In various engineering construction projects, there is a kind of material that, although not often in the spotlight of the public, plays a vital role. That is geotextiles.
I. Overview of Geotextiles
Geotextiles, also known as geotextile fabrics, are water-permeable geosynthetic materials made by needling or weaving synthetic fibers. They possess excellent physical properties and chemical stability and can function under various complex environmental conditions.
There are numerous types of geotextiles. According to different manufacturing processes and uses, they can be divided into non-woven geotextiles and woven geotextiles. Non-woven geotextiles are made by randomly arranging fibers and needling them together, having good filtration, separation, and drainage properties. Woven geotextiles are formed by interweaving warp and weft threads, with relatively high strength, and are suitable for reinforcement and protection engineering.
II. Application Scope of Geotextiles
Road Engineering
In road subgrades, geotextiles can play a separation role, preventing the mixing of soil materials of different particle sizes and maintaining the stability of the subgrade. For example, when constructing a new road, laying geotextiles between the soil foundation and the subgrade can effectively prevent the fine-grained soil in the soil foundation from entering the subgrade and affecting the strength and stability of the subgrade.
Geotextiles can also be used in the reinforcement engineering of roads. When building roads on soft soil foundations, due to insufficient bearing capacity of the foundation, it is easy to cause road settlement and cracking. At this time, laying geotextiles in the foundation can increase the tensile strength of the foundation and reduce settlement and uneven settlement. For example, in the widening projects of expressways, geotextiles are often used to strengthen the joint parts of the new and old roadbeds to prevent uneven settlement of the new and old roadbeds.
In addition, geotextiles have good drainage properties. In the drainage system of roads, geotextiles can be used as a filter layer to prevent drainage pipes from being blocked and ensure the smooth operation of the drainage system.
Water Conservancy Engineering
In embankment projects, geotextiles are one of the indispensable materials. They can be used for filtration and drainage of embankments, preventing the soil particles in the embankments from being washed away by water flow. Meanwhile, they can ensure that the moisture inside the embankments can be discharged in a timely manner, reduce the saturation line of the embankments, and improve the stability of the embankments. For example, in the construction of earth-rock dams, a layer of geotextiles is usually laid between the dam body and the dam foundation as a filter layer to prevent the loss of soil particles in the dam body.
Anti-seepage of canals is also an important application area of geotextiles. In irrigation canals and water conveyance canals, due to the long-term scouring and infiltration of water flow, it is easy to cause canal leakage and damage. Laying geotextiles can effectively reduce the leakage loss of canals and improve the utilization efficiency of water resources. Meanwhile, geotextiles can also protect the lining structures of canals and extend the service life of canals.
Geotextiles can also be used in the anti-seepage projects of reservoirs. Laying geotextiles on the dam body, reservoir bottom, and slopes of reservoirs can effectively prevent water leakage in reservoirs and ensure the safe operation of reservoirs.
Environmental Protection Engineering
Landfills are one of the important application sites of geotextiles. In landfills, geotextiles can be used for the isolation, anti-seepage, and drainage of garbage. They can prevent harmful substances in the garbage from permeating into the soil and groundwater, causing environmental pollution. Meanwhile, geotextiles can also collect landfill leachate and guide it to sewage treatment facilities for treatment. For example, in modern landfills, multiple layers of geotextiles are usually laid between the garbage layer and the soil to form a complete anti-seepage system.
The construction of sewage treatment plants also cannot do without geotextiles. In the pools, aeration tanks, and sedimentation tanks of sewage treatment plants, geotextiles can be used as anti-seepage layers and filter layers to prevent sewage leakage and sludge loss. Meanwhile, geotextiles can also be used for sludge dewatering in sewage treatment plants to improve the dewatering efficiency of sludge.
