CN104132846A

CN104132846A - Tube pile body concrete total cross section intensity examination method

Info

Publication number: CN104132846A
Application number: CN201410310097.6A
Authority: CN
Inventors: 郭杨; 崔伟; 吴平; 柯宅邦; 费爱民
Original assignee: Anhui Institute of Architectural Research and Design
Current assignee: Anhui Institute of Architectural Research and Design
Priority date: 2014-06-30
Filing date: 2014-06-30
Publication date: 2014-11-05
Anticipated expiration: 2034-06-30
Also published as: CN104132846B

Abstract

The invention relates to a tube pile body concrete total cross section intensity examination method. The method comprises the following steps: one tube pile in each batch of square piles is drawn, three standard test pieces with height diameter ratio of 1: 1 are cut in a tube pile stirrup non-encryption zone, three standard test pieces are respectively performed with a compressive strength test, then a compressive strength mean value can be calculated; then subtraction is carried out from the compressive strength value of a certain standard test piece to the compressive strength mean value so that intensity range of the standard test piece can be obtained; if the ratio of absolute value of the intensity range for any standard test piece and the compressive strength mean value is less than 30%, the compressive strength mean value is taken as the compressive strength of the pile body concrete; if the ratio of absolute value of the intensity range for any standard test piece and the compressive strength mean value is greater than 30%, minimum compressive strength value is taken as the compressive strength of the pile body concrete. The method has the advantages of scientific material selection, simple process and reasonable method, simultaneously, the obtained concrete compressive strength accords with practical compressive strength of the tube pile body concrete.

Description

A kind of tubular pile body concrete total cross-section ruggedness test method

Technical field

The present invention relates to a kind of tubular pile body concrete total cross-section ruggedness test method.

Background technology

Pretensioned prestressed concrete pipe pile, refers to a kind of slender hollow body concrete prefabricated element that adopts pretensioned prestressing and centrifugal casting to make.Such stake has that the raw quality of the industrial scale of being suitable for is easy to ensure, bearing capacity of single pile is high, to fast, the on-the-spot advantage such as pollution-free of engineering geologic condition strong adaptability, speed of application; therefore, the application of pretensioned prestressed concrete pipe pile in engineering is more and more extensive.

Tubular pile body strength grade of concrete is generally C60 or C80, the construction of pile tube is general hammering method or the static pressure method of adopting at present, two kinds of methods require highly to tubular pile body intensity, as tubular pile body undercapacity, easily cause cracking of pipe pile or quick-fried stake accident in work progress.Because the existing pile concrete compressive strength method of inspection is checked and is obtained compressive strength and actual pile concrete compressive strength and do not meet, therefore in the time there is cracking of pipe pile or quick-fried stake accident in work progress, tend to cause the dispute to on-the-spot tubular pile body compressive strength of pile tube manufacturer and tube pile construction unit.

In order accurately to detect and to reflect actual pile concrete compressive strength, improve in the urgent need to the ruggedness test method to pile concrete.

Summary of the invention

The object of this invention is to provide a kind of tubular pile body concrete total cross-section ruggedness test method.Method of inspection selection science in the present invention, method is reasonable, and assay is comparatively accurate.

For achieving the above object, the present invention adopts following technical scheme:

A kind of tubular pile body concrete total cross-section compressive strength method of inspection, it comprises the steps:

1), extract a root canal pile by every batch of pile tube, in the pile tube stirrup non-encrypted area of this pile tube, cutting processing is made three standard specimens, the height of described three standard specimens and external diameter ratio are 1:1, then three standard specimens are carried out respectively to compressive strength test, obtain the compression strength value of each standard specimen;

2), calculate the compressive strength mean value of three standard specimens; Then to each standard specimen, the compression strength value of this standard specimen is deducted to described compressive strength mean value, obtain the intensity extreme difference of this standard specimen;

3) if the absolute value of the intensity extreme difference of each standard specimen and the ratio of described compressive strength mean value in 30% time, getting described compressive strength mean value is pile concrete compressive strength; If when the absolute value of the intensity extreme difference of any standard specimen and the ratio of described compressive strength mean value are greater than 30%, the minimum compression strength value of getting in three standard specimens is pile concrete compressive strength.

