According to the knowledge of architectural knowledge column of this website, Zhong Da Consulting Company summarized the basic situation of rotary excavation pile foundation construction as follows:
First of all, let's understand the basic situation of rotary excavation pile foundation:
What is rotary excavation pile?
Rotary drilling pile is an engineering term, which generally refers to the pile type constructed by rotary drilling rig, which is the full name of rotary drilling cast-in-place pile, and is referred to as rotary drilling pile in engineering. Because of mechanical operation, the number of workers is not high, which can save a lot of labor costs.
How do general construction enterprises control the construction quality of rotary excavation piles? What are the points that need attention?
Control of pore-forming quality
Hole-forming is an important link in the construction of rotary excavation pile. In the process of construction, problems such as hole collapse, shrinkage cavity, pile hole deviation and pile tip failing to meet the design bearing layer requirements are easy to occur. Therefore, the following points should be paid attention to in the construction technology and construction quality control of pore-forming:
(1) Jump excavation method is adopted.
The construction of rotary excavation pile is to form holes first and then piles. Therefore, the soil around the hole wall will inevitably produce dynamic pressure on the pile. In addition, in the early stage of pile concrete pouring, the strength of pile concrete is very low, which is easy to cause shrinkage. Therefore, it is an important technical measure to prevent hole collapse and shrinkage by jumping excavation in the process of hole formation.
(2) Ensure the pile location and hole-forming depth.
(1) After the pile casing is positioned, check the position of the pile casing in time, strictly control the deviation between the center of the pile casing and the center line of the pile, and carefully check whether the backfill soil is dense;
(2) In the process of construction, the hole depth must be accurately controlled, and besides the rotary drilling rig itself, manual measurement should be carried out and recorded;
(3) When using mud to protect the wall to form a hole, it may happen that the mud specific gravity is improperly controlled during the first hole cleaning or the drilling tool collides with the hole wall when lifting, resulting in excessive hole collapse and sediment, which makes it difficult to draw lines during the second hole cleaning. Therefore, after lifting the drilling tool, check the hole-forming depth with the measuring rope. If the measuring depth of the measuring rope is less than that of the drill pipe, it is necessary to drill the drill pipe again and clean the hole.
④ The measuring rope commonly used in construction may shrink when it meets water, because its maximum shrinkage rate is 1.2%. In order to improve the measurement accuracy of the measuring rope, it should be pre-wetted and recalibrated before use, and it should be checked frequently during use.
(3) In order to ensure that the vertical accuracy of hole formation meets the design requirements, strict control should be carried out from the following two aspects:
(1) increase the bearing area of the pile driver to stabilize the pile driver;
(2) After measurement and positioning, cross-check points shall be set, and the verticality of pile body shall be checked frequently during construction. For more information about bid writing and improving the winning rate, click on the bottom customer service for free consultation.