蒸发池HDPE土工膜的稳定性和安全性,以期望为相关工程提供技术参考。

Modern Corrosion Mapping of Storage Tank Bottoms--Notable Advancements in Critical Zone Coverage,Inspection Efficiency and Data Integrity

Every day,an NDT(Non-Destructive Testing)report will govern key decisions and inform inspection strategies that could affect the flow of millions of dollars which ultimately affects local environments and potential risk to life.There is a direct correlation between report quality and equipment capability.The more able the equipment is-in terms of efficient data gathering,signal to noise ratio,positioning,and coverage-the more actionable the report is.This results in optimal maintenance and repair strategies providing the report is clear and well presented.Furthermore,when considering tank floor storage inspection it is essential that asset owners have total confidence in inspection findings and the ensuing reports.Tank floor inspection equipment must not only be efficient and highly capable,but data sets should be traceable and integrity maintained throughout.Corrosion mapping of large surface areas such as storage tank bottoms is an inherently arduous and time-consuming process.MFL(magnetic flux leakage)based tank bottom scanners present a well-established and highly rated method for inspection.There are many benefits of using modern MFL technology to generate actionable reports.Chief among these includes efficiency of coverage while gaining valuable information regarding defect location,severity,surface origin and the extent of coverage.More recent advancements in modern MFL tank bottom scanners afford the ability to scan and record data sets at areas of the tank bottom which were previously classed as dead zones or areas not scanned due to physical restraints.An example of this includes scanning the CZ(critical zone)which is the area close to the annular to shell junction weld.Inclusion of these additional dead zones increases overall inspection coverage,quality and traceability.Inspection of the CZ areas allows engineers to quickly determine the integrity of arguably the most important area of the tank bottom.Herein we discuss notable developments in CZ coverage,inspection efficiency and data integrity that combines to deliver an actionable report.The asset owner can interrogate this report to develop pertinent and accurate maintenance and repair strategies.

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied analytically.The solutions for the velocity potential are derived out by the liquid subdomain method.Equivalent models with mass-spring oscillators are established to replace continuous fluid.Combined with the least square technique,Chebyshev polynomials are employed to fit horizontal,rocking and horizontal-rocking coupling impedances of soil,respectively.A lumped parameter model for impedance is presented to describe the effects of soil on tank structures.A mechanical model for the soil-foundation-tank-liquid-baffle system with small amount of calculation and high accuracy is proposed using the substructure technique.The analytical solutions are in comparison with data from reported literature and numerical codes to validate the effectiveness and correctness of the model.Detailed dynamic properties and seismic responses of the soil-tank system are given for the baffle number,size and location as well as soil parameter.

Numerical simulation on sand sedimentation and erosion characteristics around HDPE sheet sand barrier under different wind angles

For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area.

Protective benefit of folded linear HDPE board sand fences along the Golmud-Korla Railway,China:Field observation and wind tunnel study

The Milan Gobi area of the Golmud-Korla Railway in northwest China is located in the lower dispersal area of the mountain pass and has strong winds with evident double wind direction characteristics.This study introduced a novel sand fence deployment technique,termed‘folded linear deployment',designed to position the sand fence orthogonally to the two predominant wind directions for optimal protection.This study used wind tunnel and field tests to evaluate the wind and sand flow characteristics,as well as the windproof and sandresistant performance of folded linear HDPE(Highdensity polyethylene)board sand fences.The results suggest that the airflow around the fence creates clear zoning characteristics.The deceleration area on the BSF(backwind side of the sand fence)is much larger than that on the DSF(downwind side of the sand fence).Thus,sand particles are primarily deposited on the BSF.At different wind speeds,the airflow at 2 and 5 h on the DSF is not disturbed.The WSP(wind speed profile)presents a logarithmic distribution.The airflow is disturbed at 1-20 h on the BSF,and the WSP gradually deviates from the logarithmic law.However,as the airflow moves away from the fence,the WSP gradually approaches a logarithmic distribution.Meanwhile,the WPE(windproof efficiency)and SRE(sand-resistant efficiency)of the sand fence exceed 80%.In addition,the results of wind tunnel tests are compared with those of field tests.The overall dispersion is good,and the best dispersion is found at z/H=2.00,indicating good agreement between the two test results.This study provides a scientific basis for the design of sand hazard control measures,similar to the railway project in the Gobi Gale area.

Flow field, sedimentation, and erosion characteristics around folded linear HDPE sheet sand fence: Numerical simulation study

Wind and sand hazards are serious in the Milan Gobi area of the Xinjiang section of the Korla Railway. In order to ensure the safe operation of railroads, there is a need for wind and sand protection in heavily sandy areas. The wind and sand flow in the region is notably bi-directional. To shield railroads from sand, a unique sand fence made of folded linear high-density polyethylene(HDPE) is used, aligning with the principle that the dominant wind direction is perpendicular to the fence. This study employed field observations and numerical simulations to investigate the effectiveness of these HDPE sand fences in altering flow field distribution and offering protection. It also explored how these fences affect the deposition and erosion of sand particles. Findings revealed a significant reduction in wind speed near the fence corner;the minimum horizontal wind speed on the leeward side of the first sand fence(LSF) decreased dramatically from 3 m/s to 0.64 m/s. The vortex area on the LSF markedly impacted horizontal wind speeds. Within the LSF, sand deposition was a primary occurrence. As wind speeds increased, the deposition zone shrank, whereas the positive erosion zone expanded. Close to the folded corners of the HDPE sand fence, there was a notable shift from the positive erosion zone to a deposition zone. Field tests and numerical simulations confirmed the high windproof efficiency(WE) and sand resistance efficiency(SE) in the HDPE sand fence. Folded linear HDPE sheet sand fence can effectively slow down the incoming flow and reduce the sand content, thus achieving good wind and sand protection. This study provides essential theoretical guidance for the design and improvement of wind and sand protection systems in railroad engineering.