Railway Engineering
In railway subgrades, geotextiles can play the roles of separation, reinforcement, and drainage. They can prevent the soil particles in the subgrades from being taken away by train vibration and water flow, and at the same time increase the strength and stability of the subgrades. For example, in the construction of high-speed railways, in order to ensure the smooth operation of trains and the stability of subgrades, geotextiles are usually laid in the subgrades.
In railway tunnel engineering, geotextiles can be used for waterproofing and drainage of tunnels. They can prevent groundwater from permeating into the interior of tunnels and affecting the safety of tunnel use. Meanwhile, geotextiles can also collect the seepage water in tunnels and guide it to the drainage system for discharge.
Mining Engineering
During the mining process, geotextiles can be used for the protection and drainage of mine slopes. They can prevent slope collapse and soil erosion, and at the same time ensure the safe production of mines. For example, in the mining of open-pit mines, geotextiles are usually laid on the slopes and vegetation is planted to achieve the purposes of protection and greening.
The construction of mine tailing ponds also requires geotextiles. Geotextiles can be used for the anti-seepage and drainage of tailing ponds to prevent harmful substances in the tailings from permeating into the soil and groundwater, causing environmental pollution.
III. Advantages of Geotextiles
Good Physical Properties
Geotextiles have relatively high strength and durability and can withstand relatively large tensile and compressive forces. In engineering applications, they can effectively enhance the tensile strength and stability of soil masses, preventing soil deformation and destruction.
Geotextiles have good water permeability, which can enable the moisture in soil masses to be discharged in a timely manner, reduce the water content of soil masses, and improve the stability of soil masses. Meanwhile, they can also prevent water flow from scouring the soil surface and protect the surface of soil masses.
Good Chemical Stability
Geotextiles have good chemical stability and can resist the erosion of chemical substances such as acids, alkalis, and salts. Under various harsh environmental conditions, they can maintain stable performance and will not undergo degradation and aging.
Convenient Construction
Geotextiles are lightweight and convenient for handling and laying. They can be cut and spliced according to engineering needs. The construction is simple and fast, which can greatly shorten the project cycle.
Environmental Protection and Energy Saving
Geotextiles are an environmentally friendly material. They can be recycled and will not cause pollution to the environment. Meanwhile, they can reduce the amount of earth excavation and filling in engineering construction, reduce engineering costs, and save resources.
