不良地基土及处理方法中英对照

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1、不良地基土与地基处理方法 摘 要:地基基础工程对于高层建筑的安全及使用至关重要其造价高、工期长。科学合理地选择地基处理方式对于现代土木工程建设有着重要的意义。 关键词:地基土地基地基处理1. 常见不良地基土及其特点1.软粘土 软粘土也称软土，是软弱粘性土的简称。它形成于第四纪晚期，属于海相、泻湖相、河谷相、湖沼相、溺谷相、三角洲相等的粘性沉积物或河流冲积物。多分布于沿海、河流中下游或湖泊附近地区。常见的软弱粘性土是淤泥和淤泥质土。软土的物理力学性质包括如下几个方面：（1）物理性质 高粘粒含量、高含水量、大孔隙比，因而其力学性质也就呈现与之对应的特点-低强度、高压缩性、低渗透性、高灵敏度（2）力

2、学性质 软粘土的强度极低 软粘土的压缩性很大 渗透系数很小3工程特性 软粘土地基承载力低，强度增长缓慢；加荷后易变形且不均匀；变形速率大且稳定时间长；具有渗透性小、触变性及流变性大的特点。常用的地基处理方法有预压法、置换法、搅拌法等。1.2 杂填土 杂填土主要出现在一些老的居民区和工矿区内，是人们的生活和生产活动所遗留或堆放的垃圾土。这些垃圾土一般分为三类：即建筑垃圾土、生活垃圾土和工业生产垃圾土。 杂填土的主要特点是无规划堆积、成分复杂、性质各异、厚薄不均、规律性差。因而同一场地表现为压缩性和强度的明显差异，极易造成不均匀沉降，通常都需要进行地基处理。1.3 冲填土 冲填土是人为的用水力冲填

3、方式而沉积的土。近年来多用于沿海滩涂开发及河漫滩造地。冲填土地基一般具有如下一些重要特点。 颗粒沉积分选性明显同时在深度方向上存在明显的层理。2 冲填土的含水量较高，一般大于液限，呈流动状态。3 冲填土地基早期强度很低，压缩性较高1.4 饱和松散砂土 粉砂或细砂地基在静荷载作用下常具有较高的强度。但是当振动荷载地震、机械振 动等作用时，饱和松散砂土地基则有可能产生液化或大量震陷变形，甚至丧失承载力。常用的处理方法有挤出法、振冲法等。1.5 湿陷性黄土 在上覆土层自重应力作用下，或者在自重应力和附加应力共同作用下，因浸水后土的结构破坏而发生显著附加变形的土称为湿陷性土 在湿陷性黄土地基上进行工程

4、建设时，必须考虑因地基湿陷引起附加沉降对工程可能造成的危害，选择适宜的地基处理方法，避免或消除地基的湿陷或因少量湿陷所造成的危害。1.6 膨胀土 膨胀土的矿物成分圭要是蒙脱石，它具有很强的亲水性，吸水时体积膨胀，失水时体积收缩。这种胀缩变形肚往很大，极易对建筑物造成损坏。 常用的地基处理方法有换土、土性改良、预浸水，以及防止地基土含水量变化等工程措施。1.7 含有机质土和泥炭土 当土中含有不同的有机质时，将形成不同的有机质土，在有机质含量超过一定含量时就形成泥炭土，它具有不同的工程特性，有机质的含量越高，对土质的影响越大，主要表现为强度低、压缩性大，并且对不同工程材料的掺入有不同影响等，对直接

5、工程建设或地基处理构成不利的影响。1.8 山区地基土 山区地基土的地质条件较为复杂，主要表现在地基的不均匀性和场地稳定性两个方面。由于自然环境和地基土的生成条件影响，场地中可能存在大孤石，场地环境也可能存在滑坡、泥石流、边坡崩塌等不良地质现象1.9 岩溶喀斯特 在岩溶喀斯特地区常存在溶洞或土洞、溶沟、溶隙、洼地等。地下水的冲蚀或潜蚀使其形成和发展，它们对结构物的影响很大，易于出现地基不均匀变形、崩塌和陷落。第 2 节 地基处理方法2.1 置换法1换填法 就是将表层不良地基土挖除，然后回填有较好压密特性的土进行压实或夯实，形成良好的持力层。从而改变地基的承载力特性，提高抗变形和稳定能力。2振冲置

