A construction access structure and construction method for the bottom gallery of a large arch dam

Abstract

The present invention discloses a construction passage structure and a construction method for the bottom gallery of a large arch dam. The arch dam is provided with a grouting gallery at the bottom layer of the arch dam and a monitoring branch gallery connected to the grouting gallery. The construction passage extends from the end of the monitoring branch gallery towards the downstream dam surface of the arch dam to form a reserved gallery as the construction passage for the bottom gallery of the arch dam. Among them: the bottom plates at both ends of the reserved gallery are smoothly connected to the elevation of the monitoring branch gallery and the bottom plate of the outer water cushion pond on the dam surface; a composite rubber water stop is arranged downstream of the intersection of the reserved gallery and the monitoring branch gallery, and a wide flat copper water stop is arranged upstream near the downstream dam surface of the reserved gallery. The passage structure of the gallery in the present invention effectively forms a passage for the bottom grouting gallery during grouting, improving the construction efficiency of grouting; by adopting the construction passage set in the present invention, the cost is relatively low, the passage is formed relatively quickly, and it can be implemented and completed synchronously with the bottom grouting gallery and the monitoring branch gallery.

Description

Technical Field

[0001] The invention belongs to the technical field of large-scale water conservancy construction design, especially to the design and construction technology of the construction passage of the bottom gallery of the dam in water conservancy construction design, and particularly relates to a structure and construction method of the construction passage of the bottom gallery of a large arch dam. Background Art

[0002] During the construction of a large arch dam project, a bottom grouting gallery is arranged at a position where the bottom elevation does not exceed 20 m above the construction base elevation. The bottom grouting gallery can only enter and exit from the middle and high parts of the arch dam through the inclined galleries arranged on both sides of the arch dam, and the height difference generally exceeds 50 - 70 m. The inclined gallery has a stepped ground at about 45 degrees, and the construction is extremely inconvenient. Therefore, during the grouting construction of the bottom grouting gallery, a relatively convenient traffic road needs to be arranged to enter the bottom grouting gallery to facilitate the construction.

[0003] There are generally two ways to construct the construction passage for the existing technology of grouting construction of the bottom grouting gallery.

[0004] The first way is to directly enter and exit from the middle and high parts of the arch dam, go down along the inclined gallery, and walk to the bottom grouting gallery. The disadvantage of this way is that all the personnel, materials, and equipment for grouting construction are transported manually, walking in and out along the inclined gallery, and the construction efficiency is extremely low, resulting in an increase in labor costs.

[0005] The second way is to use the low-line over-dam transportation road arranged in the bank slope mountain body, descend at a road surface slope of about 10% - 15%, excavate a traffic tunnel in the mountain body, pass through the dam foundation, and connect it to the bottom grouting gallery as the construction passage of the bottom grouting gallery, and then block the traffic tunnel later. The disadvantage of this way is that in general arch dam design, the low-line over-dam transportation road arranged in the bank slope mountain body is arranged flush with the top elevation of the side wall of the plunge pool to facilitate the arrangement of the maintenance passage from the low-line over-dam transportation road to the top of the plunge pool. Generally, the height difference between the bottom grouting gallery of the arch dam and the top elevation of the side wall of the plunge pool usually exceeds 50 m. Then, the passage from the low-line over-dam transportation road to the bottom grouting gallery by arranging a traffic tunnel downhill will be more than 350 m long. The excavation period of the passage itself will be more than 3.5 months, and the cost will exceed 3.5 million yuan. The cost is relatively high, and the traffic tunnel still has to be blocked in the later stage. Summary of the Invention

[0006] The invention discloses a structure and construction method of the construction passage of the bottom gallery of a large arch dam according to the deficiencies of the existing technology. The problem to be solved by the invention is to provide a structure and its setting method for extending the construction passage of the bottom grouting gallery downward in the direction of the downstream dam surface by using the existing monitoring branch gallery structure.

