阅读说明：本技术 旧坝溢流坝段***拆除方法 (Blasting demolition method for overflow dam section of old dam ) 是由 陈祖荣 蒋亨强 孟继慧 刘振宇 赖建文 罗志敏 胡豹 林立 吴勍 于 2020-07-01 设计创作，主要内容包括：一种旧坝溢流坝段爆破拆除方法,其要点在于,按项目类型、爆破高程、蓄水控制水位要求,分层进行拆除,多次爆破,其拆除步骤：安装防护浮船-拆除闸门及相关金属预埋件-爆破溢流堰顶-垂直方向进行分层,逐次爆破-单次爆破先进行下游区域-将溢流坝段拆除至最后一层时,在底部上游侧预留挡水坎,将爆破平面用混凝土整平,最后拆除预留混凝土坎,新坝开始蓄水,完成拆除。本发明施工效果好,有效地控制了爆渣下泄走向,避免落入上游库区,效果显著,可缩短工期1/4,在垂直方向层数分区及分块数量控制爆破拆除施工过程中,可在分区分块施工期间,对上次爆破爆渣辅助以挖掘、自卸车进行清理转运,装渣作业按秩序进行,保证施工安全。(A blasting demolition method for an overflow dam section of an old dam is characterized in that demolition is carried out in a layered mode according to project types, blasting elevations and water storage control water level requirements, multiple times of blasting are carried out, and demolition steps are as follows: installing a protective pontoon, removing a gate and related metal embedded parts, blasting an overflow weir crest, layering in the vertical direction, blasting one by one, firstly blasting a downstream area by single blasting, and when an overflow dam section is removed to the last layer, reserving a water retaining bank on the upstream side of the bottom, leveling a blasting plane by concrete, finally removing the reserved concrete bank, and beginning water storage of a new dam to finish the removal. The invention has good construction effect, effectively controls the downward discharge trend of the blasting slag, avoids falling into an upstream reservoir area, has obvious effect, can shorten the construction period 1/4, can assist the last blasting slag to be excavated and unloaded by a dumper to carry out cleaning and transferring during the partition and partition construction in the partition and partition quantity control blasting demolition construction process in the vertical direction, and ensures the construction safety because the slag loading operation is carried out according to the order.)

1. A blasting demolition method for an overflow dam section of an old dam is characterized in that the method comprises the steps of controlling water level according to project type, blasting elevation and water storage, demolishing in a layered mode, blasting for multiple times, when an overflow dam is demolished to the last layer, reserving a water retaining bank on the upstream side of the bottom, leveling a blasting plane with concrete, demolishing the reserved concrete bank at last, and beginning water storage of a new dam, wherein the demolition steps comprise:

1.1 installing a protective pontoon in an upstream reservoir area;

1.2. demolition gate and related metal embedded parts

1.3, blasting the top of an overflow weir below a gate;

1.4. layering in the vertical direction and blasting successively;

1.5. when the first layer is dismantled, the dam crest of the old dam is used as a construction road;

1.6. constructing from the middle of the dam body to the ends of the two dams;

1.7. carrying out single blasting on a downstream area to form high topography at an upstream side and low topography at a downstream side;

1.8. after the downstream side blasting is finished, deslagging is carried out, and then upstream side blasting is carried out;

1.9. after the blasting of the downstream side of the last layer is finished, a blank face is formed, and a water retaining ridge is formed on the upstream side;

1.10. constructing a downstream side empty concrete cushion layer to form a flat permanent structural surface;

1.11. removing the reserved water retaining bank on the upstream side;

1.12. and (5) storing water in the new dam, and finishing the dismantling.

2. The method for demolishing an overflow dam section of an old dam according to claim 1, wherein the demolishing is carried out in layers including four layers, a first layer: from the top to the upper end surface of the gate orifice, the upper end surface of the gate orifice of the second layer reaches the bottom of the overflow weir crest, the third layer is 5-7 m, and the fourth layer is the rest part.

