CN115013055A - Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof - Google Patents

Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof Download PDF

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Publication number
CN115013055A
CN115013055A CN202210664762.6A CN202210664762A CN115013055A CN 115013055 A CN115013055 A CN 115013055A CN 202210664762 A CN202210664762 A CN 202210664762A CN 115013055 A CN115013055 A CN 115013055A
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ditch
tunnel
bottom plate
double
drainage
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陈仁东
石岩
庞康
赵强
刘明高
李非桃
王霞
郭淞
孙烨
刘翔宇
梁志超
汤弘
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Beijing General Municipal Engineering Design and Research Institute Co Ltd
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Beijing General Municipal Engineering Design and Research Institute Co Ltd
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F16/00—Drainage
    • E21F16/02—Drainage of tunnels
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/045—Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/14—Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A30/00—Adapting or protecting infrastructure or their operation
    • Y02A30/60—Planning or developing urban green infrastructure

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  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
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  • Environmental & Geological Engineering (AREA)
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  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Road Paving Structures (AREA)

Abstract

A double-hole open-cut tunnel with a central drainage blind ditch and a construction method thereof comprise the following steps: excavating on a slope or excavating earthwork under a vertical type enclosure structure support till the elevation of the bottom surface of the structural bottom plate; continuously downwards excavating earthwork in the middle of the foundation pit and corresponding to the central drainage ditch arranged in the middle of the cross section of the tunnel until the bottom elevation of the central drainage ditch below the bottom surface of the structural bottom plate; applying a leveling layer and a waterproof layer; binding structural steel bars of the bottom plate and pouring concrete of the bottom plate to synchronously form a cavity, namely a central drainage ditch, below the middle wall; continuously pouring the side wall, the middle wall and the top plate reinforced concrete until a complete double-hole closed frame structure is formed; and a water drain pipe for connecting the roadside water collection ditch with the open mouth or the water drain hole and the central water drain ditch is synchronously constructed. The invention can avoid the control of the vertical position of the structural bottom plate by the local space requirement of the depth of the drainage ditch, integrally improve the elevation of the structural bottom plate, reduce the work load and reduce the engineering risk.

Description

Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof
Technical Field
The invention belongs to the technical field of constructional engineering, and particularly relates to a double-hole open-cut tunnel with a central drainage blind ditch and a construction method thereof, which are a drainage technical scheme of the double-hole tunnel constructed by an open-cut method.
Background
When urban underground roads or highway tunnels are constructed by an open cut method, a closed frame structure with a double-hole rectangular cross section is generally adopted. On the basis of meeting the building clearance, the geometric dimension of the section of the inner contour of the structure still needs to reserve necessary space for the installation and operation and maintenance of equipment and facilities such as a pavement structure, a roadside anti-collision guardrail or a kerb, a drainage ditch, a cable trench, a decorative surface layer, a tunnel interior ventilation, illumination, fire protection, electrical, monitoring, traffic engineering and the like, and reduces the construction cost of the tunnel engineering by compressing the width and the height of the cross section as much as possible on the premise of meeting the requirements of various basic functions. The cross section size and the overall arrangement of escape canal wherein, directly influence the horizontal, vertical interior profile size of tunnel section. In order to facilitate the drainage of the road surface and ensure the driving safety, a cross slope (figure 1) is arranged on the road surface in the tunnel. When the single-breadth road adopts the one-way cross slope 4-2, the left side of the driving direction generally inclines to the right side, namely the left side is high and the right side is low in the forward driving direction. A drainage ditch 3 is arranged at the low point of the cross slope of the road surface, namely the right side. When the full-section observation of the up-down and bidirectional traveling is carried out, the transverse center of the road surface is high, the two sides of the road surface are low, and drainage ditches 3 are distributed on the two sides of the road. The washing wastewater and the fire-fighting wastewater in the tunnel are collected to the drainage ditch 3 along the cross slope of the road surface, then flow to the water collecting tank located at the vertical low point of the tunnel along the longitudinal downstream of the inner bottom of the ditch, and finally are discharged out of the tunnel by the drainage pump. The roadside drain 3 is generally in the form of a reinforced concrete underdrain with a cover plate that is perforated with drainage holes to facilitate the flow of pavement water into the trench. Meanwhile, when the drainage ditch needs to be dredged, the cover plate is lifted to carry out maintenance operations such as dredging and dredging.