[0007] The invention is realized through the following technical solutions:

[0008] Construction channel structure for the bottom gallery of a large arch dam. The large arch dam is provided with a grouting gallery at the bottom of the arch dam and a monitoring branch gallery connected to the grouting gallery. It is characterized in that: the construction channel extends from the end of the monitoring branch gallery towards the downstream dam face of the arch dam to form a reserved gallery as the construction channel for the bottom gallery of the arch dam; among them: the bottom plates at both ends of the reserved gallery are smoothly connected to the elevation of the monitoring branch gallery and the bottom plate of the outer water cushion pond on the dam face; a composite rubber water stop is provided 40 cm downstream of the intersection of the reserved gallery and the monitoring branch gallery, and a 60-cm-wide flat copper water stop is provided 40 cm upstream of the downstream dam face of the reserved gallery.

[0009] The control gradient of the reserved gallery is less than 20%; the longitudinal bottom plate of the reserved gallery is a continuous sloping bottom plate or a flat bottom plate without steps.

[0010] The cross-sectional dimensions of the reserved gallery are the same as those of the monitoring branch gallery.

[0011] A sandbag covering protection layer is provided for the composite rubber water stop at the bottom plate of the reserved gallery, a protection channel steel is covered on the upper part of the flat copper water stop at the bottom plate, and sandbags are provided at both ends of the channel steel to slow down the gradient for protection.

[0012] The present invention discloses a construction method for the construction channel of the bottom gallery of a large arch dam, including the following steps:

[0013] (1) According to the bottom plate elevation, dimensions and coordinates of the bottom grouting gallery and the monitoring branch gallery of the large arch dam, combined with the elevation of the bottom plate of the water cushion pond on the downstream side of the arch dam, arrange the axis of the reserved gallery; the bottom plates at both ends of the reserved gallery must be smoothly connected to the elevation of the monitoring branch gallery and the bottom plate of the outer water cushion pond on the dam face;

[0014] (2) Clean the foundation of the arch dam section where the reserved gallery is arranged, and construct the arch dam body below the elevation of the bottom plate of the reserved gallery; each water stop is pre-buried along with the preparation of the bin.

[0015] (3) After constructing to the elevation of the bottom plate of the reserved gallery, start to prepare the bin for the side wall of the gallery, and the dam body of this dam section of the arch dam at the same elevation as the side wall of the gallery is constructed synchronously with the gallery; during the construction of the side wall, the bottom plate of the water cushion pond on the downstream side of the reserved gallery can be constructed simultaneously.

[0016] (4) When the side wall of the reserved gallery is constructed to 0.5 - 1 m below the elevation of the arch foot of the top arch, the top arch of the reserved gallery and the remaining side wall are prepared for construction simultaneously, and the first concrete covering thickness above the elevation of the top arch of the top arch is 1 - 1.5 m.

[0017] (5) After the concrete of the top arch of the reserved gallery reaches the design strength, after removing the supports and formworks, protect the exposed bottom plate water stop of the reserved gallery. The composite rubber water stop is protected by covering with sandbags, and after the flat copper water stop is constructed, the water stop is bent, and a channel steel is covered on the upper part for protection, and sandbags are used at both ends of the channel steel to slow down the gradient; complete the construction of the reserved gallery.

[0018] (6) During the subsequent passage of the reserved corridor, during the intermittent time of passage, the bottom slab, side walls and top slab of the corridor are timely roughened to shorten the straight-line construction period of the later concrete backfilling and plugging.

[0019] The present invention utilizes the monitoring branch corridor of the bottom grouting corridor of a large arch dam, extends towards the downstream dam surface of the arch dam, penetrates to the downstream dam surface to set a reserved corridor, and the reserved corridor and the monitoring branch corridor together serve as the construction passage for entering the bottom grouting corridor of the arch dam. After the grouting construction is completed, the reserved corridor is plugged and backfilled.

