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 18,2014

January 21.2014

Project name
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Owner
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Investigation Company
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Design Company
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Construction Company
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Testing Company
：

The Main testing Technicist and
Certificate No.
：

Compiled by
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Checked by
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Review by
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Approved by
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Explanation
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Testing Company Address
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Postal code
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Table of Content

1．Project Summery 4
2．Principles and Methods of Testing 6
2.1 Low Strain Integrity Testing 6
2.2 High Strain Dynamic Testing 6
3．Equipment 7
4．Test Result 8
4.1 Detection of low strain pile integrity 8
4.2 High strain detection of vertical bearing capacity of a single pile 9
5．Conclusion 10

Figure: 11
1.Low-strain curve 11
2.High-strain curve 13
3.Foundation pile detection plan 18
1．Project Summery
The 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 type
Foundation Types
Characteristic value
of subgrade bearing（kN/m2）
Fire emergency Center
19.3
Reinforced Concrete Frame
Independent column base or pile
180
Ammonia Tank
19.7
Local Steel Frame
Raft or piles & raft
200
Torch
21.6
Steel Frame
Raft or piles & raft
180～200
Urea Plant
19.7
Steel Frame
Independent column base or pile
200
Packing House
20.3
Steel Frame
Independent column base or pile
200
Bulk Urea Warehouse
20
Steel Portal Frame(Steel)
Independent column base or pile
200
Urea Bagged Warehouse
20.3
Steel Portal Frame(Steel)
Independent column base or pile
200
Central Control Building
19.5
Reinforced Concrete Frame
Independent column base or pile
200
Cooling Water Unit
19.4
Steel Frame with tower pool below
Raft or piles & raft
180
Sewage-treatment Unit
17.5
Reinforced Concrete Frame
Independent column base or pile
180
Natural Gas Metering Station
19.5
Reinforced Concrete Frame
Independent column base or pile
180
Main Substation
19.5
Reinforced Concrete Frame
Independent column base or pile
200
Synthetic Ammonia Installation Substation
19.5
Reinforced Concrete Frame
Independent column base or pile
200
Urea Plant Distribution Room
19.7
Reinforced Concrete Frame
Independent column base or pile
200
Integrated Warehouse
19.0
Steel Portal Frame(Steel)
Independent column base or pile
180
Laboratory Technical Building
19.3
Reinforced Concrete Frame
Independent column base or pile
200
Chemical Warehouse
19.0
Reinforced Concrete Frame
Independent column base or pile
180
Administration Building
19.0
Reinforced Concrete Frame
Independent column base or pile
200
Dinning Rooms
19.0
Reinforced concrete structure
Independent column base or pile
180
Guard House
18.5
Reinforced Concrete Frame
Independent column base or pile
150
Demi water system general
19.3
Steel Portal Frame(Steel)
Independent column base or pile
180
A2 district Air Compressor building
19.7
Frame-bent
Independent column base or pile
200
D1 district Combination Compressor building
19.7
Frame-bent
Independent column base or pile
200
The 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”.
2．Principles and Methods of Testing
2.1 Low-Strain Pile Integrity Testing
The 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/Vb
where 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 correct
2.2 High Strain Dynamic (Drop-Weight) Testing
Place 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 doesn't 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.

3．Equipment

The 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 follows
1、
RS-1616K（P）dynamic test of piled foundation instrument
1 set
2、
Strain-Measurement Sensor
2
3、
Piezoelectric Accelerometer
2
4、
High Strain Adapter
1
5、
Accelerometer
2
6、
Rod,Knockdown hammer and hammer and auxiliary equipment
1 set
4．Test Result
4.1 Low-Strain Pile Integrity Testing
This 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 pile
Pile integrity category
Principles of classification
Ⅰpile
Pile integrity
Ⅱ pile
Pile has a slight defect,will not affect the bearing capacity of pile
Ⅲ pile
Pile with obvious defects，have an impact on the bearing capacity of pile
Ⅳ pile
Pile is seriously flawed

Table of the integrity decision of pile
Category
Time-domain signal characteristics
Ⅰ
The device receives reflected waves without defects while gains the reflected waves from the bottom of the piles before the moment of 2L/c
Ⅱ
The 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
Ⅲ
The reflected waves contain definite defects, with other characteristics between class type of Ⅱ and Ⅳ
Ⅳ
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 method
No.
Pile No.
Pile length
（m）
Pile diameter
（mm）
Wave speed
（m/s）
Integrity description
Category
1
1
18.1
500
3868
Pile integrity
Class I
2
3
18.1
500
3935
Pile integrity
Class I
3
4
18.1
500
3901
Pile integrity
Class I
4
5
18.1
500
3835
Pile integrity
Class I
5
6
18.1
500
3868
Pile integrity
Class I
6
7
18.1
500
3835
Pile integrity
Class I
7
9
18.1
500
3935
Pile integrity
Class I
8
10
18.1
500
3835
Pile integrity
Class I
9
11
18.1
500
3803
Pile integrity
Class I
10
12
18.1
500
3709
Pile integrity
Class I
4.2 High strain Testing for vertical bearing capacity of a single pile
This 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 described in the each test piles figures ’Measured Force and the Measured Velocity Curve’。Using the CCWAPC fitting analysis software that provided by Rock engineering in Wuhan technology development company to fitting analysis calculation, results are detailed in the test pile ’Results of Fitting Analysis of High Strain software CCWAPC’. Based on the analysis results, determine that the value of bearing capacity of piles show as the table below:
Summery of the test result about pile high
No.
Pile No.
Pile diameter(mm)
Pile length(m)
Characteristic value of single pile vertical bearing capacity (kN)
By the measurement of high-strain curve-fitting to determine the vertical ultimate bearing capacity of a single pile (kN)
1
2
500
18.1
1000
2115.0
2
3
500
18.1
1000