阅读说明：本技术 旧水坝的拆除方法 (Method for dismantling old dam ) 是由 陈祖荣 朱晓秦 刘振宇 赖建文 吴勍 胡豹 林立 贾文博 张廷松 于 2020-07-01 设计创作，主要内容包括：一种旧水坝的拆除方法,其要点在于,保留旧水坝主体,对于旧水坝要拆除部分,将下游侧先爆破到要拆除的高度,而保留上游侧挡水坎,将新旧坝之间做充蓄水前的场地整理、回填碎渣,制作护坦,在护坦与坝趾之间填筑大块石,形成消力池,再逐步拆除挡水坎,分步为新坝蓄水,拆除挡水坎步骤为：1)确定挡水坎拆除高程；2)横向进行分块,每块纵向分次爆破,爆破方向：上游往下游方向爆破；3)确定爆破高度和宽度,限制水流量；4)当新坝各项安全指标均已稳定,再将未拆除的预留挡水坎全部拆除到设计的拆除高度。本发明的优点在于容易控制缺口大小,防止大坝大面积拆除时出现大水流,对下游建筑设施造成损害,通过护坦,减小挡水坎充水的势能。(The utility model provides a demolish method of old dam, its main points lie in, remain old dam main part, to the old dam part of will demolising, blast the downstream side to the height that will demolish earlier, and remain upstream side retaining bank, do the place arrangement before filling the retaining between new and old dam, backfill the disintegrating slag, make the apron, fill the bold stone between apron and dam toe, form the absorption basin, demolish the retaining bank step by step again, the retaining for new dam step by step, demolish the retaining bank step and do: 1) determining the dismantling elevation of the water retaining bank; 2) transversely partitioning, blasting each block longitudinally and repeatedly, wherein the blasting direction is as follows: blasting from upstream to downstream; 3) determining the blasting height and width, and limiting water flow; 4) and when all safety indexes of the new dam are stable, completely removing the undetached reserved water retaining bank to the designed removal height. The invention has the advantages that the size of the gap is easy to control, the damage to downstream building facilities caused by large water flow when the dam is dismantled in a large area is prevented, and the potential energy of water filling of the water retaining bank is reduced through the flat protector.)

1. A method for dismantling an old dam is characterized in that an old dam body is reserved, a concrete wall with the downstream side of blasting to the height to be dismantled is reserved for the part to be dismantled of the old dam, the concrete wall with the upstream side of thickness and the water surface height of (3-5) m (3.5-6) m is reserved as a water retaining bank, a field between the new dam and the old dam is arranged and backfilled with crushed slag before water is filled and stored, a flat protector is manufactured at the position 5m-10m away from a blasting notch of a water retaining dam section and outside a downstream dam toe, large stones are filled between the flat protector and the dam toe to form a stilling pool, then the water retaining bank is dismantled step by step, water is stored for the new dam, and the water retaining bank dismantling step is as follows: 1) determining the dismantling elevation of the water retaining bank; 2) transversely partitioning, blasting each block longitudinally and repeatedly, wherein the blasting direction is as follows: blasting from upstream to downstream; 3) determining the height and width of each explosion and limiting water flow; 4) when the water stored in the front new dam reaches a certain height, the gap is sealed, the water storage speed is slowed down, the condition of the new dam body after water storage is detected, when all safety indexes of the new dam are stable, the undetached reserved water retaining bank is completely dismantled to the designed dismantling height.

2. The method as claimed in claim 1, wherein the apron is formed by stacking a plurality of load-bearing cages, the upper layer is n rows, the lower layer is n +1 or n +2 rows, the load-bearing cages are formed by an outer shell and an inner load, the outer shell is in a grid hole shape, the inner load is stones larger than the grid holes of the outer shell, the inner space of the outer shell is filled with the stones, the length of the apron formed by splicing the load-bearing cages is larger than the length of the gap of the dam, and the length of the apron is 2-5 times of the length of the gap.

