阅读说明：本技术 一种围堰的施工方法 (Construction method of cofferdam ) 是由 陈洁波 李培源 张秋明 郑燕琼 赵雪君 李绵鑫 于 2020-12-31 设计创作，主要内容包括：本发明涉及水利水电工程施工技术领域,公开了一种围堰的施工方法,其包括以下步骤：清除河床底上的杂物；戗堤填筑,采用上下游双戗立堵的方式填筑戗堤,由下向上铺设隔水层、覆盖层和堆石体；填筑防渗墙,在所述堆石体内部填筑防渗墙,所述防渗墙的底部嵌有风化岩；帷幕灌浆,帷幕的顶部伸出所述覆盖层并位于所述堆石体内部,所述帷幕的底部伸出所述隔水层并位于所述隔水层的下方；所述防渗墙的底端与所述帷幕的顶端相连；在所述堆石体的坡面铺设混凝土护面。本发明的施工方法效率高、防渗止水效果好。(The invention relates to the technical field of hydraulic and hydroelectric engineering construction, and discloses a cofferdam construction method, which comprises the following steps: removing impurities on the bottom of the river bed; filling the dike by adopting a mode of vertical plugging of upstream and downstream dual dikes, and laying a waterproof layer, a covering layer and a rockfill body from bottom to top; filling an impervious wall, wherein the impervious wall is filled in the rockfill body, and weathered rocks are embedded at the bottom of the impervious wall; grouting a curtain, wherein the top of the curtain extends out of the covering layer and is positioned inside the rockfill body, and the bottom of the curtain extends out of the waterproof layer and is positioned below the waterproof layer; the bottom end of the impervious wall is connected with the top end of the curtain; and paving a concrete protective surface on the slope surface of the rockfill body. The construction method of the invention has high efficiency and good seepage-proofing and water-stopping effects.)

1. A construction method of a cofferdam is characterized by comprising the following steps:

removing impurities on the bottom of the river bed;

filling the dike by adopting a mode of vertical plugging of upstream and downstream dual dikes, and laying a waterproof layer, a covering layer and a rockfill body from bottom to top;

filling an impervious wall, wherein the impervious wall is filled in the rockfill body, and weathered rocks are embedded at the bottom of the impervious wall;

grouting a curtain, wherein the top of the curtain extends out of the covering layer and is positioned inside the rockfill body, and the bottom of the curtain extends out of the waterproof layer and is positioned below the waterproof layer; the bottom end of the impervious wall is connected with the top end of the curtain;

and paving a concrete protective surface on the slope surface of the rockfill body.

2. A method of constructing a cofferdam according to claim 1, wherein said step of filling a cut-off wall in said rockfill includes:

and slotting along the central axis of the upper end of the rockfill body, and filling self-setting mortar, wherein the self-setting mortar is embedded into the weathered rock.

3. The cofferdam construction method according to claim 2, wherein a composite geomembrane is provided in the cutoff wall, the self-setting mortar is filled on both sides of the composite geomembrane, and a protective layer for covering the cutoff wall is provided on the top end of the rockfill body.

4. The construction method for a cofferdam according to claim 2, wherein after the step of grooving along the central axis of the upper end of the rockfill body and then filling self-setting mortar, the construction method further comprises:

and (3) punching and smashing by using a heavy hammer to embed the self-setting mortar into the weathered rock.

5. The construction method of a cofferdam according to any one of claims 2 to 4, wherein said step of curtain grouting follows said step of filling up the impervious wall; before the curtain grouting step, the construction method further includes:

pre-embedding an insertion pipe for grouting the curtain, wherein the insertion pipe penetrates through the impervious wall;

and performing curtain grouting after the self-setting mortar is filled for 10 d.

6. A method of constructing a cofferdam according to claim 1, wherein said step of filling a cut-off wall in said rockfill includes:

and drilling the rockfill body and simultaneously carrying out high-pressure spray irrigation and filling the impervious wall.

7. The cofferdam construction method according to claim 6, wherein said rockfill body is drilled in a quincunx hole pattern.