The road surface width range includes a lane width and a roadside width, and the roadside width is called as a curb width according to the urban road specification and a lateral width according to the highway specification. In order to prevent the roadside drainage ditch and the cover plate thereof from invading into the traffic lane range to influence the driving safety or comfort, the drainage ditch and the cover plate thereof are arranged in the width of the roadside, namely the width of the drainage ditch and the cover plate thereof is not more than the width of the roadside. According to the specifications, the roadside width varies according to the designed driving speed. The roadside drains must have a cross-sectional area that satisfies drainage capabilities, and increasing depth is necessary when the width of their inner profile is limited by the width of the roadside. The overall height of the roadside drain 3 includes: cover plate thickness, clear height in the drainage ditch and the thickness of the bottom plate as a single component. The top surface of the cover plate is flush with the road surface 4-1, and the bottom surface of the drainage ditch is arranged on the top surface of the tunnel main body structure bottom plate 6-2. That is, the overall height of the drainage ditch controls the height of the pavement 4-1 to the top surface of the tunnel body structure bottom plate 6-2. Therefore, the elevation of the top plate of the main structure bottom plate is controlled by the depth of the roadside drainage ditch, and the elevation of the bottom surface of the structure bottom plate determines the excavation depth 8 of the foundation pit by the open cut method.
The logic chain for combing the vertical design of the tunnel can be known as follows: need set up the escape canal in the tunnel, escape canal cross sectional area needs to satisfy drainage ability, adopts the scheme that increases the escape canal degree of depth to reach required escape canal cross sectional area under the limited condition of width, and the inside degree of depth of escape canal or called ditch structure height has decided major structure bottom plate vertical position, and then has influenced tunnel foundation ditch excavation degree of depth and engineering volume. Because the roadside ditch 3 is limited in width, the roadside ditch only belongs to a partial width range in the transverse width range of the full cross section of the up-down bidirectional traveling crane, but the depth requirement of the partial width is controlled, the depth is usually increased, and the depth within the full width range of the cross section is uneconomical and unreasonable.
It is uneconomical to be represented by: the depth of the roadside drainage ditch 3 is increased, so that the burial depth of a main structure bottom plate 6-2 is increased, the depth 8 of a foundation pit is increased, the earth excavation amount of the foundation pit is increased, and the exposed height of the enclosure structure 7 is increased; secondly, the distance between the top surface of the pavement structure layer 4-1 and the top surface of the main structure bottom plate 6-2 is enlarged, and the engineering quantity of the roadbed backfill layer 5 is increased; the height of the side wall 6-1 of the main structure of the tunnel is increased, and the corresponding engineering quantity of the reinforced concrete structure is increased. It is unreasonable to reflect in: the construction risk of open cut foundation pit engineering is improved due to the fact that the depth of a foundation pit is increased by 8; and the load born by the structure is increased due to the increase of the height of 6-1 of the side wall of the main body structure of the tunnel.
In a word, the depth requirement of the partial component of the roadside drainage ditch influences and even controls the depth requirement, so that the whole section of the main body structure is vertically deepened, and the main body structure is uneconomical and unreasonable. Especially for tunnel engineering with significant strip structure characteristics, minor optimization in cross-sectional design has significant improvement benefits when multiplied by the tunnel length.
Disclosure of Invention
The invention provides a double-hole open excavation method tunnel with a central drainage blind ditch and a construction method, and aims to solve the technical problem that the vertical position of a bottom plate of a main structure of the tunnel is controlled by a roadside drainage ditch and realize optimization of cross section arrangement of the tunnel.
