update孟加拉OCell法桩基静载试验方案提交

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1、GOVERNMENT OF THE PEOPLES REPUBLIC OF BANGLADESHOFFICE OF THE PROJECT DIRECTORPAIRA BRIDGE (LEBUKHALI BRIDGE) CONSTRUCTION PROJECTROADS AND HIGHWAYS DEPARTMENTROAD TRANSPORT AND HIGHWAY DIVISIONMINISTRY OF ROAD TRANSPORT AND BRIDGESCONSTRUCTION OF 1470 METER LONG PAIRA BRIDGE (LEBUKHALI BRIDGE) OVER

2、 THE RIVER PAIRA INCLUDING APPROACH ROAD, BANK PROTECTIVE AND RELATED WORK ATTH KM BARISAL-PATUAKHLI ROAD(N-8)PAIRA BRIDGE (LEBUKHALI BRIDGE) Loading Test Project of the Piles试桩静载试验实施方案中国北京建筑大学 北京市城市交通基础设施建设工程技术研究中心中国黑龙江路桥一公司Beijing Urban Transportation Infrastructure Engineering Technology Research

3、 CenterBUCEA, BEIJING CHINANo. 1st Branch of Heilongjiang Road and Bridge Co., Ltd., Haerbin CHINA2016-02-21PAIRA BRIDGE (LEBUKHALI BRIDGE) CONSTRUCTION PROJECT-Loading Test Project of the Piles试桩静载试验实施方案目录1工程概况/Engineering background31.1桥梁概况/Bridge configuration31.2试桩概况/ Outlines of the testing pil

4、es32试验依据及要求/Test basis and requirements62.1试验依据/Test basis62.2试验要求/Test requirements63试验原理/ Test principles74实施方案/Test project114.1试桩位置/ The location of testing piles114.2荷载箱的选择/ The choice of loading cells124.3测试仪器安装/ Installation of test instruments144.3.1荷载箱和连接的压力管线/Load box and its connected pre

5、ssure pipeline144.3.2振弦式位移传感器/Vibrating displacement sensor154.3.3应变杆/Strain bars154.4.4振弦式应变计/ Vibrating strain extensometer154.3.5塑料管/Plastic pipe154.3.6动力组件/Power components154.3.7安装基准梁及数据采集系统/The installation of reference beam & data collectionsystem164.4试桩进度安排/ Testing Schedulre174.5现场测试/Field

6、Test174.5.1端部承载力试验（3.5m试桩) /Bearing capacity test of pile end (for 3.5m test piles)174.5.2总承载力和分层侧壁摩擦力试验（3.5m试桩) /Total bearing capacity test & layered sidewall friction for 3.5m test piles194.5.3总承载力和分层侧壁摩擦力试验（其它试桩)/Test of total bearing capacity and layered sidewall friction test (for Other test p

7、iles)204.6结果分析/Analysis of test results204.7报告内容/Report contents205需要业主和施工方提供的协助/ Needed assistance provided by owners and constructors 216验证荷载数量及观测耗材预估/Estimation list of proof load and observation materials237附件/Attachments257.1 O-C安装试验过程/ The process of O-Cell installation test l257.2 囊式荷载箱安装试验过程

8、/Installation and test procedure of capsule-type load cell267.3 国产设备及试验性能简介/Introduction to the domestic equipment and its test performance277.4 相关业绩简介/Introduction to our relevant achievements281工程概况/Engineering background1.1桥梁概况/Bridge configurationBridge configurations as based on the Employers r

9、equirement have been summarized below. Outline configurations for Main Bridge and Extra-dosed type of super structure maintaining minimum span requirement by the consultants. 需要中文原文？ The height of tower will be within the limit set by the Civil Aviation Authority for the flight path.1) 桥梁长度/Length o

10、f the Paira Bridge主桥/Main bridge：630m(115m+2200m+115m)引桥(高架桥)/Bridge with viaduct：840m主跨/Main span：200m2) 桥面布置/Bridge deck行车道宽/Carriage way width：27.3m人行道宽(含路缘石) Width ofFootpath with Kerb：21.10m (Minimum)防撞墙宽/ width of bump wall：0.305m (Minimum)中间带宽Width ofCentral barrier：2.96(Minimum)上部结构类型/Types

11、of superstructure：Pre-stressed concrete Extra-dosed Box-Girder 3) 结构类型/Types of structure上部结构类型/Types of superstructure：预应力箱梁、预应力混凝土斜拉桥箱梁/Pre-stressed Concrete Box-Girder, Pre-stressed concrete Extra-dosed Box-Girder 下部结构类型/Types of substructure：钢筋混凝土（桥台)、实体墩、竖井、箱型墩塔/RCC Abutments, Reinforced Concre

12、te Solid Piers, Shafts, Box-Type Piers /Pylon4)基础类型/ Types of Foundation:斜拉桥主墩的基础/Foundation of the Main Extra-dosed Span.5m钢筋混凝土圆形桩/RCC Solid Circular Pile with 3.5m diameter引桥的墩台基础为/ The pier foundation of approach span2.5m/1.5m钢筋混凝土圆形桩/RCC Solid Circular Pile for Viaduct Support span with 2.5 m/1

13、.5 m diameter 1.2试桩概况/ Outlines of the testing piles工程师指定在主桥桥墩P16, P17, P18,P19和P20位置选择工作桩或制作试桩进行奥斯托堡法加载试验。P16和P20桥墩桩基直径为2.5m，初步设计桩长110m；P17, P18和P19墩塔桩基直径为3.5m，初步设计桩长130m。初始试验在试桩上进行，试桩验证荷载不超过设计荷载的250%。然后在工作桩上进行加载试验，工作桩验证荷载规范没有规定，但是根据规范中工作桩作为反力桩的要求，应控制桩顶位移不超过0.5mm。The Osterberg Load Test will be tak

14、en at the main bridge drawings P16, P17, P18, P19, and P20, which will be specified by project engineers either through working piles or building test piles. The diameter of bridge pile foundation on P16 and P20 is 2.5m, and the preliminary design of its pile length is 110m. The diameter of bridge p

15、ile foundation on P18 and P19 is 3.5m, and the preliminary design of its pile length is 130m.The initial test will be carried out on test piles, whose verification load should not exceed 250% of the designed load. Then the loading test will be carried out on working piles, whose top displacements sh

16、ould not exceed 0.5mm based on the requirements of working piles as counterforce one in the code requirements, though it is not regulated in the verification load code.图1-1 主桥立面图 /Fig.1-1 Elevation of the Main Bridge表1-1 试桩工程数量表/Table 1-1 Quantities of pilot test pilesO-cell tests (Osterberg cells)

17、to be carried out at pile locationP16, P17, P18, P19 and P20 as directed by the Engineer.单位/unit数量/numFor 2.5m dia cast-in-situ RCC piles-Design vertical load 50MN.-i) Initial pile load test on pilot/non-working pile(including cost of pilot pile). Load test vertical load 125MN.(250%)Nos.1ii) Routine

18、 pile load test on working piles. Load test vertical load 75MN.(150%)Nos.2For 3.5m dia cast-in-situ RCC piles-Design vertical load 110MN.-i) Initial pile load test on pilot/non-working pile ( includingcost of pilot pile). Load test vertical load 275MN.Nos.1ii) Routine pile load test on working piles

19、. Load test vertical load 165MN.(150%)Nos.32试验依据及要求/Test basis and requirements2.1试验依据/Test basis1 Paira Bridge Construction Project Tender Documents: Technical Specification.2 The AASHTO LRFD Bridge Specification (3rdEdition,2004).3 The AASHTO Bridge Design Specification (6thEdition,2012).4 ASTM D1

20、143-07：Standard test methods for deep foundations under static axial compressive load.5 Optimum loading specifications for O-cell bi-directional static load testing.6 TheIndustry Standard of the Peoples Republic of China: Pile static load test with self-balancing method (JT/T 738-2009).2.2试验要求/Test

21、requirements1)试桩制作/The preparation of pilot test pile测试桩应选择与工作桩相似水文地质环境、采用相同设备和材料进行施工。试桩成孔的尺寸、形状位置必须合乎设计要求，需进行成孔质量检测。Each pilot test pile shall be constructed in a manner with similar hydrogeological environment that to be used for the construction of the working piles, and by the use of similar equ

