CN105201009A - Tower foundation negative-pressure construction method for river channel - Google Patents

Abstract

A negative pressure construction method for tower foundations used in river courses, which can improve the quality of tower foundations and ensure the stability and safety of towers during use. The steps are as follows: build embankments upstream of the pre-construction site for drainage; The excavation method is constructed at the pre-construction site, and the river water infiltrated into the foundation pit is discharged to the downstream of the foundation pit by using a water pump during the excavation process; a square mold formed by splicing four templates in pairs is placed at the center of the bottom of the foundation pit ;Use a water pump to suck up the water infiltrated into the mold and discharge it to the downstream of the foundation pit; apply high-grade concrete to the inner bottom of the mold for sealing; The river water in the foundation pit is continuously discharged to the downstream of the foundation pit, and the water outlet is kept at the position of 1/3-1/2 of the height of the mold; after placing the reinforcement cage in the mold, pour concrete directly into the mold and vibrate it with a vibrator; keep in good health.

Description

A negative pressure construction method for tower foundations used in river courses

technical field

The invention relates to a negative pressure construction method for a pole tower foundation used in a river course.

Background technique

When the power sector transmits power lines across the river, especially when the river is wide, some towers are inevitably built in the river. When constructing the tower foundation in the river channel, the foundation pit should be dug out in the river channel, and a mold should be put into the foundation pit, and the river water in the mold should be drained and concrete should be poured into the mold. Due to the loose sand and soil in the river, the concrete mortar in the mold will leak into the foundation pit outside the mold through the sand and soil below the mold, resulting in poor foundation quality of the tower, and the tower is easy to fall and unsafe during use.

Contents of the invention

In order to solve the above technical problems, the present invention provides a negative pressure construction method for tower foundations used in river courses, which can improve the foundation quality of towers and ensure the stability and safety of towers during use.

A negative pressure construction method for pole and tower foundations used in river courses, which is special in that the specific steps are as follows:

1. Drainage

Build embankments 5m-10m upstream of the pre-construction site to intercept the river water, and make drainage to discharge the river water downstream by bypassing the pre-construction site;

2. Foundation pit excavation

The large-scale excavation of natural slope is used for construction at the pre-construction site, and the water pump is used to discharge the river water infiltrated into the foundation pit to the downstream of the foundation pit during the excavation process; when quicksand is encountered, the excavation slope is enlarged until the excavation is reached specified depth;

3. Place the mold

Place a square mold formed by splicing four templates two by two at the center of the bottom of the foundation pit, and install a fence around the mold to tightly fix the mold;

4. Drainage inside the mold

Use a water pump to absorb the water seeping into the mold and discharge it to the downstream of the foundation pit;

5. Mold plugging

Apply high-grade concrete to the inner bottom of the mould;

6. Drainage outside the mold

Put the suction pipe of the water pump in the foundation pit outside the mold, so that the river water seeping into the foundation pit outside the mold is continuously discharged to the downstream of the foundation pit, and keep the water outlet at 1/3-1/2 of the height of the mold;

7. Foundation pouring

After placing the reinforcement cage in the mold, pour concrete directly into the mold and vibrate with a vibrator;

8. Concrete health

Natural health preservation for more than 30 days, turn off the water pump, remove the mold, and complete the work.

Further, under the condition that quicksand is serious and expanding the excavation slope cannot eliminate the influence of quicksand, pine piles are drilled around the foundation pit, and soil retaining boards are placed to block quicksand.

Further, the pine piles are driven at a distance of not less than 200mm from the edge of the foundation pit, and one pile is driven at intervals of not more than 300mm.

The beneficial effects of the present invention are: after using the water pump to drain the river water infiltrated into the mould, apply high-grade concrete to the inner bottom of the mould; It is located at 1/3 to 1/2 height of the mold, so that the river water seeping into the foundation pit outside the mold is continuously discharged to the downstream of the foundation pit. Under the condition of ensuring that the river water seeping into the foundation pit outside the mold does not overflow into the mold, the plugging in The high-grade concrete on the inner bottom of the mold is water-sealed, and prevents the water at the water pump outlet from agitating and damaging the bottom of the foundation pit, thereby avoiding the leakage of the concrete in the mold, ensuring the quality of the tower foundation, and ensuring that the tower is stable during use. Safety, thus ensuring the safe operation of electricity.

Description of drawings

Fig. 1 is the construction schematic diagram of the present invention;

In the figure: 1-dam, 2-foundation pit, 3-water pump, 4-square mold, 5-enclosure, 6-high-grade concrete, 7-pine pile, 8-soil retaining board, 9-tower foundation concrete.

Detailed ways

Example 1

As shown in the figure, a negative pressure construction method for the tower foundation used in the river, the steps are as follows:

1. Drainage: build a dam 6m upstream of the pre-construction site 1 to intercept the river water, and conduct drainage to discharge the river water downstream by bypassing the pre-construction site.

