[雙語翻譯]--港航外文翻譯--碼頭岸壁后側(cè)群樁橫向位移的振動(dòng)臺(tái)模型試驗(yàn)（原文）

1、Shaking Table Model Tests on Pile Groups behind Quay Walls Subjected to Lateral SpreadingRamin Motamed1 and Ikuo Towhata2Abstract: This paper presents experimental results of 1-g shaking table model tests on a 3?3 pile g

2、roup behind a sheet-pile quay wall. The main purpose was to understand the mechanisms of liquefaction-induced large ground deformation and the behavior of the pile group subjected to the lateral soil displacement. The sh

3、eet-pile quay wall was employed to trigger the liquefaction-induced large deformation in the backfill, and a study was made of the effect of several parameters such as soil density, amplitude and frequency of input motio

4、n, pile head fixity, and superstructure on the magnitude of soil lateral displacement and the maximum lateral force of liquefied soil. Furthermore, distribution of the maximum lateral force within the group pile was thor

5、oughly studied. It was found that the force varies depending on the position of individual piles in the group. To evaluate the contribution of each pile in the total lateral force, a new two-dimensional parameter that is

6、 called contribution index was introduced and recommended values for each pile were suggested. Finally, it is concluded that displacement and velocity of soil are the most important parameters that affect the distributio

7、n of the lateral forces in the group pile, and these two parameters are highly dependent on the configuration of the ground ?geometry?.DOI: 10.1061/?ASCE?GT.1943-5606.0000115CE Database subject headings: Soil liquefactio

8、n; Displacement; Pile groups; Harbors; Walls; Shake table tests.Author keywords: Liquefaction-induced ground displacement; Pile group; Quay wall.IntroductionPile foundations located in loose sandy ground near a waterfron

9、t structure or in sloping ground are susceptible to large ground displacement due to extensive liquefaction. Several examples have been reported in the literature about the 1964 Niigata, 1983 Nihonkai-Chubu, and 1995 Kob

10、e earthquakes ?Hamada et al. 1986; Hamada et al. 1996; Tokimatsu and Asaka 1998; Matsui and Oda 1996; Tokimatsu et al. 1996?. The significant damage to pile foundations highlighted the importance of the kinematic force,

11、i.e., the lateral force induced by the flow of liquefied soil. Therefore, a proper understanding of the behavior of pile founda- tions subjected to lateral soil movement is of major concern to geotechnical engineering. A

12、lthough the dynamic behavior of pile foundations in dry soil has been investigated in detail, their be- havior has not been fully understood in the case of a large ground flow of liquefied sand. McVay et al. ?1998? condu

13、cted centrifuge experiments on two pile groups ?3?3 and 7?3? and found that an individual pile row’s contribution to a group’s lateral resistance did not change with the size of the group, but only with its row position.

14、 More- over, it was shown that the leading row is subjected to the largestlateral load, and that the middle pile in each row demonstrates a slightly less lateral force than the side piles. Similarly, Kimura et al. ?2002?

15、 demonstrated shadow effects in centrifugal model tests. Their results illustrated that the percentage of lateral load de- creased as it moved in a downstream direction in the sloping ground, while this trend was not val

16、id for the pile at the down- stream edge ?fourth pile row? which received a greater load than the third row for the monotonic force. Comparable results were also reported by Rollins et al. ?2005? through field testing on

17、 a pile group. Tokimatsu and Suzuki ?2004? and Tokimatsu et al. ?2001, 2005? conducted several large shaking table tests on a pile group, and focused on the cyclic behavior of a soil-pile-structure model. However, the la

18、teral force of the liquefied soil was out of scope. Rollins et al. ?2005a,b? used explosives to reproduce the liquefaction. Their results revealed that leading-row piles carried considerably more load than middle and tra

19、iling-row piles. Ashford et al. ?2006? reported the results of their full scale experiments on pile groups and a quay wall subjected to blast- induced lateral spreading, which were conducted in Japan. In their paper, it

20、was shown that in 4-pile and 9-pile groups, the pile in the rear row ?closest to the quay wall? carried larger bending mo- ments than the pile in the front row. Furthermore, Sato ?1997? conducted centrifuge tests on a gr

21、avity type quay wall and a 2 ?3 pile group and found that piles near the quay wall were likely to receive greater damage than piles far from the quay wall. Recently, a full scale shaking table experiment was conducted at

22、 E-Defense Research Center ?NIED? in Japan on a 2?3 pile group and a sheet-pile quay wall model in which the pile group was subjected to the liquefaction-induced lateral flow of liquefied sand. Further information on thi

23、s full scale shaking table test can be found in Motamed ?2007?, Motamed et al. ?2009?, Tabata et al. ?2007?, and MEXT and NIED ?2006?. Although several experiments on piles in sloping and horizon- tal ground models have

24、been conducted by centrifuge, large shak-1JSPS Postdoctoral Fellow, Dept. of Civil Engineering, Tokyo Insti- tute of Technology, 2-12-1M1-9, Ookayama, Meguro-ku, Tokyo 152- 8552, Japan; formerly, Ph.D. Student, Dept. of