HDPE管道电热熔连接工艺的运用与研究

在城市水环境综合治理工程中,高密度聚乙烯HDPE管作为其中重要的施工管材,已经在越来越多的工程实际中被使用。作为HDPE管的接头连接是保证整条管线密封不漏的关键技术,在实际施工中严格按照工艺步骤实施,确保两个接头完全熔接成一体。通过现场实际工艺操作和工艺性试验,对熔接工艺加以总结和分析。

鹿泉区市政工程HDPE管施工技术及应用

鹿泉区农村人居环境整治工程HDPE管施工点分散,施工数量巨大,从如何提高HDPE管施工效率和工程质量角度出发,结合鹿泉区市政给排水工程施工实际,从管道特点、材料选择、现场安装、测试、维保等方面进行HDPE管施工技术研究,针对HDPE管施工技术在市政给排水施工中可能遇到的问题和挑战,提出应对策略和建议,以期为相关人员提供参考。

市政给排水施工中HDPE管施工技术研究

市政给排水工程涉及城市污水排放和饮用水供应,如果施工不当会影响城市水质和环境治理,甚至造成重伤事故,因此工程的施工质量、管材选择尤其重要,而HDPE管作为全新材料,凭借其诸多优势,目前已被广泛应用到市政给排水工程之中。本文展开对市政给排水施工中HDPE管施工技术的研究,自HDPE管施工全流程入手,分别探讨HDPE管不同施工工序下的技术要点,供我国市政给排水部门、施工单位参考与借鉴,为提升给排水工程施工质量,为城市建设、发展保驾护航。

混凝土排水管与HDPE管工艺与性能对比研究

文章对比研究了混凝土排水管与HDPE管的工艺与性能,包括生产工艺、机械性能、耐腐蚀性能等。通过对不同类型管的全面分析,得出混凝土排水管与HDPE管在生产工艺、机械性能和耐腐蚀性能等方面存在差异的结论。混凝土排水管采用离心、滚压等工艺制作,具有较高的抗压强度和耐久性,适用于大型排水工程。而HDPE管则采用滑模工艺制作,具有轻便、耐腐蚀、连接方便等优点,适用于城市排给水等工程。在选择管道材料时,应综合考虑使用场景和性能要求,结合实际情况进行科学选择。

房建工程室内HDPE排水管道安装防渗技术研究

房建工程特别是医院建筑,室内排水管道是一项重要设施,不仅需要合格的管道材料质量,对管道安装防渗技术也有严格的要求。通过对HDPE管道表面裂纹现状及发展特性进行研究,确定了管道裂纹的临界长度,并基于Paris公式对管道裂纹发展进行预测,结果表明现场所用管材质量均能满足要求。同时从预留洞、套管、立管、支管、预留洞封堵、闭水试验等各个方面提出了管道安装防渗操作要点,保证了管道安装质量。

HDPE管道热熔接头相控阵超声CIVA仿真

针对HDPE管道热熔接头声衰减大,检测信噪比低的特点,文章通过CIVA仿真软件中的超声模块对两种规格的HDPE管道进行了声场模拟,研究探头频率、阵元间距和阵元排列对热熔接头中声场分布的影响,优化了检测用相控阵探头参数。按照优化的探头参数和检测工艺在含标准反射体和典型缺陷的试件上进行声场仿真,检测工艺可对φ168.3 mm和φ914.4 mm管道中预设的不同深度和类型的典型缺陷全部检出,整体检测效果较好。该仿真研究为相控阵探头参数设计和下一步的工艺验证性能试验及现场检测打下了理论基础。

市政给排水管道工程HDPE管施工技术要点

在当前给排水施工出现了越来越多的管道类型,每种管道都有各自的特性,在施工建设期间需择优选择。HDPE管表现出了较高的性能优势,在当前的市政给排水管道工程中HDPE管广受关注且得到了相对成功的应用。未来的给排水管道项目中需继续推广HDPE管施工技术。基于此,本文从HDPE管的性能出发,引入某市政给排水管道工程案例,分析了HDPE管的有关技术,以期为同类型项目提供参考与借鉴。

建筑室外工程HDPE钢丝网骨架复合管施工技术

本文以西宁曹家堡机场T3航站楼改扩建工程项目为例,结合施工现场情况,总结创新形成一种建筑室外工程HDPE钢丝网骨架复合管施工技术,主要应用于长距离埋地用供水系统,适合各种地质情况,有应用工具简单、数量少、便于操作、施工速度快等优点。