3. The method for demolishing by blasting an overflow dam section of an old dam according to claim 1, wherein the multiple blasting is seven blasting in total, and the first blasting area is: a weir crest portion; a second blasting area: a downstream side of the first layer; and a third blasting area: upstream side of the first layer + the second layer; fourth blast zone: a third layer downstream side portion; fifth blasting area: a third layer upstream side portion; and a sixth blasting area: a fourth layer downstream side portion; a seventh blasting area: the fourth layer upstream side portion.

4. The demolition blasting method of an old dam overflow dam as claimed in claim 1, wherein the installation of the protection pontoon at the upstream reservoir area in step 1.1 is the installation of a pontoon at the upstream reservoir area, the pontoon is composed of: flotation pontoon, protection network, fixed stock, protection railing, wire rope constitute, and a plurality of flotation pontoon is connected and is formed the pontoon frame, and inside is fixed with the protection network, forms the string bag, installs the protection railing in the peripheral top in the outside of pontoon, and fixed stock passes through wire rope one end and is connected with the outside of pontoon.

5. The method as claimed in claim 1, wherein the thickness and height of the weir is (3-5) m (4-6.5) m.

6. A method for demolishing an overflow dam of an old dam by blasting is characterized in that the height of a new dam is 94.50m, and the height is EL175.0-EL 269.5; the height of an old dam is 91.7m, the height is EL176.0-EL267.7, the total width of the old dam is 1080m, the old dam is divided into 1-60# dam sections, part of the old dam is reserved as a viewing platform in the old dam dismantling process, an overflow dam is positioned in the 10-19# dam sections, the width of each dam section is 18m, the old dam belongs to the part to be dismantled, and the dismantling step comprises the following steps:

6.1. installing a pontoon at an upstream reservoir area, wherein the pontoon is 25m long and 15m wide and comprises: the floating pontoon type floating pontoon structure comprises a plurality of floating pontoons, a protective net, a fixed anchor rod, a protective railing and a steel wire rope, wherein the plurality of floating pontoons are connected to form an outer frame of the floating pontoon, 1 row of floating pontoons are respectively arranged at the periphery and the middle of the outer frame, the protective net is fixed inside the floating pontoon to form a net bag, the protective railing is arranged above the periphery of the outer side of the floating pontoon, and the fixed anchor rod is connected;

6.2. firstly, dismantling a gate and a related metal embedded part;

6.3, blasting the overflow weir crest below the gate, wherein the weir crest part EL 252.50-EL251.00m, the layer height is 1.5m, the total width sum is 140m, and the total height of each dam section is 14m and 10 dam sections;

6.4. then dividing the part to be demolished into 4 layers in the vertical direction, demolishing by blasting for 6 times, wherein the specific construction sequence is as follows: first layer: the dismounting range from the top to the upper end surface of the gate opening is height EL 267.70-EL262.50m, the height of the old dam is 91.7-87.5m, and the layer height is 4.2 m; the width of a single dam section is 18m, the total width of 10 dam sections is 180m, the first blasting is the downstream side of the first layer, and the thickness is 5.75 m; the second layer: the height EL 262.50-EL251.00m and the height of an old dam are 87.5-75m from the upper end surface of the orifice of the gate to the bottom of the top of the overflow weir, the secondary blasting range is the upstream side of the first layer plus the second layer, the dismantling range is the height EL 267.70-EL251.00m and the layer height is 16.7m, and the third layer is the part below the weir top: the dismantling range is height EL 251.00-EL245.00m, the height of the old dam is 75-69m, and the layer height is 6.0 m; blasting for two times: a first blasting area: the downstream part of EL 251.00-EL245.00m has the layer height of 6.0m, the width of 180m and the average thickness of 13.5 m; a second blasting area: the upstream part of the EL 251.00-EL245.00m has the layer height of 6.0m, the width of 180m and the average thickness of 3.9 m; fourthly, fourth layer: the dismantling range is height EL 245.00-EL239.90m, height of an old dam 69-63.9m and layer height 5.1 m; blasting for two times: a first blasting area: the downstream part of EL 245.00-EL239.90m is 5.1m in layer height, 180m in width and 15.5 m in average thickness; and (3) reserving the upstream concrete wall with the thickness of 3m as a water retaining bank, constructing a flat layer by using concrete on the downstream side free face and the residual faces blasted at the two sides to form a flat permanent structural face, and blasting the water retaining bank.

