简述国外地基处理方法

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国外地基处理发展现状

国外地基处理发展现状

国外地基处理发展现状
地基处理是指对土壤和地基进行改造和加固,以提高地基的稳定性和承载能力。

在国外,地基处理技术得到了广泛应用,并取得了较为显著的成果。

目前,国外地基处理技术主要可分为物理处理、化学处理和生物处理三种类型。

物理处理包括土壤加固、振动加固、加筋加固、挤压加固等方法。

其中,土壤加固主要采用填充、振实和夯实等方式,以提高地基承载能力;振动加固则侧重于利用振动作用使土壤变得更加坚实;加筋加固主要采用钢筋、纤维等材料,以增加土壤的抗拉强度和抗剪强度;挤压加固则采用注浆和压缩空气等方式,以使空隙率降低,土壤变得更加坚实。

化学处理包括灌浆加固、土壤改性、化学浸润等方法。

其中,灌浆加固主要采用水泥、聚氨酯等材料,以填充土壤孔隙,提高土壤的强度和稳定性;土壤改性则是通过加入特定的化学药剂,改变土壤结构和性质,以提高土壤的稳定性;化学浸润则是利用化学反应改变土壤内部结构,使其具有更好的稳定性和强度。

生物处理则是利用生物学技术,如植被修复、微生物增强等方式,改善地基土壤的结构和性质,提高其稳定性和承载能力。

综上所述,国外地基处理技术多种多样,不同的处理方法适用于不同的地质环境和工程需要。

随着科技的不断进步和经验的不断积累,地基处理技术也将不断发展和完善,以更好地满足工程建设的需要。

100930软土地基处理新技术2(强夯)

100930软土地基处理新技术2(强夯)

青岛港8号码头强夯挤淤工程
强夯与强夯置换


Dynamic Consolidation to create “compacted sand raft” to allow slab-on-grade and for infrastructure Dynamic Replacement sand columns to support column loads; increase bearing capacity and reduce settlement
动力置换类型
整式置换
桩式置换
桩式置换
整式置换
动力置换 (Railway track, Malaysia)
桩式置换
动力置换
ALEXANDRIA CITY CENTER (Shopping center - Egypt)
动力置换的应用范围
动力置换的应用范围
3 设计计算
3.1有效加固深度
H——有效加固深度(m) M——夯锤重(t) h——落距(m) α——系数
3.2 夯锤和落距
单击夯击能为夯锤重M与落距h的乘积, 一般说夯击时最好锤重和落距大, 则单击能量大,夯击击数少,夯击遍数也相应减少, 加固效果和技术经济较好。
整个加固场地的总夯击能量(即锤重×落距×总夯击数)
除以加固面积 称为单位夯击能。
加固宽度计算图
3.3 最佳夯击能
在夯击能作用下,地基中出现的孔隙水压力达到土的自重压力 这样的夯击能称为最佳夯击能。
完善,设计工作依赖于施工前的试夯所得数据。
图5-26 强力夯实法
湿软地基加固
梅拉经验公式 H 0.1wh (5-3-1)
式中: H —加固地基的影响深度,m;