3. A method as claimed in claim 1, wherein the water level of the reservoir of the old dam rises by 9 to 11m per day within 3 to 4 days after the first explosion.

4. A method of demolishing an old dam according to claim 3, wherein the head of the first explosion is 0.3-0.6 m.

5. A method as claimed in claim 1, wherein the second blasting is performed at a position where the adjacent sections of the dam are blasted for the first time, and the adjusted head is 0.5-0.9 m.

6. A method as claimed in claim 1, wherein the second explosion has a head of 0.5-0.9m, and the level of the reservoir water between the old and new dams rises by 9-11m per day.

7. A method as claimed in claim 1, wherein the height of the crushed slag backfilled between the new dam and the old dam is 28-33m, the porosity is 1/3, and after the first blasting, the second blasting is performed when the water storage height reaches 40-50% of the total designed water storage height.

8. The method for dismantling the old dam as claimed in claim 1, wherein the step 4 is that when the water level of the new dam reaches 81-87%, the gap is sealed, the water storage speed is reduced, and the water level of the new dam and the old dam rises 1.0-2.0m every day to detect the condition of the new dam after water storage.

9. The method for demolishing an old dam according to claim 1, wherein when the notch of the water-retaining bank is demolished by blasting, a digital detonator is used for blasting operation, and the left and right cross sections of the cross section adopt a light blasting hole mode to reduce the destructive power of the main blasting hole to the demolished reserved water-retaining bank.

10. The method for dismantling the old dam as claimed in claim 1, wherein the elevation of the dam bottom of the new dam is EL175, the height of the new dam is 94.50m, the elevation is EL175.0-EL269.5m, and the normal impoundment level is EL263.5 m; the elevation of the dam bottom of the old dam is EL176, the height of the old dam is 91.7m, the elevation of the old dam is EL 176.0-EL 267.7, and the total volume between the old dam and the old dam is 360 ten thousand m³The total width of old dam 1080m, divide into 1-60# dam sections, keep old dam main part, explode in old dam part, preparation manger plate bank, the manger plate bank is located old dam upstream side, it is 3m 4.2 m's concrete wall to keep upstream side thickness water level height to be as the manger plate bank, the height of the detritus of backfilling between new and old dam is 30m, the porosity is 1/3, demolish the manger plate bank step by step again, the retaining water of step by step is new dam, the manger plate bank transversely divides 4 storehouse blocks altogether, do: the 1 st bin block dismantling range is 16# dam section to 25# dam section, and the total number of 10 dam sections is 180 m; the 2 nd bin block dismantling range is 6# dam section to 15# dam section, and the total number of 10 dam sections is 180 m; the 3 rd bin block dismantling range is 26# dam section to 34# dam section, and the total number of the dam sections is 9 dam sections 162 m; the 4 th bin block dismantling range is 35# dam section-43 # dam section, 9 dam sections are used totally, the first and second notch blasting are carried out, and the blasting direction is as follows: blasting toward the downstream direction in the upper reaches, the blasting of 1 st ~ 4 storehouse piece manger plate bank main part, the blasting direction: performing 45-degree inclined blasting from upstream to downstream, wherein the bottom of the blasted water retaining ridge is a 40-degree slope, and the bottom elevation is gradually decreased from downstream to upstream; the water retaining bank gap of the 1 st bin block is removed and is firstly fixed at the 25# dam section, the gap removal height is 4.6m, the first water head is 0.4m, the gap length is 5m, in the area of EL175.0-EL205.0 within 3-4 days after blasting, the water level of the stored water between the new dam and the old dam rises 10m every day, and a gap is stacked at the position 15m away from the left side and the right side of the sealing seam of the 25# dam section and the 26# dam sectionThe layer gunny bag leads the wall, reduce rivers diffusion range, reach more than 31m when the water level, begin the breach blasting of second time, the breach is at 26# dam section, the breach is demolishd the height and is 4.9m, the breach is 0.3m lower than the breach for the first time, breach length is 5m, the flood peak is 0.7m, increase the discharge, keep retaining water level rate of rise 10 m/day, when the water level reachd EL230.0, slow down retaining rate, retaining water level rate of rise reduces to 1.0 m/day-2.0 m/day, use equipment to block the breach, until the normal back of new dam retaining detection data, can dig the breach again, accelerate retaining rate.

