阅读说明：本技术 一种混凝土大坝坝段基坑排水及其坝基浇筑方法 (Concrete dam section foundation pit drainage and dam foundation pouring method thereof ) 是由 吴刚 赵正平 许泾川 方涛 雷汉勋 张斌 于 2020-12-22 设计创作，主要内容包括：本发明公开了一种混凝土大坝坝段基坑排水及其坝基浇筑方法,包括步骤：一、施工准备；二、混凝土大坝坝段基坑排水体系的施工；三、混凝土大坝坝段的坝基浇筑并进行基坑排水；四、混凝土大坝坝段基坑排水体系回填浇筑。本发明通过设置混凝土大坝坝段基坑排水体系对坝段基坑进行引水式排水,抽排水位置固定,在有效地降低施工难度、加快施工进度的同时能够有效缓减了基坑混凝土浇筑工作面的积水问题,减少混凝土浇筑时水泥浆的流失,以保证大坝基础混凝土施工质量,此外在大坝基础坝体浇筑完成后进行体系内部的混凝土回填,保证大坝基础的稳定性,回填效果好,便于推广使用。(The invention discloses a method for draining foundation pits of a concrete dam section and pouring a dam foundation of the foundation pits, which comprises the following steps: firstly, construction preparation; secondly, constructing a foundation pit drainage system of the dam section of the concrete dam; thirdly, pouring a dam foundation of the dam section of the concrete dam and draining the foundation pit; and fourthly, backfilling and pouring the foundation pit drainage system of the dam section of the concrete dam. According to the invention, the drainage system of the foundation pit of the dam section of the concrete dam is arranged to conduct water diversion type drainage on the foundation pit of the dam section, the drainage position is fixed, the construction difficulty is effectively reduced, the construction progress is accelerated, meanwhile, the problem of water accumulation on the concrete pouring working surface of the foundation pit can be effectively reduced, the loss of cement paste during concrete pouring is reduced, so that the construction quality of the concrete of the dam foundation is ensured, in addition, the concrete in the system is backfilled after the pouring of the dam body of the dam foundation is completed, the stability of the dam foundation is ensured, the backfilling effect is good, and the popularization and the use are convenient.)

1. The utility model provides a concrete dam segment foundation ditch drainage and dam foundation pouring method thereof, which is characterized in that, the quantity of concrete dam segment is a plurality of, a plurality of concrete dam segment is laid along river course width direction, the dam segment that the elevation of the bottom surface of foundation ditch (1) is less than the foundation ditch bottom surface average elevation of a plurality of dam segments of concrete dam in the concrete dam segment is marked as the concrete dam segment to be constructed, drainage and dam foundation pouring are carried out to any foundation ditch of the concrete dam segment to be constructed, the concrete process is as follows:

step one, construction preparation: cleaning the bottom surface of a foundation pit (1) of a dam section of the concrete dam;

step two, construction of a foundation pit drainage system of the dam section of the concrete dam: constructing a foundation pit drainage system of a dam section of a concrete dam, wherein the foundation pit drainage system of the dam section of the concrete dam comprises two groups of first temporary water collecting units which are respectively abutted against the upstream side edge of a foundation pit (1) of the dam section of the concrete dam and the downstream side edge of the foundation pit (1) and are used for collecting water seepage of a foundation pit (1) foundation rock surface and a second temporary water collecting unit arranged in the middle area of the foundation pit (1);

the first temporary water collecting unit comprises a plurality of first temporary water collecting columns (2) which are abutted against the vertical surface of the foundation pit (1) and a first temporary water guiding channel (3) which is arranged on the bottom surface of the foundation pit (1) and is used for communicating two adjacent first temporary water collecting columns (2);

the second temporary water collecting unit comprises a plurality of second temporary water collecting columns (4) arranged on the bottom surface of the foundation pit (1), and the second temporary water collecting columns (4) are communicated with the first temporary water collecting columns (2) closest to the second temporary water collecting columns through second temporary water diversion channels (5);

water suction pumps (7) are arranged in the first temporary water collecting column (2) and the second temporary water collecting column (4); the top of the first temporary water collecting column (2) is flush with the top of the foundation pit (1), and the top elevations of the second temporary water collecting column (4) are both greater than the elevations of the river bed surface (12) on the upstream side and the river bed surface (13) on the downstream side;

step three, pouring a dam foundation of a concrete dam section and draining a foundation pit;

and step four, backfilling and pouring the foundation pit drainage system of the dam section of the concrete dam.

2. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the implementation process of pouring the dam foundation of the concrete dam section and draining the foundation pit in the third step is as follows:

concrete is poured in the foundation pit (1), and when the poured concrete reaches the bottom of the second temporary water collecting column (4), a water suction pump (7) in the second temporary water collecting column (4) is opened to drain the foundation pit;

concrete is continuously poured in the foundation pit (1), when the poured concrete reaches the bottom of the first temporary water collecting column (2), a water suction pump (7) in the first temporary water collecting column (2) is opened to drain the foundation pit,

until the top of the poured concrete is higher than the upstream side river bed surface (12) and the downstream side river bed surface (13), a poured dam foundation (8) is formed.

3. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the implementation process of backfilling and pouring of the concrete dam foundation pit drainage system in the fourth step comprises the following steps:

step 401, after pouring of the dam foundation is completed, removing the water suction pumps (7) in the second temporary water collecting columns (4), keeping the water suction pumps (7) in the plurality of first temporary water collecting columns (2) to continuously pump water, blanking from the second temporary water collecting columns (4) to pour underwater self-compacting concrete (9), and enabling the underwater self-compacting concrete (9) to flow to the first temporary water collecting columns (2) through the second temporary water diversion channels (5);

step 402, observing the discharge of the water suction pump (7) in the first temporary water collecting column (2), and when underwater self-compacting concrete (9) appears in the discharge of the water suction pump (7) in the first temporary water collecting column (2), removing the water suction pump (7) at the position, and keeping the water suction pumps (7) in the rest first temporary water collecting columns (2) to continuously pump and discharge water; until the water suction pumps (7) in the plurality of first temporary water collecting columns (2) are all dismounted;

observing the backfill height of the underwater self-compacting concrete (9) in the first temporary water collecting column (2), finishing the backfill of the second temporary water diversion channel (5) when the top height of the underwater self-compacting concrete (9) in the first temporary water collecting column (2) connected with the second temporary water diversion channel (5) exceeds the top height of the second temporary water diversion channel (5), and pouring the underwater self-compacting concrete (9) from the first temporary water collecting column (2) until the backfill of the first temporary water diversion channel (3) is finished;

and finally, discharging and pouring the underwater self-compacting concrete (9) from the first temporary water collecting column (2) until the backfilling and pouring of the first temporary water collecting column (2) are completed, and completing the backfilling of the concrete dam foundation pit drainage system.

4. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the top elevation of first interim diversion passageway (3) is by first interim water collecting column (2) that are close to second interim water collecting column (4) and set up to keeping away from first interim water collecting column (2) direction crescent that second interim water collecting column (4) set up, the top elevation of second interim diversion passageway (5) is by second interim water collecting column (4) to first interim water collecting column (2) direction crescent.

5. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the second temporary water collecting columns (4) are arranged in a foundation pit (1) area with the bottom surface elevation lower than the designed bottom surface elevation of the foundation pit (1), and the number of the second temporary water collecting columns (4) is 2-3.

6. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the temporary water collecting unit of the second further comprises a third temporary water collecting column (6) arranged in the middle of the bottom surface of the foundation pit (1), the third temporary water collecting column (6) is arranged in the area of the foundation pit (1) with the bottom surface elevation lower than the designed elevation of the bottom surface of the foundation pit (1), the distance between the third temporary water collecting column (6) and the first temporary water collecting columns (2) is larger than a set distance threshold value, the top elevation of the third temporary water collecting column (6) is the same as that of the second temporary water collecting column (4), the third temporary water collecting column (6) is formed by splicing fast and easy closing nets, and a water suction pump (7) is arranged in the third temporary water collecting column (6).

7. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the first temporary water collecting column (2) is enclosed by a three-surface quick and easy closing-up net and a vertical surface of the foundation pit (1); the first temporary diversion channel (3) is enclosed by two quick and easy closing-up nets, a vertical surface of the foundation pit (1) and the bottom surface of the foundation pit (1).

8. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 1, wherein: the second temporary water collecting column (4) is a square water collecting column which is formed by splicing four-side quick and easy closing nets; the second temporary diversion channel (5) is a concave diversion channel which is formed by splicing three-side quick and easy closing-up nets, and two sides of the concave diversion channel are abutted to the vertical surface of the foundation pit (1).

9. The foundation pit drainage and dam foundation pouring method for the dam section of the concrete dam as claimed in claim 3, wherein: and in the fourth step, the underwater self-compacting concrete (9) is poured from the second temporary water collecting column (4) and the underwater self-compacting concrete (9) is poured from the first temporary water collecting column (2) through the concrete guide pipe (10).