[0020] The reserved corridor extends from the end of the monitoring branch corridor to the downstream dam surface, and the cross-sectional dimensions are the same as those of the monitoring branch corridor. The elevation of the bottom slab on the downstream side of the reserved corridor is flush with the elevation of the bottom slab on the upstream side of the plunge pool.

[0021] A composite rubber waterstop is set 40 cm downstream of the intersection of the reserved corridor and the monitoring branch corridor, and a 60-cm-wide flat copper waterstop is set 40 cm away from the downstream dam surface of the reserved corridor. The composite rubber waterstop at the bottom slab of the reserved corridor is protected by covering with sandbags. After the construction of the flat copper waterstop at the bottom slab is completed, the waterstop is bent, and the upper part is covered with channel steel for protection. Sandbags are used at both ends of the channel steel to slow down the slope.

[0022] The steel bars of the reserved corridor are constructed according to the steel bar configuration of the monitoring branch corridor.

[0023] After the formwork of the reserved corridor is removed, the bottom slab, side walls and top arch are timely roughened to facilitate the later concrete plugging and backfilling.

[0024] In the later stage, the reserved corridor is plugged by pumping secondary aggregate concrete with the same strength grade as the same part of the arch dam, and the plugging surface must be joint grouted.

[0025] The reserved corridor of the present invention extends downstream towards the dam surface by utilizing the monitoring branch corridor, which can save the later plugging project quantity. The bottom plates at both ends of the reserved corridor must be smoothly connected to the elevations of the monitoring branch corridor and the plunge pool bottom plate, which limits the present invention to the situation where the elevation difference between the monitoring branch corridor and the plunge pool bottom plate is not large. Otherwise, the longitudinal comprehensive slope of the reserved corridor will be too large, and generally the controlled slope is preferably not more than 20%; the longitudinal bottom plate of the reserved corridor is a sloped bottom plate or a flat bottom plate without forming steps. A composite rubber waterstop is provided 40 cm downstream of the intersection of the reserved corridor and the monitoring branch corridor, and a 60-cm-wide flat copper waterstop is provided 40 cm upstream of the downstream dam surface of the reserved corridor. The composite rubber waterstop at the bottom plate of the reserved corridor is protected by covering with sandbags. After the construction of the flat copper waterstop at the bottom plate is completed, the waterstop is bent, and the upper part is covered with [32a channel steel for protection, and sandbags are used at both ends of the channel steel to slow down the slope. During the subsequent passage, the intermittent time of passage is utilized to roughen the corridor bottom plate, side walls and roof in a timely manner, which can shorten the straight-line construction period of the later concrete backfilling and plugging. The reserved corridor is later plugged by pumping secondary aggregate concrete with the same strength grade as the same part of the arch dam, and the plugging surface must be joint grouted.

[0026] Compared with the prior art, the advantages of the present invention are: an access road during the grouting period of the bottom grouting corridor is effectively formed, and the construction efficiency of grouting is improved. By adopting the present invention to set up the construction channel, the cost is relatively low, and the direct economic cost is less than 300,000 yuan. If the form of arranging a traffic tunnel is adopted, the direct cost will exceed 3.5 million yuan. By adopting the design structure and method of the present invention, the channel is formed relatively quickly and can be implemented and completed synchronously with the bottom grouting corridor and the monitoring branch corridor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the transverse section of the arch dam and the layout of the channels in the dam body in the embodiment of the present invention; in the figure, the arrow is the water flow direction;

[0028] Figure 2 is a schematic diagram of the vertical section of the arch dam and the layout of the channels in the dam body in the embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of the vertical section perpendicular to the water flow direction of the arch dam and the layout of the channels in the dam body in the embodiment of the present invention, that is Figure 1 the schematic diagram of the A-A section structure in

[0030] Figure 4 is a schematic diagram of the partial transverse section layout of the grouting corridor and the monitoring branch corridor in the embodiment of the present invention, that is Figure 1 the enlarged schematic diagram of the middle grouting corridor and the monitoring branch corridor;