22、ipment and materials. The hole size, the pile shape and the position shall follow the design requirements, and the quality detection of the holes should be required. Any variation shall only be permitted with prior approval.2)加载设备/ Loading equipments根据试桩桩径、预估极限承载力大小的具体要求，可选用单个荷载箱，也可以多个并联布置；为了满足特定的要求

23、，荷载箱可以单层布置，也可以多层布置。每个荷载箱在使用前均经过授权计量单位进行压力荷载的标定。选用的荷载箱直径应小于桩径，荷载箱一般焊接在主筋上。加载设备应控制在1.5倍的工作压力下不破坏。A single load cell or multiple ones with parallel arrangement can be chosen according to specific requirements of pilot test pile diameter and its estimated ultimate bearing force. In order to meet the spe

24、cific requirements, the loading cells can be arranged in single layer or multiple layers. Calibrations load and pressure for each load cell beore use must be calibrated by authorized measurement department.The diameter of the load cell should be less than the diameter of the pile, and it is generall

25、y soldered to the main steel bar. The loading equipment should be controlled without damage at 1.5 times of the working pressure.The hydraulic jack, pump, hoses, pipes, couplings and other apparatus to be operated under hydraulic pressure shall be capable of withstanding a test pressure of 1.5 times

26、 the maximum working pressure without leaking.缺中文原文 3)注浆/Grouting工作桩试验完成后，通过预留的注浆管（直径25mm)对试验过程中由荷载箱工作形成的桩身开裂空间进行注浆，以作永久性封闭。After the work of pile test is finished, the pile cracking space formed by the working of load cell must be grouted through the reserved grouting pipe whose diameter is 25mm so

27、 as to keeping permanent closure.3试验原理/ Test principles1)奥斯托堡法The Osterberg load test methodOsterberg Cell Load Test（简称为O-Cell试验 )，是由美国西北大学Prof. Osterberg于1991年创导的一种独特的桩基荷载试验方法，简称奥氏法。其利用桩的自重、桩周土的摩擦力与桩端土阻力作为一对反力的基本原理，借助埋设于桩身（底)的压力盒向上、向下同时施加荷载，以独立地获取桩侧阻力位移曲线及桩底阻力位移曲线。奥氏法的核心设备是称为O-Cell（国内通常称之为荷载箱或压力盒)的

28、大吨位液压千斤顶。试验时通过桩顶液压管路向 O-Cell加载，O-Cell向下的作用力由桩端承载力平衡，向上的作用力由桩身的侧摩擦力平衡。一般将O-Cell放置在桩底的底部，形象地称为桩底加载法。经过二十多年的不断探索改进，现在O-Cell除了放置于桩的底部外，还可以放置在桩身不同中的不同部位，也可以在同一根桩内放置若干的O-Cell。常规桩顶加载试验的桩顶荷载P等于桩侧摩阻力F和桩端阻力Q之和，即P=F+Q，不计试桩前桩身自重W在桩端的反力。奥氏法试桩时通常采用荷载箱在桩底部产生向上、向下二个方向的荷载P0，向上的荷载P0=W+F，向下的荷载与桩端的桩身自重反力及由加载产生的端部反力增量Q之

29、和平衡，即P0=W+Q，受力机理和桩顶加载相同。于是该二种试桩方法的荷载换算如下：P=F+Q=（P0 -W)+（P0 -W)=2 P0 -2W （其中O-Cell加载量P0 =液压表读数标定常数)。Osterberg Cell Load Test, i.e. O-Cell Test, is a unique method of pile load test method created and guided by Prof. J. Osterberg at Northwestern university in 1991. Based on the balance principle of a

30、pair of counter forces between the pile weight and the counter directional forces including soil friction force around pile and resistance force at the bottom end, such curves as between resistance around a pile and displacement, and between resistance at the bottom end and displacement, will be obt

31、ained respectively, while the loads are applied from the upward and the downward simultaneously by means of the pressure cells which are located at the middle pile or at the pile bottom.The key equipment of the O-Cell method, which is commonly referred to as load cell or pressure cell in China, is a