10. The method for foundation pit drainage and dam foundation pouring of the concrete dam section according to claim 9, wherein the method comprises the following steps: in the step 402, when the underwater self-compacting concrete (9) is poured from the first temporary water collecting column (2), a concrete chute (11) is erected between the poured dam body (8) and a concrete guide pipe (10) in the first temporary water collecting column (2).

Technical Field

The invention belongs to the technical field of concrete dam construction, and particularly relates to drainage of a foundation pit of a dam section of a concrete dam and a dam foundation pouring method thereof.

Background

In the dam foundation pit concrete construction process, because there is the flood peak reason in foundation pit bottom surface and river course rivers surface, infiltration such as basement rock crack, broken zone are almost inevitable. Particularly, when the first layer of concrete of the dam foundation is poured, the phenomena of water soaking or water passing of a part of the poured concrete surface, water accumulation of an un-poured rock base surface and the like often occur, the position of a temporary drainage facility needs to be changed constantly, and the situations of part of cement paste loss, concrete water-cement ratio change and the like are inevitably caused, so that the pouring quality of the concrete is influenced. The current common methods for pouring concrete in a foundation pit comprise:

1. a bin surface extruding and discharging method: the method is only suitable for the bin surface with small water seepage amount, the field operation is troublesome, and the construction quality is difficult to control; in addition, as the concrete pouring area is continuously enlarged, after the water seepage points of the poured area are covered, the water seepage pressure cannot be effectively released, and part of the water seepage pressure is transferred to the uncovered area, so that the water seepage quantity of the uncovered area is increased.

2. A peripheral seepage-proofing method: before or during excavation of the foundation pit, seepage-proofing treatment is carried out on the periphery of the foundation pit, such as construction of seepage-proofing curtains and the like, the method is high in cost, influences the construction progress and is difficult to guarantee good implementation effect.

How to rapidly and effectively clear accumulated water and avoid cement slurry loss so as to ensure that the concrete pouring quality is not or less influenced, and the construction cost is reasonable, which is the problem to be solved at present.

Disclosure of Invention

The invention aims to solve the technical problem that the defects in the prior art are overcome, and the dam section foundation pit drainage and the dam foundation pouring method of the concrete dam are provided.

In order to solve the technical problems, the invention adopts the technical scheme that: a foundation pit drainage and dam foundation pouring method for a concrete dam section is characterized in that the number of the concrete dam section is multiple, the multiple concrete dam sections are arranged along the width direction of a river channel, the dam section, of which the bottom elevation of a foundation pit in the concrete dam section is lower than the average elevation of the bottom of the foundation pit of the multiple dam sections of the concrete dam, is marked as the concrete dam section to be constructed, and drainage and dam foundation pouring are carried out on any foundation pit of the concrete dam section to be constructed, and the concrete process is as follows:

step one, construction preparation: cleaning the bottom surface of a foundation pit of a dam section of the concrete dam;

step two, construction of a foundation pit drainage system of the dam section of the concrete dam: constructing a foundation pit drainage system of a dam section of the concrete dam, wherein the foundation pit drainage system of the dam section of the concrete dam comprises two groups of first temporary water collection units which are respectively abutted against the upstream side edge and the downstream side edge of the foundation pit of the dam section of the concrete dam and are used for collecting foundation pit bedrock surface seepage water, and a second temporary water collection unit arranged in the middle area of the foundation pit;

the first temporary water collecting unit comprises a plurality of first temporary water collecting columns which are abutted against the vertical surface of the foundation pit and a first temporary water diversion channel which is arranged on the bottom surface of the foundation pit and is used for communicating two adjacent first temporary water collecting columns;

the second temporary water collecting unit comprises a plurality of second temporary water collecting columns arranged on the bottom surface of the foundation pit, and the second temporary water collecting columns are communicated with the first temporary water collecting columns closest to the second temporary water collecting columns through second temporary water diversion channels;

water suction pumps are arranged in the first temporary water collecting column and the second temporary water collecting column; the top of the first temporary water collecting column is flush with the top of the foundation pit, and the top elevations of the second temporary water collecting column are both larger than the elevation of the river bed surface on the upstream side and the elevation of the river bed surface on the downstream side;

step three, pouring a dam foundation of a concrete dam section and draining a foundation pit;

and step four, backfilling and pouring the foundation pit drainage system of the dam section of the concrete dam.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the implementation process of pouring the dam foundation of the concrete dam section and draining the foundation pit in the third step is as follows:

