Q/CR 549.3-2016 Technical Standard for Geosynthetics in Railway Engineering Geomembrane

Q/CR 549.3-2016 Technical Standard for Geosynthetics in Railway Engineering Geomembrane

This issue introduces the standard of China Railway Corporation - "Geosynthetic Materials for Railway Engineering Part 3 Geomembrane" (Q/CR549.3-2016), which was promulgated and implemented on January 8, 2017.

Geomembrane has been widely used in the field of railway engineering. For example, in railway subgrade engineering, it is used for the reinforcement of new railway subgrade beds, the existing railway subgrade beds are muddy, ballast bags and other diseases treatment, and special rocks such as expansive soil and loess are used. In the land area, surface water seepage is prevented, and the underground capillary water is cut off in saline soil and permafrost areas; in tunnel waterproofing and drainage projects, geomembranes are laid after the tunnel is lined for waterproofing; in slab-type ballastless track structures, the base plate Lay composite geomembrane under the anti-skid and so on.

Although geomembrane has a wide range of application fields, many application types, and different technical requirements, the railway industry has never had corresponding product standards. In the design and construction, the design and construction of various railway engineering construction projects are mainly formulated according to national or other industry standards. and inspection parameters, etc., resulting in inconsistent geomembrane product standards used in the railway industry, inconsistent inspection methods and means, many human control factors, and difficult to control product quality on site.

In order to ensure project quality, absorb new technological achievements, standardize the application of geomembrane in railway engineering design and construction, reflect the characteristics of railway engineering, and unify relevant technical requirements, China Railway Corporation established a project to formulate the "Geosynthetic Materials for Railway Engineering No. 1". Part 3 Geomembrane Product Standard.

The main content of the standard

(1) The classification method, naming format, product specification and application scope of geomembrane products are formulated.

(2) The technical requirements for geomembrane and composite geomembrane products for railway engineering are formulated, and clear requirements are put forward in terms of raw materials, appearance quality and technical performance.

(3) The test methods for the sampling of geomembrane products, sample preparation, appearance, size and other indicators are proposed, and the tensile breaking strength, yield strength and elongation, puncture resistance, carbon black content, carbon Black dispersion, density, right-angle tear load, oxidation induction time, low temperature impact embrittlement performance, dimensional stability, tensile breaking strength and elongation of composite geomembrane, CBR burst strength, hydrostatic pressure resistance, unit area Quality, Tear Strength, Dynamic Perforation (Drop Cone), Coefficient of Friction, In-Plane Water Flow, Creep, Oxidation Resistance, Acid and Alkaline Resistance, Puncture Strength, Joint/Seam Breaking Strength, UV Resistance, Penetration Coefficient, wear resistance, peel strength, constant load elongation and constant elongation load and other indicators of the test methods, and the main test principles, equipment, samples and test procedures are specified in detail in the form of an appendix.

(4) The inspection rules for geomembrane products are formulated, including inspection classification, factory inspection, type inspection, batch grouping and sampling, and judgment rules.

(5) The specific requirements for the marking, packaging, transportation and storage of geomembrane products are specified.

A brief introduction to some standards

The following is a brief introduction to some of the contents of the standard. For more detailed instructions, please read the product standard.

(1) The classification of geomembrane products in railway engineering is specified

(1) Geomembrane is mainly classified as high-density polyethylene (HDPE) geomembrane by raw materials.

(2) Composite geomembrane can be divided into non-woven composite geomembrane and woven composite geomembrane according to the type of substrate product.

(3) Composite geomembrane can be divided into waterproof partition type composite geomembrane, transverse drainage type composite geomembrane and reinforced composite geomembrane according to the function of use.

(4) The composite geomembrane can be divided into one cloth and one membrane, two cloths and one membrane according to the product structure.

(2) Determined the naming standard of geomembrane products in railway engineering

The product naming format of geomembrane is shown in the following figure:

For example, GMB/HDPE-0.3 means: the geomembrane material is high-density polyethylene, and the film thickness is 0.3mm.

The product naming format of composite geomembrane is shown in the following figure:

For example, GMB2/PETFNG2/HDPE-16-700-0.35 means: composite geomembrane, the base material is two layers of polyester filament non-woven geotextile, the membrane material is a layer of high-density polyethylene geomembrane, two fabrics and one film, The nominal strength is 16kN/m, the total mass per unit area is 700g/m2, and the film thickness is 0.35mm.

(3) Define the application scope of railway engineering geomembrane products

Geomembrane and composite geomembrane are widely used in railway engineering. In roadbed engineering, it is mainly used for subgrade reinforcement, subgrade disease treatment, prevention of surface water seepage in special rock and soil areas or partition of underground capillary water, etc.; in tunnel engineering It is mainly used for waterproofing and drainage after lining; in ballastless track structure, it is mainly used for waterproofing, drainage and anti-skid under the base plate.

Since the "Railway Tunnel Drainage Board" has been compiled in the railway tunnel project, the performance requirements and engineering application effects of the composite geomembrane under the base plate in the track project have yet to be tested. Therefore, the compilation of this geomembrane standard is only aimed at the application in roadbed engineering. geomembrane products. In railway subgrade engineering, its main functions are waterproof partition, lateral drainage and reinforcement, etc. The main application scope of geomembrane products is shown in the following table:

(4) The technical indicators of geomembrane products in railway engineering are specified

This standard divides technical indicators into basic items and optional items. The basic items are the indicator requirements that the product must meet, and the optional items are the indicator requirements that must be met according to design or actual needs. Taking high-density polyethylene geomembrane products as an example, the specific requirements for the basic items of technical performance are shown in the following table: