CN-121992796-A - Construction method of composite supporting structure suitable for height limiting condition

CN121992796ACN 121992796 ACN121992796 ACN 121992796ACN-121992796-A

Abstract

The invention discloses a composite supporting structure construction method suitable for height limiting conditions, and relates to the technical field of foundation pit supporting construction. The method comprises the following steps of S1, carrying out high-pressure jet grouting construction and measurement positioning, S2, carrying out drilling operation at a positioning pile position to form a pile hole, S3, lowering a steel pipe section into the pile hole, welding adjacent steel pipe sections, S4, inserting I-steel sections into the steel pipe section, welding adjacent I-steel sections, S5, injecting slurry into the steel pipe and gaps between the steel pipe and the pile hole wall, and forming the composite support pile after the slurry is solidified. The invention greatly enhances the rigidity of the supporting structure by the sleeve embedding combination of the steel pipe and the I-steel, and simultaneously adopts a construction mode of sectionally welding and lowering, thereby effectively solving the problem that the traditional pile anchor supporting construction cannot be carried out by using large machinery in a height-limiting area below a high-voltage line and the like, and ensuring the construction safety and the integral stability of the supporting structure.

Inventors

LAN TIAN
CHEN GANG
Fu Linrui
YANG LIN
YUE YANG
WANG JIAN
XIN ZHE
LIU FEIFEI

Assignees

中建八局第二建设有限公司

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (10)

1. A construction method for a composite supporting structure suitable for a height limiting condition is characterized by comprising the following steps of firstly flattening and positioning a site, paying off and positioning a construction area to determine a pile position center, secondly forming holes, drilling pile holes at the pile position center by a drilling machine, wherein the diameter of each pile hole is larger than that of a steel pipe to be lowered, thirdly, manufacturing and placing the steel pipe, hoisting and lowering the steel pipe in sections into the pile holes, welding and connecting adjacent steel pipe sections at an orifice, fourthly, manufacturing and placing I-steel, hoisting and inserting the I-steel sections into the steel pipe in sections, welding and connecting the adjacent I-steel sections at the orifice, and fifthly, grouting, namely, filling slurry into the steel pipe through a grouting pipe to fill the space inside the steel pipe and gaps between the outer wall of the steel pipe and the wall of the pile hole until the slurry is solidified to form a supporting pile.
2. The construction method of the composite supporting structure suitable for the height limiting condition, which is disclosed in claim 1, is characterized in that in the third step, the steel pipe is determined to have a sectional length according to the field height limiting condition, a section of pre-drilled grouting hole area is arranged at the bottom of the steel pipe, the length of the pre-drilled grouting hole area is 0.5m, a plurality of grouting holes are distributed in the pre-drilled grouting hole area, the diameter of each grouting hole is 10-15mm, and the distance between each grouting hole and each grouting hole is 100-150mm.
3. The construction method of a composite supporting structure suitable for height limiting conditions according to claim 1, wherein in the third step, welding connection between adjacent steel pipe sections adopts a side welding mode, and a sleeve pipe used for side welding is the same as the steel pipe.
4. The construction method of the composite supporting structure suitable for the height limiting condition of claim 1, wherein in the fourth step, welding connection between adjacent I-steel sections comprises the specific steps of butt welding an upper section I-steel section and a lower section I-steel section, and after welding, adopting a steel plate to weld and reinforce a web plate and a flange of the two I-steel sections respectively.
5. The construction method of the composite supporting structure suitable for the height limiting condition according to claim 4, wherein the thickness of the steel plate is not less than 10mm, and the height of a welded seam formed by welding is not less than 10mm.
6. The construction method of the composite supporting structure suitable for the height limiting condition according to claim 1, wherein the sectional welding positions of the steel pipes and the sectional welding positions of the I-steel are staggered in the depth direction and cannot be overlapped.
7. The construction method of the composite supporting structure suitable for the height limiting condition of claim 1, wherein in the fifth step, the grouting pipe is lowered together with the steel pipe, grouting materials adopt cement paste, the water cement ratio is 0.50, the strength of the grouting body is not less than 20MPa, and in the grouting process, after the cement paste flows out of the steel pipe, the pipe is not pulled out temporarily, and the grouting pipe is pressurized and kept for a plurality of minutes until the cement paste flows out of the steel pipe again.
8. The construction method of the composite supporting structure suitable for the height limiting condition according to claim 1, further comprising a high-pressure jet grouting construction step for reinforcing the stratum before the second step.
9. The construction method of the composite supporting structure suitable for the height limiting condition according to claim 1, wherein in the second step, horizontal correction is carried out after the drilling machine is in place, the vertical alignment of the axis of the drill rod to the hole site is ensured, the deviation of the hole site after the hole is formed is not more than 50mm, and the deviation of the verticality is not more than 0.5%.
10. The construction method of the composite supporting structure suitable for the height limiting condition is characterized by comprising pile holes, steel pipe columns, I-steel, grouting concretions and reinforcing steel plates, wherein the pile holes are formed in soil layers of areas to be reinforced, the steel pipe columns are vertically arranged in the pile holes, the I-steel is vertically inserted into inner cavities of the steel pipe columns, the grouting concretions are filled in the inner cavities of the steel pipe columns and gaps between the outer walls of the steel pipe columns and the walls of the pile holes, the steel pipe columns are formed by sequentially splicing multiple sections of steel pipe sections along the axial direction, the I-steel is formed by sequentially splicing multiple sections of I-steel along the axial direction, the positions of steel pipe column connecting nodes and I-steel connecting nodes are staggered from each other in the vertical direction and do not overlap, the steel pipe column connecting nodes are reinforced by adopting a side welding structure, and the I-steel connecting nodes are reinforced by adopting reinforced steel plates.