concrete is poured in the foundation pit, and when the poured concrete reaches the bottom of the second temporary water collecting column, a water suction pump in the second temporary water collecting column is opened to drain the foundation pit;

continuously pouring concrete in the foundation pit, opening a water suction pump in the first temporary water collecting column when the poured concrete reaches the bottom of the first temporary water collecting column to drain the foundation pit,

and forming the poured dam foundation until the top of the poured concrete is higher than the upstream side river bed surface and the downstream side river bed surface.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the implementation process of backfilling and pouring of the concrete dam foundation pit drainage system in the fourth step comprises the following steps:

step 401, after pouring of the dam foundation is completed, removing the water pumps in the second temporary water collecting columns, keeping the water pumps in the plurality of first temporary water collecting columns to continuously pump and drain water, blanking and pouring underwater self-compacting concrete from the second temporary water collecting columns, and enabling the underwater self-compacting concrete to flow to the first temporary water collecting columns through second temporary water diversion channels;

step 402, observing the drainage of the water pumps in the first temporary water collecting column, and when underwater self-compacting concrete appears in the drainage of the water pumps in the first temporary water collecting column, removing the water pumps at the position, and keeping the water pumps in the rest first temporary water collecting column to continuously pump and drain water; until the water suction pumps in the plurality of first temporary water collecting columns are all dismounted;

observing the backfill height of the underwater self-compacting concrete in the first temporary water collecting column, finishing the backfill of the second temporary water collecting channel when the top height of the underwater self-compacting concrete in the first temporary water collecting column connected with the second temporary water collecting channel exceeds the top height of the second temporary water collecting channel, and pouring the underwater self-compacting concrete from the first temporary water collecting column until the backfill of the first temporary water collecting channel is finished;

and finally, pouring underwater self-compacting concrete from the first temporary water collecting column until the first temporary water collecting column is backfilled and poured, and then completing backfilling of a concrete dam foundation pit drainage system.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the top elevation of first interim diversion passageway is by being close to the first interim water collecting column that the interim water collecting column of second set up to keeping away from the first interim water collecting column direction crescent that the interim water collecting column of second set up, the top elevation of the interim diversion passageway of second is by the interim water collecting column of second to first interim water collecting column direction crescent.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the second temporary water collecting columns are arranged in a foundation pit area with the foundation pit bottom surface elevation lower than the designed foundation pit bottom surface elevation, and the number of the second temporary water collecting columns is 2-3.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the second collects water the unit temporarily still including setting up the interim water column of third in foundation ditch bottom surface middle part, and the setting of the interim water column of third is less than the foundation ditch region of foundation ditch bottom surface design elevation at foundation ditch bottom surface elevation, and the interim water column of third all is greater than the distance threshold value of settlement with the distance of a plurality of interim water columns of first, and the top elevation of the interim water column of third is the same with the top elevation of the interim water column of second, and the interim water column of third is by the net concatenation shaping of closing up soon easily, is provided with the suction pump in the interim water column of third.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the three-side fast and easy closing-up net of the first temporary water collecting column and the vertical surface of the foundation pit are enclosed; the first temporary diversion channel is formed by enclosing a quick and easy closing-up net on two surfaces, a foundation pit vertical surface and a foundation pit bottom surface.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: the second temporary water collecting column is a square water collecting column which is formed by splicing four-side quick and easy closing nets; the second temporary diversion channel is a concave diversion channel, the concave diversion channel is formed by splicing three-side fast and easy closing-up nets, and two sides of the concave diversion channel are abutted to the vertical face of the foundation pit.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: and in the fourth step, the underwater self-compacting concrete is poured from the second temporary water collecting column and the underwater self-compacting concrete is poured from the first temporary water collecting column through the concrete guide pipe.

The method for draining the foundation pit of the concrete dam section and pouring the dam foundation of the concrete dam is characterized by comprising the following steps of: when the underwater self-compacting concrete is poured from the first temporary water collecting column in the step 402, a concrete chute is erected between the poured dam body and a concrete guide pipe in the first temporary water collecting column.

Compared with the prior art, the invention has the following advantages:

1. for a single concrete dam section, the invention can effectively relieve the problem of water accumulation on the concrete pouring working surface of the foundation pit, reduce the loss of cement paste during concrete pouring, ensure the construction quality of the dam foundation concrete and facilitate popularization and use.