7. The method of demolishing an old dam by blasting according to any one of claims 1 or 6, wherein the downstream side of the blasting is thicker than the upstream side.

8. The method of claim 7, wherein the upstream side of the blast thickness is not greater than 5 m.

9. The demolition method by blasting of an old dam overflow dam according to claim 4, characterized in that anchor rod fixing points are arranged every 3m horizontally outside the protective pontoon, and two anchor rod wire ropes are fixed at each fixing point.

10. The demolition method by blasting of an old dam overflow dam as claimed in claim 4, wherein when the length of the pontoon exceeds 20m, a pontoon is added in the middle.

Technical Field

The invention belongs to construction technology for buildings, in particular to a blasting demolition method for an overflow dam section of an old dam.

Background

Demolition of concrete blasting in hydropower stations is an important process in engineering construction of hydropower stations. The method is mainly used for removing the old dam of the hydropower station, particularly for removing the complicated structure parts such as an overflow dam section and the like. The integral blasting demolition of concrete is a blasting engineering with high risk and high technological content. And the slag is removed by one-time blasting, the single slag removal workload is large, and the slag is removed under the condition of abundant water.

At present, the whole blasting technology is generally adopted for blasting demolition of overflow dam sections of hydropower stations in China, and because the blasting volume is large, the deep hole blasting technology is required, the workload of hole forming operation, charging operation and hole blocking is large, and more labor and machinery are required. The working face of the top of the conventional dam overflow dam section is narrow and small, generally about 10 meters, each side can only accommodate one hole-forming operation machine, the deep hole-forming operation needs to take a long time, and the control of the whole engineering construction period is not facilitated. Meanwhile, the large-volume concrete deep hole blasting technology is not favorable for removing contour line control, blasting cracks are easy to occur on the surface of the foundation concrete, and the deviation regulation of blasting removal of engineering projects is difficult to achieve.

Disclosure of Invention

The invention aims to provide a blasting demolition method for an overflow dam section of an old dam, which can avoid blasting slag from falling into an upstream reservoir area, has short overall construction period and high construction safety.

The technical scheme adopted by the invention is a blasting demolition method for an overflow dam section of an old dam, which is characterized in that demolition is carried out in a layered manner according to project types, blasting elevations and water storage control water level requirements, multiple times of blasting are carried out, when the overflow dam section is demolished to the last layer, a water retaining bank is reserved on the upstream side of the bottom, a blasting plane is leveled by concrete, finally, the reserved concrete bank is demolished, a new dam starts to store water, and the demolition steps are as follows:

1.1 installing a protective pontoon in an upstream reservoir area;

1.2. demolition gate and related metal embedded parts

1.3, blasting the top part of an overflow weir below the gate;

1.4. layering in the vertical direction and blasting successively;

1.5. when the first layer is dismantled, the dam crest of the old dam is used as a construction road;

1.6. constructing from the middle of the dam body to the ends of the two dams;

1.7. carrying out single blasting on a downstream area to form high topography at an upstream side and low topography at a downstream side;

1.8. after the downstream side blasting is finished, deslagging is carried out, and then upstream side blasting is carried out;

1.9. after the blasting of the downstream side of the last layer is finished, a blank face is formed, and a water retaining ridge is formed on the upstream side;

1.10. constructing a downstream side empty concrete cushion layer to form a flat permanent structural surface;

1.11. removing the reserved water retaining bank on the upstream side;

1.12. and (5) storing water in the new dam, and finishing the dismantling.