[0031] Figure 5 is Figure 4 the enlarged schematic diagram of the C-C section in

[0032] In the figure, 1 is the grouting gallery, 2 is the reserved gallery, 3 is the downstream dam surface of the arch dam, 4 is the monitoring branch gallery, 5 is the floor slab of the plunge pool, 21 is the composite rubber water stop, 22 is the copper water stop, 23 is the sandbag, 24 is the channel steel, and L is the intersection point of the monitoring branch gallery and the construction access. Specific Embodiment

[0033] The present invention will be further described below in conjunction with specific embodiments. The specific embodiments are further explanations of the principles of the present invention and do not limit the present invention in any way. Technologies identical or similar to the present invention do not exceed the scope of protection of the present invention.

[0034] In conjunction with the attached drawings.

[0035] For the construction access structure of the bottom gallery of a large arch dam, the large arch dam is provided with a grouting gallery at the bottom layer of the arch dam and a monitoring branch gallery connected to the grouting gallery. The construction access extends from the end of the monitoring branch gallery towards the downstream dam surface of the arch dam to form a reserved gallery as the construction access for the bottom gallery of the arch dam; wherein: the bottom slabs at both ends of the reserved gallery are smoothly connected to the elevations of the monitoring branch gallery and the floor slab of the plunge pool outside the dam surface;

[0036] A composite rubber water stop is provided 40 cm downstream of the intersection point of the reserved gallery and the monitoring branch gallery, and a 60-cm-wide flat copper water stop is provided 40 cm upstream of the downstream dam surface of the reserved gallery.

[0037] The control slope of the reserved gallery is less than 20%; the longitudinal bottom slab of the reserved gallery is a continuous slope bottom slab or a flat bottom slab without steps.

[0038] The cross-sectional dimensions of the reserved gallery are the same as those of the monitoring branch gallery.

[0039] A sandbag covering protection layer is provided for the composite rubber water stop at the bottom slab of the reserved gallery, a protection channel steel is covered on the upper part of the flat copper water stop at the bottom slab, and sandbags are provided at both ends of the channel steel to slow down the slope protection layer.

[0040] The construction method of the construction access for the bottom gallery of the large arch dam of the present invention includes the following steps:

[0041] (1) According to the floor elevation, dimensions and coordinates of the bottom grouting gallery and the monitoring branch gallery of the arch dam, and in combination with the floor elevation of the plunge pool on the downstream side of the arch dam, arrange the axis of the reserved gallery; the bottom slabs at both ends of the reserved gallery must be smoothly connected to the elevations of the monitoring branch gallery and the plunge pool floor slab; the dimensions of the reserved gallery must first meet the requirement that after its later plugging, it can resist the operating condition of the full water head of the plunge pool, and secondly, for the convenience of construction, it should be as consistent as possible with the cross-sectional dimensions of the monitoring branch gallery.

[0042] (2) First, clean the foundation of the arch dam section where the reserved gallery is arranged, and then construct the arch dam body below the floor elevation of the reserved gallery. All water stops are embedded along with the preparation of the warehouse.

[0043] (3) After construction reaches the elevation of the reserved corridor floor, the corridor sidewall preparation begins. The arch dam section at the same elevation as the corridor sidewall is constructed simultaneously with the corridor, with the sidewall layer height ranging from 1.5m to 3m. During the sidewall construction, the water cushion pond floor on the downstream side of the reserved corridor can be constructed simultaneously.

[0044] (4) When the corridor side walls are constructed to a height of 0.5m to 1m below the arch foot elevation, the corridor arch and the remaining side walls are prepared for construction simultaneously. The initial concrete cover thickness above the arch crown elevation is 1m to 1.5m. The corridor arch is supported by a steel full-frame support, which is removed only after the arch concrete reaches the design strength.