The technical scheme of the invention is realized as follows:
a construction method of a double-hole open-cut tunnel with a central drainage blind ditch is characterized by comprising the following steps:
(1) excavating by slope or excavating earthwork under a vertical type enclosure structure support till the elevation of the bottom surface of a structural bottom plate is 6-2;
(2) continuing to downwards excavate earthwork in the middle of the foundation pit, which corresponds to the range of the central drainage ditch arranged in the middle of the cross section of the tunnel, until the bottom elevation of the central drainage ditch below the bottom surface of the structural bottom plate 6-2; applying a leveling layer and a waterproof layer;
(3) binding structural steel bars of the bottom plate and pouring bottom plate concrete 6-2 to synchronously form a cavity, namely a central drainage ditch 3-1, positioned below the middle wall 6-3; continuously pouring the side wall 6-1, the middle wall 6-3 and the top plate reinforced concrete until a complete double-hole closed frame structure 1 is formed;
(4) then, constructing a roadbed backfill layer 5 and a pavement structure layer 4-1 of the internal structure to form a pavement cross slope 4-2; a roadside water collection ditch 3-2 which is opened or provided with a water drainage hole and a water drainage pipe 3-3 which is connected with the roadside water collection ditch and the central drainage ditch are synchronously constructed; roadbed backfill layers at two sides of the middle wall 6-3 of the roadside water collecting channel; the water drain pipe penetrates through the structural bottom plate 6-2; the roadside catchment ditch is the lowest part of the road surface cross slope 4-2.
The double-hole open-cut tunnel with the central drainage blind ditch comprises a double-hole closed frame 1 of an open-cut construction tunnel, drainage ditches, a pavement structure layer 4-1, a roadbed backfill layer 5 and a pavement cross slope 4-2, wherein the drainage ditches, the pavement structure layer 4-1, the roadbed backfill layer 5 and the pavement cross slope 4-2 are arranged in the frame, and the double-hole closed frame comprises main structure side walls 6-1, a main structure bottom plate 6-2, main structure middle walls 6-3 and a top plate; wherein,
the drainage ditch is a central drainage ditch 3-1 which is arranged below the bottom surface of the bottom plate 6-2 of the main body structure and is adjacent to the bottom of the middle wall 6-3 of the main body structure; the road surface cross slope direction 4-2 of the single-width road is from the right side of the driving direction to the left side, namely the left side is low and the right side is high in the forward driving direction, and the transverse center of the bidirectional driving road surface is low and the two sides are high; an open road side water collecting channel 3-2 with a water drainage hole or an opening is arranged at the position of the low point of the cross slope of the road surface, namely the joint with the middle wall 6-3 of the main body structure, and is positioned on the top surface of the bottom plate 6-2 of the main body structure; and a downward drain pipe 3-3 is arranged between the roadside water collecting channel and the central drainage channel and connected with each other, and the drain pipe penetrates through a structural bottom plate 6-2.
The double-hole open excavation tunnel with the central drainage blind ditches is characterized in that the tunnel structure is a double-hole closed frame with a single middle wall, the central drainage ditches 3-1 are arranged into double cavities and symmetrically arranged on two sides of the bottom of the middle wall 6-3 of the main body structure, and roadside water collection ditches 3-2 and water drainage pipes 3-3 are arranged on two sides of the middle wall 6-3 of the main body structure corresponding to the cavities and connected with each other.
The double-hole open cut tunnel with the central drainage blind ditch is characterized in that the tunnel structure is a three-hole closed frame with double middle walls, the central drainage ditch 3-1 is arranged to be a single cavity and is positioned at the bottom of the double middle walls, and roadside water collection ditches 3-2 and water drainage pipes 3-3 are respectively arranged on two sides of the middle walls 6-3 of the main body structure to be connected.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the central drainage blind ditch and the main structure bottom plate 6-2 are of an integrated concrete pouring connection structure; or is an independent single component separated from the main structure bottom plate 6-2 and adopts a vertical arrangement mode of being overlapped up and down.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the central drainage ditch is arranged in the center of the cross section of the tunnel.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the inner bottom wall of the central drainage ditch 3-1 is longitudinally arranged from high to low slope surfaces and connected with a water collecting tank at a low point, and finally is discharged out of the tunnel by a drainage pump station.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that water flow in the tunnel is collected into the roadside water collecting ditch 3-2 along the direction 4-2 of a cross slope of a road surface, is collected into the central drainage ditch 3-1 through the water drain pipe 3-3, then flows to a water collecting pool at a low point along the longitudinal direction, and finally is discharged out of a hole through the drainage pump station.