IV. Summary
As an important geosynthetic material, geotextiles have a wide range of applications in fields such as road engineering, water conservancy engineering, environmental protection engineering, railway engineering, and mining engineering. They have advantages such as good physical properties, chemical stability, and convenient construction, and can provide effective guarantees for engineering construction. With the continuous progress of science and technology and the continuous development of engineering construction, the application prospects of geotextiles will be even broader.
一,土工布简介 土工布作为一种重要的土工合成材料,在各类工程中发挥着关键作用.它主要由合成纤维通过针刺或编织工艺制成,成品呈布状. 土工布分为有纺土工布和无纺长丝土工布.有纺土工布是通过在经纬方向上至少交织两组纱线生产而成,厚度较薄,一般为 0.2mm,0.4mm,0.7mm,抗拉能力较强,约 250kg/cm²,渗透系数较大,约 6.1×10⁻⁴cm/s.无纺土工布则是在机械设备的帮助下,通过针刺等生产工艺,将长丝与短纤维交织而成. 土工布的规格多样,一般宽度为 4 - 6 米,长度为 50 - 100 米.幅宽可达 9 米,是国内最宽产品.单位面积质量也有多种选择,从 100g/m² 到 1000g/m² 不等. 土工布具有众多优良特性.它强力高,无论是在干湿状态下都能保持充分的强力和伸长.耐腐蚀性能出色,在不同酸碱度的泥土及水中能长久地耐腐蚀.透水性好,纤维间的空隙使其具有良好的渗水性能.抗微生物性好,对微生物,虫蛀均不受损害.同时,由于材质轻,柔,运输,铺设,施工都非常方便. 二,土工布特点 (一)性能卓越 土工布的强力高这一特点,使其在各种工程环境中都能保持稳定的性能.例如在铁路路基加筋,公路路面养护等工程中,即便面临不同的气候条件和外力作用,也能确保工程结构的完整性.据相关数据显示,使用塑料纤维制成的土工布,在干湿状态下都能保持充分的强力和伸长,其强力可达到一定数值,具体数值因不同规格和生产工艺而有所差异,但总体来说,能够满足各类工程的强度要求. 耐腐蚀性能是土工布的又一重要优势.无论是在酸性土壤还是碱性水环境中,土工布都能长久地保持稳定,不被腐蚀.在不同酸碱度的泥土及水中,土工布的使用寿命可长达数年甚至更久.这一特性使得它在水利工程,环保工程等领域得到广泛应用,例如在垃圾填埋场中,土工布可以隔离垃圾中的有害物质,防止其对周围土壤和地下水造成污染,即使长期处于复杂的化学环境中,也能保持良好的性能. 透水性好是土工布的显著特点之一.纤维间的空隙为水的流动提供了良好的通道,故有良好的渗水性能.在防洪工程中,土工布能够有效地防止水流冲刷导致的土体侵蚀,增强坡面的稳定性.当水由细料土层流入粗料土层时,土工布能让水流通过,同时有效地截留土颗粒,细沙,小石料等,保持水土工程的稳定. 抗微生物性好也是土工布的一大优点.对微生物,虫蛀均不受损害,这使得土工布在长期使用过程中不会因为生物因素而降低性能.在一些特殊的工程环境中,如潮湿的地下工程,长期暴露在自然环境中的堤坝防护工程等,土工布的抗微生物性能够确保其性能的稳定和持久. 施工方便这一特点使得土工布在各类工程中的应用更加便捷.由于材质轻,柔,运输成本低,搬运过程中也更加省力.在铺设施工过程中,布面平整,适当留有变形余量,可根据实际情况进行搭接,缝合和焊接等操作.长丝或短丝土工布的安装通常用搭接,缝合和焊接几种方法,缝合和焊接的宽度一般为 0.1m 以上,搭接宽度一般为 0.2m 以上.可能长期外露的土工布,则应焊接或缝合,以确保其性能的稳定和持久. (二)规格优势 土工布的幅宽可达 9 米,这在国内同类产品中是最宽的规格.如此宽的幅宽能够减少工程施工中的拼接次数,提高施工效率,降低工程成本.同时,单位面积质量在 100 - 1000g/m² 的多种选择,使得工程设计人员可以根据不同的工程需求,选择合适的土工布规格.例如,在一些对强度要求较高的工程中,可以选择单位面积质量较大的土工布;而在一些对成本控制要求较高的工程中,可以选择单位面积质量较小的土工布.这种规格齐全的特点,为各类工程提供了更多的选择空间,满足了不同工程的个性化需求. 四,土工布铺设 (一)铺设前的准备工作 土工布卷在安装展开前要避免受到损坏.土工布卷应该堆放于经平整不积水的地方,堆高不超过四卷的高度,并能看到卷的识别片.土工布卷必须用不透明材料覆盖以防紫外线老化.在储存过程中,要保持标签的完整和资料的完整. (二)运输中的注意事项 在运输过程中(包括现场从材料储存地到工作地的运输),土工布卷必须避免受到损坏.受到物理损坏的土工布卷必须要修复.受严重磨损的土工布不能使用.任何接触到泄漏化学试剂的土工布,不允许使用在本工程上.例如,在运输的过程中,要尽可能保证不让它受到毁坏,也不能让它触碰到一些化学药品,以防止它在运输的中途被腐蚀. (三)铺设方法及连接方式 铺设方法：用人工滚铺;布面要平整,并适当留有变形余量. 连接方式： 所有的缝合必须要连续进行(例如,点缝是不允许的).在重叠之前,土工布必须重叠至少 150mm.小缝针距离织边(材料暴露的边缘)至少是 25mm. 缝好的土工布接缝包括 1 行又线锁口链形缝法.用于缝合的线应为小张力超过 60N 的树脂材料,并有与土工布相当或超出的抗化学腐蚀和抗紫外线能力. 任何在缝好的土工布上的 "漏针" 必须在受到影响的地方重新缝接. 布的搭接根据地形及使用功能可分为自然搭接,缝接或焊接.在湿 (雨,雪) 天气条件下无法进行热粘合的情况下,土工布应采用其他方法 -- 缝纫方法,使用特殊的缝纫机进行双线缝纫和耐化学腐蚀的 UV 缝纫线.热风焊接是长丝土工布的连接方法,它使用热风枪瞬间加热两块布在高温下的连接,使两块布的一部分达到熔融状态,并立即使用一定的外力将它们紧紧地结合在一起.
