CN214401844U

CN214401844U - Gravity type cofferdam

Info

Publication number: CN214401844U
Application number: CN202022402753.9U
Authority: CN
Inventors: 董学刚; 马如彬; 邹恒; 刘华根; 顾威; 黄璟; 韩洁
Original assignee: Shanghai Municipal Engineering Design Insitute Group Co Ltd
Current assignee: Shanghai Municipal Engineering Design Insitute Group Co Ltd
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-10-15
Anticipated expiration: 2030-10-26

Abstract

The utility model provides a gravity type cofferdam, this gravity type cofferdam is including setting up the reinforced concrete pipe rockfill barricade in the foundation ditch front portion, the reinforced concrete pipe rockfill barricade includes the reinforced concrete pipe that a plurality of roots arranged side by side, the reinforced concrete pipe is vertical to be put, hugs closely the reinforced concrete pipe inner wall and places many steel pipes, reinforced concrete socle portion pours the concrete under water, and inside gravel mixture that backfills forms barricade overall structure, reinforced concrete pipe rockfill barricade rear piles up the soil in bags and forms the soil in bags weir body. The gravity type cofferdam structure of the utility model has clear stress condition and safe and reliable structure, the gravity type structure of the front row reinforced concrete pipe bears the lateral pressure of the back bagged soil, and the back bagged soil weir body bears the water head pressure and the anti-seepage function; the construction method is low in cost, high in practicability and convenient to construct. The method overcomes the limitation of the application of the conventional cofferdam form on the rock-based steep-slope river channel, and solves the problem of creating dry-dam construction conditions for abutment foundation pits on the side slope of the river channel in the mountainous area.

Description

Gravity type cofferdam

Technical Field

The utility model relates to a river course engineering construction technical field discloses a gravity type cofferdam.

Background

A bridge is newly built on a mountain river, and often a bridge abutment is arranged on a rocky base slope with good geological conditions, so that on one hand, the bridge abutment has good stress conditions, and on the other hand, compared with the bridge abutment arranged in a rear land area, the bridge span can be reduced, and the engineering investment is reduced. The abutment construction excavates the foundation ditch on the river course side slope, and the elevation of foundation ditch outside top is often less than the river course normal water level, faces the problem that the river water flows backward, needs to fill in the cofferdam manger plate in the outside, creates the dry land construction condition for the abutment construction.

The conventional cofferdam mainly comprises a bagged soil cofferdam, a wood pile cofferdam, a steel sheet pile cofferdam and the like, and the bagged soil cofferdam filled on the steep slope has poor self-stability and large volume and has influence on functions of river flood discharge, navigation and the like; and the foundation condition causes construction difficulty for the pile foundation type cofferdam. The conventional cofferdam form is difficult to apply to a rock-based steep slope river channel, so that a novel cofferdam applicable to the rock-based steep slope and a construction method thereof are urgently needed to be explored.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a gravity type cofferdam overcomes the limitation that conventional cofferdam form was used on the cliff s abrupt slope river course to the solution is for the problem of the bridge abutment foundation ditch creation dry wall construction conditions on mountain area river course slope.

In order to solve the technical problem, the utility model discloses a following technical scheme can solve:

a gravity type cofferdam which characterized in that: be equipped with the foundation ditch on the river course side slope, this gravity type cofferdam is including setting up the reinforced concrete pipe rockfill barricade in the foundation ditch front portion, the reinforced concrete pipe rockfill barricade includes the reinforced concrete pipe that a plurality of roots arranged side by side, the reinforced concrete pipe is vertical to be put, hugs closely the reinforced concrete pipe inner wall and places many steel pipes, reinforced concrete socle portion has pour the concrete under water, the inside backfill of reinforced concrete pipe has the grit mixture to form barricade overall structure, reinforced concrete pipe rockfill barricade rear piles up the soil in bags and forms the soil in bags weir body.

Furthermore, the reinforced concrete pipe is formed by vertically splicing at least two reinforced concrete pipe sections.

Furthermore, a bamboo net piece is vertically paved behind the reinforced concrete pipe, and a smooth interface is provided for the rear stacked bagged soil.

Furthermore, a PE impermeable membrane is integrally paved in a foundation pit behind the bamboo net pieces, the end part of the PE impermeable membrane is inserted into a groove on the upper side of a side slope behind the foundation pit, plain concrete is filled in the groove, and bagged soil is stacked on the PE impermeable membrane, so that a full-length impermeable body is formed on the interface of the bagged soil and original soil, the seepage diameter is lengthened, and the size of a weir body of the bagged soil can be reasonably reduced.