国外夯土技术

国外夯土技术

国外夯土技术国外夯土技术(rammed earth)是一种传统建筑技术,通过将土壤、砂石及其他添加剂进行夯实,构建坚固耐用的建筑结构。

这种古老而又现代的建筑技术在许多国家和地区得到了广泛应用,并在各种气候条件下展现出了其独特的环保、节能和可持续发展的优势。

本文将以国外夯土技术为主题,介绍其历史渊源、技术特点、应用范围以及未来发展方向等方面的内容。

一、历史渊源国外夯土技术可以追溯至古代文明时期,在许多古代文明中都有夯土建筑的存在。

在中国,夯土历史可以追溯至唐宋时期的土砖结构。

印度、埃及、希腊等古代文明也都有夯土建筑的遗迹。

夯土技术真正得以发展和传承的地区主要集中在非洲、中东和南美洲等地区。

在这些地区,夯土被广泛应用于建筑、城墙、庙宇等各种建筑类型中,并且一直保持着传统的夯土建筑文化。

直至今日,这些地区仍有许多夯土建筑得以保存,成为当地文化和历史的重要组成部分。

二、技术特点国外夯土技术在坚固耐用、环保节能等方面具有独特的技术特点。

2.1 坚固耐用:夯土建筑由于土壤经过夯实,并在固化后具有相当高的抗压强度,因此夯土建筑具有非常好的抗震、抗风、抗火等特点。

在一些地震频发的地区,夯土建筑成为了人们居住的首选。

2.2 环保节能:夯土技术使用的原材料大多采自当地土壤资源,减少了对其他能源资源的依赖。

夯土建筑在建造过程中不需高温烧制,避免了对大量燃料的消耗,不会产生大量的CO2排放,因此具有很好的环保优势。

2.3 调湿保温:由于夯土的孔隙结构较大,具有很好的调湿性能,使得夯土建筑在夏季能够有效降温,在冬季能够有效保温,减少了对空调和暖气等设备的需求。

三、应用范围国外夯土技术的应用范围非常广泛,不仅仅局限于传统的民居建筑,还涉及到公共建筑、景观建筑、农业设施等多个领域。

3.1 传统民居:在非洲、中东和南美洲等地区,夯土建筑一直是主要的民居建筑形式。

非洲的土耳其式住宅、南美洲的阿德拜式建筑等,都采用了夯土技术。

3.2 公共建筑:除了民居建筑,夯土技术还在一些公共建筑中得到了应用,如教堂、城墙、城堡等。

地基处理实例——比萨斜塔纠偏工程

地基处理实例——比萨斜塔纠偏工程

最新课件
8
方案征集
• 查阅1996 年的文献, 据Prof .Burland 答记 者问时称, 当时斜塔拯救委员会提出的掏土 方案是借鉴墨西哥城天主教堂的纠偏经验, 采用内径150mm 的套管, 以与水平夹角30 度的方向钻入,孔口距塔轴线近20m , 注意 到基础的圆形轮廓, 这种方案对施工场地的 要求很高, 套管细长, 不易操作, 掏土部位及 掏土量也不易掌握。该方案并未付诸实施。
最新课件
12
参考文献
1、刘祖德,叶勇,比萨斜塔的最新动向及纠偏方案探讨,土工基础,2000年3 月,第14卷第1期;
2、徐牧野,苏霄,外国建筑史——比萨斜塔,人民美术出版社,2007年4月第 三版;
3、袁建新,关于比萨斜塔的整治情况,岩土力学,1994年6月,第15卷,第2 期
4、刘祖德,抽土纠偏“扶正”比萨斜塔,岩土力学与工程学报,2002年第六期
地基处理实例 ——比萨斜塔纠偏工程
最新课件
1
斜塔简介
• 比萨斜塔(意大利语:Torre pendente di Pisa或Torre di Pisa)是意大利比萨城大教堂的独立式钟楼,于意大利托 斯卡纳省比萨城北面的奇迹广场上。钟楼始建于1173年, 设计为垂直建造,但是在工程开始后不久(1178年),便 由于地基不均匀沉降和土层松软而倾斜,1372年完工,塔 身倾斜向东南。比萨斜塔是比萨城的标志,1987年它和相 邻的大教堂、洗礼堂、墓园一起因其对11世纪至14世纪意 大利建筑艺术的巨大影响,而被联合国教育科学文化组织 评选为世界遗产。举世闻名的比萨斜塔, 建于公元1173 ~ 1350 年, 历经800 年风雨, 最大沉降量3m , 沉降差达 1 .8m , 塔顶中心偏移已达5 .5m 以上,刚体倾角为 5°30′(1991), 刚体倾斜速率4″~6″/年, 至今尚未稳定。

地基处理方法总结

地基处理方法总结

地基处理方法总结一.强夯法1.强夯法的简单描述强夯法是一种利用重锤(一般100--600kN),在6--40m 高处自由落下,对较厚的松软土层进行强力夯实的方法。

它也称动力固结法2.强夯法的发展历史强夯法起源于法国,是法国Menard 技术公司于首创的一种地基加固方法,它通过一般8~30t 的重锤(最重可达200t)和8~20m 的落距(最高可达40m),对地基土施加很大的冲击能,提高地基土的强度、降低土的压缩性、改善砂土的抗液化条件等。

