【DOC】-土木工程毕业外文翻译---软土路基处理方法概述-建筑结构.doc

【精品文档】如有侵权，请联系网站删除，仅供学习与交流【DOC】-土木工程毕业外文翻译-软土路基处理方法概述-建筑结构.精品文档.Overview of Soft Subgrade TreatmentAbstract: The reinforcement of soft soil roadbed There are many ways, several to explain the reinforcement mechanism of the role, scope, and individual project example elaboration. New reinforcement materials and new technology development and utilization of soft subgrade reinforcement played an important role to do with the simple description.When road works are often encountered in soft soil subgrade, the carrying capacity of the foundation have become increasingly demanding due to the development of highway, railway, natural soft ground is far from meeting these high-grade structures are the foundation bearing force requirements. 1980s and 1990s, due to population expansion of land resources are becoming increasingly tense, soft soil subgrade reinforcement technology has made great progress, and economic conditions have improved, a variety of soft soil reinforcement theory has been fully Application and verification of soft base reinforcement technology has made rapid progress in different areas are covered; to the 1990s, a variety of soft foundation treatment technology has been widely used in various road projects.Foundation in soft soil, usually in soft new moon or under the state of the flow of new moon of the clay. Which is characterized by the natural water content, void ratio, compressibility factor, low strength and creep, thixotropy, and other special engineering geological properties, poor engineering geological conditions. Selection of soft soil roadbed application must be put forward practical measures.Soil, such as in the construction of the base of the embankment or bridge and culvert structures, optimum moisture content is not easy to grasp, is extremely difficult to achieve the required degree of compaction can not meet the density requirements after the opening, often a roadbed instability or excessive settlement. Its obvious dangers, therefore prohibiting the use.Construction of embankment on soft ground, especially Bridge Approach, if not take effective measures for the reinforcement, it will have varying degrees of collapse slip or subsidence, resulting in road damage or is not working is known as the Bump. In general, in addition to ensure that the new subgrade Using density to reduce the settlement In addition, the total settlements of the foundations of the original ground must meet the basic stability of the settlement roughly more than 80% of the total settlement amount, to allow resurfacing. Serious settlement of soft ground, not only to increase the amount of fill, and subsidence or horizontal displacement of the bridge near the filling, retaining walls, culverts, and even the technical standards of the nearby residential, farmland, and the route will have a huge impact .To this end, according to the engineering properties of foundation soil, the selection of appropriate measures to deal with. After a long practice, the formation of roads, railways, various forms of soft ground, combined with a lot of construction companies many years of experience in construction and related experts and scholars discussed summarized as follows:A replacement cushion methodWhen the thickness of the soft soil, soft soil below the subgrade surface within part or all of the excavation, then change to fill the greater intensity of soil or other stability, non-erosive materials (usually good water permeability in coarse sand) called Replacement Cushioning. This economical and practical method to deal with the height of 2 to 3m, if the thickness of the soft soil is too large, then using the replacement method will increase the disposable side and dug side content and increase the cost of the project.Replacement higher shear strength of soil, so as to achieve the goal of enhanced foundation bearing capacity to meet the requirements of the structures on the foundation.Reinforcement Method Replacement, Stone Fill, cushion, COMPACTED silt several. Cushioning according to the different materials can be divided into the sand (gravel) cushion, gravel pads, fly ash cushion, the cushion of dry residue, soil (dust, ash) cushion. Representatives of sand cushion method and replacement method.Gravel cushion: when the embankment height is less than 2 times the limit height, soft soil layer is thin, the filling material is more difficult, or rainy season, construction, gravel (sand) cushion between the fill and the basement to set up a drainage face, so that the foundation by filling load in the foundation soil pore water discharge speed to accelerate the consolidation to improve the bearing capacity of foundations, reduce sedimentation, to prevent the foundation of local shear deformation. Pay attention to controlling the filling speed, the materials used to clean coarse sand with mud is not more than 5%, or maximum particle size less than 5cm natural