毕业设计文献翻译.docx

1、毕业设计文献翻译本科毕业设计（论文）外文翻译题 目 某大学科技楼结构设计及基坑支护学 院建工学院专业土木工程班级学号学生姓名指导教师教务处制外文资料来源及题目（原文附后）。1. 资料来源：指导老师给题2. 题目：Design Charts for Piles Supporting Embankments on Soft Clay3. 作者：H. G. Poulos, F.ASCE译成中文后题目（译文附后）软土地基上桩承式路堤的设计图表指导教师审阅意见： 签名：年 月 日Design Charts for Piles Supporting Embankments on Soft ClayH. G

2、. Poulos, F.ASCEAbstract: This paper describes the development and application of design charts for piled embankment designs.It outlines the computational approach adopted,the geotechnical profiles used,and the application of the design procedure using the charts.The soil profile used for the charts

3、 is representative of a Malaysian soft clay profile,involving a more or less normally consolidated soil,with a strength and stiffness that varies linearly with depth.Such a profile is typical of the ground conditions in a variety of countries in the Southeast Asian region.The design charts address t

4、he issues of pile capacity,settlement due to embankment load,settlement due to a temporary piling construction platform,and lateral response of piles near the edge of the embankment.The charts consider variations in ground conditions,embankment height,pile length,and pile spacing.An illustrative exa

5、mple is given to demonstrate the use of the charts.CE Database subject headings: Embankments; Foundation design; Lateral displacement; Pile foundations; Settlement; Soil settlement; Clays; Soft soils.IntroductionPiled embankments provide a possible solution for the construction of roads and transpor

6、t corridors over soft soils. They have the advantage of being relatively rapid to construct and do not require the extended time periods that many conventional forms of ground improvement demand (e.g., preloading). Piled embankments have been used increasingly in a number of regions, including Europ

7、e, Southeast Asia, and Australasia. A variety of methods of design have developed, ranging from relatively simplistic approaches (for example, British Standards Institution 1995) to relatively sophisticated methods involving advanced numerical analysis (e.g., Russell and Pierpoint 1997; Kempton et a

8、l. 1998;Hsi 2001; Han and Gabr 2002; Wong 2002). The majority of the simpler methods address only the stability or ultimate limit state,or else focus on the issue of load sharing and arching between the piles and the ground(e.g., Ting and Toh 1983; Hewlett and Randolph 1988; Low et al. 1994). The si

9、mpler design methods currently available give little or no consideration to settlements and deformations. In many cases, such deformations may have a profound influence on the longterm performance of the embankment, and design criteria frequently specify upper limits to the values of settlement and

10、differential settlement that can be tolerated. While advanced numerical analyses may be appropriate and necessary for detailed design, they are generally not suited to a rapid assessment of the feasibility of piled embankment construction for a particular site. To facilitate preliminary assessment a

11、nd design of piled embankments,a series of design charts has been developed. The charts consider variations in ground conditions, embankment heights, and pile types. For simplicity, a perfectly flexible embankment has been assumed. Consideration is also given to the effects of soil movements arising

12、 from the construction of a temporary piling platform fill (typically 1 to 1.5 m thick).The soil profile used for the charts is representative of a Malaysian soft clay profile, involving a more or less normally consolidated soil, with a strength and stiffness that varies linearly with depth. Such a

13、profile is typical of the ground conditions in a variety of countries in the Southeast Asian region.This paper describes the development and application of the design charts for piled embankment designs. It outlines the computational approach adopted, the geotechnical profiles used, and the applicat

14、ion of the design procedure using the charts. Illustrative examples are given to demonstrate the use of the charts.Geotechnical ModelA considerable amount of information on the geotechnical characteristics of soft marine clay deposits in Malaysia is available(e.g., Ramli et al. 1994; Ramli and Ismae

15、l, personal communication,1992; Sagae and Goh 1997; Tan et al. 2004). There is an indication that, below a surface desiccated crust 23 m thick, the clays are more or less normally consolidated and have an undrained shear strength that increases linearly with depth. On the basis of the available data

16、, the relationship chosen for the present study is represented by the relationship su = 10 + 1.5z kPa (1)where z=depth below the soil surface(m).This relationship is perhaps more conservative than that suggested by Ramli et al. (1994) and is towards the lower end of the range of values given by Tan