Technical Field

The invention belongs to the field of old dam demolition, and particularly relates to a demolition method for an old dam after a new dam is built.

Background

The development of domestic water conservancy projects is rapid, the construction of domestic hydropower stations is slowly in a saturation state in recent decades, and no precedent for blasting demolition of large dam bodies exists in China, and most of the large dam bodies are repaired by renovating old dams. With the service life of the domestic dam becoming longer and longer, the potential safety hazard of the old dam cannot be fundamentally solved only by maintenance, so that the dam dismantling is an inevitable fact, and the technology of the domestic dam dismantling needs to be further improved. The old dam is located in a hydroabundant place, and a new dam is generally built in front of (i.e. downstream) the old dam, which puts higher requirements on the removal of the old dam.

Disclosure of Invention

The object of this patent is to provide a method of demolition of an old dam to protect the safety of the new downstream dam from damage.

The technical scheme adopted by the invention is a method for dismantling an old dam, which is characterized in that an old dam body is reserved, for a part to be dismantled of the old dam, a downstream side is firstly blasted to the height to be dismantled, a concrete wall with the thickness of an upstream side and the height of a water surface being (3-5) m (3.5-6) m is reserved as a water retaining ridge, a field before water is filled and stored between the new dam and the old dam is arranged and backfilled with crushed slag, a protection pad is manufactured at a position 5m-10m away from a blasting notch of a water retaining dam section and outside a downstream dam toe, large stones are filled between the protection pad and the dam toe to form a stilling pool, then the water retaining ridge is dismantled step by step, water is stored for the new dam, and the water retaining ridge is dismantled step by step: 1) determining the dismantling elevation of the water retaining bank; 2) transversely partitioning, blasting each block longitudinally and repeatedly, wherein the blasting direction is as follows: blasting from upstream to downstream; 3) determining the height and width of each explosion and limiting water flow; 4) when the water stored in the front new dam reaches a certain height, the gap is sealed, the water storage speed is slowed down, the condition of the new dam body after water storage is detected, when all safety indexes of the new dam are stable, the undetached reserved water retaining bank is completely dismantled to the designed dismantling height.

The invention creatively provides an old dam body, for a part to be dismantled of an old dam, the downstream side is firstly blasted to the designed height to be dismantled, and a concrete wall with a certain height at the upstream side is reserved as a water retaining bank.

The invention relates to a dam construction method, which comprises the steps of constructing a dam, constructing a dam foundation on the dam foundation, constructing a dam section on the dam foundation, constructing a dam foundation on the dam foundation, constructing a dam on the dam foundation, constructing a protection dam section on the dam foundation, constructing a protection dam on the protection dam foundation, constructing a protection dam foundation on the protection dam.

The apron is formed by stacking a plurality of bearing cages, the upper layer is n rows, the lower layer is n +1 or n +2 rows, each bearing cage is composed of a shell and an internal load, the shell is in a grid hole shape, the internal load is a stone block larger than grid holes of the shell, the internal space of the shell is filled, the length of the apron formed by splicing the bearing cages is larger than the length of a gap for dismantling the dam, and the length of the apron is 2-5 times of the length of the gap.

And (3) controlling the flow of the overflow water of the demolished section of the large dam body, and forming an expected overflow section S according to accurate controlled blasting, wherein the flow calculation formula is Q = S V, Q is the flow, S is the area of the overflow section, and V is the flow speed.