32、 large tonnage hydraulic jack. When the O-Cell load test pile is carrying out, the load to O-Cell is applied by hydraulic pipeline at the pile top, and here the downward force of O-Cell is balanced by bearing capacity at the end of the pile and the upward force is balanced by the friction force arou

33、nd pile. While the O-Cell is placed at the bottom of the pile, it is vividly called loading method of pile bottom. After 20 years of continuous exploration and improvements, the O-Cell can not only be placed at the bottom of the pile, but also be placed at different parts of the pile, and many O-Cel

34、ls can be placed in a pile.The pile load P of conventional pile load test equals the friction around a pile F and the resistance at the bottom of a pile Q, that is P = F + Q, without including the reaction produced by the self weight W of a pile at the end before testing. When O-Cell method is used

35、in working pile, usually load P0 is produced by load cells in two directions (upward and downward) at the bottom of the tank. The upward load P0=W+F and the downward load is balanced by the weight of the pile and the reaction force increment at end of a pile Q due to being generated by loading, that

36、 is P0 =W+Q. The mechanism is same to loading at the top of a pile. So the load conversion of these two test methods is as follows: P=F+Q = (P0-W)+(P0 -W)=2P0-2W (1)where O-Cell loading =manometer readings calibration constant.图3-1 奥氏测桩法与传统静载方法原理对比Fig.3-1 O-Cell pile test method and the traditional

37、principle of comparative static load图3-2 奥氏测桩法Fig.3-2 The Osterberg load test method图3-3 奥氏测桩法实测荷载位移曲线示例Fig.3-3 The curve sample of the O-cell test pile method measured load displacement 图3-4 奥氏测桩法等效桩顶加载法荷载沉降曲线示例Fig.3-4 The curve sample of o-cell test pile method of equivalent pile load-settlement t

38、op loading method2)自平衡法/self-balanced method奥氏法在国内被业界称为自平衡法，自九十年代后期由美国引入中国，先后有一些国内工程采用自制的O-Cell进行试桩。自平衡法即利用上段桩侧阻力和下段桩侧阻力与端阻的自相平衡的一种测桩法。桩身某一位置，其上段桩身自重及桩侧极限摩阻力之和与下段桩桩侧极限摩阻力及极限桩端阻力之和基本相等，即为平衡点。近几年来，国内研制成功和迅速推广普及的专业荷载箱（如腔式荷载箱、囊式荷载箱)，在提高桩基安全性、试验成功率、试验安全性、试验准确性的同时，降低了检测项目成本，对自平衡测桩法的发展和完善提供了强有力的支持。The o-ce

39、ll was called self-balanced method in Chinese domestic industry, introduced from the United States since 1990s, some of the domestic engineering project in China have used homemade O-Cell to test pile. Self-balanced method is to use resistance from the top period of the pile and the resistance from

40、the descend period of the pile to reach equilibrium. The balance point is a particular location of pile, its weight of top pile and the sum of its frictional resistance of pile side in the upper limit was equal to the sum of the descend period of pile side friction and the pile tip resistance limit.

41、In recent years, with the successful development and rapid popularization of domestic professional load cases (such as cavity load cases, bladder type load box), the safety of the pile foundation, test success rate, test security, and test accuracy is increasing at the same time, the detection of th

42、e project cost is reducing, which provided a strong support for the development and perfection of the self-balanceding test method.图3-5 自平衡法测桩原理Fig.3-5 A sketch of the self-balance pile test4实施方案/Test project4.1试桩位置/ The location of testing piles工程师指定在主桥桥墩P16, P17, P18,P19和P20位置选择工作桩或制作试桩进行奥斯托堡法加载试验

43、。Specific locations will be chosen at Main Bridge pier P16, P17, P18, P19, and P20 by project engineers, where Osterberg load test will be taken through working piles or making test piles.4.2荷载箱的选择/ The choice of loading cells合格的荷载箱，是测桩成功的必要条件，但绝不是充分条件。低品质的荷载箱产品，主要表现在加载失败率较高或者加载（线性)性能超差，这将直接影响桩基加载试验