The invention mainly aims at the blasting demolition of an overflow dam section, and mainly embodies the block oriented blasting technology for controlling the water level of a reservoir and partitioning dry land. The concrete construction process comprises the following steps: safety protection, measurement and setting-out, hole position arrangement, hole forming operation, charging operation, blast hole blockage, network connection, blasting warning, safety inspection and blasting slag clearing.

And determining the number of layers, partitions and blocks in the vertical direction to control blasting demolition according to the actual elevation of the overflow dam section to be blasted demolition. In order to prevent part of fine concrete from falling into an upstream reservoir area during blasting, a pontoon is arranged in the upstream reservoir area during blasting.

When this patent technique blasting construction was blasted earlier in every layer of blasting time and is blasted the upstream side earlier, and the blasting faces the free surface and is old dam downstream side, strict control reservoir area flyrock. The downstream blasting demolition flyrock and the concrete slag all slide to the downstream side and cannot fall into the reservoir area. And when the part on the upstream side is blasted and removed, the row spacing of the encrypted holes is adopted, the single-hole explosive loading is reduced, so that the effect of directional control blasting is achieved, and the slag is turned into the downstream side by adopting an excavator after blasting.

The layered dismantling refers to four layers, namely a first layer: from the top to the upper end surface of the gate orifice, the upper end surface of the gate orifice of the second layer reaches the bottom of the overflow weir crest, the third layer is 5-7 m, and the fourth layer is the rest part.

The multiple blasting refers to seven times of blasting, and the first blasting area is as follows: a weir crest portion; a second blasting area: a downstream side of the first layer; and a third blasting area: upstream side of the first layer + the second layer; fourth blast zone: a third layer downstream side portion; fifth blasting area: a third layer upstream side portion; and a sixth blasting area: a fourth layer downstream side portion; a seventh blasting area: the fourth layer upstream side portion.

Step 1.1 said installing a containment vessel at an upstream reservoir area, wherein the vessel is comprised of: flotation pontoon, protection network, fixed stock, protection railing, wire rope constitute, and a plurality of flotation pontoon is connected and is formed the pontoon frame, and inside is fixed with the protection network, forms the string bag, installs the protection railing in the peripheral top in the outside of pontoon, and fixed stock passes through wire rope one end and is connected with the outside of pontoon.

Utilize the flotation pontoon to build a surface of water platform, link to each other it with the dam through the stock, seal whole surface of water through the protection network, prevent to explode the sediment and fall into the aquatic, the blasting completion at every turn in time clears up the sediment that explodes on the pontoon.

And anchor rod fixing points are arranged at the outer side of the protective floating pontoon every 3m in horizontal distance, and two anchor rod steel wire ropes are fixed at each fixing point.

When the length of the pontoon exceeds 20m, a pontoon is added in the middle.

The thickness multiplied by the height of the reserved water retaining ridge is (3-5) mx (4-6.5) m.

For a new dam height of 94.50m, the elevation is EL175.0-EL 269.5; the height of an old dam is 91.7m, the height is EL176.0-EL267.7, the total width of the old dam is 1080m, the old dam is divided into 1-60# dam sections, part of the old dam is reserved as a viewing platform in the old dam dismantling process, an overflow dam is positioned in the 10-19# dam sections, the width of each dam section is 18m, the old dam belongs to the part to be dismantled, and the dismantling step comprises the following steps:

1. installing a pontoon at an upstream reservoir area, wherein the pontoon is 25m long and 15m wide and comprises: the floating pontoon type floating pontoon structure comprises a plurality of floating pontoons, a protective net, a fixed anchor rod, a protective railing and a steel wire rope, wherein the plurality of floating pontoons are connected to form an outer frame of the floating pontoon, 1 row of floating pontoons are respectively arranged at the periphery and the middle of the outer frame, the protective net is fixed inside the floating pontoon to form a net bag, the protective railing is arranged above the periphery of the outer side of the floating pontoon, and the fixed anchor rod is connected;

2. firstly, dismantling a gate and a related metal embedded part;

3. then, the overflow weir crest below the gate is blasted, the weir crest part EL 252.50-EL251.00m, the layer height is 1.5m, the single dam section is 14m, 10 dam sections are totally arranged, and the total width sum is 140 m;