1969年首先用于法国戛纳附近芒德利厄海边20来幢八层楼居住建筑的地基加固工程,之后在国外迅速得到推广应用。

我国于1978年首次由交通部一航局科研所及其协作单位在天津塘沽新港三号公路进行了强夯法试验研究,并获得成功。

自引进到80年代初,约8年。

本阶段工程应用强夯能级比较小,一般仅为1000kN*m ,处理深度5m 左右,以处理浅层人工填土为主。

80年代初到90年代初。

本阶段兴建国家重点工程山西化肥厂,为了消除黄土地基的湿陷性,国家化工部组织开发了6250kN*m 能级强夯,使有效处理深度提高到了10m 左右。

90年代初到2002年,本阶段以兴建国家重点工程三门峡火力发电厂为契机,成功开发了8000kN*m 能级强夯,使强夯消除黄土湿陷性的深度达到15m 。

2002年底至今,强夯工程最高应用能级已经达到10000kN*m 。

为了更进一步扩大强夯的应用范围,在强夯技术的基础上,还形成了强夯置换和柱锤冲扩等新技术 。

目前,国内所用的单击能为50-8000kn.m ,多数应用100-200kN.m 。

3.强夯法的加固机理强夯法利用重夯锤,高落距产生的高夯击能给地基一冲击力,在地基中长生冲击波,振密,挤密地基土体。

当夯击时,夯锤对地基浅部土体进行冲切,土体结构破坏,形成夯坑,并对夯坑周围的土体进行动力挤压,夯坑四周地表可能产生隆起。

多孔隙、粗颗粒、非饱和土多采用动力加固,动力加固的主要机理是冲击型动力荷载使土体中的孔隙减小,土体变得密实,从而提高地基土强度。

土木工程毕业外文翻译---软土路基处理方法概述

土木工程毕业外文翻译---软土路基处理方法概述

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 thethree-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 containing Water 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 isgenerally 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 Ф7cm 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。

强夯国内外研究现状12.24

强夯国内外研究现状12.24
目前国内外关于强夯法加固地基土的机理,尚未形成统一的认识[5]。强夯加 固理论主要体现在强夯对地基土的作用机理及动力学特征和孔隙水压力变化规 律方面。
1975年,L.Menard发表了“动力固结法的理论与实践”。他根据强夯法应用 于饱和粘性土时夯击瞬间就发生数十厘米沉降的现象,分析了夯击过程中土体强 度的增长、夯击能的传递、孔隙水的变化和强夯的时间效应等,但对渗透系数的 变化和触变机理未作深入的探讨,只做了宏观的解释[6]。
梅纳根据饱和粘性土经受强夯后产生数十厘米间变形的现象提出了新的动 力固结理论。并以此理论还提出动力固结模型。但是,他只对新的动力固结理论 做了宏观的解释,此模型只具有定性描述的意义[7]。
1984年,Gambin[8]在第八界非洲地区土力学与基础工程会议上,发表了“十
批注 [l1]: 现状包括强夯加固地基研 究现状和强夯室内模型试验研究现 状两个部分,缺少室内模型试验部分。
郑颖人[12]等将其分为四个阶段:夯击能转换与夯坑受冲剪阶段,土体液化 或破坏阶段,固结压密阶段和触变恢复阶段。并在此基础上提出了适用于软粘土 地基的强夯工艺。
批注 [l4]: 仅仅简单的罗列,无总结 性,修改为“在**研究方面,哪些人 做了哪些相关工作”不要一个人一个 人的简单罗列。
批注 [l5]: 仅仅是简单的罗列,某个 人认为怎么样,没有总结!
[10] Leon.F.J..Dynamic pre-compaction Treatment-A Case History International Symposium on Case
Historied in Geotechnical Engineering.1981 [11] 肖衡林,余天庆. 山区挡土墙土压力的现场试验研究[J].岩土力学,2009,30(12):3771-3778. [12] 郑颖人,李学志,冯遗兴等. 软粘土地基的强夯机理及其工艺研究[J].岩土力学与工程学报,

国外软土基础处理Franki桩基介绍

国外软土基础处理Franki桩基介绍

国外软土基础处理Franki桩基介绍摘要:委内瑞拉卡夫雷拉电厂项目是我公司在中南美洲施工的一个燃油燃气发电项目,项目坐落于瓦伦西亚湖畔,基础松软,基础处理是项目的一个重要部分,该项目基础处理业主当地化的法国公司Franki公司进行1100多跟桩的基础处理工作,该公司是专业的基础处理公司,拥有多台专业基础处理设备,并且该公司在基础处理设备和该基础处理方法享有专利权,该基础处理设备命名为Franki成套基础处理设备,该桩型命名为Franki桩,这儿简单介绍一下该基础处理的施工方法。

Abstract: venezuela kraft ray pull power plant project is my company in south of the construction of a fuel gas power project, the project is located in valencia lake, soft foundation, foundation treatment is an important part of the project, the project owners of localization based processing French company Franki company with more than 1100 of the pile foundation processing, this company is specialized in the foundation processing company, with more than a professional foundation treatment equipment, and the company in the basic processing equipment and the foundation treatment enjoy the patent right, the foundation treatment equipment named Franki complete sets of foundation treatment equipment, this pile type named Franki pile, brief introduction of the basic here with the construction methods.1. 定义Franki桩学名为压力贯入式基础(Pressure Injected Footing 简称PIF)包含一个通过夯击零塌落度的砼进入土壤的扩大基础和一个设计好去传递上部结构荷载到扩大基础的砼或者钢筋砼传力桩。