2. For the whole dam, the system is arranged on a plurality of concrete dam sections with lower foundation pit bottom surfaces and larger water seepage amount, and the other concrete dam sections have less water accumulation amount due to unchanged water seepage channels, so that a temporary water collecting column is not needed to be arranged, the cleaning workload of the adjacent concrete dam sections and the water drainage amount in the pouring process are greatly reduced, and the construction effect is good.

3. According to the invention, concrete backfill is carried out in the system after the dam body of the dam foundation is poured, so that the stability of the dam foundation is ensured, and the backfill effect is good.

4. According to the invention, the first temporary water collecting column, the first temporary water diversion channel, the second temporary water collecting column and the second temporary water diversion channel are manufactured by using the quick and easy closing-up net, and the quick and easy closing-up net can effectively intercept concrete, and meanwhile, does not need to be dismantled and roughened in the later stage, so that the construction is convenient and efficient.

5. The drainage position of the invention is fixed, compared with the existing foundation pit drainage method, the construction is faster, the concrete pouring operation is basically not influenced, and the construction difficulty is reduced.

In conclusion, the dam section foundation pit is subjected to diversion type drainage by the concrete dam section foundation pit drainage system, the problem of water accumulation of a concrete pouring working surface of the foundation pit can be effectively solved, the loss of cement paste during concrete pouring is reduced, the construction quality of the dam foundation concrete is guaranteed, and concrete in the system is backfilled after the pouring of the dam foundation dam body is completed, so that the stability of the dam foundation is guaranteed, the backfilling effect is good, and the method is convenient to popularize and use.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic structural diagram of a foundation pit drainage system of a dam section of a concrete dam adopted by the invention.

Fig. 2 is a sectional view a-a of fig. 1.

Fig. 3 is a construction state diagram of the first temporary water collecting unit on the upstream side when backfilling.

FIG. 4 is a block diagram of a method flow of the present invention.

Description of reference numerals:

1, foundation pit; 2-a first temporary catchment column; 3-a first temporary diversion channel;

4-a second temporary catchment column; 5-a second temporary diversion channel; 6-a third temporary water collecting column;

7-a water pump; 8-dam foundation; 9-underwater self-compacting concrete;

10-concrete conduit; 11-concrete chute; 12-upstream side river bed surface;

13-downstream river bed surface.

Detailed Description

As shown in fig. 1, fig. 2 and fig. 4, the method for foundation pit drainage and foundation pouring of a concrete dam section of the present invention includes the steps of setting a plurality of concrete dam sections, arranging the plurality of concrete dam sections along the width direction of a river, marking a concrete dam section to be constructed, which is a dam section in which the elevation of the bottom surface of a foundation pit 1 in a concrete dam section is lower than the average elevation of the bottom surface of the foundation pit of the plurality of concrete dam sections of the concrete dam, as a foundation pit of the concrete dam section to be constructed, and performing drainage and foundation pouring of the foundation pit of any concrete dam section to be constructed, wherein the concrete steps are as follows:

step one, construction preparation: cleaning the bottom surface of a foundation pit 1 of a dam section of the concrete dam;

step two, construction of a foundation pit drainage system of the dam section of the concrete dam: constructing a foundation pit drainage system of a dam section of the concrete dam, wherein the foundation pit drainage system of the dam section of the concrete dam comprises two groups of first temporary water collecting units which are respectively abutted against the edge of the upstream side of the foundation pit 1 and the edge of the downstream side of the foundation pit 1 of the dam section of the concrete dam and are used for collecting water seepage of the foundation pit 1 and a second temporary water collecting unit arranged in the middle area of the foundation pit 1;

the first temporary water collecting unit comprises a plurality of first temporary water collecting columns 2 which are abutted against the vertical surface of the foundation pit 1 and a first temporary water diversion channel 3 which is arranged on the bottom surface of the foundation pit 1 and is used for communicating two adjacent first temporary water collecting columns 2;

the second temporary water collecting unit comprises a plurality of second temporary water collecting columns 4 arranged on the bottom surface of the foundation pit 1, and the second temporary water collecting columns 4 are communicated with the first temporary water collecting columns 2 closest to the second temporary water collecting columns through second temporary water diversion channels 5;

water suction pumps 7 are arranged in the first temporary water collecting column 2 and the second temporary water collecting column 4; the top of the first temporary water collecting column 2 is flush with the top of the foundation pit 1, and the top elevations of the second temporary water collecting column 4 are both greater than the elevation of the upstream river bed surface 12 and the elevation of the downstream river bed surface 13;

step three, pouring a dam foundation of a concrete dam section and draining a foundation pit;

and step four, backfilling and pouring the foundation pit drainage system of the dam section of the concrete dam.

