scholarly journals A Treatment Technology for Optimizing the Stress State of Railway Tunnel Bottom Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zili Han ◽  
Weibin Ma ◽  
Jinfei Chai ◽  
Zhenyu Zhu ◽  
Chuannian Lin ◽  
...  
Keyword(s):  
Drainage System ◽  
Size Variation ◽  
High Strength ◽  
Normal Operation ◽  
Railway Transportation ◽  
Treatment Technology ◽  
Railway Tunnel ◽  
Continuous Increase ◽  
Diversion Structure ◽  
Short Time

With the continuous increase of railway transportation volume, the aging problem of railway tunnel bottom structure is becoming more and more serious, which seriously threatens the safe operation of trains. Based on the cause analysis and field detection of the defects at the railway tunnel bottom structure, the “Anchor-Grouting-Drainage” treatment technology of the railway tunnel bottom structure is summarized. The research shows that (1) the technology is simple and can effectively repair the defects of railway tunnel bottom structure under the conditions of the narrow site, short time of maintenance skylight, strict requirements of track size variation, and no interference with the normal operation of the train, which has great significance and broad application prospect. (2) The drainage system of the existing railway tunnel bottom structure can be applied to the reconstruction of the railway tunnel bottom structure. The high-strength transverse diversion structure at the bottom of the tunnel has the advantages of strong bearing capacity, large drainage capacity, and corrosion resistance, which can provide a reference for the subsequent implementation of the reconstruction project at the railway tunnel bottom structure.

JESSOP JS17Cr-4Ni

Alloy Digest ◽  
1982 ◽  
Vol 31 (7) ◽  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Food Processing ◽  
Precipitation Hardening ◽  
High Strength ◽  
Heat Treating ◽  
Steel Company ◽  
Lower Strength ◽  
Nickel Copper ◽  
Short Time

Abstract JESSOP JS17Cr-4Ni is a martensitic, precipitation-hardening chromium-nickel-copper stainless steel. It provides an excellent combination of high strength and hardness, short-time low-temperature precipitation hardening and good mechanical properties at temperatures up to 600 F (316 C). Its corrosion resistance is quite good but inferior to lower strength grades produced for corrosion-resistance applications. JS17Cr-4Ni is used widely for critical applications in the aerospace, chemical, food processing and other industries. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-412. Producer or source: Jessop Steel Company.

scholarly journals Forming a Flanged Hole When Quenching Press-Hardened Steel for Mechanical Fastening

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 721
Author(s):  
Yongjun Jeon ◽  
Hyunseok Choi ◽  
Dongearn Kim
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Expansion Ratio ◽  
Hardened Steel ◽  
Continuous Increase ◽  
Pilot Hole ◽  
Experimental Apparatus ◽  
Mechanical Fastening ◽  
Hole Flanging

The recent stringent regulations on vehicle safety and reducing CO2 emissions have led to a continuous increase in the application of press-hardened steel (PHS) in automobiles. Similar to other high-strength steels, assembling PHS components using the common welding techniques employed in automotive production lines is significantly difficult because of the surface coating layers and the additives within. This difficulty in post-processing, attributed to its high strength, also limits the mechanical fastening of PHS components. Therefore, this study aims to develop a process for forming a structure enabling mechanical fastening by sequentially applying piercing and hole-flanging operations during the hot stamping process. Our experimental apparatus was designed to perform the hole-flanging operation after the piercing operation within a single stroke at a specific temperature during the quenching process of PHS. At high temperatures of 440 °C or higher, the hole-flanging process was conducted in a direction opposite to that of the piercing operation for creating the pilot hole. An extruded collar with a height of 8.0 mm and a diameter of 17.5 mm was achieved, which is hole expansion ratio(HER) of 82.5%.

Size Effect in Plastic Deformation and Failure of Metallic Glasses

2020 ◽  
Vol 405 ◽  
pp. 212-216
Author(s):  
Jozef Miškuf ◽  
Kornel Csach ◽  
Alena Juríková ◽  
Mária Demčáková ◽  
Mária Demčáková ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Metallic Glasses ◽  
High Strength ◽  
Dimple Size ◽  
Deformation And Failure ◽  
Composition And Structure ◽  
Instantaneous Deformation ◽  
20 Nm ◽  
Short Time ◽  
Stored Elastic Energy

Depending on the composition and structure of metallic glasses cells with the dimensions in the range from tenths nanometers to tenths micrometers were observed on the ductile fracture surface. The variation in dimple size was compared with the serrations presented on the loading curve at the nanoindentation of the metallic glasses with different compositions. Higher instantaneous deformation can be connected with simultaneous shearing at more suitable shear band configurations. The cell morphology with the various cell sizes is observed at the failure of the metallic glasses. At the failure of high strength metallic glasses, the cells are formed in short time due to the release of high amount of stored elastic energy. In this case the uniform cell morphology with the cell size of about 20 nm is observed.