25、Civil Engineering, The Univ. of Tokyo ?corresponding author?. E-mail: motamed@cv.titech.ac.jp 2Professor, Dept. of Civil Engineering, The Univ. of Tokyo, 7-3-1, Hongo, Bukyo-ku, Tokyo 113-8656, Japan. Note. This manuscri

26、pt was submitted on December 19, 2007; ap- proved on March 9, 2009; published online on March 13, 2009. Discus- sion period open until August 1, 2010; separate discussions must be submitted for individual papers. This pa

27、per is part of the Journal of Geotechnical and Geoenvironmental Engineering, Vol. 136, No. 3, March 1, 2010. ©ASCE, ISSN 1090-0241/2010/3-477–489/$25.00.JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING ©

28、; ASCE / MARCH 2010 / 477J. Geotech. Geoenviron. Eng. 2010.136:477-489.Downloaded from ascelibrary.org by Changsha Univ Of Sci all rights reserved.ing tables, and field tests, few studies were done on waterfront models

29、in which a pile group is located behind a waterfront struc- ture. Therefore, this paper aims to study the behavior of a 3?3 pile group behind a sheet-pile quay wall subjected to a liquefaction-induced lateral flow of liq

30、uefied sand. The main pur- pose of this series of 1-g shaking table model tests is to investi- gate the behavior of a pile group subjected to the kinematic force due to the flow of liquefied ground that is caused by the

31、extensive deformation of a sheet-pile quay wall.1-g Shaking Table TestsIn total, ten experiments were performed on a 3?3 pile group with pile spacing of 2.8 pile diameters ?2.8?D=2.8?3.2 cm? and a sheet-pile quay wall. C

32、onfigurations of the models were identical except the thickness of liquefiable soil. Figs. 1 and 2 illustrate the schematic plan views and cross sections of the mod- els in Tests 23 and 27 in which the thickness of soil

33、layer was 50 and 45 cm, respectively. Table 1 summarizes the features of each experiment.Material PropertiesTables 2 and 3 provide information about material properties of the pile foundation and the sheet-pile quay wall

34、. To reproduce the in situ stress-strain behavior of liquefied soil, a model ground was prepared with much lower density than the prototype density ?Towhata 2008?. The configuration of the model ground was a horizontal l

35、iquefiable soil deposit made of Albany Silica sand ?see Table 4 for properties? with the relative density of mainly 30%. The model ground was prepared according to the water sedimen- tation method. Further details of mod

36、el preparation, materials, and instrumentations can be found in Motamed ?2007?.Experimental ProgramExperiments were divided into two main categories: without pile head constraint ?Fig. 1? and with pile cap ?Fig. 2?. In t

37、he former case, piles were fixed at the bottom and free at the top, similar toa cantilever beam. In contrast, in the latter configuration, pile heads were also constrained by a cap ?see Table 5 for properties?. Table 1 l

38、ists the summary of the experiments in which the effect of the following parameters was investigated: the amplitude and frequency of input motion, density of the soil, pile head con- straint, and inertial force of the su

39、perstructure. As shown in Table 1, three different amplitudes of input motion ?150, 300, and 600 Gal? and two frequencies ?5 and 10 Hz? were applied. It should be noted that prior to conducting the main experiments, thre

40、e tests were run under identical conditions to satisfy the repeatability and reliability of the data, the results of which can be found in Mota- med ?2007?.Measurements and Data ProcessingModels were densely instrumented

41、 with various sensors such as accelerometers, pore water pressure ?PWP? transducers, inclinom- eters, laser displacement transducers, and a ShapeTape ?Figs. 1 and 2?. In addition, many strain gauges were pasted on the pi

42、les and the sheet-pile quay wall to measure bending strain. In total, more than 120 channels of data were recorded during each test. In the following subsections, test results are presented. Furthermore, it should be not

43、ed that since the main objective of this study concerns the kinematically induced-lateral force of liquefied soil, the monotonic component of the recorded parameters was fo- cused on after filtering out the cyclic compon

44、ent. This process will be addressed in detail in the section related to pile bending moment. The sign convention in this study is depicted in Fig. 3; the factors of horizontal ground displacement, inertial force, and lat

45、eral soil pressure were considered positive in the seaward di- rection, while acceleration was assumed to be positive in the land- ward direction.Table 2. Material Properties of Pile FoundationMaterial Height ?cm? Outer/

46、inner diameter ?cm? E ?N·cm2? I ?cm4?Polycarbonate 53 3.2/2.7 27?104 2.5385Table 3. Material Properties of Sheet-Pile Quay WallMaterial Height ?cm? Width ?cm? Thickness ?cm? E ?N·cm2? I ?cm4? for width=38.5 cmA

47、luminum 32 38.5 0.2 70?105 0.02566Table 4. Properties of Albany Silica SandSpecific gravity ?g/cm3? Maximum void ratio, ?emax? Minimum void ratio, ?emin? Mean grain size, D50 Coefficient of uniformity, Uc2.6463 0.741 0.4

48、70 0.302 2.237Table 5. Material Properties of Pile CapMaterial Size ?cm?cm? Thickness ?cm? E ?N·cm2? I ?cm4? Weight ?kg?Polycarbonate 23?23 2 27?104 15.33 1.265Fig. 3. Sign convention in this studyJOURNAL OF GEOTECH