It should be noted that, for the whole dam, only a plurality of concrete dam sections with lower foundation pit bottom and larger water seepage are arranged in the system, and the remaining concrete dam sections have less water accumulation because the water seepage channels are not changed, so that no temporary water collecting column is needed to be arranged, thereby greatly reducing the cleaning workload of the adjacent concrete dam sections and the water discharge in the pouring process, and the pumping and drainage positions are relatively fixed, thereby effectively reducing the construction difficulty and accelerating the construction progress³The water seepage amount is considered to be larger per hour.

In this embodiment, first interim water collecting column 2, first interim diversion passageway 3, the interim water collecting column 4 of second and the interim diversion passageway 5 of second are by reinforcing bar anchor on foundation ditch 1, when guaranteeing foundation ditch 1 concrete placement the position of first interim water collecting column 2, first interim diversion passageway 3, the interim water collecting column 4 of second and the interim diversion passageway 5 of second is fixed, guarantees the construction effect.

In this embodiment, the second temporary water collecting column 4 is communicated with the first temporary water collecting column 2 closest to the second temporary water collecting column to reduce the layout length of the second temporary water diversion channel 5, and the water diversion device is economical and practical.

It should be noted that, during the pouring process of the dam 8, the constructor needs to turn on the water pump 7 in the area covered by the concrete in time to effectively release the water pressure of the water seepage point, so as to avoid the increase of the seepage flow rate of the area not covered by the concrete, and needs to pay attention to control the pouring speed of the concrete near the temporary diversion channel, especially at the top, so as to ensure that the concrete is not damaged. So, the back is originally pour to the concrete, by the upstream and downstream rock base infiltration of concrete coverage area, interim leading channel seepage along the way all can collect to first interim catchment water column 2 and second interim catchment water column 4 back and outwards pump drainage in the lump through first interim leading channel 3 and second interim leading channel 5, avoid causing concrete placement face that the local infiltration point location was raised and lead to overflowing to take away unfavorable condition such as cement thick liquid because of the concrete coverage, the rock base infiltration pressure and the drainage degree of difficulty in uncovered region have been alleviateed, the drainage degree of difficulty that closes on concrete dam section concrete placement in-process has also been slowly reduced.

It should be noted that, for a single concrete dam section, the invention can effectively alleviate the problem of water accumulation on the concrete pouring working surface of the foundation pit 1, and reduce the loss of cement paste during concrete pouring so as to ensure the construction quality of the dam foundation concrete;

according to the invention, concrete backfill is carried out in the system after the dam body 8 of the dam foundation is poured, so that the stability of the dam foundation is ensured, and the backfill effect is good.

According to the invention, the first temporary water collecting column 2, the first temporary water diversion channel 3, the second temporary water collecting column 4 and the second temporary water diversion channel 5 are manufactured by using the quick and easy closing-up net, and the quick and easy closing-up net can effectively intercept concrete, and meanwhile, does not need to be dismantled and roughened at the later stage, so that the construction is convenient and efficient.

The drainage position of the invention is fixed, compared with the existing foundation pit drainage method, the construction is faster, the concrete pouring operation is basically not influenced, and the construction difficulty is reduced.

It should be noted that the first temporary water collecting column 2 is located on the vertical surface of the foundation pit 1, so that the top of the first temporary water collecting column 2 is flush with the top of the foundation pit 1, the second temporary water collecting column 4 is located in the middle of the foundation pit 1, and the backfill of the second temporary water collecting column 4 can be performed only after the concrete pouring elevation needs to exceed the elevation of the upstream side river bed surface 12 and the elevation of the downstream side river bed surface 13, so that the elevation of the top of the second temporary water collecting column 4 also needs to exceed the elevation of the upstream side river bed surface 12 and the elevation of the downstream side river bed surface 13, and the subsequent backfill construction is facilitated.

In this embodiment, the implementation process of pouring the dam foundation of the concrete dam section and performing foundation pit drainage in the third step is as follows:

concrete is poured in the foundation pit 1, and when the poured concrete reaches the bottom of the second temporary water collecting column 4, a water suction pump 7 in the second temporary water collecting column 4 is opened to drain the foundation pit;

continuously pouring concrete in the foundation pit 1, and when the poured concrete reaches the bottom of the first temporary water collecting column 2, opening a water suction pump 7 in the first temporary water collecting column 2 to drain the foundation pit until the top of the poured concrete is higher than the foundation pit 1;

and erecting a template at the top of the foundation pit 1, and continuously pouring concrete until the top of the poured concrete is higher than the upstream side river bed surface 12 and the downstream side river bed surface 13 to form a poured dam foundation 8.