8. The cofferdam construction method according to claim 1, wherein said impervious wall is embedded in said concrete facing at the hip bend.

9. The cofferdam construction method according to claim 1, wherein a lateral buffer strip is provided at the front end of the face of the rockfill.

10. The cofferdam construction method according to claim 1, wherein the water facing side of the covering layer is provided with a reinforcement cage, and stones are provided in the reinforcement cage.

Technical Field

The invention relates to the technical field of hydraulic and hydroelectric engineering construction, in particular to a construction method of a cofferdam.

Background

The cofferdam is a necessary water retaining building for protecting dry construction of hydraulic buildings such as dams or plants, generally belongs to temporary engineering, but can also be combined with main engineering to form a part of permanent engineering, and the earth-rock cofferdam can fully utilize local materials, has strong adaptability to the foundation and is simple in construction process.

The seepage-proofing system of the cofferdam is in a central position and directly related to success or failure of engineering, and the existing cofferdam has the problems of long construction period and unsatisfactory seepage-proofing effect of the seepage-proofing wall.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the cofferdam construction method has high construction efficiency and good seepage-proofing and water-stopping effects.

In order to solve the technical problem, the invention provides a cofferdam construction method, which comprises the following steps:

removing impurities on the bottom of the river bed;

filling the dike by adopting a mode of vertical plugging of upstream and downstream dual dikes, and laying a waterproof layer, a covering layer and a rockfill body from bottom to top;

filling an impervious wall, wherein the impervious wall is filled in the rockfill body, and weathered rocks are embedded at the bottom of the impervious wall;

grouting a curtain, wherein the top of the curtain extends out of the covering layer and is positioned inside the rockfill body, and the bottom of the curtain extends out of the waterproof layer and is positioned below the waterproof layer; the bottom end of the impervious wall is connected with the top end of the curtain;

and paving a concrete protective surface on the slope surface of the rockfill body.

Further, the step of filling the impervious wall in the rockfill comprises the following steps:

and slotting along the central axis of the upper end of the rockfill body, and filling self-setting mortar, wherein the self-setting mortar is embedded into the weathered rock.

Furthermore, a composite geomembrane is arranged in the impervious wall, self-setting mortar is filled on two sides of the composite geomembrane, and a protective layer for covering the impervious wall is arranged at the top end of the rockfill body.

Further, after the step of grooving along the central axis of the upper end of the rockfill body and then filling self-setting mortar, the construction method further includes:

and (3) punching and smashing by using a heavy hammer to embed the self-setting mortar into the weathered rock.

Further, the step of curtain grouting follows the step of filling the impervious wall; before the curtain grouting step, the construction method further includes:

pre-embedding an insertion pipe for grouting the curtain, wherein the insertion pipe penetrates through the impervious wall;

and performing curtain grouting after the self-setting mortar is filled for 10 d.

Further, the step of filling the impervious wall in the rockfill comprises the following steps:

and drilling the rockfill body and simultaneously carrying out high-pressure spray irrigation and filling the impervious wall.

Further, the rock-fill body is drilled in a plum-blossom-shaped hole distribution mode.

Furthermore, the impervious wall is embedded into the concrete protective surface at the bend position of the dike.

Furthermore, a transverse buffer zone is arranged at the front end of the upstream face of the rockfill body.

Furthermore, the side of the overburden facing the water is equipped with the reinforcement muscle cage, be equipped with the stone in the reinforcement muscle cage.

Compared with the prior art, the cofferdam construction method provided by the technical scheme has the beneficial effects that:

the construction efficiency is accelerated by filling the dike in a mode of vertical plugging of upstream and downstream dual dikes, the lower side is prevented from seepage and water by using a curtain grouting mode, the upper side is prevented from seepage and water by using an anti-seepage wall, and the anti-seepage effect is good; weathered rocks are embedded at the bottom of the impervious wall, so that the stability and the impervious effect of the wall are improved; the slope surface of the rockfill body is paved with a concrete protective surface to effectively prevent water flow from scouring the rockfill body and prevent water pollution. The invention is especially suitable for construction with larger engineering quantity.

