A,TRDThe method of pileConstruction quality requirements

1,TRDusing42.5Ordinary Portland cement,cement≥18%,28Day unconfined compressive strength requirements≥1.2Mpa;

2,TRDIn theHIf the section steel has a joint, the joint should be located below the excavation face, and two adjacentHSection steel joints should be staggered1mThe above;

3, the allowable deviation of pile bottom and pile top elevation is+10cm.-5cm/The root;

4And allowable deviation of pile position is5cm/The root;

5And vertical degree of pile body≤1/200;

6, vertical degree of section steel≤1/200;

7The length of section steel is allowed to deviate±1cm/The root;

8And allowable deviation of section steel bottom elevation-3cm/The root;

9The plane position of section steel is allowed to deviate:Parallel to the foundation pit3cm/Root, perpendicular to the direction of the foundation pit1cm/The root;

10And allowed deviation of centroid Angle3°/The root;

11Steel surround Rin, steel support insideHThe section steel should be reliably connected, and the steel should be enclosedTRDThe gaps between the construction piles are filled with fast hard fine stone concrete, and the supporting prestress can be applied only when the strength is reached.

Second,TRDThe method of pileConstruction quality control measures

1,TRDConstruction quality measures of construction method mixing pile

(1) the pile position lofting error is less than2cm, the depth error is less than＋10 cm, the vertical degree of pile body according to the design requirements, the error is not greater than the length of pile body1%.

(2) Strict control of the slurry ratio, to achieve the construction of the listing, and equipped with full-time personnel responsible for the management of the slurry configuration.

(3) before constructionTRDPile machine for maintenance, as far as possible to reduce the construction process due to equipment failure caused by quality problems. Special personnel are responsible for the operation of the equipment. Before working, the performance and test operation of the equipment must be checked to ensure the normal construction of the equipment.

(4) Adjust the vertical degree of pile frame by looking at the indicator needle, and check with the theodolite.

(5) During the implementation of the project, it is strictly forbidden to shift the positioning steel plate. Once it is found that the excavator will collide with the positioning steel plate and cause it to move out of position when removing the trench soil, the excavator will immediately set the line again and construct in strict accordance with the design drawings.

(6The site layout should comprehensively consider various factors to avoid multiple relocation and displacement of equipment and ensure the continuity of construction as far as possible.

(7It is strictly prohibited to use expired cement and damp cement, and each batch of cement can be used after passing the test.

2Construction of cold joint treatment

Once there is a cold seam in the construction process, the wall is formed at the joint(Length of0.5M)Re-cut and stir to ensure water stop effect.

3Ensure wall lap at the corner of foundation pit

Because this foundation pit has many corners and overlaps with the underground continuous wall which has been constructed previously, the corners and overlaps are extrapolated to both sides according to the design requirements0.5m To ensure the corner and other lap joints, to ensure the continuity of construction and foundation pit water stop effect.

4Ensure the strength and uniformity of pile body

(1) Strictly control the amount of cement and the height of the liquid level of the mixing barrel, the total amount of water consumption is controlled, and the specific gravity meter is used to check the specific gravity of cement slurry at any time.

(2The soil should be fully stirred and cut, so that the original soil is fully broken, which is conducive to the uniform mixing of cement slurry and soil to ensure the quality of construction.

(3Grout segregation can not occur, cement grout should be made strictly according to the predetermined proportion, in order to prevent mortar segregation, is conducive to cement slurry and soil mixing evenly.

(4) During the grouting stage, the grouting pipeline shall not be blocked, and the phenomenon of broken grouting is not allowed. The pile body shall be grouting evenly, and the sandwich layer of soil slurry shall not occur.

(5) Stop the pump immediately if the pipeline is blocked. After the processing is finished, the stirring drill tool should be started and stopped immediately1Continue grouting after about minutes, etc40~60Second to resume transverse stirring cut.

5, quality inspection method

According to the relevant regulations, each class should make one group7.07×7.07×7.07 cm 3Cement-soil test block. The sample is from the soil-cement slurry displaced in the groove, cured according to the prescribed conditions, and sent to the laboratory for compressive strength test after reaching the age, and the test report should be submitted to the supervision engineer in time.

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