高低应变检测报告(英文版).doc

Pile High-Strain Dynamic (Drop-Weight) Testing and Low-Strain Pile Integrity Testing Report（Final）Project Name：Testing Location：Testing Time：January 18,2014January 21.2014Project name：Owner ：Investigation Company：Design Company：Construction Company：Testing Company：The Main testing Technicist and Certificate No.：Compiled by：Checked by：Review by：Approved by：Explanation：Testing Company Address：Postal code：Table of Content1Project Summery42Principles and Methods of Testing62.1 Low Strain Integrity Testing62.2 High Strain Dynamic Testing63Equipment74Test Result84.1 Detection of low strain pile integrity84.2 High strain detection of vertical bearing capacity of a single pile95Conclusion10Figure:111.Low-strain curve112.High-strain curve133.Foundation pile detection plan181Project SummeryThe proposed building(structure) divide into Working Area and Equipment Area. Working area mainly include: Fire Emergency Center, Administration Building, Dinning Room, Prayer Room etc.; Equipment area mainly include: Main Substation, Stream&Generating Set, Integrated Pumping station, Waste Disposal Plant, Cooling Water Unit, Packing House, Torch, Synthetic Ammonia Installation, Ammonia Tank, Urea Plant, Urea Bagged Warehouse, Bulk Urea Warehouse etc. Major building(structure)shown in the table below:Project Name Outdoor ground designed levation（m）Structure typeFoundation TypesCharacteristic value of subgrade bearing（kN/m2）Fire emergency Center19.3Reinforced Concrete FrameIndependent column base or pile 180Ammonia Tank19.7Local Steel FrameRaft or piles & raft 200Torch 21.6Steel FrameRaft or piles & raft180200Urea Plant19.7Steel FrameIndependent column base or pile 200Packing House20.3Steel FrameIndependent column base or pile 200Bulk Urea Warehouse20Steel Portal Frame(Steel)Independent column base or pile200Urea Bagged Warehouse20.3Steel Portal Frame(Steel)Independent column base or pile200Central Control Building19.5Reinforced Concrete FrameIndependent column base or pile200Cooling Water Unit19.4Steel Frame with tower pool belowRaft or piles & raft180Sewage-treatment Unit17.5Reinforced Concrete FrameIndependent column base or pile180Natural Gas Metering Station19.5Reinforced Concrete FrameIndependent column base or pile180Main Substation19.5Reinforced Concrete FrameIndependent column base or pile200Synthetic Ammonia Installation Substation19.5Reinforced Concrete FrameIndependent column base or pile200Urea Plant Distribution Room 19.7Reinforced Concrete FrameIndependent column base or pile200Integrated Warehouse19.0Steel Portal Frame(Steel)Independent column base or pile180Laboratory Technical Building19.3Reinforced Concrete FrameIndependent column base or pile200Chemical Warehouse19.0Reinforced Concrete FrameIndependent column base or pile180Administration Building19.0Reinforced Concrete FrameIndependent column base or pile200Dinning Rooms 19.0Reinforced concrete structureIndependent column base or pile180Guard House18.5Reinforced Concrete FrameIndependent column base or pile150Demi water system general19.3Steel Portal Frame(Steel)Independent column base or pile180A2 district Air Compressor building19.7Frame-bentIndependent column base or pile200D1 district Combination Compressor building19.7Frame-bentIndependent column base or pile200The detection of the project, using bored pile foundation, and technology of long spiral drilled, the total number of pile is 12, length 18.9m,effective length 18.1m,diameter 500mm,single-pile vertical bearing capacity characteristic value of 1000kN,concrete class C30.Our Company undertake the Engineering Foundation pile detection tasks, use High-Strain Dynamic (Drop-Weight) Testing method to detect the vertical bearing capacity of a single pile which detection number is 5,and use the low-strain method to detect the pile integrity, the amount of which is 10. The testing work began on January 18,2014,completed on January 18,2014. According to drilling report，the stratum consists of plain and miscellaneous fill, Silt , Silty clay, clay etc.,described as below:Layer 0，Miscellaneous fill: variedness，mainly composed of construction waste. Just No.JT2 pore is distributed at preliminary prospecting.Layer 0A，Plain fill:brick red with gray,mainly silty sand,mixed with a little silt.Just No.140 and 144 pore are distributed.Layer 1A0，Silty clay:from brick red to yellowish-brown with gray,mixed with a little silty sand.Soft plastic.High compressibility.Local distribution.Layer 