Description

Construction method of composite supporting structure suitable for height limiting condition Technical Field The invention relates to the technical field of foundation pit supporting construction, in particular to a composite supporting structure construction method suitable for height limiting conditions. Background When a city central area is built for projects such as hospitals and commercial complexes, foundation pit supporting engineering often faces the extremely complex situation of surrounding environments. For example, a job site may be closely adjacent to a municipal road, underground pipelines are dense, and an above-ground space may present obstacles such as 10KV high-voltage lines. Conventional support structure designs often take the form of pile anchor supports, rotary-excavated cast-in-place piles, and the like, which typically require large drilling rigs or pile driving equipment to approach. However, when a high-voltage line exists above a construction area and the distance is too close, large equipment cannot meet the safety distance specification requirement, and even cannot spread out the operation arm support in a height-limited space. If conventional small-sized equipment is adopted, a supporting pile with high rigidity and good integrity is difficult to construct, and the supporting safety requirement of a deep foundation pit is difficult to meet. Therefore, there is a need to develop a special supporting construction method which can not only utilize small equipment for construction under the condition of limited height, but also ensure that the supporting structure has sufficient rigidity and integrity. Disclosure of Invention Aiming at the defects of the prior art, the invention develops a construction method of the composite supporting structure suitable for the height limiting condition, and can realize the construction of the high-rigidity supporting pile in a limited space. The technical scheme includes that the construction method of the composite supporting structure suitable for the height limiting condition comprises the following steps of firstly flattening and positioning a site, paying off and positioning in a construction area to determine a pile position center, secondly forming holes, drilling pile holes in the pile position center by a drilling machine, wherein the diameter of each pile hole is larger than that of a steel pipe to be lowered, thirdly manufacturing and placing the steel pipe, hoisting and lowering the steel pipe in a segmented mode into the pile holes, welding and connecting adjacent steel pipe sections at the hole openings, fourthly manufacturing and placing I-steel, hoisting and inserting the I-steel sections into the steel pipe in a segmented mode, welding and connecting the adjacent I-steel sections at the hole openings, and fifthly grouting, namely injecting slurry into the steel pipe through a grouting pipe to fill the space in the steel pipe and gaps between the outer wall of the steel pipe and the wall of the pile hole until the slurry is solidified to form a supporting pile. In the third step, the steel pipe is provided with a section of pre-drilled grouting hole area at the bottom according to the field height limiting condition, the length of the pre-drilled grouting hole area is 0.5m, a plurality of grouting holes are distributed in the area, the diameter of each grouting hole is 10-15mm, and the distance between each grouting hole and each grouting hole is 100-150mm. In the third step, the welding connection between the adjacent steel pipe sections adopts a side welding mode, and the material of a sleeve used for side welding is the same as that of the steel pipe. In the fourth step, the welding connection between the adjacent I-steel sections comprises the specific steps of butt welding the upper and lower I-steel sections, and after welding, respectively welding and reinforcing the webs and flanges of the two I-steel sections by adopting a steel plate. The thickness of the steel plate is not less than 10mm, and the height of a welding seam formed by welding is not less than 10mm. The sectional welding positions of the steel pipes and the sectional welding positions of the I-steel are staggered in the depth direction and cannot be overlapped. In the fifth step, the grouting pipe is lowered together with the steel pipe, cement slurry is adopted as grouting material, the water-cement ratio is 0.50, the strength of the grouting body is not less than 20MPa, and in the grouting process, after the cement slurry flows out of the steel pipe, the grouting pipe is not pulled out, and the grouting pipe is pressurized and kept for a plurality of minutes until the cement slurry flows out of the steel pipe again. And before the second step, a high-pressure jet grouting construction step is further included and is used for reinforcing the stratum. In the second step, the horizontal correction is carried out after the drilling machine is in place, so th