One of the features of the present invention: the tunnel drainage ditch 3-1 is arranged below the main body structure bottom plate 6-2, the drainage ditch can be combined with the main body structure bottom plate 6-2 to form a component part of a stress structure, and a hollow inner cavity formed by enclosing the structure is used as a drainage ditch; or can be used as a single component, separated from the main structure bottom plate 6-2 and vertically arranged in a stacking way. A semicircular open roadside water collecting channel 3-2 is arranged at the low point of the cross slope of the road surface, and a vertical water drain pipe 3-3 is arranged between the roadside water collecting channel and the central water drain channel for communication.
The invention is characterized in that: the tunnel drainage ditch 3-1 is arranged in the center of the cross section of the tunnel, namely near the middle wall 6-3 of the double-hole closed frame constructed by the open cut method. The road surface cross slope direction 4-2 of the single road is from the right side of the driving direction to the left side, namely the left side is low and the right side is high in the forward driving direction. A central drainage ditch 3-1 is arranged at the low point of the cross slope of the road, namely the left side. When the full-section observation of the up-down and bidirectional traveling is carried out, the transverse center of the road surface is low, the two sides of the road surface are high, and the center drainage ditch 3-1 is distributed in the center of the road. This escape canal can be according to the structural style of wall among the closed frame construction of diplopore, design for single chamber or two-chamber escape canal.
In order to ensure that the middle wall 6-3 is straight and continuous in stress, and the structural load passing through the middle wall is reliably transmitted to the foundation, when the tunnel structure adopts a double-hole closed frame of a single middle wall (figure 2), the drainage ditch is provided with double cavities and positioned at two sides of the single middle wall, and the drainage ditch collects the pavement wastewater of the left and right cavities respectively; when the tunnel structure employs a three-hole closed frame of double middle walls (fig. 3), the drainage ditch can be incorporated into a single chamber, located between the double middle walls.
Flushing wastewater and fire-fighting wastewater in the tunnel are collected into a roadside water collecting channel 3-2 along the cross slope direction 4-2 of the road surface, are collected into a central drainage channel 3-1 through a drainage pipe 3-3, flow to a water collecting pool at a low point along the longitudinal direction, and are finally discharged out of the tunnel by a drainage pump station.
The invention has the technical characteristics that:
in the prior art, the drainage ditch 3 is arranged above the top surface of the main structure bottom plate 6-2, the depth of the drainage ditch influences and controls the vertical position of the main structure bottom plate 6-2, namely, a strong association relation is formed between the drainage ditch and the structure bottom plate.
In the technical scheme of the invention, the central drainage ditch 3-1 is arranged below the bottom surface of the main structure bottom plate 6-2, so that the strong association relation between the central drainage ditch 3-1 and the structure bottom plate 6-2 is eliminated, and the defects that the drainage ditch is used as a local component to influence and control the vertical position of the whole section are avoided. The drainage ditch is formed by further digging downwards in the foundation pit of the main structure below the bottom plate, so that the local component needs to be dug downwards, and the local digging is also realized on the cross section of the foundation pit, but not deepened in the full-width range of the cross section.
The central drainage ditch 3-1 is arranged below the bottom surface of the main structure bottom plate 6-2, and is separated from the pavement structure layer 4-1 by the main structure bottom plate 6-2 no matter being used as a part of a main stress structure or being a single component, so that the width of the central drainage ditch is not limited by the width of the road side any more, and the driving safety or comfort can not be influenced even if the drainage ditch is arranged below the width range of the traffic lane. The width of the drainage ditch can be determined according to the width of the central separation belt and the layout requirements of the drain pipe and the inspection well, so that the effective drainage cross-sectional area of the drainage ditch is easier to meet.