Drawings

FIG. 1 is a flowchart of a method of constructing a cofferdam according to an embodiment of the present invention;

fig. 2 is a schematic sectional view of a cofferdam structure obtained by the construction method of the embodiment of the present invention.

The concrete waterproof layer comprises 1-a waterproof layer, 2-a covering layer, 3-a rock-fill body, 4-a seepage-proof wall, 5-a curtain, 6-weathered rock, 7-a concrete facing, 8-a buffer belt, 9-a reinforcing rib cage, 10-a protective layer and 11-a composite geomembrane.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

As shown in fig. 1 and 2, the present invention provides a cofferdam construction method, which comprises the following steps:

s1, removing impurities on the bottom of the river bed;

if sundries exist on the riverbed, the seepage-proofing effect of the cofferdam is affected, and the cofferdam is likely to be damaged by water.

S2, filling the dike by adopting an upstream and downstream dual dike vertical plugging mode, and paving a waterproof layer 1, a covering layer 2 and a rockfill body 3 from bottom to top;

the upstream and downstream are under construction simultaneously, have increased the efficiency of construction, and water barrier 1 prevents that water from stretching into the weir body from the bottom, and overburden 2 improves the weir body height, and rockfill body 3 blocks the water inflow of top.

S3, filling a impervious wall 4, filling the impervious wall 4 in the rockfill body 3, and embedding weathered rocks 6 at the bottom of the impervious wall 4;

specifically, a impervious wall 4 is filled after drilling a hole in the center of the rockfill 3;

s4, curtain grouting, wherein the top of a curtain 5 extends out of the covering layer 2 and is positioned inside the rockfill body 3, and the bottom of the curtain 5 extends out of the waterproof layer 1 and is positioned below the waterproof layer 1; the bottom end of the impervious wall 4 is connected with the top end of the curtain 5;

and S5, paving a concrete protective surface 7 on the slope surface of the rockfill body 3. Concrete protective surfaces 7 can be paved on the water-facing slope surface and the backwater slope surface respectively.

Based on the scheme, the construction efficiency is accelerated by filling the dike in a mode of vertical plugging of upstream and downstream dual dikes, the lower side is prevented from seepage and water by using a curtain grouting mode, the upper side is prevented from seepage and water by using the anti-seepage wall 4, and the anti-seepage effect is good; weathered rocks 6 are embedded at the bottom of the impervious wall 4, so that the stability and the impervious effect of the wall are improved; the slope laying concrete protective surface 7 of the rockfill body 3 effectively prevents water flow from scouring the rockfill body 3 and can also prevent water pollution.

In the present embodiment, as shown in fig. 2, the step of filling the cut-off wall 4 in the rock-fill body 3 includes: the rockfill 3 is grooved along the central axis of the upper end thereof and then filled with self-setting mortar, which is embedded in the weathered rock 6.

The self-setting mortar is prepared by using cement and bentonite as main raw materials and adding a retarder and a dispersant, and during the drilling process, the mortar is injected into the slotted hole, so that the mortar plays a role in wall fixing, is continuously mixed with sand in the stratum and is automatically set into the impervious wall 4. The wall body built by the self-setting mortar has good continuity, simple and convenient construction, high speed and low cost.

In this embodiment, the rock-fill body 3 is drilled by overlapping the slots. The overlapped slotted holes, namely the adjacent slotted holes have overlapped parts, and the overlapping thickness can be specifically determined according to the field condition.

As shown in fig. 2, a composite geomembrane 11 is arranged in the impervious wall 4, the self-setting mortar is filled on both sides of the composite geomembrane 11, and a protective layer 10 for covering the impervious wall 4 is arranged on the top end of the rockfill 3. The composite geomembrane 11 has good waterproof performance, the seepage-proofing performance can be greatly improved by arranging the composite geomembrane 11 in the seepage-proofing wall 4, the composite geomembrane 11 is arranged in the groove before the self-setting mortar is filled, and then the self-setting mortar is filled on two sides of the composite geomembrane 11 simultaneously, so that the construction efficiency is improved.