scholarly journals Review of Application and Innovation of Geotextiles in Geotechnical Engineering

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1774 ◽  
Author(s):  
Hao Wu ◽  
Chongkai Yao ◽  
Chenghan Li ◽  
Miao Miao ◽  
Yujian Zhong ◽  
...  
Keyword(s):  
Soil Pollution ◽  
High Performance ◽  
Low Cost ◽  
Geotechnical Engineering ◽  
Drainage System ◽  
High Strength ◽  
Present Situation ◽  
Soft Foundation ◽  
And Function ◽  
Erosion Protection

Most geotextiles consist of polymers of polyolefin, polyester or polyamide family, which involve environmental problems related to soil pollution. Geotextiles can be used for at least one of the following functions: Separation, reinforcement, filtration, drainage, stabilization, barrier, and erosion protection. Due to the characteristics of high strength, low cost, and easy to use, geotextiles are widely used in geotechnical engineering such as soft foundation reinforcement, slope protection, and drainage system. This paper reviews composition and function of geotextiles in geotechnical engineering. In addition, based on literatures including the most recent data, the discussion turns to recent development of geotextiles, with emphasis on green geotextiles, intelligent geotextiles, and high-performance geotextiles. The present situation of these new geotextiles and their application in geotechnical engineering are reviewed.

scholarly journals Pengaruh Aerasi Dalam Constructed Wetland Pada Pengolahan Air Limbah Domestik

2018 ◽  
Vol 16 (2) ◽  
pp. 155
Author(s):  
Euis Nurul Hidayah ◽  
Andrysah Djalalembah ◽  
Gina Aprilliana Asmar ◽  
Okik Hendriyanto Cahyonugroho
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Drainage System ◽  
Domestic Wastewater ◽  
Septic Tank ◽  
Source Water ◽  
Treatment Technology ◽  
Detention Time ◽  
Domestic Wastewater Treatment ◽  
Natural Treatment

ABSTRAKPenanganan air limbah domestik Kota Surabaya selama ini dilakukan dengan 2 cara, yakni untuk blackwater dialirkan ke tangki septik dan greywater dialirkan ke drainase tanpa pengolahan. Hal ini menyebabkan peningkatan pencemar pada sungai sebagai air baku. Salah satu teknologi alternatif yang dapat diaplikasikan dengan mudah dan rendah biaya operasional dibanding pengolahan air limbah lainnya adalah constructed wetland dengan menggunakan tanaman Iris pseudoacorus sebagai kombinasi pengolahan biofilter dan proses fitoteknologi. Penelitian ini dilakukan untuk mengetahui efisiensi dari constructed wetland dengan tanaman Iris pseudoacorus untuk mengolah limbah domestik, serta menentukan bagaimana pengaruh dari adanya aerasi dan pengaruh waktu tinggal pada sistem constructed wetland dalam menurunkan bahan organik dan nitrogen pada air limbah. Penelitian ini dilakukan dalam skala uji laboratorium menggunakan reaktor berkapasitas 30 liter. Air limbah dialirkan pada reaktor dengan waktu tinggal 2 hari dan 3 hari, dengan variasi aerasi dan efisiensi pencemar diukur dengan parameter BOD, dan ammonia. Hasil penelitian ini menunjukan bahwa kemampuan penyisihan BOD, dan ammonia dari limbah air domestik oleh reaktor constructed wetland dengan tambahan aerasi dan waktu tinggal selama 4 hari sangat efektif. Reaktor ini mampu menurunkan nilai BOD hingga 96% dan nilai ammonia sebesar 97%.ABSTRACTWastewater domestic in Surabaya City has been treated in two methods, including septic tank for blackwater and directly discharged into drainage system for greywater. This caused an increasing pollutant loading in source water. Constructed wetland with Iris pseudoacorus, one of the alternative natural treatment technology through biofilter and phytotechnology process, could be applied easily and less costly to other treatment. This research was conducted to know the efficiency of constructed wetland with Iris pseudoacorus in domestic wastewater treatment, and to reveal the effect of aeration and detention time in reducing organic and nitrogen content in domestic wastewater. Experiment has been conducted on a laboratory scale of continue aerated reactor and without aeration as control reactor. Detention time (days) 2 and 3 was setup, then sample was taken for BOD and ammonia measurement. The results indicated that constructed wetland with aeration and detention time 4 days had a higher performance to remove BOD up to 96% and ammonia up to 97% than without aeration and less than 4 days process.Keywords: Domestic Wastewater, Constructed Wetland, Phytotechnology, Iris pseudoacorus, Aeration.Sitasi: Hidayah, E. N., Djalalembah, A., Asmar, G.A. dan Cahyonugroho, G.A. (2018). Pengaruh aerasi dalam constructed wetland pada pengolahan air limbah domestik. Jurnal Ilmu Lingkungan, 16(2),155-161, doi:10.14710/jil.16.2.155-161