If set up the escape canal below the structural bottom plate, still the same with prior art scheme position, arrange in the both sides of two width of cloth road cross sections, though can also reach the effect that the position local deepening that is equipped with the escape canal, the whole promotion of structural bottom plate elevation can reduce the earthwork volume of foundation ditch excavation. However, since the locally deepened positions are located on both sides of the transverse width of the excavation of the foundation pit and adjacent to the enclosure structure, it is difficult to effectively play a role in reducing the excavation depth of the foundation pit. Meanwhile, the locally deepened range is overlapped with a passive soil pressure area providing lateral resistance for the enclosure structure, namely, an original soil body of the passive soil pressure area of the enclosure structure is excavated due to local deepening, so that the exposed height of the enclosure structure is increased, and the stress of the enclosure structure is unreasonable.
Therefore, the scheme of the invention provides that 4-2 of the cross slope direction of the pavement, which is usually adopted in the prior art scheme, is changed, namely the distribution position of the low points of the pavement on the cross section is changed, and the roadside drainage ditches arranged on two sides in the prior art scheme are changed into the central drainage ditch positioned near the middle wall, so that the drainage ditches arranged below the bottom plate are necessarily locally deepened to be far away from the enclosure structure, undisturbed soil close to a passive soil pressure area of the enclosure structure is reserved as far as possible, the exposed height of the enclosure structure is reduced, the stress condition of the enclosure structure is favorably improved, and the engineering quantity of the enclosure structure is reduced.
The invention has the advantages of
The drainage ditch provided by the invention is arranged below the bottom surface of the structural bottom plate, the cross slope direction of a road is changed, and the position of the low point of the road surface is adjusted, so that the drainage ditches arranged at two sides in the prior art are changed into the technical scheme of being arranged below a middle wall of a double-hole structure, the control of the local space requirement of the depth of the drainage ditch on the vertical position of the structural bottom plate can be avoided, the elevation of the structural bottom plate is integrally improved, and the engineering quantity and the engineering risk are reduced. Due to the integral lifting of the vertical elevation of the tunnel structure bottom plate, the excavation depth of the foundation pit can be reduced, the excavation earth volume of the foundation pit can be reduced, and the stress condition of the enclosure structure can be improved; the height of the side wall of the main body structure can be reduced; the backfill construction amount of the base course of the pavement can be reduced.
Drawings
FIG. 1 is a schematic view showing the overall structure of a closed frame structure and a drainage ditch with a rectangular cross section of a double hole of the prior art,
FIG. 2 is a schematic view showing the overall structure of a center drain of a single mid-wall structure according to an embodiment of the present invention,
FIG. 3 is a schematic view showing the overall structure of a center drain of a double middle wall structure according to an embodiment of the present invention,
figure 4 is a schematic view comparing the excavation depths of the foundation pit according to the prior art and the present invention,
description of the figure numbering:
a double-hole closed frame structure 1, a roadside cable trench and a cover plate thereof 2, a roadside drainage trench 3, a central drainage trench 3-1, a roadside water collection trench 3-2, a water drainage pipe 3-3 (connecting the roadside water collection trench and the central drainage trench), a pavement structure layer 4-1, a pavement cross slope (direction) 4-2, a roadbed backfill layer 5, (a main structure) side wall 6-1, (a main structure) structure bottom plate 6-2, (a main structure) middle wall 6-3, a support structure 7, (a foundation pit excavation depth) a foundation pit depth 8, a foundation pit excavation local depth 8-1, a foundation pit bottom excavation line 9 in the prior art, a foundation pit bottom excavation line 10-1 in the scheme (B) or the scheme (C),
Detailed Description
In order to clearly understand the technical scheme of the invention, the following detailed description is made in conjunction with the accompanying drawings.