After the first explosion, the water level of the stored water between the new dam and the old dam rises by 9-11m every day within 3-4 days. The required flow section S can be calculated according to the required flow by the formula.

The water head of the first explosion is 0.3-0.6 m. S = height width = H W, giving the width W of the notch.

The second blasting position is the dam section adjacent to the first blasting. Because dams are built according to mountains usually, the shape between the new dam and the old dam is like a bucket, the water level rising speed is reduced along with the rising of the water level and the same water injection amount, and a gap needs to be enlarged to achieve a certain rising speed.

The water head of the second explosion is 0.5-0.9m, and the water level of the stored water between the new dam and the old dam rises 9-11m every day. The increase in head also contributes to the increase in flow.

And after the first blasting, performing second blasting when the water storage height reaches 40-50% of the total designed water storage height.

And 4, when the water stored in the new dam of the previous square reaches a certain height, slowing down the water storage speed to detect the condition of the new dam after water is stored when the water storage level reaches 81-87%.

The gap is sealed, the water storage speed is slowed down, and the water storage level between the new dam and the old dam rises by 1.0-2.0m every day.

When the water retaining bank notch is demolished by blasting, a digital detonator is used for blasting operation, and the left and right cross sections of the cross section adopt a light blasting hole mode, so that the destructive power of the main blasting hole to the undetached reserved water retaining bank is reduced.

The elevation of the new dam bottom is EL175, the height of the new dam is 94.50m, the elevation is EL175.0-EL269.5m, and the normal water storage level is EL263.5m; the elevation of the dam bottom of the old dam is EL176, the height of the old dam is 91.7m, the elevation of the old dam is EL 176.0-EL 267.7, and the total volume between the old dam and the old dam is 360 ten thousand m³The total width of the old dam is 1080m, the old dam is divided into 1-60# dam sections, the main body of the old dam is reserved, local blasting is carried out on the old dam, a water retaining bank is manufactured and positioned on the upstream side of the old dam, a concrete wall with the thickness of the upstream side and the height of the water surface being 3m 4.2m is reserved as the water retaining bank, and the height of broken slag backfilled between the new dam and the old dam is equal to that of the broken slagThe water retaining bank is 30m, the porosity is 1/3, the water retaining bank is gradually removed, water is stored for the new dam step by step, the water retaining bank is divided into 4 bin blocks in total in the transverse direction, and the method comprises the following steps: the 1 st bin block dismantling range is 16# dam section to 25# dam section, and the total number of 10 dam sections is 180 m; the 2 nd bin block dismantling range is 6# dam section to 15# dam section, and the total number of 10 dam sections is 180 m; the 3 rd bin block dismantling range is 26# dam section to 34# dam section, and the total number of the dam sections is 9 dam sections 162 m; the 4 th bin block dismantling range is 35# dam section-43 # dam section, 9 dam sections are used totally, the first and second notch blasting are carried out, and the blasting direction is as follows: blasting toward the downstream direction in the upper reaches, the blasting of 1 st ~ 4 storehouse piece manger plate bank main part, the blasting direction: performing 45-degree inclined blasting from upstream to downstream, wherein the bottom of the blasted water retaining ridge is a 40-degree slope, and the bottom elevation is gradually decreased from downstream to upstream; the water retaining bank gap of the 1 st bin block is removed and is firstly fixed at a 25# dam section, the gap removal height is 4.6m, the first water head is 0.4m, the gap length is 5m, in the EL175.0-EL205.0 area within 3-4 days after blasting, the water level of the new dam and the old dam is increased by 10m every day, a layer of bale guide wall is stacked at the 15m position away from the left side and the right side of the sealing seam of the 25# dam section and the 26# dam section, the water flow diffusion range is reduced, when the water level reaches more than 31m, the second gap blasting is started, the second gap is at the 26# dam section, the gap removal height is 4.9m, the gap is 0.3m lower than the first gap, the gap length is 5m, the water head is 0.7m, the water level flow is increased, the water retaining water level increase rate is 10 m/day, when the water level reaches EL230.0, the water retaining rate is reduced, the water retaining increase rate is reduced to 1.0 m/day-2.0 m/, and the notch can not be dug again until the water storage detection data of the new dam is normal, so that the water storage speed is accelerated.