A construction method of a gravity type cofferdam is characterized by comprising the following steps:

(1) locally excavating a riverway side slope, excavating a cofferdam foundation bed and carrying out leveling treatment on the cofferdam foundation bed;

(2) installing a reinforced concrete pipe retaining wall, vertically placing reinforced concrete pipe joints on a leveled underwater foundation bed, arranging the reinforced concrete pipe joints orderly, pouring underwater concrete at the bottoms of the reinforced concrete pipe joints, inserting a plurality of steel pipes into the inner wall of the pipe at the front of initial setting and fixing the steel pipes, backfilling a sandstone mixture to the tops of the pipe joints after final setting of the concrete, backfilling a stone and gravel mixture, inserting a second reinforced concrete pipe joint to be connected to be high, and continuously backfilling the sandstone to the top of the pipe to form the reinforced concrete pipe retaining wall;

(3) laying a bamboo net piece and an impermeable film, laying the bamboo net piece behind the reinforced concrete pipe retaining wall, laying a PE impermeable film in a pit formed along the back surface of the retaining wall and the side slope excavation surface, inserting the end part of the impermeable film into a groove on the upper side of the side slope behind the foundation pit, and backfilling plain concrete;

(4) and stacking the bagged soil, namely stacking the bagged soil from bottom to top to a designed elevation from the bottom of the pit.

The utility model discloses owing to adopted above-mentioned technical scheme, following beneficial effect has:

1. the cofferdam adopts gravity type structure, through the combination of reinforced concrete pipe barricade and bagged soil, adaptable batholith abrupt slope river course construction condition.

2. The cofferdam structure has clear stress condition and safe and reliable structure. Under the condition of normal water level and positive water retaining, the rear bagged soil weir body bears the water head pressure and the seepage-proofing function; under the condition of low water level, the gravity type structure of the front row of reinforced concrete pipes bears the lateral pressure of the rear bagged soil.

3. Compared with the bagged soil piling cofferdam, the cofferdam has the characteristic of small volume, avoids the construction problem of throwing and filling bagged soil in large volume underwater, reduces the functional influence on river flood discharge, navigation and the like, and saves the construction cost.

4. The cofferdam not only can be applicable to the rock-base, but also can more extensively be applicable to the higher soil foundation of bearing capacity, compares with steel sheet pile cofferdam, the cofferdam only needs to carry out local excavation to the bank slope, need not pull out the stake after using, and is less to the influence of bank slope. Compared with the steel sheet pile cofferdam, the cofferdam has low manufacturing cost.

5. The cofferdam reinforced concrete pipe adopts a drainage engineering standard pipeline, the steel pipes in the sleeve adopt scaffold standard steel pipes, and the pipeline splicing and bagged soil piling of different sizes can adapt to different water retaining water head requirements.

6. The reinforced concrete pipe, the scaffold steel pipe and the bagged soil adopted by the cofferdam can be recycled and reused after construction is completed, so that the use cost is reduced.

Drawings

The present invention will be further explained with reference to the accompanying drawings:

fig. 1 is a schematic plan view of the novel gravity cofferdam applicable to the rock foundation steep slope and the cofferdam in the construction method of the utility model;

FIG. 2 is a schematic structural view of the cofferdam of the present invention;

fig. 3 is a schematic structural view of a reinforced concrete pipe according to the present invention.

In the figure: 1-a reinforced concrete pipe retaining wall; 2-a bagged soil weir body; 3, constructing a foundation pit on the bridge bearing platform; 4-reinforced concrete rabbet pipes; 5-a steel pipe; 6-mixture of broken stone and block stone; 7-underwater concrete; 8-bamboo mesh sheet; 9-PE impermeable membrane; 10-bagging soil; 11-a groove; 12-the retaining wall centerline; 13-cofferdam crest; 14-a slope line; 15-side line excavation of the foundation pit; 16-river channel side slopes; 17-cofferdam foundation bed.

Detailed Description

The present invention will be more clearly and completely described with reference to the following preferred embodiments of the present invention and the accompanying drawings. These embodiments are provided only for illustrating the present invention and are not intended to limit the present invention.

As shown in figure 1, a bridge bearing platform is arranged on a rocky foundation river bank with a steep gradient, a foundation pit river side top mark is lower than a riverway normal water level, and a cofferdam engineering is required to be filled on the bank slope to create dry land excavation construction conditions. By adopting a gravity cofferdam mode, the reinforced concrete pipe retaining wall 1 at the outer side bears the lateral pressure of the bagged soil at the rear side, and the bagged soil weir body 2 bears the water head pressure and the anti-seepage function. The retaining wall restrains the bagged soil behind the wall, so that the bagged soil pile body with a certain height stably stands on the steep slope, the piling amount of the bagged soil is reduced, and the stability of the underwater bagged soil body is improved. The underwater concrete pouring is beneficial to enhancing the bonding effect of the pipe bottom and the base surface, improving the anti-sliding stability of the reinforced concrete pipe retaining wall, and simultaneously fixing the eight steel pipes on the inner wall of the pipeline together with backfilled sand and stone materials, thereby being beneficial to the integral bending strength of the reinforced concrete pipe.