Preferably, step 1) in, first the core that cutting obtains on pile tube carries out end face processing, adopts epoxy mortar or polymer cement mortar levelling, can make standard specimen.

Beneficial effect of the present invention is: selection science of the present invention, step is simple and method is reasonable, the more realistic tubular pile body concrete crushing strength of concrete crushing strength that inspection institute obtains simultaneously.

Brief description of the drawings

Fig. 1 is the test section schematic diagram that intercepts ratio of height to diameter 1:1 in this explanation in pile tube stirrup non-encrypted area.

Fig. 2 is the end face machining sketch chart of the pile tube test section of intercepting in this explanation.

In figure, the implication of label symbol is as follows:

1-end plate, 2-spiral bar, 3-prestressed steel bar

4-pile protection hoop, 5-test section

Long L1-the pile tube of L-pipe pile hoop reinforcement length

L2-pile tube stirrup non-encrypted area length

D-pile tube overall diameter H-test section height t-pile tube wall thickness

Embodiment

As shown in Figure 1, from having the pile tube of intensity dispute or the pile tube of same batch, extract a root canal pile, pile tube length is L, regulation and stipulation, the pitch of pile tube two ends 2000mm scope inside spin muscle is 45mm (being pile tube hoop reinforcement), and the pitch of remainder spiral bar is 80mm (being pile tube stirrup non-encrypted area).Shown in Fig. 1, the region at length L 1 place, pile tube hoop reinforcement is pile tube hoop reinforcement, L1=2000mm; And the region at length L 2 places, pile tube stirrup non-encrypted area is pile tube stirrup non-encrypted area.

Intercepting test section 5 in the region at length L 2 places, pile tube stirrup non-encrypted area is standard specimen, and test section height H is identical with pile tube overall diameter D, and the ratio of height to diameter of test section 5 pile bodies is 1:1.

First test section 5 after sawing carries out end face processing, and two of test section 5 end faces all adopt epoxy mortar or polymer cement mortar levelling to obtain end plate 1, and the ratio of height to diameter of test section 5 pile bodies that contain end plate 1 remains 1:1.

Carrying out the size that should be standard specimen by following specifying measurement test section 5 before compressive strength test:

(1) mean diameter

Measure on orthogonal two positions, test section 5 middle parts with vernier caliper, get the arithmetic mean of measurement as the diameter of test section 5, be accurate to 0.5mm;

(2) highly

By steel tape or Steel Ruler, test section 5 is measured, be accurate to 1mm;

(3) verticality

The angle of measuring 5 two end faces of test section and bus with vernier protractor, is accurate to 0.1 °;

(4) flatness

Abut against with Steel Ruler or angle square on the end face of test section 5, one side is rotated Steel Ruler, and one side is measured the gap between Steel Ruler and test section 5 end faces with clearance gauge; Also can adopt other specialized equipments to measure.

When the dimensional discrepancy of test section 5 and presentation quality exceed following numerical value, corresponding test data is invalid:

(1) the actual ratio of height to diameter (H/D) of test section 5 be less than requirement ratio of height to diameter 0.95 or be greater than at 1.05 o'clock;

(2) differ by more than 2mm along arbitrary diameter and the mean diameter of test section 5 height;

(3) irregularity degree of test section 5 end faces is greater than 0.1mm in 100mm length;

(4) non-perpendicularity of test section 5 end faces and axis is greater than 1 °;

(5) test section 5 has crack or has other larger defects.