6、换法 利用专门的振冲机具，在高压水射流下边振边冲，在地基中成孔，再在孔中分批填入碎石或卵石等粗粒料形成桩体。该桩体与原地基土组成复合地基，达到提高地基承载力减小压缩性的目的。3夯挤置换法 利用沉管或夯锤的办法将管锤置入土中，使土体向侧边挤开，并在管内或夯坑放人碎石或砂等填料。该桩体与原地基土组成复合地基，由于挤、夯使土体侧向挤压，地面隆起，土体超静孔隙水压力提高，当超静孔隙水压力消散后土体强度也有相应的提高。2.2 预压法1堆载预压法 在建造建筑物之前，用临时堆载砂石料、土料、其他建筑材料、货物等的方法对地基施加荷载，给予一定的预压期。使地基预先压缩完成大部分沉降并使地基承载力得到提高后，卸除

7、荷载再建造建筑物。2真空预压法 在软粘土地基表面铺设砂垫层，用土工薄膜覆盖且周围密封。用真空泵对砂垫层抽气，使薄膜下的地基形成负压。随着地基中气和水的抽出，地基土得到固结。为了加速固结，也可采用打砂井或插塑料排水板的方法，即在铺设砂垫层和土工薄膜之前打砂井或插排水板，达到缩短排水距离的目的。3降水法 降低地下水位可减少地基的孔隙水压力增加上覆土自重应力，使有效应力增加，从而使地基得到预压。这实际上是通过降低地下水位，靠地基土自重来实现预压目的。4电渗法 在地基中插入金属电极并通以直流电，在直流电场作用下，土中水将从阳极流向阴极形成电渗。不让水在阳极补充而从阴极的井点用真空抽水，这样就使地下水位

8、降低，土中含水量减少。从而地基得到固结压密，强度提高。电渗法还可以配合堆载预压用于加速饱和粘性土地基的固结。2.3 压实与夯实法（1）表层压实法 采用人工夯，低能夯实机械、碾压或振动碾压机械对比较疏松的表层土进行压实。也可对分层填筑土进行压实。当表层土含水量较高时或填筑土层含水量较高时可分层铺垫石灰、水泥进行压实，使土体得到加固。（2）重锤夯实法 重锤夯实就是利用重锤自由下落所产生的较大夯击能来夯实浅层地基，使其表面形成一层较为均匀的硬壳层，获得一定厚度的持力层。（3）强夯 强夯是强力夯实的简称。将很重的锤从高处自由下落，对地基施加很高的冲击能，反复多次夯击地面，地基土中的颗粒结构发生调整，土

9、体变为密实，从而能较大限度提高地基强度和降低压缩性。2.4 挤密法（1）振冲密实法 利用专门的振冲器械产生的重复水平振动和侧向挤压作用，使土体的结构逐步破坏，孔隙水压力迅速增大。由于结构破坏，土粒有可能向低势能位置转移，这样土体由松变密。（2）沉管砂石桩碎石桩、灰土桩、OG 桩、低标号桩等 利用沉管制桩机械在地基中锤击、振动沉管成孔或静压沉管成孔后，在管内投料，边投料边上提振动沉管形成密实桩体，与原地基组成复合地基。（3）夯击碎石桩块石墩 利用重锤夯击或者强夯方法将碎石块石夯人地基，在夯坑里逐步填人碎石块石反复夯击以形成碎石桩或块石墩。2.5 拌和法（1）高压喷射注浆法高压旋喷法以高压力使水泥

10、浆液通过管路从喷射孔喷出，直接切割破坏土体的同时与土拌和并起部分置换作用。凝固后成为拌和桩柱体，这种桩柱体与地基一起形成复合地基。 也可以用这种方法形成挡土结构或防渗结构。（2）深层搅拌法 深层搅拌法主要用于加固饱和软粘土。它利用水泥浆体?嗷蚴曳厶遄魑鞴袒粒锰刂频纳畈憬涟杌到袒了腿说鼗林杏胪燎恐平涟瑁纬伤嗍彝恋淖澹朐鼗槌筛春系鼗嗤磷奈锢砹灾嗜【鲇诠?化剂与土之间所产生的一系列物理-化学反应。固化剂的掺人量及搅拌均匀性和土的性质是影响水泥土桩柱性质以至复合地基强度和压缩性的主要因素。2.6 加筋法（1）土工合成材料 土工合成材料是一种新型的岩土工程材料。它以人工合成的聚合物，如塑料、化纤、合成橡

