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TB/T 2897-1998 PDF in English

TB/T 2897-1998 (TB/T2897-1998, TBT 2897-1998, TBT2897-1998)
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TB/T 2897-1998: PDF in English (TBT 2897-1998)

TB/T 2897-1998
Sub-ballast for ballast bed of railways
Issued by. Ministry of Railways of the People’s Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 References ... 4
3 Terms ... 4
4 Technical requirements ... 4
5 Inspection rules ... 6
6 Transportation, storage ... 8
Sub-ballast is an important part of the ballast bed of railways and is located between
the ballast layer of the ballast bed and the surface layer of the subgrade bed. It plays
the role of transmitting and distributing the train loads, preventing mutual penetration
of top-ballast and surface layer particles of subgrade bed, water seepage transition
and antifreeze-and-insulation. In the past, China borrowed the experience of using
river sands as sub-ballast from the former Soviet Union. Since there is no material
standard, the above-mentioned functions of the sub-ballast cannot be guaranteed and
the material source of the sub-ballast is limited. On the basis of reference to the
relevant standards such as the sub-ballast material standards of the United States
Railway Engineering Association (AREA), Japan railway subgrade bed surface layer
(JISA5001 particle size transitional gravel layer) material standards, combining China's
national conditions and railway situation, this Standard is developed.
This Standard is proposed by Railway Engineering Research Institute of China
Academy of Railway Sciences.
This Standard is under the jurisdiction of Institute of Standard Metrology of National
Railway Administration of the People’s Republic of China.
Railway Engineering Research Institute of China Academy of Railway Sciences is
responsible for the drafting of this Standard.
Main drafters of this Standard. Zeng Shugu, Zhang Wensheng, Xu Yongxian, Wang
Hong, Liu Zengjie.
Sub-ballast for ballast bed of railways
1 Scope
This Standard specifies the technical requirements, inspection rules and transportation,
storage of sub-ballast for ballast bed of railways (hereinafter referred to as sub-ballast).
This Standard applies to national railways; local railways and industrial enterprise
railways may also refer to this Standard.
2 References
The following standards contain provisions which, through reference in this text,
constitute provisions of this standard. At time of publication, the editions indicated were
valid. All standards are subject to revision, and parties to agreements based on this
standard are encouraged to investigate the possibility of applying the most recent
editions of the standards indicated below.
TB/T 2140-90 Railway ballast
TB/T 2328.1~18-92 Test method for railway ballast
3 Terms
The plasticity index Ip. the plasticity index is equal to the difference between the liquid
limit LL and the plastic limit PL.
Ip = LL - PL
4 Technical requirements
4.1 Sub-ballast material may be taken from natural gravel material, or may be taken
from rocks or natural pebbles, gravels by crushing, screening.
4.2 Sub-ballast material’s particle size grading shall comply with the provisions of Table
1, and the particle content of fine aggregate below 0.5 mm sieve that pass through the
0.075 mm sieve shall be less than or equal to 66 %. The matching of the particle size
grading of sub-ballast material with the particle size grading of the ballast layer in the
ballast bed and the surface layer of the subgrade bed is shown in Figure1.
4.4.4 The mass percentage of clay and other impurities is less than or equal to 0.5 %.
5 Inspection rules
Sub-ballast material shall be subjected to type inspection and production inspection.
The type inspection is a ministerial level, and the production inspection is a bureau
5.1 Type inspection
5.1.1 When establishing the sub-ballast material mining and processing base, the
particle size grading and material property inspection of the finished product shall be
carried out by the designated organization of the National Railway Administration of
the PRC according to the requirements of 4.2 to 4.4. Approved by the competent
department of the National Railway Administration of the PRC and issued sub-ballast
mining qualification certificate before production.
5.1.2 Sampling
Divide the mining resource zone by the commissioned mine organization, and develop
appropriate mining and processing procedures by the construction organization. In
each given resource zone, 400 kg of representative samples are processed according
to the developed mining and processing procedures, which is submitted to the
designated organization of the National Railway Administration of the PRC for
5.1.3 When the resource zone changes significantly, and the quality of sub-ballast
cannot meet the requirements of this Standard, it shall carry out type inspection again.
5.2 Production inspection
5.2.2 According to the requirements of 4.2 to 4.4, the production organization carries
out an inspection when every 4 × 104 m3 of sub-ballast are produced. If the annual
output is less than 4 × 104 m3, the inspection shall be carried out once a year.
5.2.2 Sampling
Sub-ballast material samples are taken from the finished product discharge port or
finished product transport belt. Take four sub-samples at intervals, with each sub-
sample weigh about 100 kg and total weight of 400 kg, to send to the inspection
department for inspection.
5.2.3 For sub-ballast material’s particle size grading and clay content indicators, in
addition to inspect once a week, each production shift shall be monitored by visual
inspection. If any problem is found, it shall inspect and handle promptly. Monitoring
and inspection results shall be filled in the production diary, as the basis for the
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.