Monitoring and Modeling of Landslide Processes on the Example of the City of Sochi

10.12737/342 ◽  
2013 ◽  
Vol 1 (1) ◽  
pp. 54-61
Author(s):  
Дарья Лейер ◽  
Сергей Маций ◽  
Sergey Maciy ◽  
Екатерина Безуглова ◽  
Ekaterina Bezuglova
Keyword(s):  
Retaining Wall ◽  
Normal Operation ◽  
Railway Tunnel ◽  
Recent Developments ◽  
Landslide Processes ◽  
Complex Monitoring ◽  
Protective Structures ◽  
Landslide Slope ◽  
Slope Condition ◽  
The City

ssible designing of reinforcement constructions. Yet some problems in simulation of landslide situation do occur. Options for using different soil models and calculation schemes are being analyzed on the example of protective structures construction for railway tunnel in the city of Sochi region. Simulation of landslide slope condition is carried out using geotechnical software Plaxis conside­ring different soil models (Linear Elastic и Mohr-Coulomb) and «reconstruction» of structures displacements. The value of retaining wall displacement alongside landslide slope as well as retaining walls sections inner movement is being estimated by results of complex monitoring. Recent developments were causing threat to the safety of building and construction works continuation at the railway and also to the normal operation of structures lower down the slope.

scholarly journals Analysis of External Water Pressure for a Tunnel in Fractured Rocks

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ze-jun Liu ◽  
Yong Huang ◽  
Ding Zhou ◽  
Hong Ge
Keyword(s):  
Water Conservation ◽  
Water Pressure ◽  
Scientific Evidence ◽  
Drainage System ◽  
Fracture Network ◽  
Influential Factor ◽  
Normal Operation ◽  
Fracture Development ◽  
External Water Pressure ◽  
External Water

External water pressure around tunnels is a main influential factor in relation to the seepage safety of underground chambers and powerhouses which make managing external water pressure crucial to water conservation and hydropower projects. The equivalent continuous medium model and the discrete fracture network (DFN) model were, respectively, applied to calculate the seepage field of the study domain. Calculations were based on the integrity and permeability of rocks, the extent of fracture development, and the combination of geological and hydrogeological conditions in the Huizhou pump-storage hydropower station. The station generates electricity from the upper reservoir and stores power by pumping water from the lower to the upper reservoir. In this paper, the external water pressure around the cavern and variations in pressure with only one operational and one venting powerhouse were analyzed to build a predictive model. The results showed that the external water pressure was small with the current anti-seepage and drainage system that normal operation of the reservoir can be guaranteed. The results of external water pressure around the tunnels provided sound scientific evidence for the future design of antiseepage systems.

Phase Transformations in D6AC Steel during Continuous Cooling

2017 ◽  
Vol 265 ◽  
pp. 712-716 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim Ryzhkov ◽  
Aleksandra A. Kuklina
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Transformations ◽  
High Strength ◽  
Treatment Technology ◽  
Heat Treatment Technology ◽  
Cooling Conditions ◽  
Drill Bits ◽  
Steel Drill ◽  
Quenching And Tempering

The CCT diagram of the high strength D6AC steel was plotted using the dilatometer data, microstructure investigation, and hardness measurements. The microstructure of the steel under consideration was estimated after various cooling conditions and quenching and tempering. The heat treatment technology of D6AC steel drill bits was developed to obtain the required mechanical properties.

scholarly journals Oblique penetration mechanism of hybrid composite laminates

2021 ◽  
Vol 28 (1) ◽  
pp. 568-578
Author(s):  
Meng Han ◽  
Chuwei Zhou ◽  
Vadim V. Silberschmidt ◽  
Xindong Ma ◽  
Mao Liu ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Hybrid Composites ◽  
High Strength ◽  
Oblique Impact ◽  
Contact Forces ◽  
Dissipation Energy ◽  
Penetration Mechanism ◽  
Oblique Impacts ◽  
Viscoelastic Constitutive Model ◽  
Short Time

Abstract Hybrid fiber composites are widely used to improve the anti-penetration performance. Carbon/Kevlar hybrid composites are used in aircrafts and safety devices, thanks to the strong toughness of Kevlar fibers and high strength of carbon fibers. In the present work, the contact force of hybrid composites under oblique impact is derived. The viscoelastic constitutive model of Kevlar layer is investigated and the dissipation energies of composites for different high velocity oblique impacts are simulated. The results show that hybrid composites have good bullet-proof performance, the contact forces are fluctuant in short time and the frictional dissipation energy allows us to prevent penetration.

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