1, the hole setting-out error of biaxial mixing pile is less than 50mm, and the verticality error of pile body is less than1100.
2, strictly control the slurry ratio, do the listing construction, and equipped with full-time personnel responsible for the management of slurry configuration, the water cement ratio of this project is 0.55, and the cement is 42.5 ordinary portland cement.
3. Strictly control the drilling and sinking speed. The lifting (sinking) speed of the bit is not more than 0.5m/min, the lifting amount of the bit per revolution is 1.0 ~ 1.5cm, and the grouting amount is 30L/min.
4. Before the construction of double-shaft mixing pile, the mixer should be maintained to minimize the quality problems caused by equipment failure in the construction process. The equipment shall be operated by special personnel, and the performance of the equipment must be checked before taking up the post to ensure the normal operation of the equipment.
5. Check the verticality of the double-shaft mixing pile frame with two 90-degree theodolite.
6. Various factors shall be comprehensively considered in site layout to avoid equipment relocation and displacement, and ensure the continuity of construction as far as possible.
7, it is forbidden to use expired cement, cement be affected with damp be affected with damp, for each batch of cement for second-round exam qualified rear can use.
8, to ensure the strength and uniformity of biaxial mixing pile requirements:
The soil should be fully mixed, and the sinking and lifting speed of the borehole should be strictly controlled to make the undisturbed soil fully broken, which is beneficial to the uniform mixing of cement slurry and soil. The cement slurry cannot be separated, and the cement slurry should be prepared in strict accordance with the predetermined mixture ratio. In order to prevent the slurry from separating, it must be stirred for 30 seconds before being poured into the slurry storage barrel. In the grouting stage, the slurry conveying pipeline cannot be blocked and slurry is not allowed to be broken. The whole pile must be grouted evenly, and there can be no mud interlayer. If the pipeline is blocked, stop the pump immediately. After the treatment, the mixed drilling tool should be lifted and lowered 1. Grouting can be continued before Om.
9. During the construction of double-shaft mixing pile, check the blade length and wear after drilling every day. If it is found that the length is not enough, it should be trimmed to ensure the effective pile diameter. Mixing pile diameter is 700mm, lap width is not less than 200 mm.
10, the soil should be fully mixed and broken, so as to destroy the structure of the undisturbed soil and facilitate the cement mixing evenly, so it is necessary to strictly carry out the second spraying and the third mixing.
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