17、et al. (2004), but appears to be a reasonable(albeit conservative) fit to the data.For the estimation of settlements due to surface loadings, data from the available references was examined, and values adopted for the compression ratio Cc /(1+e0) in the upper 15 m were 0.30 for the normally consolid

18、ated state and 0.05 for the overconsolidated state. Below 15 m, the compression ratio was taken to be 0.15 for the normally consolidated state and 0.025 for the overconsolidated state. It is understood that the lower compression ratio below 15 m may be a consequence of this soil having a lower water

19、 content, plasticity index, and liquidity index than the soil above it. The upper 5 m was assumed to be overconsolidated,with the remainder of the soil profile being normally consolidated.For the estimation of pile settlements, it was assumed that the embankment piles would be driven, and account wa

20、s taken of the effects of pile installation in stiffening the soil around the driven piles. Based on correlations developed by Poulos(1972D)for soft clays, a drained Youngs modulus of the soil around the pile of 300su was adopted for the design charts. Consideration is given here only to the long-te

21、rm settlements of the embankment, which include both undrained and consolidation components, but excluding any long-term creep settlements.For estimation of pile capacity, the ultimate skin friction was related to the undrained shear strength via the adhesion factor ,which is itself a function of su

22、 (Tomlinson 1986). The value of was typically within the range 0.91.0. The ultimate base resistance was taken as 9sub, where sub=undrained shear strength in the vicinity of the pile tip.For the purposes of the design charts, the basic value of the total thickness of the soft clay layer was taken to

23、be 40 m, but the effects of shallower layer depths were also investigated and expressed in terms of correction factors to the results for the 40-m layer depth. Underlying the soft clay is a layer of stiff clay, whose properties were assessed from data presented by Ramli et al.(1994). It is recognize

24、d that the chosen soil profile is rather specific and that the influence of such important factors as stress history, stratigraphy, and soil properties are not incorporated into this study. Nevertheless, it is felt that the charts may provide a reasonable indication of the design requirements for pi

25、les supporting embankments on relatively thick deposits of clay that are essentially normally consolidated.Fig. 1 summarizes the geotechnical model adopted for the development of the design charts.Fig. 1. Assumed geotechnical profileDevelopment of Design ChartsThe design of piles for piled embankmen

26、ts requires consideration of at least four issues: Geotechnical capacity of the piles; Settlement of the piles; Lateral response of the piles; and Structural capacity of the piles.For the purposes of developing design charts, attention here is focused on the first two issues, but some consideration

27、is also given to the other two. If the pile heads are properly attached to a slab or mattress, then lateral pile deflections should not be a concern unless ground movements are generated by some other activity adjacent to the piles, e.g., filling or excavation. Such effects are examined in this pape

28、r. The axial forces for structural design of the piles should include both those arising from the applied loading and the downdrag forces developed by ground movements due to the placement of fill for a piling platform. Consideration is also given to these downdrag forces here.Analysis ProcedureThe

29、main analyses were carried out to obtain three aspects of the behavior of embankment piles:1. The axial load-settlement behavior, including the ultimate axial load capacity and the single pile head stiffness;2. The effect of group interaction on pile head stiffness; and3. The effect on the piles of

30、vertical ground movements induced by the construction of the fill for the piling platform (the possible effects of lateral ground movements were not considered).For these analyses, two computer programs were used: PIES (for Items 1 and 3 above) and DEFPIG (for Item 2). Both programs were developed a

31、t the University of Sydney, Australia.PIES computes the axial movement and load distribution within a pile subjected to axial load and/or externally imposed vertical soil movements. The program uses a simplified boundary element formulation, and the soil can be represented either by an elastic conti

32、nuum or a series of springs. In each case, nonlinear response of the interface can be incorporated by assuming an elastic-plastic or hyperbolic relationship between soil stiffness and stress level, and by allowing for the effects of pile-soil slip and base bearing failure by specifying limiting values of shaft resistance and end-bearing resistance. DEFPIG is a program for calculating the deformations and load distribution within a group of piles subjected to vertical,horizontal, and moment loading. The program considers