1A1-1,silty sand:brown with gray,mixed with a little silt and a very small amount of clay.From very wed to saturation,loose.High compressibility.Scattered distribution.Layer 1A1,silty sand:from brick red to brown-yellowish with gray,mixed with a little silt and a very small amount of clay.From very wed to saturation,from loose to slightly dense.High compressibility.Local distribution.Layer 1A,Silty clay:gray,yellowish-brown,with a little silty sand.Plastic.Medium plastic.Widely distributed.Layer 1A2,silt:from yellowish-brown to brick red,mixed with a little clay.Medium dense,from wed to very wed.Medium compressibility.Scattered distribution.Layer 2A0,silt:from yellowish-brown to brown with gray,mixed with a little of clay.From medium to dense，from wed to very wed.Medium compressibility.Local distribution.Layer 2A,Silty clay:from yellowish-brown to brick red,mixed with a little of clay silt. Frome medium plastic to hard plastic.Medium compressibility.Local distribution.Layer 2A1,silty sand:light brown and yellowish-brown with gray，mixed with a little of clay silt.Medium dense,saturation.Medium compressibility.Widely distributed.Layer 3A,silty sand:gray,yellowish-brown,mixed with a little of clay middle-fine-sand and silt.Dense,saturation.Medium biased toward high compressibility.Widely distributed.Layer 3B,silty sand:gray,yellowish-brown,containing mica,mixed with a little of clay middle-fine-sand and silt.dense,saturation.Medium biased toward high compressibility.Widely distributed.Layer 3B1,Silty clay:from light brown to blue-gray,mixed with a little of clay middle-fine-sand.hard plastic.Medium compressibility.Scattered distribution.Layer 3C,silty sand:from gray to yellowish-brown,containing mica，mixed with a little of clay middle-fine-sand and silt.Dense,saturation.Low compressibility.Widely distributed.Layer 3D,silty sand:from gray to yellowish-brown,containing mica,mixed with a little of clay middle-fine-sand and silt.From slightly dense to medium dense，saturation.Just No.JT1 pore are distributed at preliminary prospecting.Medium compressibility.The physical and mechanical properties of aquifers is provided by the detailed survey report according to” Project Geotechnical Investigation Report”.2Principles and Methods of Testing2.1 Low-Strain Pile Integrity TestingThe Sonic-Echo test is performed by striking the pile head with a light hammer and measuring the response of the pile with a sensor (accelerometer or geophone velocity transducer) coupled to the pile head. The hammer blow generates a compressive stress wave which is channeled down the pile shaft as a bar-wave. The latter is partly reflected back towards the pile head by any change in impedance within the pile. These impedance changes can be as a result of changes in pile section, concrete density or shaft-soil properties. The stress wave is transmitted through the pile at velocity, Vb (where Vb is the bar-wave velocity of propagation through the pile material) and the time lapse, t, between the hammer impulse and the arrival of the reflected waves at the pile head from pile tip is a measure of the distance traveled by the stress wave, such that:t = 2L/Vbwhere L represents the distance to the reflecting surface (pile tip in this case). If the value of Vb, is known, or can be estimated within reasonable limits, then will give an estimate of the pile length or the depth to any other reflecting surface within the pile. If the pile length is known, then a comparison can he made between (he length calculated from the test result and the known length, in order to verify that the depth to the reflecting surface is correct2.2 High Strain Dynamic (Drop-Weight) TestingPlace a weight and decoupling device over the pile head. Releasing the decoupling in the experiment,the weight fall free and impact the pile head, generated stress wave spread down along the pile. cause of the soil resistance stress wave is reflected back to the pile head, and change the motion speed of particle of the pile. Using the strain and acceleration sensors at a distance of 1.5 to 2 times of the pile diameter record the acceleration and stress wave of pile when the weight fall free. Using pile analyzer curve fitting calculate the bearing capacity that is equivalent to the bearing capacity under static load based on the measured curve below: Assume the pile and the soil mechanics model and model parameters of each unit, using the measurement of velocity or force curve as the input boundary conditions, Numerically solving wave equation, Inverse the force or velocity curve of the pile head. If the calculated curves doesnt match the measured curve, it means that the model and the measured curve is not reasonable, targeted to adjust the model and parameters and then calculated, Until the calculated curve and the measured curve is match and can not be improve easily. At this time, the assumption model and parameters can simulate the static load tests, according to the simulation of static load test, the bearing capacity of the pile can be analysis and calculated. 