建筑-土木工程-外文翻译-外文文献-英文文献及译文-土工织物加筋垫层加固软土地基.doc

Geotextile reinforced by soft soil1. Introduction Geotextile known, it has high tensile strength, durability, corrosion resistance, texture, flexibility, combined with good sand, to form reinforced composite foundation, effectively increase the shear strength , tensile properties, and enhance the integrity and continuity of soil. Strengthening mechanism for the early 60s in the 20th century, Henri Vidal on the use of triaxial tests found a small amount of fiber in the sand, the soil shear strength can improve the image of more than 4 times in recent years, Chinas rock Laboratory workers also proved in the reinforced sand can effectively improve the soils bearing capacity, reduce the vertical ground settlement, effectively overcome the poor soil and continuity of overall poor performance. As with the above properties of reinforced soil and the characteristics of its low price, so the project has broad application prospects. 2.1 Project Overview The proposed retaining wall using rubble retaining wall of gravity, the wall is 6 meters high, the bearing capacity of foundation soil required to 250kPa, while the basement geology from the top down as follows: clay to a thickness of 0.7 to 2 meters saturated, soft plastic; muddy soil, about 22 - 24 meters thick, saturated, mainly plastic flow, local soft plastic; sand layer to a thickness of 5 to 10 meters, containing silty soil and organic matter, saturated, slightly wet; gravel layer, the thickness of the uneven distribution points, about 0 to 2.2 meters, slightly dense; weathered sandstone. Including clay and silty soil bearing capacity is 70kPa, obviously do foundation reinforcement. 2.2 Enhanced Treatment of reinforced foundation cushion Reinforcement replacement method can be used for sand and gravel used for soil treatment, but due to loose bedding, based on past experience, with a gravel mat to treat a large settlement of the foundation always exist, even the characteristics of poor, often resulting in cracks in the superstructure, differential settlement of the image, this works for 6-meter-high rubble retaining walls, height and large, and because the walls are 3 meters high wall, if there is differential settlement of retaining walls, cracks, will result in more serious consequences and thus should be used on the cushion reinforcement through economic and technical analysis, decide on the sand and gravel stratum were reinforced hardening. Reinforcement treatment method: first the design elevation and the basement excavation to 200mm thick layer of gravel bedding, and then capped with a layer of geotextile, and then in the thick sand and gravel on the 200, after leveling with the yellow sand using roller compaction; second with loaded bags of sand and gravel laying of geotextile, the gap filled with slag, geotextile bags capped 100 thick gravel, roller compaction. Its on repeat laying geotextile compacted gravel, until the design thickness of the cushion, the bridge is 1 m thick cushion, a total of 4 layers of geotextile, two bags of sand. This method works fast, simple machine, investment, after years of use, that reinforce good effect, building and construction units are satisfied. 