44、的成功率，以及试验数据的真实性和准确性。Qualified load cell is a necessary condition of success, but is not a sufficient condition. Load case of low quality products, mainly displays its failure rate in the loading is higher or load (linear) performance is poor, which will directly affect the success rate of pile load

45、test, and the authenticity and accuracy of test data.1)O-Cell荷载箱/O-Cell load cases采用奥斯托堡的专利产品O-Cell。根据本工程特点，选用的Cell数量及主要参数应满足表4-1之要求。Using the patented product O Cell，according to the engineering features, Cell number and main parameters should satisfy the requirements of table 4-1.表4-1试验选用O-Cell主要指

46、标Table 4-1 Main parameters in test for using O - Cell 试桩/ test pile荷载箱/ load cells桩类别/category of pile验证荷载/proof load桩数量/the numberof pileO-Cell数量/the number of O-Cell 直径/diameter最大行程/maximum stroke极限加载量/limit load3.5m试桩/ test pile275 MN14660mm150mm32MN*4*34660mm150mm3.5m工作桩/working pile165 MN34660m

47、m150mm32MN*4*22.5m试桩/ test pile125 MN13660mm150mm32MN*3*22.5m工作桩/working pile75 MN23660mm150mm32MN*3*2图3-6 O-Cell 平面布置 Fig.3-6 Layout of O-Cell2)囊式荷载箱/load cases of capsule type采用国内自制的囊式荷载箱。根据本工程特点，选用的荷载箱数量及主要参数应满足表4-2之要求。Using the domestic capsule type load cases. According to the engineering featu

48、res,the number of load cases and main parameters shall meet the requirements of table 4-2.表4-2试验选用囊式荷载箱主要指标Table 4-2 Main parameters in test using for Capsule-type Load Cells试桩/ test pile荷载箱/load cells桩类别/category of pile验证荷载/proof load桩数量/the pile number囊式荷载箱数量/the capsule type load cases number直径/

49、diameter最大行程/maximum stroke极限加载量/limit load3.5m试桩/ 3.5m test pile275 MN18650mm200mm15MN*8*38650mm200mm3.5m工作桩/3.5m working pile165 MN38650mm200mm15MN*8*22.5m试桩/ 2.5m test pile125 MN16650mm200mm15MN*6*22.5m工作桩/2.5m working pile75 MN26650mm200mm15MN*6*2图3-6 囊式荷载箱平面布置/ Fig.3-6 The layout of capsule typ

50、e load cases 4.3测试仪器安装/ Installation of test instruments测试仪器包括荷载箱及其连接的压力管线、振弦式位移传感器、应变杆和振弦式应变计等组成。Testing instrument should include load cells，its connected pressure pipeline, vibrating wire displacement sensors，strain rod and vibration chord strain gauge, etc.4.3.1荷载箱和连接的压力管线/Load box and its conne

51、cted pressure pipeline1) 根据3.5m试桩的基本要求和提供的该桩设计极限承载力，采用2层荷载箱的方法来分别测试桩侧摩阻力和桩端极限承载力。荷载箱放置在桩中性点和桩底1.5m处。每层荷载箱串联。荷载箱进、出水口分别通过压力管线连接到测试平台。测试时，压力管线两端分别连接压力传感器和空气压缩机驱动的水泵，空气压缩机提供动力水泵产生压力水，使荷载箱产生向上和向下的推力，压力传感器显示荷载箱内压力，即其产生的向上和向下的推力。2) 其余试桩和工作桩测试采用单层荷载箱，根据桩周的土质状况和桩的类别，确定荷载箱位置。1) According to the basic require

52、ments of 3.5 m test pile and the pile ultimate bearing capacity design, we adopt the method of 2-layer load cases to respectively test the limit bearing capacity of pile side friction and pile end. Load box will be placed in a neutral point of pile and pile bottom of 1.5 m. Each layer load box serie

53、s. Through pressure pipeline the inlet and outlet of load cases are connected to the test platform respectively. In the testing, both ends of pressure pipeline will connect pressure sensor and air compressor driven pump respectively, the air compressorwill powe pump pressure water, so that the load

