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Guangzhou Hedong Bridge East Approach construction technology of large diameter bored piles


10) * 1.2/2.5 (where L is the pile length) to 20rtl pile length, for example, data generation is ≥ 3.14 (O.35 * 8.496 +1.8 * 2. 3) / 4l, ≥ 6.67m3, take 8mJ. La perfusion 1.8m diameter pile its initial filling volume should be 8, taking into account the use of commodity La, can guarantee the infusion, so the use of 1.6m, 15m long funnel to meet the requirements of the beginning of irrigation. According to GY-20 with the main hoist rope pulley can be lifting four 12t, when the funnel all the 3m3 concrete, its gravity is 3 * 25 = 7.5t, pile pile frame to meet the lifting requirements, but taking into account the initial filling of concrete , will have a greater momentum, so the channel Diaozhu funnel with steel frame. Figure 1. Lifting hook rig diagram 1 2.52 protracted struggle catheter may be subject to the maximum pressure Pmax = generation data Pmax: 2.5 * 38-1.238: c I - Concrete gravity 494 duct pressure test conducted in 49.4kPa k - required a high degree of perfusion of concrete experience, try to fight its vertical test tube, sealing, inspection holes are clear - mud weight to meet the design requirements. - Drilling mud within the highly perfused 2.5.3 Concrete pile diameter and the diffusion coefficient based on projected number of concrete No. 8 Zhan Wei: Guangzhou Hedong Bridge East Approach construction technology of large diameter bored piles 27 volume. Provided by the mixing of concrete, mixed with 1 to 3 2 to 4 stone, water-cement ratio of 0.5 to 06, plus retarder, per cubic meter of concrete to ensure that the minimum content of cement, concrete should be mixed evenly, to the site is not segregation , between the slump in the l8 ~ 22, a better fluidity and workability. Perfusion, in the funnel filled, will be ready to blanking mixer state,[link widoczny dla zalogowanych], to be cut off immediately after the ball material to add, the bottom of the catheter from the bottom of the hole should be 40cm, to ensure that the impact of free fall of concrete to remove part of the I residue, buried in the concrete have a certain depth, the removal of channel loading, pile driver to switch to direct loading, so that split tube. In the concrete perfusion process, expected to control the speed of falling concrete and not too fast, to prevent the steel skeleton and the formation of floating balloon catheter should be removed after a certain concentration of buried pipes, split pipes when rapid control of 15min, the tube buried in the depth of concrete in about 2 ~ 4m, concrete should be continuous infusion, catheter removal should be centered, not tilted, and affect the steel skeleton, while a certain degree of anti-insert and remove part of the air and tap concrete, and so forth, until the filling Design of Concrete Pile height above the top elevation of about 50cm, you can stop the pouring, the pile is completed. Three days later, the need to 50cm mortar content in addition to cutting a big pile head concrete section to ensure the top of the pile concrete strength to meet the design requirements and have a certain roughness. 3 Conclusion drawn by the dynamic testing and core testing, Hedong Bridge East Approach all qualified large-diameter bored piles, concrete piles closely connected with the bedrock. Practice shows that pay close attention to the construction process of the organization and management, strictly control the construction hole, pay attention to the combination of device parameters such as technical processing, and enhanced process control perfusion concrete bored pile construction quality is to ensure that key.