Construction method of large-diameter cast-in-place pile in complex strata

Abstract

The invention relates to the field of foundation construction, and specifically discloses a construction method for large-diameter cast-in-situ piles in complex strata, including: 1) Positioning and drawing circles on the construction site according to the pile hole design drawings to form pile hole circle lines, outside the pile hole circle lines Position and draw a circle to form the circle line of the pile protection hole, and set some circle lines of the pile protection hole along the circumference of the pile hole circle line to surround the pile hole circle line; A pile protection pipe with the same outer diameter as the pile protection hole is inserted into the pile protection hole, and the depth of the pile protection hole is greater than that of the pile hole; 3), the pile protection concrete mixture is injected into the pile protection pipe; 4), after standing for 7 days, Drill and dig the pile hole according to the pile hole circle line; 5), sink the steel cage into the pile hole; 6), inject the cast-in-situ pile concrete mixture into the pile hole, and maintain the pile; the pile protection concrete mixture includes: water, cement, powder Coal ash, sand, stone, water reducer, early strength agent, anti-cracking agent, the present invention has the advantage of reducing the occurrence of collapsed holes.

Description

technical field [0001] The invention relates to the field of foundation construction, in particular to a construction method for large-diameter cast-in-situ piles in complex strata. Background technique [0002] Complex strata are formed by a series of geological processes. Due to geological tectonic movement, the strata will be affected by pressure, tension, shear force, torsion, etc., causing folds and fractures in the strata, which will cause damage to the strata, making the strata unfavorable. Then evenly and continuously. [0003] The foundation is the foundation of the building. Because the stratum is formed by rocks and soil, the bearing capacity of the soil is insufficient. Therefore, it is usually necessary to construct piles in the stratum to use the piles to form supporting components, so as to support the building. For large volume For construction, the required diameter of the pile body is relatively large. Usually, piles with a diameter of more than two meters...

AI Technical Summary

Problems solved by technology

[0004] During the construction of cast-in-situ piles, the difficulty lies in drilling the pile holes. Due to the difference in soil pressure on both sides of the pile hole walls, and vibration and other forces will be generated during drilling, if the pile hole walls are not protected, it is easy to cause hole collapse Therefore, the mud protection process is generally adopted to increase the pressure on the pile hole wall towards the pile hole side through the mud to resist the pressure brought by the soil on the pile hole wall, thereby protecting the pile hole and reducing the occurrence of hole collapse. However, In complex formations, due to discontinuities in the formation, when drilling to the bottom of the fracture, the mud will flow out from the cracks. Because the mud has a certain viscosity, for small or a small number of cracks, the mud loss rate is relatively slow. Supplement the mud in time to maintain the mud pressure, so as to maintain the effect of the retaining wall, but the number of cracks in the complex stratum is more than that in the ordinary stratum, and the hole wall area of ​​the large-diameter pile hole is large, so that the area connected between the crack and the pile hole Also large, the mud is prone to instant rapid loss, resulting in untimely mud replenishment, so that the mud pressure in the pile hole decreases rapidly, while the drilling is still in progress, and because the pile hole diameter is larger, the pressure on both sides of the pile hole wall The bigger the difference is, the hole collapse will be easily caused by the vibration generated during drilling, so there is still room for improvement

Images