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国外地基处理方法总结
【摘要】:对目前使用过的各种地基处理方法作了全面的概括和分析,对各种地基处理方法的原理和适用场合做了简单的介绍,为地质条件不好或软弱地基处理方法的选择提供了依据。

【关键词】:地基处理、软地基、湿陷性黄土地基
一:常用的地基处理方法
1、换填垫层法
适用于浅层软弱地基及不均匀地基的处理。

其主要作用是提高地基承载力,减少沉降量,加速软弱土层的排水固结,防止冻胀和消除膨胀土的胀缩。

2、强夯法
适用于处理碎石土、砂土、低饱和度的粉土与粘性土、湿陷性黄土、杂填土和素填土等地基。

3、强夯置换法
适用于高饱和度的粉土,软-流塑的粘性土等地基上对变形控制不严的工程,在设计前必须通过现场试验确定其适用性和处理效果。

强夯法和强夯置换法主要用来提高土的强度,减少压缩性,改善土体抵抗振动液化能力和消除土的湿陷性。

对饱和粘性土宜结合堆载预压法和垂直排水法使用。

4、砂石桩法
适用于挤密松散砂土、粉土、粘性土、素填土、杂填土等地基,提高地基的承载力和降低压缩性,也可用于处理可液化地基。

对饱和粘土地基上变形控制不严的工程也可采用砂石桩置换处理,使砂石桩与软粘土构成复合地基,加速软土的排水固结,提高地基承载力。

5、振冲法
分加填料和不加填料两种。

加填料的通常称为振冲碎石桩法。

振冲法适用于处理砂土、粉土、粉质粘土、素填土和杂填土等地基。

对于处理不排水抗剪强度不小于20kPa的粘性土和饱和黄土地基,应在施工前通过现场试验确定其适用性。

不加填料振冲加密适用于处理粘粒含量不大于10%
的中、粗砂地基。

振冲碎石桩主要用来提高地基承载力,减少地基沉降量,还可用来提高土坡的抗滑稳定性或提高土体的抗剪强度。

6、水泥土搅拌法
分为浆液深层搅拌法(简称湿法)和粉体喷搅法(简称干法)。

水泥土搅拌法适用于处理正常固结的淤泥与淤泥质土、粘性土、粉土、饱和黄土、素填土以及无流动地下水的饱和松散砂土等地基。

不宜用于处理泥炭土、塑性指数大于25的粘土、地下水具有腐蚀性以及有机质含量较高的地基。

若需采用时必须通过试验确定其适用性。

当地基的天然含水量小于30%(黄土含水量小于25%)、大于70%或地下水的pH值小于4时不宜采用于法。

连续搭接的水泥搅拌桩可作为基坑的止水帷幕,受其搅拌能力的限制,该法在地基承载力大于140kPa的粘性土和粉土地基中的应用有一定难度。

7、高压喷射注浆法
适用于处理淤泥、淤泥质土、粘性土、粉土、砂土、人工填土和碎石土地基。

当地基中含有较多的大粒径块石、大量植物根茎或较高的有机质时,应根据现场试验结果确定其适用性。

对地下水流速度过大、喷射浆液无法在注浆套管周围凝固等情况不宜采用。

高压旋喷桩的处理深度较大,除地基加固外,也可作为深基坑或大坝的止水帷幕,目前最大处理深度已超过30m。

8、预压法
适用于处理淤泥、淤泥质土、冲填土等饱和粘性土地基。

按预压方法分为堆载预压法及真空预压法。

堆载预压分塑料排水带或砂井地基堆载预压和天然地基堆载预压。

当软土层厚度小于4m时,可采用天然地基堆载预压法处理,当软土层厚度超过4m时,应采用塑料排水带、砂井等竖向排水预压法处理。

对真空预压工程,必须在地基内设置排水竖井。

预压法主要用来解决地基的沉降及稳定问题。

9、夯实水泥土桩法
适用于处理地下水位以上的粉土、素填土、杂填土、粘性土等地基。

该法施工周期短、造价低、施工文明、造价容易控制,目前在北京、河北等地的旧城区危改小区工程中得到不少成功的应用。

10、水泥粉煤灰碎石桩(CFG桩)法
适用于处理粘性土、粉土、砂土和已自重固结的素填土等地基。

对淤泥质土应根据地区经验或现场试验确定其适用性。

