• Title/Summary/Keyword: Mud-pumping

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Characteristics of Behavior of the Soft Roadbed through Long-Term Instrumentation on the Field Test (운행선상의 연약노반 시험부설구간에서의 장기계측을 통한 거동 특성)

  • Lee Jin-Wook;Choi Chan-Yong;Lee Sung-Hyok;Lee Cnang-Youl
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1058-1064
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    • 2004
  • As one of reinforcing methods for soft roadbed, the problems that mud-pumping and settlement occurred by soft roadbed, were investigated, evaluated and analyzed through installing relatively economical and efficient geosynthetics on the selected track-bed for testing. Mock-heang to Dong-ryang on the filed resting sections in the Chung-buk lines were selected as investigating the state of track and prepared field after selecting three of 1,700 spots which often make mud-pumping and requiting maintenance for that. Long curved line radiuses(R) of Mock-heang to Dong-ryang are 500m that were installed with 4 types of geosynthetics layers and one ballast layer. Installed testing cross-section is 200m totally with 40 m between places. Strength or prepared roadbed was measured to investigate the state of roadbed and track with constructing(installing) field testing sections and physical properties of roadbed soils were evaluated and analyzed. Also, mud-pumping, settlement of elastic or plastic sleeper, failure or track, wheel-loads, transverse and earth pressures were measured after installing field testing sections.

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A Study on the Characteristics of Behavior of Railway Roadbed due to Softening (철도노반의 연약화에 따른 거동특성 연구)

  • Lee Jin Wook;Lee Sung Hyuck;Kim Dae Sang;Kwon Byung Sung
    • Proceedings of the KSR Conference
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    • 2003.10b
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    • pp.182-187
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    • 2003
  • The analysis of mud pumping which causes track irregularities during softening of present roadbed is needed in order to prepare countermeasure that is efficient and reasonable against the softening of railway roadbed. In this study, model tests were performed in order to evaluate property of the railway softening under the train loading, considering the wheel load and the impact coefficient due to the train passing velocity. The existence of the mud pumping, settlements of roadbed and vertical earth pressure were measured under the train loading.

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An Experimental Study of Diminution of Ballast Track Bridges Vibration due to the Variation of Ballast Depth (도상두께 변화에 따른 유도상교량 궤도 진동저감의 실험적 연구)

  • Kwon, Soon-Jung;Lee, Sang-Bae;Hong, Cheng-Hi
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1222-1229
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    • 2011
  • Railway bridges are divided into ballastless and ballast track bridges. The ballast abrasion occurs on the ballast track upon bridges more than soil roadbed because the track vibration occurs a lot in the ballast track upon bridges due to girder vibration when a train's weight is loaded onto track even though the identical ballast is used. The phenomena of mud pumping especially, which occurs when drainage is not properly secured for heavy rain, leads to the increase of maintenance work load and the decline of ride comfort. There are countermeasures such as ballast change, installation of cross-drainage for poor drainage, gutter establishment, ballast lifting methods, ballast mats and resilient sleepers laying for the mud pumping. The ballast thickness range in domestic railroad construction rule is uniformly set up according to the design speed of railroad and passing tonnage of train without considering field conditions which is considered in foreign railroad companies. The purpose of this study is to verify the effect of vibration decrease by measuring the acceleration, displacement and ride comfort of ballast track with the change of ballast thickness on the ballast track bridges and to suggest the optimal height of ballast on the Yocheon Bridge built for the test in Honam Line.

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The influence of fine particle migration on pore structure of overlying ballast under cyclic loading

  • Yu Ding;Yu Jia;Zhongling Zong;Xuan Wang;Jiasheng Zhang;Min Ni
    • Geomechanics and Engineering
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    • v.35 no.6
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    • pp.627-636
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    • 2023
  • The essence of subgrade mud pumping under train load is the migration of fine particles in subgrade soil. The migration of fine particles will change the pore structure of overlying ballast, thus affecting the mechanical properties and hydraulic properties of ballast layer. It is of great theoretical significance and engineering value to study the effect of fine particle migration on the pore structure of ballast layer under cyclic loading. In this paper, a tailor-made subgrade mud pumping test model and an X-ray computed tomography (CT) scanning equipment were used to study the influence of migration of fine particles in subgrade soil on the pore parameters (plane porosity, volume porosity, pore distribution and pore connectivity) of overlying ballast under cyclic loading. The results show that the compression of ballast pores and the blockage of migrated fine particles make the porosity of ballast layer decreases gradually. And the percentage of small pores in ballast layer increases, while the percentage of large pores decreases; the connectivity of pores also gradually decreases. Based on the test results, an empirical model of ballast porosity evolution under cyclic loading is established and verified.