3 Experience To achieve the reinforced soil reinforcement effect, must be reinforced earth construction technology, construction strict quality control: 1, geotextile should increase the initial pre-stress, and its end should be a reliable anchor to play the tensile strength of geotextile, anchoring more firmly, more capacity to improve, the foundation of the stress distribution more uniform, geotextile side Ministry of fixed length by laying end to ensure the fold, the folded end wrapped sand to increase its bond strength to ensure that the use will not be pulled out during the period. Second, the construction process have a significant effect on the reinforcement effect, the construction should be as soon as possible so that geotextile in tension, tensile strength geotextile can be played only when the deformation, so do not allow construction of geotextile crease occurs, the earth Fabric tension leveling as much as possible. Geotextile in order to have enough by the early Dutch strain, according to the following procedure works: laying geotextile; leveled the tension at both ends; both ends of the folded package gravel and sand filling at both ends; center fill sand; 2 higher end of sand; Finally, the center of sand filling. Click here to enable the construction method of forming corrugated geotextile being stretched as soon as possible, to play a role in the early loaded. Third, the construction of geotextile-reinforced cushion should the level of shop using geotextile geotextile and laying of gravel bags cushion the turn to play bag cushion integrated turn out good, flexural rigidity, and dispersion of good and peace bedding layer of the overall continuity of good advantages. 4 Conclusion Geotextile reinforced by soft soil is an effective, economical, safe, reliable, simple method, but the literature describes only qualitative, experience more components, yet the lack of rigorous The theoretical formula, reliable test data to be adequate, these are yet to be theoretical workers and the general engineering and technical personnel continue to explore. 土工织物加筋垫层加固软土地基1. 引言土工织物又称土工聚合物，它具有高抗拉强度，耐久性、耐腐蚀性，质地柔韧，能与砂土很好地结合，组合成加筋土复合地基，有效地提高土的抗剪强度、抗拉性能，增强土体的整体性和连续性。对于其加固机理，早在20世纪60年代，Henri Vidal就用三轴试验发现了在砂土中加入少量纤维后，土体的抗剪强度可提高4倍以上的形象，近年来，我国岩土工作者也在试验室中证明了在砂土中加筋可有效地提高土体的地基承载力，减少地基竖向沉降量，有效地克服土体整体性差及连续性差的性能。由于加筋土具有以上的性能，且其价格低廉的特点，使其在工程中具有广泛的应用前景。2.1工程概况拟建挡土墙采用重力式毛石挡土墙，墙高为6米，要求地基土的承载力为250kPa,而基底的地质情况自上而下为：粘土，厚约0.72米,饱和，软塑；淤泥质土，厚度约2224米，饱和，流塑为主，局部软塑；细砂层，厚约510米，含淤泥质土及有机质，饱和，稍湿；卵石层，厚度分分布不均，约02.2米，稍密；风化中砂岩。其中粘土及淤泥质土承载力为70kPa,显然地基要做加固处理。2.2地基垫层的加筋强化处理加固可采用换填法用砂砾石进行换土处理，但由于垫层的松散性，根据以往经验，用砂石垫层处理的地基时常存在沉降大、均匀性差的特点，往往造成上部结构裂缝、不均匀沉降的形象，本工程为6米高的毛石挡土墙，高度大，又由于墙上有3米高的围墙，如果出现挡土墙不均匀沉降、裂缝，将会造成较为严重的后果，故须对垫层采用加固处理，经过经济技术分析，决定采用对砂砾石垫层进行加筋强化处理。加筋处理的方法为：首先对开挖至基底设计标高并铺一层200mm厚的碎石垫层，然后的其上铺1层土工织物，再在其上200厚砂砾石，用黄砂找平后用压路机压实；第二层用装砂石的土工织物袋铺设，其空隙用矿渣填平，土工袋上铺100厚的碎石，压路机压实。其上再重复铺设土工织物碎石压实，直到垫层的设计厚度，本工程垫层厚为1米，共4层土工织物，两层袋装砂石。此法施工快，机具简单，投资省，经过几年的使用,表明加固效果好，建设及施工单位均十分满意。3几点体会为达到加筋土的加固效果，必须对加筋土施工工艺、施工质量进行严格控制：一、土工织物应预加初期应力，且其端部应有可靠的锚固，以发挥土工织物的抗拉强度，锚固愈牢固，承载力提高愈多，地基中的应力分布愈均匀，土工织物端部的固定，靠端部折起铺设长度来保证，把端部折起包裹砂体，以增加其握裹力，保证使用期间不被拔出。二、施工程序对加筋效果有重大的影响，施工时应让土工织物尽早处于受拉状态，土工织物抗拉强度只有在变形时才得以发挥，所以施工时不允许土工织物发生折皱，把土工织物尽可能拉平拉紧。为了使土工织物在受荷初期有足够的应变，可按下列程序施工：铺土工织物；拉平拉紧两端；两端折起包裹砂砾并两端填砂；中心填砂；两端砂增高；最后，中心填砂。按此方法施工时可使土工织物尽早形成波浪形被拉紧，使其在受荷初期发挥作用。三、土工织物加筋垫层的施工宜采用水平铺土工织物与土工织物碎石袋垫层交替铺设，以综合发挥袋装垫层的搞弯性好、挠曲刚度大、扩散效果好及平铺垫层的整体性的连续性好的优点。4、结束语土工织物加筋垫层加固软土地基是一种行之有效的、经济合理、安全可靠、简单易行的方法，但目前有关文献介绍的仅是定性的、经验的成分较多，尚缺乏严谨的理论计算公式、可靠充分的测试数据来加以说明，这些还有待理论工作者和广大工程技术人员的不断探索。5