The invention relates to a construction method of a double-hole open-cut tunnel with a central drainage blind ditch, which comprises the following steps:
(1) excavating on a slope or excavating earthwork under a vertical type enclosure structure 7 until the elevation of the bottom surface of a structure bottom plate 6-2 is reached; as shown with reference to figures 2-3,
(2) continuing to downwards excavate earthwork in the middle of the foundation pit, which corresponds to the range of the central drainage ditch arranged in the middle of the cross section of the tunnel, until the bottom elevation of the central drainage ditch below the bottom surface of the structural bottom plate 6-2; applying a leveling layer and a waterproof layer;
(3) binding structural steel bars of the bottom plate and pouring bottom plate concrete 6-2 to synchronously form a cavity, namely a central drainage ditch 3-1, below the middle wall 6-3 and the bottom surface of the structural bottom plate 6-2; continuously pouring the side wall 6-1, the middle wall 6-3 and the top plate reinforced concrete until a complete double-hole closed frame structure 1 is formed;
(4) then, constructing a roadbed backfill layer 5 and a pavement structure layer 4-1 of an internal structure to form a pavement cross slope 4-2, wherein the horizontal center of the pavement is low and the two sides of the pavement are high; a roadside water collection ditch 3-2 which is opened or provided with a water drainage hole and a water drainage pipe 3-3 which is connected with the roadside water collection ditch and the central drainage ditch are synchronously constructed; roadbed backfill layers at two sides of the middle wall 6-3 of the roadside water collecting channel; the water drain pipe penetrates through the structural bottom plate 6-2; the roadside catchment ditch is the lowest part of the road surface cross slope 4-2.
Referring to fig. 2-3, the double-hole open-cut tunnel with the central drainage blind ditch comprises a double-hole closed frame 1 of the open-cut construction tunnel, a drainage ditch, a pavement structure layer 4-1, a roadbed backfill layer 5 and a pavement cross slope 4-2, wherein the drainage ditch, the pavement structure layer, the roadbed backfill layer and the pavement cross slope are arranged in the frame, and the double-hole closed frame comprises main structure side walls 6-1, a main structure bottom plate 6-2, a main structure middle wall 6-3 and a top plate; wherein,
the drainage ditch is a central drainage ditch 3-1 which is arranged below the bottom surface of the bottom plate 6-2 of the main body structure and is adjacent to the bottom of the middle wall 6-3 of the main body structure; the road surface cross slope direction 4-2 of the single road is from the right side of the driving direction to the left side, namely the left side is low and the right side is high in the forward driving direction, and the transverse center of the bidirectional driving is low and the two sides are high; an open road side water collecting channel 3-2 with a water drainage hole or an opening is arranged at the position of the low point of the cross slope of the road surface, namely the joint with the middle wall 6-3 of the main body structure, and is positioned on the top surface of the bottom plate 6-2 of the main body structure; and a downward drain pipe 3-3 is arranged between the roadside water collecting ditch and the central drainage ditch and connected with the central drainage ditch by penetrating through a structural bottom plate 6-2.
The double-hole open excavation tunnel with the central drainage blind ditches is characterized in that the tunnel structure is a double-hole closed frame with a single middle wall, the central drainage ditches 3-1 are arranged into double cavities and symmetrically arranged on two sides of the bottom of the middle wall 6-3 of the main body structure, and roadside water collection ditches 3-2 and water drainage pipes 3-3 are arranged on two sides of the middle wall 6-3 of the main body structure corresponding to the cavities and connected with each other.
The double-hole open cut tunnel with the central drainage blind ditch is characterized in that the tunnel structure is a three-hole closed frame with double middle walls, the central drainage ditch 3-1 is arranged to be a single cavity and is positioned at the bottom of the double middle walls, and roadside water collection ditches 3-2 and water drainage pipes 3-3 are respectively arranged on two sides of the middle walls 6-3 of the main body structure to be connected.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the central drainage ditch and the main structure bottom plate 6-2 are of an integral connecting structure formed by pouring concrete; or is an independent single component separated from the main structure bottom plate 6-2 and adopts a vertical arrangement mode of being overlapped up and down.