Further, after the step of forming a groove along the center axis of the upper end of the rockfill body 3 and then filling the groove with self-setting mortar, the construction method further includes: and (3) punching and smashing by using a heavy hammer to embed the self-setting mortar into the weathered rock 6. Because the self-setting mortar has low self-setting wall building strength and is difficult to enter rocks, the density and the strength of the wall can be increased by punching and pounding with a heavy hammer, so that the wall is embedded into weathered rocks 6, and the anti-seepage effect is further increased.

Further, the step of curtain grouting is performed after the step of filling the cutoff wall 4; before the curtain grouting step, the construction method further includes: pre-embedding an insertion pipe for grouting the curtain, wherein the insertion pipe penetrates through the impervious wall 4; and performing curtain grouting after the self-setting mortar is filled for 10 d.

The method is characterized in that the insertion pipe for curtain grouting is pre-embedded in the self-setting mortar, so that the grouting and the self-setting mortar are not influenced by each other, the insertion pipe can also increase the strength of the impervious wall 4, and the problem of low strength of the impervious wall 4 formed by the self-setting mortar is well solved.

In other embodiments of the present invention, the step of filling the rock-fill body 3 with the impervious wall 4 comprises: and drilling the rockfill 3 and simultaneously carrying out high-pressure spray irrigation and filling the impervious wall 4.

And drilling and high-spray sprinkling irrigation filling are carried out simultaneously, so that the drilling and the sprinkling irrigation are carried out simultaneously, and the construction period is shortened.

Wherein, the rock-fill body 3 is drilled in a plum-blossom-shaped hole distribution mode. The quincunx cloth holes increase the connection strength between the wall body and the wall surface of the rockfill body 3 on one hand, and can increase the strength per se on the other hand, so that the thickness and the continuity of the wall body are guaranteed.

In addition, the impervious wall 4 is embedded into the concrete facing 7 at the bend of the dike. Because the diaphragm wall 4 is required to be connected with the concrete slope protection at the corner of the cofferdam, the end part is always difficult in diaphragm construction because two materials with different properties are connected and are positioned at the slope part which is difficult to construct. When the drill hole contacts the concrete slope surface, the feeding pressure is reduced, the drill hole is normally drilled after a small step is slowly formed on the slope surface, the hole inclination precision and the rock embedding depth can be ensured, and the anti-seepage effect is ensured when the anti-seepage wall 4 is embedded into the concrete protective surface 7.

As shown in fig. 2, as an alternative embodiment, a transverse buffer zone 8 is arranged at the front end of the upstream surface of the rockfill body 3, and the buffer zone 8 can weaken the impact of water flow on the rockfill body 3, prevent the rockfill body 3 from being damaged, and prolong the service life of the cofferdam; especially in the water flow turning position, the water flow slowing has the function of protecting the weir body from being washed out.

As an alternative embodiment, as shown in fig. 2, the water-facing side of the cover layer 2 is provided with a reinforcement cage 9, said reinforcement cage 9 being provided with stones. When cofferdam, especially at the water flow turning place, the impact of the water flow to the weir body is very large, which easily causes the weir body to be damaged by being washed out at the water facing side, and brings the material of the covering layer 2 into the water to be washed away, thus damaging the weir body; the reinforcing reinforcement cage 9 is used for reinforcing the water-facing side of the covering layer 2, and the reinforcing reinforcement cage 9 can be a reinforcement cage, is internally provided with stones and is embedded into the covering layer 2 to resist the impact of water flow.

In summary, the embodiment of the invention provides a cofferdam construction method, the construction efficiency is accelerated by adopting the mode of vertical plugging of upstream and downstream dual prop, the lower side is used for seepage prevention and water stop in the mode of curtain grouting, the upper side is used for seepage prevention and water stop by the seepage-proof wall 4, and the seepage prevention effect is good; weathered rocks 6 are embedded at the bottom of the impervious wall 4, so that the stability and the impervious effect of the wall are improved; the slope laying concrete protective surface 7 of the rockfill body 3 effectively prevents water flow from scouring the rockfill body 3 and can also prevent water pollution.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.