2. Excavation of the foundation pit: adopt the large excavation form of natural grading, and use the water pump 3 to discharge the river water infiltrated into the foundation pit 2 to the downstream of the foundation pit 2 during the excavation process; Excavate the slope until the specified depth is dug.

Under the condition that quicksand is serious and the influence of quicksand cannot be eliminated by enlarging the excavation slope, the construction method of loosening wooden piles 7 around the foundation pit 2 and placing earth retaining boards 8 to block quicksand is adopted.

Pine piles 7 are drilled at a distance of 200 mm from the two sides of the foundation pit, and one is drilled every 300 mm.

3. Place the mould: place a square mold 4 spliced by two templates at the center of the bottom surface of the foundation pit 2, and install a fence 5 outside the mold to tightly fix the mold.

4. Drainage in the mold: use the water pump 3 to suck up the water seeping into the mold and discharge it to the downstream of the foundation pit 2.

5. Mold plugging: Apply high-grade concrete 6 to the inner bottom of the mold for plugging.

6. Drainage outside the mold: put the water pump 3 in the foundation pit 2 outside the mold, so that the river water infiltrated into the foundation pit 2 outside the mold is continuously discharged to the downstream of the foundation pit 2, and keep the water outlet at 1 of the mold scheduling /3 places.

7. Foundation pouring: After placing the reinforcement cage in the mold, directly pour tower foundation concrete 9 into the mold, and vibrate with a vibrator.

8. Concrete curing: After 30 days of natural curing, turn off the water pump 3, remove the mold, and complete the work.

Example 2

As shown in the figure, a negative pressure construction method for the tower foundation used in the river, the steps are as follows:

1. Drainage: build a dam 8m upstream of the pre-construction site 1 to intercept the river water, and conduct drainage to discharge the river water downstream by bypassing the pre-construction site.

2. Excavation of the foundation pit: adopt the large excavation form of natural grading, and use the water pump 3 to discharge the river water infiltrated into the foundation pit 2 to the downstream of the foundation pit 2 during the excavation process; Excavate the slope until the specified depth is dug.

Under the condition that quicksand is serious and the influence of quicksand cannot be eliminated by enlarging the excavation slope, the construction method of loosening wooden piles 7 around the foundation pit 2 and placing earth retaining boards 8 to block quicksand is adopted.

Pine piles 7 are driven at a distance of 300 mm from the two sides of the foundation pit, and one is driven every 240 mm.

3. Place the mould: place a square mold 4 spliced by two templates at the center of the bottom surface of the foundation pit 2, and install a fence 5 outside the mold to tightly fix the mold.

4. Drainage in the mold: use the water pump 3 to suck up the water seeping into the mold and discharge it to the downstream of the foundation pit 2.

5. Mold plugging: Apply high-grade concrete 6 to the inner bottom of the mold for plugging.

6. Drainage outside the mold: put the water pump 3 in the foundation pit 2 outside the mold, so that the river water infiltrated into the foundation pit 2 outside the mold is continuously discharged to the downstream of the foundation pit 2, and keep the water outlet at 1% of the height of the mold /2 places.

7. Foundation pouring: After placing the reinforcement cage in the mold, directly pour tower foundation concrete 9 into the mold, and vibrate with a vibrator.

8. Concrete curing: After 35 days of natural curing, turn off the water pump 3, remove the mold, and complete the work.

Claims (3)

1., for the pole and tower foundation negative pressure construction method in river course, its step is as follows:

1), drainage

On the fill dam, 5m-10m place, upstream of pre-job location, river is tackled, and do drainage and river is walked around pre-job location to downstream drain;

2), excavation of foundation pit

Adopt the heavy excavation form of natural discharging slope to construct in pre-job location, and use water pump to be discharged to foundation ditch downstream by the river infiltered in foundation ditch in the process of excavation; When running into drift sand, expand the excavation gradient, until dig designated depth;

3), mould is placed

Place at place of foundation ditch bottom center the square dies that is mutually spliced between two by four pieces of templates, and install additional to enclose outside mould and stupefied mould tightly to be fixed;

4), mould internal drainage

Water pump is used to be blotted by the water infiltered in mould and be discharged into the downstream of foundation ditch;

5), mould shutoff

High-grade concrete shutoff is smeared at the inner bottom part of mould;

6), the outer draining of mould

The drinking-water pipe of water pump is placed in the foundation ditch outside mould, makes to infilter river continued emissions in the outer foundation ditch of mould to foundation ditch downstream, and keep pump mouth to be positioned at the 1/3-1/2 position of mold height;

7), basis is built

Place in mould directly to concreting in mould after reinforcing cage, and vibrate with vibrator;

8), concrete curing

Natural Health preservation more than 30 days, switches off the pump, and removes mould, fulfils assignment.

2. further, under, the expansion excavation gradient serious at drift sand can not eliminate the condition of drift sand impact, around foundation ditch, beat deal pile, place breast boards and stop drift sand.

3. further, deal pile beats the place being not less than 200mm on distance foundation ditch limit, makes a call to one every being not more than 300mm.