The concrete crushing strength of test section 5 can be calculated as follows:

f _cu,cor＝Nc/A

In formula: f _{cu, cor}the concrete crushing strength value (MPa) of-test section 5;

The maximum pressure (N) that the compression test of Nc-test section 5 records;

A-test section 5 resistance to compression area of section (mm ²);

To the same model pile tube of same engineering, at least carrying out three groups tests above, in the time that the ratio between the absolute value of intensity extreme difference and the compressive strength mean value of three standard specimens of three standard specimens is all in 30%, getting compressive strength mean value is pile concrete compressive strength; Otherwise the minimum compression strength value of getting in three standard specimens is pile concrete compressive strength.

For technical characterictic of the present invention, object and beneficial effect are had to better understanding, below in conjunction with specific embodiment, the present invention will be further described, but the present invention is not restricted to the present embodiment.

Embodiment 1

Common core drilling method detects concrete vertical compression Strength Testing Methods, its core diameter getting out is 75～100mm, differ larger with the size of conventional tubular pile body diameter 400～800mm, and subsized specimen can not react the vertical compression bearing capacity of tubular pile body all-sidedly and accurately.

Now adopt ruggedness test method in the present invention and conventional core drilling method to contrast.

The pile tube that specimen sample adopts is PHC400-AB-95 model, and its parameter is: pile tube overall diameter D is that 400mm, pile tube wall thickness t are that 95mm, centrifugal concrete Intensity Design grade are that C80, prestress reinforcement are the prestressed high strength concrete pile tube of 7 Φ 10.7mm.

Being processed into according to the cutting method in the present invention the total cross-section pile body compressive strength standard test specimen that 3 height and overall diameter (ratio of height to diameter) are 1:1 is test section 5, first test section 5 after sawing carries out end face processing, adopt epoxy mortar or polymer cement mortar levelling, finally make test section 5 Pass Tests canonical sized; In order better to compare the accuracy of two kinds of methods, on same root canal pile, drill through the sample that 3 diameters are 75mm; Two groups of samples carry out respectively compressive strength test the most at last, and interpretation of result is as table 1.

Table 1 tubular pile body total cross-section compressive strength

For the ruggedness test method in the present invention, its result of calculation is as follows:

1) the compressive strength mean value of standard specimen 1#, 2#, 3# is:

2) difference of the compressive strength of standard specimen 1# and compressive strength mean value is that intensity extreme difference is:

F _{Δ 1}=f _1#-f _flat=92.3-89.0=3.3MPa;

Can obtain

Can be regarded as out successively standard specimen 2#, 3# sample be respectively-1.8MPa of intensity extreme difference and-1.5MPa, the intensity extreme difference of three standard specimens is all less than 30% (0.3f of compressive strength mean value _flat).

Therefore, adopt the pile tube total cross-section concrete strength f of the final gained of ruggedness test method in the present invention ₁=89.0MPa, and can calculate according to " bore core and detect centrifugal strong concrete compressive strength test method " the concrete strength f that adopts core-drilling method to obtain ₂=72.6MPa; The concrete strength of the pile tube adopting in this test is C80, is f according to the compressive strength of the cube concrete anti-compression test gained tubular pile concrete at scene, pile tube field _c=80.0MPa.

It is to be noted, in ruggedness test method of the present invention, in institute's accepted standard test specimen, contain the main muscle of prestress, and reinforcing bar has certain compressive strength, therefore in ruggedness test method of the present invention, the concrete strength of gained should be greater than the actual concrete strength of pile tube, and pile tube total cross-section concrete strength f in the present embodiment ₁be greater than the actual compressive strength f of tubular pile concrete _cthereby the concrete crushing strength of the method gained of present patent application meets the actual concrete strength of pile tube more, and intensity is about 1.22～1.24 times of core drilling method concrete crushing strength value.

Claims

1. a tubular pile body concrete total cross-section compressive strength method of inspection, is characterized in that comprising the steps:

2. a kind of tubular pile body concrete total cross-section compressive strength method of inspection according to claim 1, it is characterized in that: step 1) in, first the core that cutting obtains on pile tube carries out end face processing, adopts epoxy mortar or polymer cement mortar levelling, can make standard specimen.