3EquipmentThe devices used in high strain and low strain dynamic testing are RS-1616K (S)-type pile dynamic testing instrument and its sensors, strain rings and other accessories produced by China Engineering Technology Co., Ltd., Wuhan, and these devices have acquired the national type approval of measuring instruments (CPA: State Bureau of Technical Supervision License No. 96R105-42), and its manufactory obtained the measuring equipment manufacturing production permission of the device (CMC: 96 volume of the system Hubei word 01000216-3 No.). These devices, its sensors, strain rings and other measuring are tested and certificated by the Research Institute, the certificate number: force value No. 120202795.The devices and accessories as follows1、RS-1616K（P）dynamic test of piled foundation instrument1 set2、Strain-Measurement Sensor23、Piezoelectric Accelerometer24、High Strain Adapter15、Accelerometer 26、Rod,Knockdown hammer and hammer and auxiliary equipment1 set4Test Result4.1 Low-Strain Pile Integrity TestingThis detection applies low strain dynamic testing method to detect the integrity of these piles. Live recording of the measured signal curves refer to low strain curves of the time domain.Based on Building pile testing technical specifications (JGJ106-2003), the tables of classification and decision which are the results of the detection of integrity of piles by low strain dynamic testing as follow:Table of the integrity classification of pilePile integrity categoryPrinciples of classificationpilePile integrity pilePile has a slight defect,will not affect the bearing capacity of pile pilePile with obvious defects，have an impact on the bearing capacity of pile pilePile is seriously flawedTable of the integrity decision of pileCategory Time-domain signal characteristicsThe device receives reflected waves without defects while gains the reflected waves from the bottom of the piles before the moment of 2L/cThe device receives reflected waves with a few defects while gains the reflected waves from the bottom of the piles before the moment of 2L/c The reflected waves contain definite defects, with other characteristics between class type of and The reflected waves is periodic, or contain severe defects, without reflected waves from the bottom of the piles at the moment of 2L/c;Or because severe defects of shallow piles cause the waveform showing low frequency and large scale amplitude attenuation vibration , without reflected waves from the bottom of the piles.Note:piles on the same grounds with close geological conditions, and the same type of pile, as well as the same pile process can be determined the pile integrity category by the pile-bottom reflections measured signals of other piles which has the same conditions of this site,due to the pile-end impedance of piles match with supporting layer impedance cause the measured signal without the pile-end reflected wave. According to the Classification Table of integrity of the piles and Decision Table of integrity of the piles, the analyzed the live recording of the measured signal curve and the following determing results as follow: The collection table of detection of piles by low strain dynamic testing methodNo.Pile No.Pile length（m）Pile diameter（mm）Wave speed（m/s）Integrity descriptionCategory1118.15003868Pile integrityClass I2318.15003935Pile integrityClass I3418.15003901Pile integrityClass I4518.15003835Pile integrityClass I5618.15003868Pile integrityClass I6718.15003835Pile integrityClass I7918.15003935Pile integrityClass I81018.15003835Pile integrityClass I91118.15003803Pile integrityClass I101218.15003709Pile integrityClass I4.2 High strain Testing for vertical bearing capacity of a single pileThis project detect 5 piles by using high strain，the hammer is weight 20kN,drop height is 0.5 to 1.0m.On the measurement of test pile and velocity curve is des