翻译为 English
I. Introduction to Geotextiles
Geotextiles, as an important type of geosynthetic material, play a crucial role in various engineering projects. They are mainly made of synthetic fibers through the needling or weaving processes and are in the form of fabric after production.
Geotextiles can be divided into woven geotextiles and non-woven filament geotextiles. Woven geotextiles are produced by interweaving at least two sets of yarns in the warp and weft directions. They are relatively thin, usually with thicknesses of 0.2mm, 0.4mm, and 0.7mm. They have relatively strong tensile strength, approximately 250kg/cm², and a relatively large permeability coefficient, about 6.1×10⁻⁴cm/s. Non-woven geotextiles are made by interweaving filaments and short fibers through production processes such as needling with the help of mechanical equipment.
Geotextiles come in various specifications. Generally, their widths range from 4 to 6 meters, and their lengths are from 50 to 100 meters. The maximum width can reach 9 meters, which is the widest product in China. The mass per unit area also has multiple options, ranging from 100g/m² to 1000g/m².
Geotextiles possess numerous excellent properties. They have high strength and can maintain sufficient strength and elongation both in dry and wet conditions. They have excellent corrosion resistance and can resist corrosion for a long time in soils and waters with different acid-base properties. They have good water permeability, and the gaps between the fibers endow them with good water seepage performance. They have good anti-microbial properties and are not damaged by microorganisms or insects. Meanwhile, due to their light and soft materials, they are very convenient for transportation, laying, and construction.
II. Characteristics of Geotextiles
(I) Outstanding Performance
The high strength of geotextiles enables them to maintain stable performance in various engineering environments. For example, in engineering projects such as reinforcement of railway subgrades and maintenance of highway pavements, they can ensure the integrity of the engineering structures even when facing different climatic conditions and external forces. According to relevant data, geotextiles made of plastic fibers can maintain sufficient strength and elongation both in dry and wet conditions. Their strength can reach a certain value, which varies depending on different specifications and production processes. Generally speaking, they can meet the strength requirements of various engineering projects.
Corrosion resistance is another important advantage of geotextiles. Whether in acidic soil or alkaline water environment, geotextiles can remain stable and not be corroded for a long time. In soils and waters with different acid-base properties, the service life of geotextiles can be as long as several years or even longer. This characteristic makes them widely used in fields such as water conservancy engineering and environmental protection engineering. For example, in landfills, geotextiles can isolate harmful substances in the garbage and prevent them from polluting the surrounding soil and groundwater. Even when in a complex chemical environment for a long time, they can still maintain good performance.
Good water permeability is one of the remarkable features of geotextiles. The gaps between the fibers provide good channels for the flow of water, so they have good water seepage performance. In flood control projects, geotextiles can effectively prevent soil erosion caused by water flow scouring and enhance the stability of slopes. When water flows from fine-grained soil layers to coarse-grained soil layers, geotextiles can allow the water to pass through while effectively retaining soil particles, fine sand, small stones, etc., and maintaining the stability of water and soil projects.