[0045] (5) After the concrete of the corridor arch reaches the design strength and the support and formwork are removed, the exposed bottom plate water stop of the reserved corridor is protected. The composite rubber water stop is covered with sandbags for protection. After the flat copper water stop is completed, the water stop is bent and the upper part is covered with [32a channel steel for protection. Sandbags are used at both ends of the channel steel to reduce the slope.

[0046] (6) At the same time, the steel bars on the downstream surface of the arch dam are cut off and bent after being exposed 20 cm from the concrete surface, and the exposed steel bars are well protected. When the reserved corridor is sealed later, the cut steel bars on the dam surface are supplemented according to the original design drawing.

[0047] (7) At this point, the entire reserved corridor structure is completed. During the subsequent traffic process, the corridor floor, side walls and top plates are roughened in a timely manner during the intervals between traffic, so as to shorten the linear construction period of the subsequent concrete backfilling and sealing.

[0048] like Figure 1 As shown, Figure 1 Schematic diagram of the cross section of the arch dam and the dam body arrangement channel according to an embodiment of the present invention; in the figure, the arrow indicates the direction of water flow; in order to illustrate the arrangement of the construction channel of the present invention, Figure 1 The figure shows the arc structure of the transverse section of the arch dam. The arched surface of the arc structure is the water-facing surface, that is, the direction of the arrow is the direction of water flow. The grouting gallery 1, the reserved gallery 2, the downstream dam surface 3, and the monitoring branch gallery 4 arranged in the arc structure are schematic structures. Among them, the grouting gallery 1 is not arranged on the same horizontal plane. Figure 2 , Figure 2 Schematic diagram of the vertical cross section of the arch dam and the dam body arrangement channel according to an embodiment of the present invention; Figure 2 In the embodiment, the grouting gallery 1 includes a horizontal setting part and a setting part along the slope of the dam body.

[0049] Figure 3 This is a schematic diagram of the vertical cross section of the arch dam along the water flow direction and the dam body arrangement channel according to the embodiment of the present invention, that is, Figure 1 AA cross-section structure diagram; the filled part in the figure is the reserved corridor 2, combined with Figure 4 , Figure 4It is a schematic diagram of the partial transverse section layout of the grouting gallery and the monitoring branch gallery in the embodiment of the present invention, that is Figure 1 The enlarged schematic diagram of the grouting gallery and the monitoring branch gallery in Figure 1 ; the present invention uses the reserved gallery formed by extending through from the end of the monitoring branch gallery 4 towards the downstream dam surface 3 of the arch dam as the bottom reserved gallery 2 of the arch dam; wherein: the bottom plates at both ends of the reserved gallery 2 are smoothly connected to the elevations of the monitoring branch gallery 4 and the bottom plate 5 of the external water cushion pond of the dam surface. Figure 5 Is Figure 4 The enlarged schematic diagram of the C-C section in Figure 4 ; a composite rubber water stop 21 is arranged 40 cm downstream of the intersection point L of the reserved gallery and the monitoring branch gallery, and a flat copper water stop 22 with a width of 60 cm is arranged 40 cm upstream of the downstream dam surface 3 of the reserved gallery 2. A sandbag 23 is arranged to cover the protective layer at the composite rubber water stop 21 at the bottom plate of the reserved gallery 2, a protective channel steel 24 is covered on the upper part of the flat copper water stop 22 at the bottom plate, and sandbags 23 are arranged at both ends of the channel steel 24 to slow down the slope of the protective layer

[0050] Taking the bottom grouting gallery and the monitoring branch gallery of a certain hydropower station as an example, the bottom elevation of the grouting gallery and the monitoring branch gallery is 1955 m, and the bottom elevation of the water cushion pond on the downstream side of the arch dam is also 1955 m. The arranged reserved gallery is just flush with the bottom elevation, which is convenient for passage. The length of the reserved gallery is 11 m, and the cross-sectional dimensions are the same as those of the monitoring branch gallery and the bottom grouting gallery, both of which are 3 m × 4 m (width × height), ensuring the normal passage of the grouting equipment. In this way, the grouting construction efficiency of the bottom grouting gallery is greatly improved; at the same time, the elevator equipment and the pump house equipment at the bottom of the arch dam can enter the working surface through this channel, which greatly facilitates the construction.

