Is it mandatory to test the integrity of piles in pile foundations?

Technical Code for Building Pile Foundation Testing JGJ106-2003 The number of pile integrity tests of concrete piles shall comply with the following provisions:

1. Three piles or less cushion caps under the column.

The number of random inspections shall not be less than 1.

2. The design grade is Grade A, or the geological conditions are complex, and the quality and reliability of the pile are low.

The number of random inspections shall not be less than 30% of the total piles, and shall not be less than 20; Other pile foundation works.

The number of random inspections shall not be less than 20% of the total number of piles, and shall not be less than 10. (Note: 1 For end-bearing large-diameter cast-in-place piles, within the range of the number of sampling piles specified in the above two paragraphs, the core drilling method or ultrasonic transmission method should be used to test the integrity of some of the inspected piles.)

The number of random inspections should not be less than 10% of the total number of piles.

2. Manually dug piles above the groundwater level and the bearing layer at the pile end after the final hole has passed the verification.

and single-section concrete precast piles, the number of sampling can be appropriately reduced, but should not be less than 10% of the total number of piles, and should not be less than 10. ）

3. When the number of piles in accordance with the provisions of paragraphs 1-4 is large, or in order to fully understand the integrity of the pile of the entire project, the number of sampling should be appropriately increased.

The selection of the inspected pile for the acceptance and sampling of the bearing capacity of the single pile and the integrity of the pile should meet the following requirements:

1. Piles with questionable construction quality;

2. The designer considers the pile to be important

3. Piles with abnormal local geological conditions;

4. Piles with different construction techniques;

5. When the bearing capacity is accepted and monitored, the third type of pile judged in the integrity test is appropriately selected;

6. In addition to the above provisions, piles of the same type should be evenly and randomly distributed.

7. Pure hand fighting, encouragement.

The time for pile foundation integrity testing after pile formation shall be clearly specified according to the type of pile, the type of soil, the testing method, the design requirements and the current specifications.

1. "Technical Code for Building Pile Foundation" JGJ94-94 is clear:

1 Vertical compressive static load test of single pile Horizontal static load test of single pile.

The piling process and quality control standards of the test pile should be consistent with that of the engineering pile. In order to shorten the curing time of the test pile, the concrete strength grade can be appropriately increased, or mixed with early strength agent.

2. Static load test of vertical uplift of single pile.

2. "Technical Code for Building Foundation Pile Detection" JGJ 106-2014

Pile integrity -- a comprehensive qualitative index that reflects the relative change of pile cross-sectional size, the compactness and continuity of pile material.

The start time of pile inspection shall comply with the following provisions:

1. When using low strain or acoustic transmission method to detect, the concrete strength of the inspected pile should not be less than 70% of the design strength, and should not be less than 15MPa;

2. When the core drilling method is used for testing, the age of the inspected concrete should reach 28d, or the strength of the curing specimen of the inspected pile under the same conditions should meet the design strength requirements;

3. The rest time before the bearing capacity test should not be less than the time specified in the table below.

After construction, it is advisable to first test the integrity of the engineering pile, and then carry out the bearing capacity test. When the foundation is buried deeply, the pile integrity test should be carried out after the foundation pit is excavated to the foundation elevation.

3. The purpose and inspection method of pile integrity testing.

1. For prefabricated pipe piles, all the piles are completed, and the pile foundation can be tested after the telogen period. At this time, the bearing capacity and pile integrity can also be tested.

2. For concrete cast-in-place piles, when all the construction of the piles is completed, and the concrete strength of the piles reaches more than 90%, it is basically about 25 days before the bearing capacity and pile integrity can be tested. The best test is after 28 days.

To divide the kind of detection:

Static load: after 28 days.

Acoustic measurement: before pouring concrete.

Small strain: 7 days after pouring concrete.

Great strain: 14 days after pouring concrete.

Take a look at this, "Technical Code for Building Foundation Pile Detection" JGJ106-2003, should be able to solve your problem. When you encounter a problem, look up the specification, and others will not be able to explain it to you in a sentence or two.

Prefabricated piles generally take about a week, to give the surrounding soil a recovery cycle, cast-in-place piles are generally about 28 days before the concrete matures!

The number of cushion caps under the mandatory specification column with three piles or less than three piles shall not be less than 1.

1. Pile foundation.

For cast-in-place piles with a design grade of Grade A, or complex geological conditions and low reliability of pile quality, the number of sampling should not be less than 30% of the total piles and not less than 20; The number of sampling of other pile foundation projects shall not be less than 20% of the total number of piles, and shall not be less than 10.

2. Integrity test.

Integrity testing is a necessary means to ensure the safety of the filtration process for critical sterilization-grade filtration processes. Integrity testing ensures the integrity of the filter itself and its correct installation, ensures that the correct filter is installed in the process, that the installed filter meets the manufacturer's standards, that the filtration system is airtight, and more.

3. Testing regulations for the integrity of the pile in the pile foundation.

Technical Code for Building Pile Foundation Testing JGJ106-2003 The number of pile integrity tests of concrete piles shall comply with the regulations.

Pile integrity inspection.

Mainly to detect the integrity of the pile, silver elimination detection methods include low strain method, acoustic transmission method, high strain method and core drilling method, in addition to small and medium-diameter cast-in-place piles, large-diameter cast-in-place piles are generally selected at the same time to use two or more methods to detect, so that various methods can complement each other and complement each other's advantages.

In addition, when there may be technical difficulties in determining the integrity of pile foundations with high design grade, complex foundation conditions, large variability of construction quality, or low strain integrity, it is recommended to use direct methods (static load test, core drilling and excavation, pipe piles can use in-hole cameras) for verification.

The purpose of integrity testing is to find some defects that may affect the bearing capacity of a single pile, and ultimately to reduce potential safety hazards and reliably determine the bearing capacity of engineering piles.

The integrity of the pipe pile is generally detected by the low strain reflection wave method, and the integrity of the pipe pile is judged by collecting representative waveforms, and scientifically and accurately analyzing and judging the collected waveforms.

The detection generally adopts the method of sampling, which generally requires that the number of piles under the column shall not be less than 1 for the cap with three piles or less than three piles, and the total number of sampling shall not be less than 20% of the total number of piles, and not less than 10; If the design grade is Class A, or the local geological conditions are complex, or the cast-in-place piles with low quality and reliability of the piles are used, the number of random inspections is required to be not less than 30% of the total number of piles, and the number of random inspections shall not be less than 20.

Pipe pile bearing capacity test is generally carried out by static load test of vertical compressive bearing capacity of single pile under the conditions of design grade A, complex geological conditions, low reliability of pile construction quality, new pile type or new technology adopted or squeezing effect caused by pile group construction.