11、胶等为原料，制成各种类型的产品，置于土体内部、表面或各层土体之间，发挥加强或保护土体的作用。土工合成材料可分为土工织物、土工膜、特种土工合成材料和复合型土工合成材料等类型。（2）土钉墙技术 土钉一般是通过钻孔、插筋、注浆来设置，但也有通过直接打人较粗的钢筋和型钢、钢管形成土钉。土钉沿通长与周围土体接触，依靠接触界面上的粘结摩阻力，与其周围土体形成复合土体，土钉在土体发生变形的条件下被动受力。并主要通过其受剪工作对土体进行加固，土钉一般与平面形成一定的角度，故称之为斜向加固体。土钉适用于地下水位以上或经降水后的人工填土、粘性土、弱胶结砂土的基坑支护和边坡加固。3加筋土 加筋土是将抗拉能力很强的拉

12、筋埋置于土层中，利用土颗粒位移与拉筋产生的摩擦力使土与加筋材料形成整体，减少整体变形和增强整体稳定。拉筋是一种水平向增强体。一般使用抗拉能力强、摩擦系数大而耐腐蚀的条带状、网状、丝状材料，例如，镀锌钢片；铝合金、合成材料等。2.7 灌浆法 是利用气压、液压或电化学原理将能够固化的某些浆液注入地基介质中或建筑物与地基的缝隙部位。灌浆的浆液可以是水泥浆、水泥砂浆、粘土水泥浆、粘土浆、石灰浆及各种化学浆材如聚氨酯类、木质素类、硅酸盐类等。根据灌浆的目的可分为防渗灌浆、堵漏灌浆、加固灌浆和结构纠倾灌浆等。按灌浆方法可分为压密灌浆、渗入灌浆、劈裂灌浆和电化学灌浆。灌浆法在水利、建筑、道桥及各种工程领域有

13、着广泛的应用。 参考文献1.基础工程，华南理工大学等编，中国建筑工业出版社，20082.建筑地基处理技术规程JGJ79-20023.地基基础设计与计算，人民交通出版社，20054.简明地基基础设计施工手册，中国建筑工业出版社，20035.地基处理工程设计计算与施工，中国地质大学出版社，19976.FOUNDATION DESIGN AND CONSTRUCTION，GEO PUBLICATION NO.1/2006 Poor soil and Foundation methodsAbstract: The ground foundation engineering and uses very

14、important regarding high-rise constructionssecurityits construction cost is highthe time is long. Science reasonable choice ground treatment way hasthe vital significance regarding the modern civil engineering construction.Key words: foundation soilgroundground treatment1.The most common adverse soi

15、l and its characteristics1 Soft claySoft clay also called soft soil the clay is weak and short. It was formed in the lateQuaternary a marine lagoon phase of the valley the lake is the drowning of thevalley the delta equivalent viscous alluvial sediments or river. More distributed incoastal areas mid

16、dle and lower reaches of rivers or lakes nearby areas. The weaknessis common clay mud and silt soil. Soft soil of the physical and mechanical propertiesinclude the following aspects:1 physical properties:it has high clay content and high moisture content the void ratio which showed themechanical nat

17、ure of it with the corresponding features of low-intensityhigh-compression low permeability high sensitivity.2 mechanical properties:The strength of soft clay is very low.Hydraulic Conductivity is very slow.Soft clay of the great compression.（3）engineering properties: by the garbage dumps or soil. T

18、hese waste soil generally fall into three categories:namely construction waste soil solid waste soil and industrial production of refusesoil.1.2 Miscellaneous FillMiscellaneous filling occurred mainly in the neighbourhood of some old and MiningAreas is peoples lives and production activities leftSof

19、t clay foundation bearing capacity of low intensity slow growth easy loading afterdeformation and unevendeformation rate of large and stable long time pervasivesmall and thixotropy Rheology major characteristics. The foundation used apre-pressure treatment replacement mixing method and so on. Miscel

20、laneous filling the main features is the accumulation of planning complexand varied nature uneven thickness the law worse. Thus the same venue for theperformance of compression and intensity of the obvious differences easily causeuneven settlement the foundation usually need to be dealt with.1.3 Cho

21、ng fillingFilling is man-made water-filled way of the soil and sediments. In recent years morefor coastal shoreline development and to create River floodplain.Fill the foundationgenerally has the following important features:1 （1）particles Shen points clear of the election and in the direction of th

22、e depthmarked on the bedding.（2）filling the high water content generally greater than liquid a flow state.3foundation-filling low early strength higher compression which is due toless-filling in the consolidation of state.1.4 saturated loose sand Fine sand or silt in the foundation under static load