gradation gravel. Replacement Method: water permeability material (gravel or crushed stone) in the soft soil thickness is not greater than 2m, filling replacement can reduce the compression to increase bearing capacity, shear strength, and reduce the settlement to improve the dynamic characteristics accelerate soil consolidation by drainage. It is characterized by the construction process is simple, but the cost is relatively high.Stone Fill: When the soft soil or marsh soil located underwater, replace the soil construction difficulties, and the thickness is less than 3m, the surface without a hard shell, the substrate water content over liquid limit, embankment above the weight of the soft soil that can be squeezed out, drainage more difficult when using cast stone tablets (diameter generally less than 30cm) to squeeze the deposition method. Start from the middle of the rubble, gradually extending to the sides, out of mud, to improve the subgrade strength.2 deep compactionThe use of blasting, compacting, extrusion and vibration and join the high shear strength of materials, etc., the foundation of deep soft soil density vibration and compaction of the foundation reinforcement method is called deep compaction. For soft soil thickness> 3m thick soft soil reinforcement, distribution of a wide area of soft Reinforcement processing, has consolidated its depth is up to 30m.Vibration, squeezing ground Turkey body dense consolidation, and added with high shear strength of the pile material replacement of part of the soft soil of the three-phase (gas, liquid and solid phase) portion to form a composite foundation, to improve the shear strength of purpose.Main reinforcement methods: dynamic compaction, soil (or dust, fly ash plus lime) piles, sand piles, blasting, gravel pile (vibration and substitution method), lime piles, cement, fly ash gravel pile pile (CFG), the DJM France, jet grouting piles. On behalf of rubble piles, dynamic compaction, cement and fly ash gravel piles, DJM France.The dynamic compaction method can be used to hammer compaction or dynamic compaction: sand foundation and the water content in a range of soft clay foundation. Its basic principle is: the soil under the huge impact in the soil to produce a lot of pressure and shock wave, resulting in the soil of local compression, tamping points around within a certain depth to produce the fissures good drainage channel, so that the soil pore water (gas) discharged smoothly, the rapid consolidation of soil. Dynamic compaction, foundation bearing capacity can be increased 3-4 times, compression can be reduced from 200% to 1000%. Good ram is able to hit: In theory, the best tamping can function in the foundation soil pore water pressure reaches the soil weight pressure, such tamping energy known as the best tamping energy. Therefore, according to the superposition of the pore water pressure value to determine the best tamping energy. In sandy soil, the growth and dissipation of pore water pressure of only a few minutes, the pore water pressure can not be with the tamping can increase and overlay, the maximum pore water pressure increment and the number of tamping relations to determine the best tamping can. Sea highway landslide accumulation of broken mudstone deposits thickness of 4 12M from the soil samples of the soil test report shows that for low liquid limit clay containingWater 29.8 to 20.2, the cohesiveness 13.8 12.2KPA internal friction angle of 13.8 20.2.Sand compaction piles, rubble pile reinforcement method: a kind of composite foundation, thick soft soil replacement to handle the more difficult, the foundation soil is unsaturated cohesive soil or sand, sand compaction piles or broken Shizhuang reinforcement method, the foundation soil compacting bulk density increased, pores less than to prevent liquefaction of sand in the earthquake or by vibration and improve the foundation soil shear strength and the level of resistance, reducing the consolidation settlement, so that the foundation to change uniform , play replacement, compaction, drainage and to prevent the foundation to produce sliding failure, completed ahead of the settlement to reduce the differential settlement.3 drainage consolidation methodPressure on the soft ground and in line with internal drainage, accelerate the drainage of the soft ground, speed up the processing of soft soil consolidation known as drainage consolidation method. For saturated cohesive soil foundation in handling all types of mud, silt clay and red fill.Soft ground in the role of the additional load is gradually passed to the pore water, the void ratio decreases, resulting in consolidation deformation. In this process, with the gradual diffusion of excess pore water pressure in soil, soil effective stress, and settlement in advance or improve the settling velocity.Reinforcement methods: heap preloading method sand wells France, packed sand, vacuum preloading method, electro-osmosis