In this embodiment, as shown in fig. 3, in the fourth step, the implementation process of the backfill pouring of the concrete dam foundation pit drainage system is as follows:

step 401, after pouring of the dam foundation is completed, removing the water pumps 7 in the second temporary water collecting columns 4, keeping the water pumps 7 in the plurality of first temporary water collecting columns 2 to continuously pump and drain water, blanking and pouring underwater self-compacting concrete 9 from the second temporary water collecting columns 4, and enabling the underwater self-compacting concrete 9 to flow to the first temporary water collecting columns 2 through the second temporary water diversion channels 5;

step 402, observing the discharge of the water pumps 7 in the first temporary water collecting column 2, and when the underwater self-compacting concrete 9 appears in the discharge of the water pumps 7 in the first temporary water collecting column 2, removing the water pumps 7 at the position, and keeping the water pumps 7 in the rest first temporary water collecting column 2 to continuously pump and discharge water; until the water suction pumps 7 in the plurality of first temporary water collecting columns 2 are all dismounted;

observing the backfill height of the underwater self-compacting concrete 9 in the first temporary water collecting column 2, finishing the backfill of the second temporary water guiding channel 5 when the top height of the underwater self-compacting concrete 9 in the first temporary water collecting column 2 connected with the second temporary water guiding channel 5 exceeds the top height of the second temporary water guiding channel 5, and blanking and pouring the underwater self-compacting concrete 9 from the first temporary water collecting column 2 until the backfill of the first temporary water guiding channel 3 is finished;

and finally, pouring the underwater self-compacting concrete 9 from the first temporary water collecting column 2 until the backfilling and pouring of the first temporary water collecting column 2 are finished, and at the moment, completing the backfilling of the concrete dam foundation pit drainage system.

In this embodiment, carry out the backfill of first interim diversion channel 3 and second interim diversion channel 5 earlier, guarantee that first interim diversion channel 3 and second interim diversion channel 5 do not remain the air, backfill closely knit, make the dam foundation firm.

In this embodiment, the top elevation of the first temporary diversion channel 3 is gradually increased from the first temporary water collecting column 2 close to the second temporary water collecting column 4 to the first temporary water collecting column 2 far away from the second temporary water collecting column 4, and the top elevation of the second temporary diversion channel 5 is gradually increased from the second temporary water collecting column 4 to the first temporary water collecting column 2.

In this embodiment, since the elevation of the dam 8 poured on the foundation pit is higher than the elevation of the river bed surface 12 on the upstream side and higher than the elevation of the river bed surface 13 on the downstream side, the first temporary water collecting column 2, the first temporary water diversion channel 3, the second temporary water collecting column 4 and the second temporary water diversion channel 5 all need to be backfilled, and the first temporary water collecting column 2 is located outside the poured dam 8, and pouring is not easy to control, the backfilling construction of the first temporary water diversion channel 3 and the second temporary water diversion channel 5 is firstly carried out through the second temporary water collecting column 4, the backfilled concrete adopts underwater self-compacting concrete, the underwater self-compacting concrete flows from the second temporary water collecting column 4 to the first temporary water collecting column 2, the top elevation of the second temporary water diversion channel 5 is gradually increased from the second temporary water collecting column 4 to the first temporary water collecting column 2, so that the top plate of the second temporary water diversion channel 5 forms an elevation angle, so set up and to persist the air in the diversion passageway when can avoiding backfilling, avoid influencing the backfill effect of self-compaction concrete under water, guarantee that the dam foundation is stable firm, the top elevation of first interim diversion passageway 3 sets up the reason and is the same reason.

In this embodiment, the angles of the elevation angle of the top plate of the first temporary diversion channel 3 and the elevation angle of the top plate of the second temporary diversion channel 5 are both 3 ° to 5 °.

In this embodiment, the dam 8 is located between the upstream first temporary water collecting column 2 and the downstream first temporary water collecting column 2.

In this embodiment, the underwater self-compacting concrete 9 is the underwater self-compacting concrete in the invention patent of the invention with the application number of CN 201810597714.3.

In this embodiment, the second temporary water collecting columns 4 are arranged in the area of the foundation pit 1, where the elevation of the bottom surface of the foundation pit 1 is lower than the designed elevation of the bottom surface of the foundation pit 1, and the number of the second temporary water collecting columns 4 is 2-3.

