The filter cloth of the back pressure filter in the geotechnical test mostly uses a flat cloth mechanism
There are many types of geotextiles, which can be divided into knitted fabrics, non-woven geotextile, and woven geotextiles according to production methods. Woven geotextiles are woven from two sets of polyester yarns or flat strips, including single-sided woven geotextiles (also known as geotechnical test back pressure filter cloth), double-layer geotextiles (also known as geotextile bag cloth), and knitted Yarn waterproof layer cloth. The raw material of woven geotextile is mainly woven by a polypropylene wire drawing machine, supplemented by nylon high-strength woven fabric, the width is more than 3800mm, and the specifications and models are mostly 120~150g/m2. When the project requirements are high, 200~500g/m2 fabrics can generally be used.
1. Single-sided woven geotextile
Single-sided woven geotextile is also called geotechnical test back-pressure filter cloth, which has the same structure as general woven cloth. In the geotechnical test, the filter cloth of the backpressure filter mostly adopts a plain cloth mechanism, and the main parameters such as raw materials, yarn counts, and relative density of the design scheme are specified in the application engineering. Goods should ensure super strength and water permeability. The production process is: cutting the polymer into fragments and particles → polyester yarn (or flat strip) bobbins → pellet storage → spinning (or demulsification) → warping and weaving → testing and combing, and finally, the finished geotextile is obtained.
2. Geotextile properties
Double-layer woven geotextile is also called geotextile bag cloth. The geotextile bag is a two-layer fabric with a four-layer structure, in which the second and third layers use twisted polyester yarn or thick rope as the structural reinforcement, which is thin and thick. The mold bag can be thick or thin, and the shape should not be too large or too small. The shape can be square, rectangular frame, or other geometric figures. The geotextile bag fabric is soft, in which the circulating concrete or mixed mortar is filled with a high-pressure water pump. After condensation, a hard block with high toughness and rigidity is produced. It can be integrated into all complex slope shapes, landform changes, and soil conditions, and is used for large Slope protection or soil surface lining and underwater bottom protection. It can act as a template. The performance of knitted yarn geotextile bags is reflected in the following aspects.
(1) High compressive strength, strong cold resistance (can withstand the ultra-low temperature of -40℃), and can be pre-made into various geometric shapes of different sizes and thicknesses according to engineering regulations.
(2) It is soft and ductile when pouring, which can ensure that the formed block is close to the road surface, especially when it is integrated into complex undulating terrain.
(3) It can be constructed in water, without a cofferdam construction plan or closure.
(4) Engineering construction can be mechanized and automated, with fast progress and guaranteed quality.
(5) Knitted yarn geotextile bags also have the properties of aging resistance, corrosion resistance, antibacterial, burst resistance, puncture resistance, good abrasion resistance, and reliable safety performance. It is a new type of textile geosynthetic material for flood prevention and disaster reduction.
3. Knitted yarn waterproof cloth
There are two kinds of cloth for the waterproof layer of knitted yarn, one membrane and one membrane. The thickness of the PVC coating is about 0132mm, which has the characteristics of high compressive strength, burst resistance, and puncture resistance. It is a unique waterproof layer of raw material for water conservancy projects, high dams, tunnel construction, engineering construction, and other engineering projects.