As shown in fig. 2, firstly, measuring and lofting, determining the arrangement position of a cofferdam on a river side slope according to the design requirements and the plane position of a drawing, determining the excavation range and elevation of the side slope on the basis of the arrangement position, and marking lines; and then, locally excavating the upper part of the riverway side slope (the position of a foundation pit of a bridge bearing platform) to create a construction interface. Excavating earth and stone on the lofted foundation surface by adopting a land excavation construction method, and leveling a foundation bed, wherein a 1:20 reverse slope is preferred; and then, locally excavating the river channel side slope 16, excavating a cofferdam foundation bed 17 and carrying out leveling treatment on the cofferdam foundation bed 17, wherein the position of the cofferdam foundation bed 17 is close to the shore side as far as possible on the premise of meeting the requirements of the excavation surface 15 of the bridge bearing platform foundation pit and the size requirements of the bagged soil weir body 2. The reinforced concrete rabbet pipe 4 is vertically placed (a drainage pipeline with a general standard is adopted to avoid links such as special prefabrication) to form the reinforced concrete pipe retaining wall 1, a reasonable size is selected according to design standards, and the distance from the plane position of the central line 12 of the retaining wall to a bridge bearing platform meets the requirement of foundation pit construction. Under the condition that the length of the reinforced concrete rabbet pipe 4 is not enough, a plurality of reinforced concrete rabbet pipes 4 are connected in series from top to bottom, 8 steel pipes 5 with the diameter of 48mm are evenly placed on the inner wall of the reinforced concrete rabbet pipe 4 in a close fit mode, the length of each steel pipe 5 meets the design requirement, a plurality of sections of the reinforced concrete rabbet pipes 4 are connected in series, C30 underwater concrete 7 with the thickness of 500mm is poured into the bottom of each reinforced concrete rabbet pipe 4, the mixture 6 of the backfilled broken stones and the blocks and stones is filled to the top elevation, the pouring of the underwater concrete 7 is beneficial to enhancing the bonding effect of the bottom and the base surface, the anti-sliding stability of the reinforced concrete pipe retaining wall 1 is improved, and meanwhile, the eight steel pipes 5 on the inner wall of the pipeline are fixed together with the backfilled gravel 6, and the integral bending strength of the reinforced concrete rabbet pipe 4 is beneficial. The reinforced concrete pipe retaining wall 1 restrains the bagged soil 2 behind the wall, so that the bagged soil pile body 2 with a certain height stably stands on the river slope 16, the piled mass of the bagged soil is reduced, and the stability of an underwater bagged soil body is improved. Vertically placing 30mm bamboo net sheets 8 close to the inner side of the reinforced concrete pipe, laying 1.5mm PE anti-seepage films 9 behind the bamboo net sheets and extending to the top of a foundation pit, excavating 300mm 400mm grooves 11, burying the top ends of the 1.5mm PE anti-seepage films 9 into the grooves 11, and backfilling C20 plain concrete in the grooves 11. Bagged soil 10 is stacked from bottom to top behind the reinforced concrete rabbet pipe 4 to a weir crest design elevation 13 from the pit bottom as an anti-seepage weir body for mainly retaining water, the weir body crest width is larger than 1m, and the side slope is payed off 14 to a river course side slope 16 according to the ratio of 1: 1. The soil 10 is not allowed to be filled with garbage, corrosive substances, etc.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that this is by way of example only and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.

Claims

1. A gravity type cofferdam which characterized in that: be equipped with the foundation ditch on the river course side slope, this gravity type cofferdam is including setting up the reinforced concrete pipe rockfill barricade in the foundation ditch front portion, the reinforced concrete pipe rockfill barricade includes the reinforced concrete pipe that a plurality of roots arranged side by side, the reinforced concrete pipe is vertical to be put, hugs closely the reinforced concrete pipe inner wall and places many steel pipes, reinforced concrete socle portion has pour the concrete under water, the inside backfill of reinforced concrete pipe has the grit mixture to form barricade overall structure, reinforced concrete pipe rockfill barricade rear piles up the soil in bags and forms the soil in bags weir body.

2. A gravity cofferdam according to claim 1, wherein: the reinforced concrete pipe is formed by vertically splicing at least two reinforced concrete pipe sections.

3. A gravity cofferdam according to claim 1, wherein: a bamboo net piece is vertically paved behind the reinforced concrete pipe, and a smooth interface is provided for the rear stacked bagged soil.

4. A gravity cofferdam according to claim 1, wherein: the method comprises the steps of integrally paving a PE anti-seepage film in a foundation pit behind a bamboo net piece, inserting the end part of the PE anti-seepage film into a groove on the upper side of a side slope behind the foundation pit, backfilling plain concrete in the groove, and stacking bagged soil on the PE anti-seepage film, so that a full-length anti-seepage body is formed on the interface of the bagged soil and original-state soil, and the seepage diameter is lengthened.