The invention has the advantages that the invention creatively provides the old dam main body, for the part of the old dam to be dismantled, the downstream side is firstly blasted to the height to be dismantled, and the concrete wall with a certain height at the upstream side is reserved as the water retaining bank. Meanwhile, temporary flat protectors are formed in the dam dismantling process by stacking the bearing cages, the potential energy of water filling of the retaining bank is reduced, large stones are filled in front of the retaining bank to form a stilling pool, water flow energy is eliminated for a new dam, and potential safety hazards are eliminated.

Drawings

FIG. 1 is a plan view of a water dam

FIG. 2 is a schematic cross-sectional view of the water dam removed

FIG. 3 is a view of a load bearing cage

Wherein: 1 bearing cage 11 housing 12 internal load 2 old dam.

Detailed Description

The invention is described in detail below with reference to the drawings

As shown in figures 1-3, the invention is suitable for the removal of the old dam after the new dam is built, the invention does not remove all the old dams when removing the old dams, the old dams at two ends are kept as the ancient sites, the middle part is removed, the communication between the two dams is ensured, the functional requirements of power generation and flood discharge of the new power station are met, the old dams are kept as cultural relics, and the functions of any water conservancy facilities such as power generation, flood control and the like are not born.

In the process of blasting the upper part of the middle part of the old dam, the downstream side is demolished to a designed demolition position below the water surface, an upstream side concrete wall with a certain height is reserved as a water retaining bank to block running water and facilitate ballast cleaning, the water retaining bank is demolished by times, sections and heights, the size of a demolition section is controlled to control water quantity, large water flow is prevented from occurring when the dam is demolished in a large area, and damage is caused to downstream building facilities, so that the water flow is accurately controlled by controlling the size of a gap formed by blasting, the new dam is protected from being damaged by the impact of the large water flow, a concrete wall with the thickness of the upstream side being (3-5) m (3.5-6) m is reserved as the water retaining bank, the height difference between the water retaining bank and the downstream side is 4.5-7 m, a site before water is filled and stored between the new dam and the old dam is backfilled and crushed slag is arranged at a position 5-10 m away from the downstream toe of the blasting gap, piling up the bearing cage to form a tail ridge, filling large stones between the retaining wall and the toe of the bearing cage, and then gradually removing the water retaining ridge, wherein the step of removing the water retaining ridge is as follows: 1) determining the dismantling elevation of the water retaining bank; 2) the method is characterized in that the method is divided into blocks transversely, a bin block is generally arranged on the left and right of each 10 dam sections, each block can be blasted longitudinally for 2-3 times, the volume between a new dam and an old dam is used as a grading basis, the volume is large, the grading is multiple, and the blasting direction is as follows: blasting from upstream to downstream; 3) determining the height and width of each explosion, limiting water flow, wherein the water head of the first explosion is 0.3-0.6m, the water level of the stored water between the new dam and the old dam rises by 9-11m every day within 3-4 days after the first explosion, and performing the second explosion when the water storage height reaches 40% -50% of the total designed water storage height after the first explosion. The second blasting position is adjacent dam section of the first blasting, the water head of the second blasting is 0.5-0.9m, and the water level of the stored water between the new dam and the old dam rises 9-11m every day; 4) when the water stored in the front new dam reaches a certain height and the general water storage level reaches 94-96%, the water storage speed is reduced, the gap is sealed, the water storage speed is reduced, the water storage level between the new dam and the old dam rises 1.0-2.0m every day, the water storage speed is reduced, the condition of the new dam after water storage is detected, and when all safety indexes of the new dam are stable, the undetached reserved water retaining bank is completely dismantled.