Optimization of Ballast Depth of Ballasted Track Bridges to Improve Ride Comfort (승차감 향상을 위한 유도상교량의 도상두께 최적화)

  • Kim, Kwan-Hyung;Kwon, Soon-Jung;Kim, Yun-Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6D
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    • pp.867-874
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    • 2011
  • The ballast abrasion occurs on the ballasted track upon bridges more than soil roadbed because the track vibration occurs a lot in the ballasted track upon bridges due to girder vibration when a train's weight is loaded onto track even though the identical ballast is used. The phenomena of mud pumping especially, which occurs when drainage is not properly secured for heavy rain, leads to the increase of maintenance work load and the decline of ride comfort. The ballast thickness range in domestic railroad construction rule is uniformly set up according to the design speed of railroad and passing tonnage of train without considering field conditions which is considered in foreign railroad companies. The purpose of this study is to verify the effect of vibration decrease by measuring the acceleration, displacement and ride comfort of ballasted track with the change of ballast thickness on the ballast tracked bridges and to suggest the optimal height of ballast on the Yocheon Bridge built for the test in Honam Line.

Study on the Reinforcing Subgrade Depths of Highspeed and Conventional Railroads (일반철도와 고속철도의 강화노반두께에 관한 연구)

  • Kim Dae-Sang;Lee Su-Hyung;Choi Chan-Yong;Hwang Seon-Keun
    • Journal of the Korean Society for Railway
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    • v.8 no.2
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    • pp.128-136
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    • 2005
  • The reinforcing subgrade, which first introduced Korea for the highspeed subgrade construction, has the many advantages to maintain the quality of ballast track as well as to prevent the softening of subgrade by mud-pumping. It causes the subgrade soil to spout into the ballast on many lines. Therefore, the application of reinforcing subgrade will be expected to increase in the future. This paper introduces the reinforcing subgrade as a maintenance-free technology f3r the railroad operation and the method f3r the determination of reinforcing subgrade depth. The criteria on reinforcing subgrade depths of highspeed and conventional railroad were verified from the calculation results based on an elastic analysis method.

Evaluation of Settlements and Vertical Stress of Reinforced Subgrade of Conventional Railroad through Numerical Analysis (수치해석을 통한 일반철도의 강화노반 침하량 및 수직응력 평가)

  • Kim Dae-Sang;Park Young-Kon;Ha Tae-Wook;Shin Min-Ho
    • Proceedings of the KSR Conference
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    • 2005.05a
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    • pp.627-632
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    • 2005
  • The reinforcing subgrade has the many advantages to maintain the quality of ballast track. It has also the function to prevent the softening of subgrade by mud-pumping. Therefore, active application of it is being expected for the future constructions of Korean railroad. In this paper, behaviors of the reinforced subgrade applied to conventional railroad were investigated through 3-D numerical analyses. The applicability of the reinforced subgrade to conventional railroad was evaluated by analyzing the distributions of the settlements and vertical stress of reinforced subgrade.

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Application of Geosynthetic-Reinforced Structures for Railway (철도구조물에 적용되고 있는 토목섬유보강구조물의 현황)

  • Shin, Eun-Chul;Lee, Joong-Hwa
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.337-349
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    • 2009
  • In recent years, the cutting and banking areas along the railway in Korea are exposed to the erosion problem during every year. The reinforcement is a composite construction material in which the strength of engineering fill is enhanced by the addition of strong tensile reinforcement in many different types. Various problems of the railway infrastructure have occurred due to the differential settlement, frost heaving, mud pumping, lack of bearing capacity, partially loss of embankment. In advanced countries, railway roadbed reinforcement is applied to solve these problems on railway roadbed. This paper presents the solution of such problems by means of the engineering works incorporated with railway reinforcement infrastructures such as geotextile bag method, existing grouting method, geocell, reinforced earth, soil nailing and so on.

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The conservation of the ancient ships salvaged in North Europe-Especially on the Conservation of the Viking ships - Especially on the Conservation of the Viking ships in Denmark (북유럽 인양목선의 보존처리-덴마아크 Viking선을 중심으로)

  • Bae, Byong-Whan
    • 보존과학연구
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    • s.7
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    • pp.278-291
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    • 1986
  • In this report the practical case of Viking ship's conservation in Denmarke specially among the Eurpoean nations is introduced. The contents of it are summarized as follows :From 1957 to 1962 the Danish National Museum Salvaged five Viking ships from the bottom of Roskilde Fjord, Which were composed of the pieces of timber whose surface was soft because they had lain on the sea bed for about a thousand years. Excavation had been carried out in the same way as in the field by driving down a sheet piling around the wrecks and pumping the water out. These pieces of the wreck ships were packed in airtight plastic bags one by one to be transported for Brede and then immidiately had to go through the treatment for conservation. The conservation treatment process for the pieces includes three steps ; the preliminary process prior to the hardening treatment, the hardening and the assemble of the ships. In the first step ; the preliminary process, all remains of mud and shells from the fjord bed are washed off, and measuring followed ; every single piece of wreckage was drawn so that the form and size of the piece, nail holes, and breaks were registered before conservation. In the second ; the hardening treatment step, the pieces of the woreckage were filled with P.E.G. This Polyethylene Glycol method was the best to handle in the subsequent mounting of the ships in the museum. In the final, the Glycol-treated pieces were pieced together to spips with support of a system of reinforcements. They were to fit in place after corrections of the form were made several times.

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