The double-hole open-cut tunnel is provided with the central drainage blind ditch, wherein the central drainage ditch is preferably arranged in the center of the cross section of the tunnel.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the inner bottom wall of the central drainage ditch 3-1 is longitudinally arranged from high to low slope surfaces and connected with a water collecting tank at a low point, and finally is discharged out of the tunnel by a drainage pump station.
The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that water flow in the tunnel is collected into the roadside water collection ditch 3-2 along the cross slope direction 4-2 of the road surface, is collected into the central drainage ditch 3-1 through the water drain pipe 3-3, then flows to a water collection pool at a low point along the longitudinal direction, and is finally discharged out of the tunnel by the drainage pump station. According to the technical scheme, the excavation line of the foundation pit bottom is locally deepened when the drainage ditch is arranged below the bottom surface of the structural bottom plate and in the central arrangement.
Referring to fig. 4, comparing the prior art solution (a), one of the possible solutions (B) and the present invention solution (C), is intended to illustrate the implementation effect of the present invention solution,
the scheme (A) is a prior art scheme, namely the situation when the roadside drainage ditch is positioned above the top surface of the structural bottom plate, wherein 8 is the depth of a foundation pit, and 9 is a foundation pit bottom excavation line in the prior art scheme;
the scheme (B) is one of possible schemes, namely, the roadside drainage ditch is positioned below the bottom surface of the structural bottom plate, but the drainage ditch is positioned at the two sides of the cross section of the foundation pit, wherein 8 is the depth of the foundation pit, 8-1 is the local deepening of the foundation pit, 9 is a foundation pit bottom excavation line in the prior art scheme, 10-1 is the foundation pit bottom excavation line in the scheme (B), 4-2 is the transverse slope direction of the road surface, and the slope is towards the two sides at the moment;
scheme (C) is the scheme of the invention, namely the roadside drainage ditch is positioned below the bottom surface of the structural bottom plate, and the drainage ditch is positioned in the center of the cross section of the foundation pit, wherein 8 is the depth of the foundation pit, 9 is the foundation pit bottom excavation line in the prior art scheme, 10-1 is the foundation pit bottom excavation line in the scheme of the invention, 8-1 is locally deepened, 4-2 is the direction of a cross slope of the road surface, and the slope is towards the center.
The bottom excavation line (10-1) of the foundation pit adopting the technical scheme of the invention is higher than the bottom excavation line (9) of the foundation pit in the prior art in elevation, and the excavation depth (8) of the foundation pit including local deepening (8-1) is reduced than the excavation depth (8) of the foundation pit in the prior art. The comparison between the scheme (B) and the scheme (C) illustrates the intention and necessity of adjusting the direction of the cross slope by the scheme of the invention to set the two sides high and the center low.

Claims (8)

1. A construction method of a double-hole open-cut tunnel with a central drainage blind ditch is characterized by comprising the following steps:
(1) excavating by slope or excavating earthwork under a vertical type enclosure structure support till the elevation of the bottom surface of a structure bottom plate (6-2);
(2) continuing to downwards excavate earthwork in the middle of the foundation pit, which corresponds to the range of the central drainage ditch arranged in the middle of the cross section of the tunnel, until the bottom elevation of the central drainage ditch below the bottom surface of the structural bottom plate (6-2); applying a leveling layer and a waterproof layer;
(3) binding structural steel bars of the bottom plate and pouring bottom plate concrete (6-2), and synchronously forming a cavity, namely a central drainage ditch (3-1), below the middle wall (6-3); continuously pouring the side walls (6-1), the middle walls (6-3) and the top plate reinforced concrete until a complete double-hole closed frame structure (1) is formed;
(4) then, constructing a roadbed backfill layer (5) and a pavement structure layer (4-1) of an internal structure to form a pavement cross slope (4-2); a roadside water collection ditch (3-2) which is synchronously opened or provided with a water drainage hole and a water drainage pipe (3-3) which is connected with the roadside water collection ditch and the central drainage ditch; roadbed backfill layers at two sides of the middle wall (6-3) of the roadside water collecting channel; the drain pipe penetrates through the structural bottom plate (6-2); the roadside catchment ditch is the lowest part of the cross slope (4-2) of the road surface.