4. then dividing the part to be demolished into 4 layers in the vertical direction, demolishing by blasting for 6 times, wherein the specific construction sequence is as follows: first layer: the dismounting range from the top to the upper end surface of the gate opening is height EL 267.70-EL262.50m, the height of the old dam is 91.7-87.5m, and the layer height is 4.2 m; the width of a single dam section is 18m, the total width of 10 dam sections is 180m, the first blasting is the downstream side of the first layer, and the thickness is 5.75 m; the second layer: the height EL 262.50-EL251.00m from the upper end surface of the gate orifice to the bottom of the top of the overflow weir, the height (downstream side) of the old dam is 87.5-75m, the secondary blasting range is the upstream side + the second layer of the first layer, the dismantling range is the height EL 267.70-EL251.00m (upstream side), and the layer height is 16.7 m; the third layer is the part below the weir crest: the dismantling range is height EL 251.00-EL245.00m, height of an old dam 75-69m and layer height 6.0 m; blasting for two times: a first blasting area: the downstream part of EL 251.00-EL245.00m has the layer height of 6.0m, the width of 180m and the average thickness of 13.5 m; a second blasting area: the upstream part of the EL 251.00-EL245.00m has the layer height of 6.0m, the width of 180m and the average thickness of 3.9 m; fourthly, fourth layer: the dismantling range is height EL 245.00-EL239.90m, height of an old dam 69-63.9m and layer height 5.1 m. Blasting for two times: as shown in fig. 7, the first burst zone: EL 245.00-EL239.90m (downstream part), layer height 5.1m, width 180m, average thickness 15.5 m; and (3) reserving the upstream concrete wall with the thickness of 3m as a water retaining bank, constructing a flat layer by using concrete on the downstream side free face and the residual faces blasted at the two sides to form a flat permanent structural face, and blasting the water retaining bank.

The downstream side of the blasting is thicker than the upstream side.

The upstream side burst thickness is no greater than 5 meters.

The area of the second layer is an overflow hole area, the blasting square quantity is small, only the overflow hole gate piers on the edge exist, the open overflow holes cannot resist the blast slag on the downstream side, the meaning of the upstream side and the downstream side is not large, and therefore the upstream side and the second layer of the first layer are blasted at one time.

The invention is determined to control blasting demolition in four layers and partitions and seven partitions in the vertical direction, and a small amount of manpower and machinery are adopted to complete the blasting demolition construction task in a planned construction period, so that the blasting demolition flyrock and concrete slag can all slide to the downstream side while the water level is controlled by the layered and partitioned directional blasting, and the difficulty of slag removal in the reservoir area caused by the fact that the flyrock and the concrete slag fall into the upstream reservoir area is avoided. The construction period in the old dam overflow dam section dismantling construction is short, compared with the existing one-time dismantling, the construction period is shortened by 1/4, and the construction period is reduced to 3 months from 4 months; the construction effect is good, the downward discharge trend of the blasting slag is effectively controlled, and the effect is obvious.

In the construction process of blasting demolition by layer division and block quantity control in the vertical direction, the invention can assist the last blasting slag to carry out cleaning and transportation by a digging and self-dumping truck during the construction of the subareas and the blocks, and the slag loading operation is carried out according to the order, thereby maintaining good construction environment, cleaning and transporting the site and ensuring the construction safety.

The method can be applied to the series of demolition of the explosion of the overflow dam section of the old dam, demolition of the reserved explosion of the large hydraulic building part and demolition of the closure overflow explosion of the cofferdams at the upstream and the downstream of the hydraulic junction.