water method, dewatering method, plastic drainage plate method.Preloading: divided into the surcharge preloading, set Preloading and less preloading, the construction process is simple, but a longer duration, surcharge preloading time is generally six months, usually used in conjunction with wastewater treatment foundation . New kiln South Road, Guangzhou City, road works is to use a heap load reinforcement of soft soil roadbed. New kiln South Road road works starting point for Guangzhou Avenue K4, +600, and finish at North Village K11, to +700, total length of about 7KM road along the stratigraphic architecture were as follows: the crust hard shell loose, miscellaneous fill, fill factors, and soft plastic like cultivated soil, thickness of 0.40 to 2.20; soft layers including the flow of plastic-like silt and silty soil, thickness of 1.51 9.39, along thickness variation; underlying layer of cohesive soil and sand heap preloading time from 1995 to 2003, about 7 to 8 years.Packed sand: soft soil subgrade for soft soil thickness, embankment stability, high filling, packed sand, increase the soft soil the vertical drainage capacity, shorten the horizontal direction of the drainage distance, accelerate the soft soil strength. Sand bags poured into the sand, sand wells can be used to hammering or vibration method of construction. Complexity of its construction process, the relatively high cost, used for a long time, can be rectangular or plum-shaped cloth pile. Geological Survey of the Pearl River area of a city road show that the foundation soil is more evenly distributed, surface 0m about Cultivate soil, then a 8.6m thick high water content, high compression, low-intensity, high content of viscous super-weak sludge. The third layer is thick and 1.0m shell powder sand; the fourth floor and 7.6m thick silty clay; 0.5m thick clay and 3.0m thick silty sand. Down for the blow count (SPT) is greater than 19 hit pebbly coarse sand layer, and then down the soil better. The foundation soil is about 20m deep mud, up to 85.7% moisture content, vane shear strength is only 4Kpa and silt distribution depth of roughly inclined by the former direction of the rear land, the former light after the dark, in front of a relatively favorable. Roads need such a large area of very soft silt foundations for the deep processing of soft foundation to prevent the construction of soft foundation settlement is slow, cause there is still a large residual settlement after the completion of the project, at the same time not cause damage to the foundation instability due to load . This area due to improper soft foundation engineering quality or safety incidents is more common, the design 7cm packed sand plus sand cushion heap load Preload soft Reinforcement by playing set the sand well Second, after the consolidation of the four-story mud soil drainage, the soil strength improved, reducing the settlement after the project put into operation, to ensure the normal use of the project to meet project design requirements.Plastic Drainage Board: Drainage Principles and packed sand factory production, its quality is stable, light weight, easy transportation and storage, construction techniques are relatively simple, less investment in labor, relatively low cost, and percolation water absorption , has a certain strength and elongation, soil disturbance is small, preloading a long time, been widely used in engineering, but improve the soil's shear capacity than packed sand.软土路基处理方法概述摘要：软土路基的加固有很多种方法，本文对常用的几种方法从加以解释对其加固机理,作用,作用范围以及个别的工程实例的阐述.新型的加固材料以及新工艺的开发和利用对提高软土路基的加固技术水平所起的重要作用等做以简单的阐述.在道路工程中经常会遇到软土路基，由于高速公路、高速铁路的发展，对地基的承载能力要求越来越高，天然的软土地基远远不能满足这些高档次的构造物对地基承载力的要求。20世纪8090年代，由于人口膨胀土地资源日益紧张，同时软土路基加固的技术也有了长足的发展，经济条件有所改善，各种软土加固理论得到了充分的应用与验证，软基加固技术也得到长足发展，在不同的领域里均有涉猎；到20世纪90年代以后,各种各样的软基处理技术已广泛地应用在各种道路工程中。地基中常见的软土，一般是指处于软朔或者流朔状态下的粘性土。其特点是天然含水量大、孔隙比大、压缩系数高、强度低，并具有蠕变性、触变性等特殊的工程地质性质，工程地质条件较差。选用软土作为路基应用，必须提出切实可行的技术措施。这种土质如在施工中出现在路基填土或桥涵构造物基础中，最佳含水量不易把握，极难达到规定的压实度值，满足不了相应的密实度要求，在通车后，往往会发生路基失稳或过量沉陷。其危害性显而易见,故禁止采用。在软土地基上修筑路堤，特别是桥头引道，如不采取有效的加固措施，就会产生不同程度的坍滑或沉陷，导致公路破坏或不能正常使用即所说的桥头跳车。    一般地，除要确保新填筑路基的密实度以减少沉降外，包括原地面的地基总沉降必须达到基本稳定，沉降量大致达到总沉降量的80%以上时，才容许铺路面。软土地基沉降严重时，不仅增加填方数量，而且沉降或水平位移对临近填土的桥台、挡土墙、涵洞，甚至对附近的住宅、农田以及路线的技术标准都会产生很大的影响。为此，根据地基土的工程特性，选用适当的处理措施。经过长期的实践，在公路、铁路中形成了多种形式的软土地基处理方法，结合很多的施工企业多年施工经验及有关专家学者的论述进行总结归纳如下：1 换填垫层法当软弱土层厚度不很大时，可将路基面以下处理范围内的软弱土层部分或全部挖除，然后换填强度较大的土或其它稳定性能好、无侵蚀性的材料(通常是渗水性好的中粗砂)称为换填或垫层法。此法处理的经济实用高度为23m，如果软弱土层厚度过大，则采用换填法会增加弃方与取土方量而增大工程成本。通过换填具有较高抗剪强度的地基土，从而达到增强地基承载力的目的，满足构筑物对地基的要求。主要加固方法有换填、抛石挤淤、垫层、强夯挤淤几种。垫层法根据材料的不同可分为砂(砾石)垫层、碎石垫层、粉煤灰垫层、干渣垫层、土(灰土、二灰)垫层。代表方法有砂垫层法及换填法。砂砾垫层：当路堤高度小于极限高度的2倍，软土层较薄，填筑材料比较困难，或雨季施工时，采用砂砾(砂)垫层，在填土与基底之间设一排水面，从而使地基在受到填土荷载后，迅速地将地基土中的孔隙水排出，加快固结速度，提高地基的承载力，减少沉降，防止地基局部剪切变形。要注意控制填土速度，所用的材料为含泥量不大于5%的洁净中粗砂，或最大粒径小于5cm的天然级配砂砾。    换填法：在软土厚度不大于2m 时，利用渗水性材料(砂砾或碎石)进行置换填土，可以降低压缩性，提高承载力，提高抗剪强度，减少沉降量，改善动力特性，加速土层的排水固结。它的特点是施工工艺简单，但费用比较高。抛石挤淤：当软土或沼泽土位于水下，更换土施工困难，且厚度小于3m，表层无硬壳、基底含水量超过液限、路堤自重可以挤出的软土之上，排水比较困难时，采用抛片石(直径