2. The double-hole open-cut tunnel with the central drainage blind ditch of claim 1 comprises a double-hole closed frame (1) of the open-cut construction tunnel, drainage ditches, a pavement structure layer (4-1), a roadbed backfill layer (5) and a pavement cross slope (4-2) which are arranged in the frame, wherein the double-hole closed frame comprises main structure side walls (6-1), a main structure bottom plate (6-2), a main structure middle wall (6-3) and a top plate; it is characterized in that the preparation method is characterized in that,
the drainage ditch is a central drainage ditch (3-1) which is arranged below the bottom surface of the bottom plate (6-2) of the main body structure and is adjacent to the bottom of the middle wall (6-3) of the main body structure; the road surface cross slope direction (4-2) of the single-width road is from the right side of the driving direction to the left side, namely the left side is low and the right side is high in the forward driving direction, and the transverse center of the bidirectional driving road surface is low and the two sides are high; an open road side water collecting channel (3-2) or a road side water collecting channel with a water drainage hole is arranged at the position of a low point of a cross slope of the road surface, namely the joint of the road side water collecting channel and the middle wall (6-3) of the main body structure, and is positioned on the top surface of the bottom plate (6-2) of the main body structure; and a downward drain pipe (3-3) is arranged between the roadside water collecting channel and the central drainage channel and connected with the roadside water collecting channel, and the drain pipe penetrates through a structural bottom plate (6-2).
3. The double-hole open-cut tunnel with the central drainage blind ditch of claim 2, characterized in that the tunnel structure is a double-hole closed frame with a single middle wall, the central drainage ditch (3-1) is arranged as a double-cavity symmetrical structure and is arranged at two sides of the bottom of the middle wall (6-3) of the main body structure, and the roadside water collection ditches (3-2) and the drainage pipes (3-3) are respectively arranged at two sides of the middle wall (6-3) of the main body structure corresponding to each chamber and are connected with each other.
4. The double-hole open-cut tunnel with the central drainage blind ditch of claim 2 is characterized in that the tunnel structure is a double-middle-wall three-hole closed frame, the central drainage ditch (3-1) is arranged as a single cavity and is positioned at the bottom of the double middle walls, and roadside water collection ditches (3-2) and drainage pipes (3-3) are respectively arranged at two sides of the middle walls (6-3) of the main body structure to be connected.
5. The double-hole open-trench tunnel with the central drainage underdrain as claimed in claim 2, wherein the central drainage underdrain and the main structure bottom plate (6-2) are integrally connected by concrete casting; or is an independent single component separated from the main structure bottom plate (6-2) and adopts a vertical arrangement mode of being overlapped up and down.
6. The dual hole open trench tunnel of claim 2, wherein the central drainage ditch is formed at the center of the cross section of the tunnel.
7. The double-hole open-cut tunnel with the central drainage blind ditch is characterized in that the inner bottom wall of the central drainage ditch (3-1) is longitudinally arranged from a high slope to a low slope and connected with a water collecting tank at a low point, and finally is drained out of the tunnel by a drainage pump station.
8. The double-hole open-cut tunnel with the central drainage blind ditch as claimed in claim 2, characterized in that the water flow in the tunnel is collected into the roadside water collection ditch (3-2) along the cross slope direction (4-2) of the road surface, is collected into the central drainage ditch (3-1) through the drainage pipe (3-3), then flows to the water collection pool at a low point along the longitudinal direction, and finally is discharged out of the tunnel by the drainage pump station.
CN202210664762.6A 2022-06-14 2022-06-14 Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof Pending CN115013055A (en)

Priority Applications (1)

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CN202210664762.6A CN115013055A (en) 2022-06-14 2022-06-14 Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210664762.6A CN115013055A (en) 2022-06-14 2022-06-14 Double-hole open-cut tunnel with central drainage blind ditch and construction method thereof

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CN115013055A true CN115013055A (en) 2022-09-06

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