Claims

1. A construction access structure for the bottom gallery of a large arch dam. The large arch dam is provided with a grouting gallery at the bottom layer of the arch dam and a monitoring branch gallery connected to the grouting gallery. It is characterized in that: The construction access passage extends from the end of the monitoring branch corridor towards the downstream dam surface of the arch dam to form a reserved corridor as the construction access passage for the bottom corridor of the arch dam. Among them: the bottom plates at both ends of the reserved corridor are smoothly connected to the elevation of the monitoring branch corridor and the bottom plate of the outer water cushion pond on the dam surface. A composite rubber water stop is set 40 cm downstream of the intersection of the reserved corridor and the monitoring branch corridor, and a 60-cm-wide flat copper water stop is set 40 cm upstream of the downstream dam surface of the reserved corridor.

2. The construction access structure for the bottom gallery of a large arch dam according to claim 1, characterized in that: The controlled slope of the reserved corridor is less than 20%; the longitudinal bottom plate of the reserved corridor is a continuous sloping bottom plate or a flat bottom plate without steps.

3. The construction access structure for the bottom gallery of a large arch dam according to claim 1, characterized in that: The cross-sectional dimensions of the reserved corridor are the same as those of the monitoring branch corridor.

4. The construction access structure for the bottom gallery of a large arch dam according to claim 1, wherein: A sandbag covering protection layer is set for the composite rubber water stop at the bottom plate of the reserved corridor, a protection channel steel is covered on the upper part of the flat copper water stop at the bottom plate, and sandbags are set at both ends of the channel steel to slow down the slope of the protection layer.

5. A construction method for the construction access of the bottom corridor of a large arch dam, characterized in that It includes the following steps: (1) According to the bottom elevation, dimensions and coordinates of the bottom grouting corridor and the monitoring branch corridor of the large arch dam, and in combination with the bottom elevation of the water cushion pond on the downstream side of the arch dam, arrange the axis of the reserved corridor; the bottom plates at both ends of the reserved corridor must be smoothly connected to the elevation of the monitoring branch corridor and the bottom plate of the outer water cushion pond on the dam surface; (2) Clean the foundation of the arch dam section where the reserved corridor is arranged, and construct the arch dam body below the elevation of the bottom plate of the reserved corridor; each water stop is pre-embedded along with the preparation of the warehouse. (3) After the construction reaches the elevation of the bottom plate of the reserved corridor, start the preparation of the side walls of the corridor, and construct the dam body of this dam section of the arch dam at the same elevation as the side walls of the corridor synchronously with the corridor; during the construction of the side walls, the bottom plate of the water cushion pond on the downstream side of the reserved corridor can be constructed simultaneously. (4) When the side walls of the reserved corridor are constructed to 0.5 - 1 m below the elevation of the arch feet of the top arch, the top arch of the reserved corridor and the remaining side walls are prepared and constructed simultaneously, and the first concrete covering thickness above the elevation of the top arch of the top arch is 1 - 1.5 m. (5) After the concrete of the top arch of the reserved corridor reaches the design strength, remove the supports and formworks, and protect the exposed bottom plate water stops of the reserved corridor. The composite rubber water stop is protected by covering with sandbags. After the flat copper water stop is constructed, the water stop is bent, and a channel steel is covered on the upper part for protection. Sandbags are used at both ends of the channel steel to slow down the slope; complete the construction of the reserved corridor. (6) During the subsequent passage of the reserved corridor, use the intermittent time of the passage to timely roughen the bottom plate, side walls and top plate of the corridor to shorten the straight-line construction period of the later concrete backfill and plugging.

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