23、 often have a high intensity. Butwhen the vibration load earthquakes vibration etc. role saturated loose sandfoundation is likely to have a large number of seismic subsidence liquefied ordeformation or even the loss of capacity.Common ways of handling out therevibro-law.1.5 Collapsible loessIn the c

24、asing layer themselves under stress or stress self-respect and common underadditional stress due to water damage to the structure of soil in significant additionaldeformation of the soil known as the collapsible soil.In collapsible loess foundation carrying out works on the building consideration mu

25、stbe given due to wet ground subsidence caused additional settlement of the projectmay cause harm to choose suitable method of dealing with the foundation to avoid oreliminate the foundation of collapsible or a small amount of subsidence caused by wetHazard. 1.6 Expansive soilExpansive soil if the m

26、ineral composition of montmorillonite-kyu it is veryhydrophilic when the water volume expansion when the volume of water losscontraction.Common ground treatment method for soil soil improvement pre-soaking and theprevention of soil moisture content such as changes in engineering measures.1.7 Contain

27、ing organic matter in soil and peatWhen the soil contains organic matter in a different it will be a different soil organicmatter organic matter content when it exceeds a certain form of peat it has differentcharacteristics of the projectthe higher the organic matter content the greater the impact o

28、n soil quality mainlyFor the low-intensity compression and the incorporation of different projects havedifferent effects on the direct construction or foundation treatment adversely affected.1.8 Mountain soilMountain soil more complicated geological conditions mainly in the foundation ofthe uneven a

29、nd stability of both venues. As the natural environment and soilconditions affect the generation site of large boulders may exist there may be spaceenvironment landslides and mud-rock flows slope failure and other adversegeological phenomenon.1.9 KarstIn karst region often exist or cave-earth dissol

30、ved ditch the gap solution such asdepression. Underground water erosion or potential erosion of its formation anddevelopment of their impact on the structure of the great easy to appear unevenground deformation and the collapse of the fall.2， Ground treatment 2.1 Replacement ActAnd then get rid of b

31、eing bad supercrust foundation soil being dug backfill soilhaving dense fairly good pressure characteristic property carrying out the compactionor densification force forming fine holding tier. Bearing the weight of changingfoundation thereby force characteristic property improves the resist deforma

32、tion andstable ability. 2 Vibrate according to displacing law Make use of special vibrating to rinse machines and tools rush near vibratingbelow high-handed water jet ready-made a hole in foundation fill in rude granulessuch as breakstone or pebble again in batches in Kong Zhong expecting forming th

33、epole body. Be the pole body and plain foundation soil turn to be composed ofcompound foundation achieve rise foundation bears the weight of a forcediminishing compressibilitys purpose. 3 Densification displaces lawMake the soil body push against to broadside coming untied put fillings such asperson

34、 breakstone or grit in to being in charge of an inner or to pounding a pit and inmaking use of the way sinking a tube or pounding a hammer to place hammer beingburied. Be the pole body and plain foundation soil turn to be composed of compoundfoundation body side direction squeezes the floor bulges s

35、ince pushing against ramming messenger earth super-quiet small opening of soil body water pressureimprovesthink that the super-quiet small opening water pressure elimination God ofthe earth body intensity also has corresponding rise. 2.2 pre-Method 1 reactor preloading law Before the construction of

36、 buildings temporary surcharge aggregate soiland other construction materials goods etc. the way the foundation to impose loadto a certain pre-pressure period. Foundation to complete the pre-compression most ofthe settlement and foundation bearing capacity is improved removable load to theconstructi

37、on of buildings. 2 vacuum-pressure method Soft clay surface at the foundation laying sand cushion and covered with soilaround the film seal. Vacuum pump used for pumping sand cushion so that thefoundations of a film under negative pressure. With the foundation out of gas andwater soil by consolidati

38、on. To speed up the consolidation may also have a well orsand into plastic drain the way that is in the laying of soil and sand cushion beforethe film into a sand drain or drainage board to shorten the distance between thepurpose of drainage. （3）Precipitation law Lowering the water table can reduce

39、the foundation of the pore waterpressure to increase the stress on soil themselves so that effective stress increased sothat the foundation be preloading. Actually this is by lowering the water table soilthemselves by pre-pressure to achieve purpose. 4 Electroosmosis law In the foundation and insert

40、 a metal electrode to-DC DC in the field the soilin the flow of water from the anode cathode formation permeability. Not to add waterin the anode and cathode from the point with a vacuum pumping wells thus loweringthe water table soil moisture reduction. To be the foundation of consolidationpressure th.