The testing of test piles shall be based on the stress state of the foundation piles determined by the design, and the corresponding static load test method shall be used to determine the ultimate bearing capacity of a single pile.
Select the pile end bearing layer.
Acoustic transmission method: detect pile defects and their locations, and determine the integrity category of the pile.
2.
Determine the process parameters of pile sinking; 3.
3.3.2 When driven precast piles have one of the following requirements, the high strain method should be used to monitor the driving process of the trial pile.
The testing quantity shall meet the design requirements, and under the same conditions, it shall not be less than 3; When the total number of engineering piles is expected to be less than 50, the number of tested piles should not be less than 2.
Selection of testing methods and testing quantity (original text) Article 3.3, Article 3.3.1 of JGJ106-2014 Technical Code for Testing of Building Foundation Piles provides the basis for design.
Projects where the static load test of a single pile is not carried out in accordance with Clause 3.3.1 of this Specification before construction; Before construction, a single pile static load test was conducted, but during the construction process, process parameters were changed or the construction quality was abnormal; 4.
3.3.3 The selection of pile integrity testing methods for concrete piles shall comply with the provisions of Article 3.1.1 of this Specification; When one method cannot comprehensively evaluate the integrity of foundation piles, two or more inspection methods should be used, and the inspection quantity should meet the following requirements: 1.
Control the stress of the pile body during pile driving; 2.
Core drilling method: detect the pile length, pile concrete strength, pile bottom sediment thickness, and pile integrity of cast-in-situ concrete piles.
This is quoted from Article 3.1.1 of the JGJ106-2014 Technical Code for the Detection of Building Foundation Piles.
Pile groups that cause soil compaction and floating or deflection during construction.
(Click here to view) Common pile foundation testing methods and purpose testing methods Test the vertical compressive static load test of a single pile to determine the vertical compressive ultimate bearing capacity of a single pile; Determine whether the vertical compressive bearing capacity meets the design requirements; Through pile body strain and displacement tests, the pile side and pile end resistance are measured to verify the vertical compressive bearing capacity test results of a single pile using the high strain method.
Rock foundation plate load test: determine the bearing capacity of a complete, relatively complete, and broken rock foundation as a natural foundation or pile foundation bearing layer.
The ultimate vertical uplift bearing capacity of a single pile is determined through a single pile vertical uplift static load test; Determine whether the vertical uplift bearing capacity meets the design requirements; Determine the horizontal critical load and ultimate bearing capacity of a single pile through pile strain and displacement tests, and determine the lateral resistance to uplift of the pile.
4.
Complex foundation conditions and low reliability of pile construction quality; 5.
Select pile driving equipment; 4.
The number of piles tested shall not be less than 10% of the total number of piles.
Low strain method testing: detecting the defects and positions of the pile body, Determine the pile integrity category.
Estimate the soil resistance parameters; Determine whether the horizontal bearing capacity or horizontal displacement meets the design requirements; By testing the strain and displacement of the pile body, measuring the bending moment of the pile body, using the core drilling method to detect the length of the cast-in-place pile, the concrete strength of the pile body, and the thickness of the sediment at the pile bottom, determining or identifying the geotechnical properties of the bearing layer at the pile end, determining the integrity category of the pile body, using the low strain method to detect the defects and positions of the pile body, and determining the integrity category of the pile body, using the high strain method to determine whether the vertical compressive bearing capacity of a single pile meets the design requirements; Detect pile defects and their locations, and determine the integrity category of the pile; Analysis of pile side and pile end resistance; Monitoring the pile driving process by using the acoustic transmission method to detect the defects and positions of the cast-in-place pile body, and determining the integrity category of the pile body.
Pile foundation with a design grade of Class A; 2.
According to Article 3.3 of the JGJ106-2014 Technical Code for the Detection of Building Foundation Piles, the detection quantity of each project of the engineering pile should meet the following requirements: 1.
Under the same construction process and similar foundation conditions, the number of trial piles should not be less than 3.
The number of piles tested shall not be less than 1% of the total number of piles and shall not be less than 3.
3.3.5 For engineering piles other than those specified in Article 3.3.4 of this specification, the vertical compressive bearing capacity of a single pile can be inspected and accepted in the following ways: 1.
When using a single pile static load test, the number of tests should comply with the provisions of Article 3.3.4 of this specification; For prefabricated piles and cast-in-place piles that meet the applicable scope of the high strain method, the high strain method can be used to test the vertical compressive bearing capacity of a single pile, and the number of tested piles should not be less than 5% of the total number of piles, and should not be less than 5.
.
For cast-in-place pile projects with a design grade of Class A for building pile foundations, or with complex foundation conditions and low reliability of pile quality, the inspection quantity should not be less than 30% of the total number of piles, and should not be less than 20 piles; For other pile foundation works, the number of piles tested shall not be less than 20% of the total number of piles, and shall not be less than 10; In addition to complying with the provisions of the preceding paragraph of this article, the number of test piles for each pile cap under the column shall not be less than 1; Large diameter rock-socketed cast-in-situ piles or large diameter cast-in-situ piles with a design grade of Class A shall be tested using the acoustic transmission method or core drilling method at a ratio of not less than 10% of the total number of piles within the range of the number of test piles specified in paragraphs 1 and 2 of this article; When the number of piles complying with Clauses 1 and 2 of Article 3.2.6 of this Specification is large, or in order to fully understand the integrity of the pile body of the entire project, it is advisable to increase the number of tests.
3.3.4 When one of the following conditions is met, a single pile vertical compressive static load test shall be used for acceptance testing of bearing capacity.
New pile types or new processes adopted in the region; 6.
The number of piles tested shall not be less than 10% of the total number of piles.
1.
The number of piles tested shall not be less than 1% of the total number of piles in the pile foundation subdivisional works under the same conditions, and shall not be less than 3; When the total number of piles is less than 50, the number of piles tested should not be less than 2.
If the design grade of building pile foundation is Grade A, the number of tested piles shall not be less than 30% of the total number of piles, and shall not be less than 20; For other pile foundation works, the number of piles tested shall not be less than 20% of the total number of piles, and shall not be less than 10.