It should be noted that, in actual construction, blasting construction is mostly adopted in the excavation mode of the foundation pit 1, so that the bottom surface of the foundation pit 1 is uneven, and the water seepage amount in an area lower than the designed elevation of the bottom surface of the foundation pit 1 is relatively large due to the fact that groundwater seepage is caused, so that the second temporary water collecting column 4 is arranged to collect groundwater seepage in the area, and the loss of cement paste in concrete is reduced.

In this embodiment, the second temporary water collecting unit further includes a third temporary water collecting column 6 arranged in the middle of the bottom surface of the foundation pit 1, the third temporary water collecting column 6 is arranged in the area of the foundation pit 1, where the elevation of the bottom surface of the foundation pit 1 is lower than the design elevation of the bottom surface of the foundation pit 1, the distances between the third temporary water collecting column 6 and the first temporary water collecting columns 2 are both greater than the set distance threshold, the top elevation of the third temporary water collecting column 6 is the same as the top elevation of the second temporary water collecting column 4, the third temporary water collecting column 6 is formed by splicing the fast and easy closing-up nets, and a water suction pump 7 is arranged in the third temporary water collecting column 6.

In this embodiment, the set distance threshold is 8m, and the distances between the third temporary water collecting column 6 and the plurality of first temporary water collecting columns 2 are all greater than 8 m; the lengths of the first temporary diversion channel 3 and the second temporary diversion channel 5 are not more than 8 m.

It should be noted that the selection of the distance threshold is determined according to the fluidity of the concrete adopted during the backfilling construction, the better the fluidity of the concrete is, the larger the distance threshold is, the concrete adopted during the backfilling construction within the distance threshold can smoothly fill the temporary diversion channel without blockage, and if the length of the temporary diversion channel is too long, the backfilling effect is poor, and the construction requirements cannot be met.

In addition, during actual construction, the concrete pouring speed in the underwater self-compacting concrete backfilling process is as high as possible, and the pouring of the temporary water diversion channel is completed before the initial setting of the concrete.

In this embodiment, the isolated setting of the interim water collecting column 6 of third is on foundation ditch 1 bottom surface, not connected with other structures, and the interim water collecting column 6 of third is taken out the drainage alone and is backfilled alone during actual construction, reduces the ponding in foundation ditch 1 middle part.

In this embodiment, the first temporary water collecting column 2 is enclosed by a three-sided fast and easy closing-up net and a vertical surface of the foundation pit 1; the first temporary diversion channel 3 is enclosed by a two-side quick and easy closing-up net, a vertical surface of the foundation pit 1 and a bottom surface of the foundation pit 1.

In this embodiment, the first temporary water collecting column forms a water storage space together with the vertical surface and the bottom surface of the foundation pit 1, and is used for receiving water seepage from the vertical surface rock base surface and the bottom surface rock base surface of the foundation pit 1, preventing concrete poured by the dam from entering, reducing water accumulation of a concrete pouring working surface, and reducing cement slurry loss in the concrete.

In addition, because the vertical surface of the foundation pit 1 is not necessarily vertical, the surface of the first temporary water collecting column 2, which is not in contact with the vertical surface of the foundation pit 1, is arranged in parallel with the vertical surface of the foundation pit 1, so that the backfilling area of concrete is reduced, and the backfilling quality is ensured.

During actual construction, first interim water collecting column 2, first interim diversion passageway 3, the interim water collecting column 4 of second, the interim diversion passageway 5 of second and the interim water collecting column 6 of third are inside all to need welding reinforcement or steel pipe to support the net that easily closes up soon, guarantee water collecting column and diversion passageway structure's stability, non-deformable when dam concreting prevents simultaneously that the infiltration of inside collection from spilling over.

In this embodiment, the second temporary water collecting column 4 is a square water collecting column formed by splicing four-sided fast and easy closing nets; the second temporary diversion channel 5 is a concave diversion channel which is formed by splicing three-side fast and easy closing-up nets, and two sides of the concave diversion channel are abutted to the vertical surface of the foundation pit 1.

In the fourth step of the present embodiment, the underwater self-compacting concrete 9 is poured from the second temporary water collecting column 4 and the underwater self-compacting concrete 9 is poured from the first temporary water collecting column 2 through the concrete conduit 10.

In this embodiment, when the underwater self-compacting concrete 9 is poured from the first temporary water collecting column 2 in step 402, a concrete chute 11 is erected between the poured dam 8 and the concrete guide pipe 10 in the first temporary water collecting column 2.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.