Drawings

FIG. 1 is a sectional view of an old dam overflow dam section for demolition by blasting in four layers

FIG. 2 is a sectional view of a first blasting demolition of an overflow dam section of an old dam

FIG. 3 is a sectional view of a secondary blasting demolition of an overflow dam section of an old dam

FIG. 4 is a sectional view of a third blasting demolition of an overflow dam section of an old dam

FIG. 5 is a sectional view of a fourth blasting demolition of an overflow dam section of an old dam

FIG. 6 is a sectional view of a fifth blasting demolition of an overflow dam section of an old dam

FIG. 7 is a sectional view of a sixth blasting demolition of an overflow dam section of an old dam

FIG. 8 is a schematic diagram of the construction of a downstream concrete cushion facing the open face

FIG. 9 is a seventh blasting demolition cross-sectional view of an overflow dam section of an old dam

FIG. 10 is a schematic view of the structure of a protective pontoon

FIG. 11 is a schematic view of the connection between the protective pontoon and the old dam

Wherein: 1 buoy, 2 protective nets, 3 anchor rods, 4 steel wire ropes, 5 protective railings and 6 old dams.

Detailed Description

The following examples, which are set forth to provide those of ordinary skill in the art with a better understanding of the present invention and are not intended to limit the invention in any way.

As shown in fig. 1 to 11, a blasting demolition method for an overflow dam section of an old dam is mainly embodied as a block oriented blasting technology for controlling reservoir water level and dry land partitioning. The overflow dam section has overflow holes, so that the cross sections with different heights are different in shape, and the solid figure is divided into an overflow hole area and an overflow hole gate pier area for illustration. In fig. 1, a thick black box represents a fractionated blasting block, and a thin vertical line represents a blast hole.

Firstly, determining the number of layers, partitions and the number of blocks to be demolished in the vertical direction according to the actual elevation of the overflow dam section to be demolished by blasting. The construction process comprises the following steps: safety protection, measurement and setting-out, hole position arrangement, hole forming operation, charging operation, blast hole blockage, network connection, blasting warning, safety inspection and blasting slag clearing. In order to prevent part of fine concrete from falling into an upstream reservoir area during blasting, a pontoon is arranged in the upstream reservoir area during blasting.

The method specifically comprises the following steps: according to project type, blasting elevation, retaining control water level, the layering is demolishd, and multiple blasting when demolishing the overflow dam to last one deck, reserves manger plate bank in bottom upper reaches side, with the concrete flattening for the blast plane, demolishs the concrete at last and reserves manger plate bank, and new dam begins to impound, its demolishs the step:

1.1 installing a protective pontoon in an upstream reservoir area;

1.2. demolition gate and related metal embedded parts

1.3, blasting the top of an overflow weir below a gate;

1.4. layering in the vertical direction and blasting successively;

1.5. when the first layer is dismantled, the dam crest of the old dam is used as a construction road;

1.6. constructing from the middle of the dam body to the ends of the two dams;

1.7. carrying out single blasting on a downstream area to form high topography at an upstream side and low topography at a downstream side;

1.8. after the downstream side blasting is finished, deslagging is carried out, and then upstream side blasting is carried out;

1.9. after the blasting of the downstream side of the last layer is finished, a blank face is formed, and a water retaining ridge is formed on the upstream side;

1.10. constructing a downstream side empty concrete cushion (the strength grade of the concrete is the same as that of the original building) to form a flat permanent structural surface;

1.11. removing the reserved water retaining bank on the upstream side;

1.12. the new dam begins to store water.

When this patent technique blasting construction was blasted earlier in every layer of blasting time and is blasted the upstream side earlier, and the blasting faces the free surface and is old dam downstream side, strict control reservoir area flyrock. The downstream blasting demolition flyrock and the concrete slag all slide to the downstream side and cannot fall into the reservoir area. The row spacing between the conventional blast holes is 1.0-2.0m, and the single-hole explosive loading range is 12.0-36 kg. The method for reducing the single-hole loading amount by adopting the row spacing of the encrypted holes during blasting demolition of the upstream side part of the invention has the row spacing between the blasting holes of 0.70-0.90m and the single-hole loading amount range of 7.5-16.0kg so as to achieve the effect of directionally controlling blasting, and the blasting slag is turned into the downstream side by adopting an excavator after blasting.