基础和桩顶之间需设置一定厚度的褥垫层,保证桩、土共同承担荷载形成复合地基。

该法适用于条基、独立基础、箱基、筏基,可用来提高地基承载力和减少变形。

对可液化地基,可采用碎石桩和水泥粉煤灰碎石桩多桩型复合地基,达到消除地基土的液化和提高承载力的目的。

11、石灰桩法
适用于处理饱和粘性土、淤泥、淤泥质土、杂填土和素填土等地基。

用于地下水位以上的土层时,可采取减少生石灰用量和增加掺合料含水量的办法提高桩身强度。

该法不适用于地下水下的砂类土。

12、柱锤冲扩桩法
适用于处理杂填土、粉土、粘性土、素填土和黄土等地基,对地下水位以下的饱和松软土层,应通过现场试验确定其适用性。

地基处理深度不宜超过6m。

13、单液硅化法和碱液法、
适用于处理地下水位以上渗透系数为0.1~2m/d的湿陷性黄土等地基。

在自重湿陷性黄土场地,对Ⅱ级湿陷性地基,应通过试验确定碱液法的适用性。

二:软弱地基处理方法
1、排水固结法
排水固结法又称预压法,其包括堆载预压法、超载预压法、真空预压法、真空与堆载联合作用法、降低地下水位法和电渗法等多种方法;通过在预压荷载作用下使软粘土地基土体中孔隙水排出,土体发生固结,土中孔隙体积减小,土体强度提高,达到减少地基施工后沉降和提高地基承载力的目的。

2、振密、挤密法
振密、挤密法有表层原位压实法、强夯法、振冲密实法、挤密密实法、爆破挤密法和土桩、灰土桩等多种方法;采用一定措施,通过振动和挤密使深层土密实,使地基土孔隙比减小,强度提高。

3、置换及拌入法
置换及拌入法有换填垫层法、振冲置换法、高压喷射浆法、深层搅拌法、褥垫法等多种方法;采用砂、碎石等材料置换软弱土地基中部分软弱土体或在部分软弱土地基中掺入水泥、石灰或砂浆等形成加固体,与未被加固部分的土体一起形成复合地基,从而达到提高地基承载力减少沉降量的目的。

4、加筋法
加筋法有加筋土法、锚固法、树根桩法、低强度砼桩复合地基法、钢筋砼桩复合地基法等多种方法。

通过在土层埋设强度较大的土工聚合物、拉筋、受力杆件等达到提高地基承载力,减小沉降,维持建筑物稳定
三:湿陷性黄土地基
1、孔内深层强夯法(DDC)
孔内深层强夯法(DDC)技术与其它技术不同之处:是通过孔道将强夯引
入到地基深处,用异型重锤对孔内填料自下而上分层进行高动能、超压强、强挤密的孔内深层强夯作业,使孔内的填料沿竖向深层压密固结的同时对
桩周土进行横向的强力挤密加固,针对不同的土质,采用不同的工艺,使
桩体获得串珠状、扩大头和托盘状,有利于桩与桩间土的紧密咬合,增大
相互之间的摩阻力,地基处理后整体刚度均匀,承载力可提高2~9倍;变形模量高,沉降变形小,不受地下水影响,地基处理深度可达30米以上。

孔内深层强夯法(DDC)技术适用范围广,可适用于大厚度杂填土、湿陷
性黄土、软弱土、液化土、风化岩、膨胀土、红粘土以及具有地下人防工事、岩溶土洞、硬夹层软硬不均等各种复杂疑难的地基处理。

该技术可根
据不同的地质情况和设计要求,就地取材,大幅度降低工程造价,施工质
量容易控制、地面振动小、施工噪音低、施工速度快;成桩直径0.6~3.0m,单桩处理面积1.0~14.0㎡,不受季节限制,同时能消纳大量建筑垃圾,
可在城区或危房改造居民区施工等特点。

2、灰土挤密桩法和土挤密桩法
适用于处理地下水位以上的湿陷性黄土、素填土和杂填土等地基,可
处理的深度为5~15m。

当用来消除地基土的湿陷性时,宜采用土挤密桩法;当用来提高地基土的承载力或增强其水稳定性时,宜采用灰土挤密桩法;
当地基土的含水量大于24%、饱和度大于65%时,不宜采用这种方法。

灰土挤密桩法和土挤密桩法在消除土的湿陷性和减少渗透性方面效果基本相同,土挤密桩法地基的承载力和水稳定性不及灰土挤密桩法。

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