54、box can generate upward and downward thrust and the pressure sensor indicates the pressure inside the load i.e. the upward and downward thrust.2) The rest test of testing piles and working piles will use single load box, the position of the load box will be determined by the soil condition and types

55、 of the pile. 4.3.2振弦式位移传感器/Vibrating displacement sensor在每层荷载箱上、下支撑钢板之间各安装4支基康（Geokon,USA)4450型振弦式位移传感器，在测试期间测量荷载箱的张开量。另外，安装有3组振弦式位移传感器（每组2支)，分别测量埋入到桩身内压缩应变杆的位移量。On each load case, between the upper support buttress plate and the lower support buttress, we will install four Geokon (Geokon, USA) 445

56、0-type vibrating wire displacement sensors, measuring the open test volume of load box during texting. In addition, it will be equipped with three vibrating wire displacement sensor group (n=2), to measure the amount of displacement buried within the pile compressive strain rod respectively.4.3.3应变杆

57、/Strain bars整个桩身内部安装3组埋入式压缩应变杆，测试期间分别监测整个桩身的变形量。The whole internal pile body will install 3 groups of embedded compression stem strain , respectively monitoring the amount of deformation during the test throughout the pile.4.4.4振弦式应变计/ Vibrating strain extensometer根据试桩参考地质钻孔资料，在主要土层分界面安装振弦应变计，在承载力测试

58、期间，通过读取应变计的读数来测量桩对各主要土层的摩擦力。According to the reference of test pile geological drilling data, vibrating wire strain gage should be installed in main soil interface.During the capacity test,the friction of the major soil will be measured by the strain gauge readings.4.3.5塑料管/Plastic pipe从每层荷载箱底板至桩顶安装

59、有2根塑料管，在测试期间，通过保持管内水位，从而平衡荷载箱打开时产生的负压。2 Plastic pipes will be installed on each load from the bottom plate to the pile top during the test. The negative pressure generated fro the opening of the box will be balanced by maintaining the water level in the tube.4.3.6动力组件/Power componentsO-Cell盒液压软管接在动力

60、组件上。动力组件是压缩空气驱动的液压泵（最小185cfm、125psi)，用于驱动O-Cell盒的压力介质是水。系统内的液压（等同于对桩的压力)也将被数据采集系统所记录。O-Cell cassette hydraulic hose is connected to the power system and components. Power unit is a pneumatically driven hydraulic pump (minimum 185cfm, 125psi), and the pressure medium for driving the O-Cell cassette i

61、s water. Hydraulic system (equivalent to the pressure of the pile) will also be recorded by data acquisition system.4.3.7安装基准梁及数据采集系统/Installation of reference beam and data collecting system在试桩开始前，在桩顶上方安装了一个基准梁，用来作为测量桩顶位移的平台。此基准梁由试桩影响区域范围外的位置提供支撑，（一般来说，此位置在试桩桩径的四倍范围外)以确保桩在测试中的移动不会影响基准梁。本梁的一端是可以自由移动

62、的，以将热影响造成的误差减到最小。本次试桩工程中，3.5m试桩在水上平台上进行工作，平台的基础桩如离试验桩的距离在15m 以上时，建议可将基准梁架设在平台上即可，同时再用其他手段（如光学测量)监测基准梁（平台)有无沉降。在基准梁上应有保护罩以避免阳光直射（阳光能造成参照梁的移动)和风的影响（风会干扰位移传感器)。位移转换器会以基准梁为基准来测量桩顶的位移及报警。计算机校准水平装置则置于桩的影响区域之外以监测参照梁的所有移动，校准目标点安装在基准梁的中心点。所有的仪器都将被连接到在试桩过程中自动读数的电脑数据采集系统。Before the beginning of pile testing, a

63、 reference beam will be installed above the top of the pile as a measure of the displacement of the pile internet. This reference beam was provided by the location region outside the scope of influence (in general, this location is outside the range of the test pile diameter four times) ,to ensure that the movement of the pile in the test will not affect the reference beam. One end of the beam can move freely to reduce the error of the heat impact. In this test pile construction, 3.5m test pile work on water platform .If the distance from the test piles