Good anti-microbial property is also a major advantage of geotextiles. They are not damaged by microorganisms or insects, which ensures that the performance of geotextiles will not be reduced due to biological factors during long-term use. In some special engineering environments, such as damp underground projects and embankment protection projects that are exposed to the natural environment for a long time, the anti-microbial property of geotextiles can ensure the stability and durability of their performance.
The convenience of construction makes the application of geotextiles in various engineering projects more convenient. Due to their light and soft materials, the transportation cost is low, and it is more labor-saving during the handling process. During the laying and construction process, the fabric surface is flat, and appropriate deformation allowances are reserved. Operations such as overlapping, stitching, and welding can be carried out according to the actual situation. The installation of filament or staple fiber geotextiles usually adopts several methods such as overlapping, stitching, and welding. The width of stitching and welding is generally more than 0.1m, and the overlapping width is generally more than 0.2m. Geotextiles that may be exposed outdoors for a long time should be welded or stitched to ensure the stability and durability of their performance.
(II) Specification Advantages
The width of geotextiles can reach 9 meters, which is the widest specification among similar domestic products. Such a wide width can reduce the number of splicing times in engineering construction, improve construction efficiency, and reduce engineering costs. Meanwhile, the multiple options of mass per unit area ranging from 100 to 1000g/m² enable engineering designers to select appropriate geotextile specifications according to different engineering requirements. For example, in some engineering projects with high strength requirements, geotextiles with a larger mass per unit area can be selected; while in some engineering projects with high requirements for cost control, geotextiles with a smaller mass per unit area can be selected. The characteristic of complete specifications provides more options for various engineering projects and meets the personalized needs of different engineering projects.
IV. Laying of Geotextiles
(I) Preparatory Work Before Laying
Geotextile rolls should be protected from damage before being installed and unrolled. They should be stacked in a flat area without water accumulation, and the stacking height should not exceed the height of four rolls. The identification tags on the rolls should be visible. Geotextile rolls must be covered with opaque materials to prevent ultraviolet aging. During the storage process, the integrity of labels and data should be maintained.
(II) Precautions During Transportation
During transportation (including the transportation from the material storage site to the work site on site), geotextile rolls must be protected from damage. Geotextile rolls that have suffered physical damage must be repaired. Geotextiles with severe abrasion cannot be used. Any geotextiles that have come into contact with leaked chemical reagents are not allowed to be used in this project. For example, during the transportation process, every effort should be made to ensure that they are not damaged and do not come into contact with some chemicals to prevent them from being corroded during transportation.
(III) Laying Methods and Connection Methods
Laying Method: Manual rolling is used for laying; the fabric surface should be flat, and appropriate deformation allowances should be reserved.
Connection Methods:
All stitching must be carried out continuously (for example, spot stitching is not allowed). Before overlapping, geotextiles must overlap by at least 150mm. The distance from the small sewing needle to the fabric edge (the exposed edge of the material) should be at least 25mm.
The sewn seams of geotextiles include a single row of double-lock chain stitch. The thread used for stitching should be a resin material with a small tension exceeding 60N and have anti-chemical corrosion and anti-ultraviolet abilities equivalent to or better than those of geotextiles.
Any "missing stitches" on the sewn geotextiles must be restitched in the affected areas.
The overlapping of the fabric can be divided into natural overlapping, stitching, or welding according to the terrain and usage functions. In wet (rainy, snowy) weather conditions where heat bonding cannot be carried out, geotextiles should adopt other methods - the sewing method, using special sewing machines for double-thread sewing and chemical-resistant UV sewing threads. Hot air welding is a connection method for filament geotextiles. It uses a hot air gun to instantaneously heat the connection of two pieces of fabric at a high temperature, making a part of the two pieces of fabric reach a molten state, and immediately use a certain external force to tightly combine them together.
