CN116838366A - Construction method for constructing corrosion-degraded medium-low mountain tunnel - Google Patents
Construction method for constructing corrosion-degraded medium-low mountain tunnel Download PDFInfo
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Classifications
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- 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
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/003—Linings or provisions thereon, specially adapted for traffic tunnels, e.g. with built-in cleaning devices
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/105—Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/107—Reinforcing elements therefor; Holders for the reinforcing elements
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
- E21D11/20—Special cross- sections, e.g. corrugated
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
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- 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
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- 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
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
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- 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
- E21D9/006—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
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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
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
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- Architecture (AREA)
- Civil Engineering (AREA)
- Environmental & Geological Engineering (AREA)
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- Lining And Supports For Tunnels (AREA)
Abstract
The application relates to a construction method for constructing a corrosion and ablation low and medium mountain tunnel, which comprises the following steps: the method comprises the steps of constructing a hole drainage project, excavating a hole side elevation slope, constructing an advanced long pipe shed support at the hole, grouting the earth surface, arranging a hole top sedimentation observation point, and excavating an open cut tunnel from top to bottom; constructing arch wall steel bars; after all the open cut tunnel lining is constructed, waterproof layer construction, tunnel gate end wall construction and retaining wall construction are carried out; the method comprises the steps of performing underground hole excavation in a drilling and blasting mode, and performing hole excavation by a full-face excavation method, a step excavation method and a step division excavation method according to surrounding rock grades; constructing an initial support, a composite waterproof layer, a tunnel drainage ditch and a drainage pipe; constructing an inverted arch in a full-width mode and pouring integrally in a segmented mode; constructing secondary lining by adopting an integral hydraulic lining trolley; and (5) constructing a tunnel pavement. According to the embodiment, when the tunnel construction passes through the structure to erode the medium and low mountain areas and the fault structural band according to the original organization construction of the new Otto method, advanced support is made, collapse is controlled, and construction safety is ensured.
Description
Technical Field
The application belongs to the technical field of tunnel construction, and particularly relates to a construction method for constructing a corrosion and denudation medium and low mountain tunnel.
Background
In order to meet the increasing travel demands of the national, a large number of mountain-along roads and road tunnels are built in western regions in China. Because of the western mountain area, the topography is complex, the fluctuation is larger, the region where the tunnel address is located is mostly in special geology, for example, the structure erodes the middle and low mountain area, and is influenced by the structure and wind effect, so that the mountain and the fluctuation, the ravines are horizontal, the topography cutting is serious, the rock mass joint crack develops, the rock mass is broken, and the surrounding rock stability is poor. In the tunnel excavation construction process, the problems of surrounding rock collapse, water inrush and the like easily occur.
Accordingly, there is an urgent need to provide a construction method for constructing a tunnel in a low and medium mountain area, which erodes and erodes, so as to solve the above-mentioned problems.
Disclosure of Invention
The present application has been made in view of the above problems, and has as its object to provide a construction method for constructing a corrosion-degraded medium/low mountain tunnel which overcomes or at least partially solves the above problems.
The embodiment of the application provides a construction method for constructing a corrosion and denudation medium and low mountain tunnel, which comprises the following steps:
according to the result of measuring and analyzing the natural geographical condition of the position of the tunnel, tunnel arrangement design and tunnel structure design are carried out, and an overall construction scheme is formulated;
retesting the topography and geology of the tunnel portal before construction, and dynamically adjusting the portal construction scheme according to retesting results;
the method comprises the steps of constructing a tunnel portal drainage project, excavating a tunnel portal side elevation slope, excavating a secondary slope and adopting a 1:0.75 slope rate above the secondary slope, excavating a primary slope by adopting a 1:0.5 slope rate, arranging the tunnel portal side slope according to 8m primary, and arranging a 2m platform on the top of the slope; the side-elevation slope of the opening is protected by adopting a hanging net and anchor spraying mode;
performing tunnel portal construction, advanced long pipe canopy support, surface grouting and arranging a tunnel top settlement observation point, then performing open cut tunnel excavation from top to bottom, performing layered support, excavating soil layers by using an excavator, and excavating rock layers by using the excavator or weak blasting; the open cut tunnel inverted arch construction adopts a full-width construction technology, a water stop belt and a water stop bar are arranged at a longitudinal annular construction joint, and in the inverted arch concrete pouring process, the assembled steel forms are fixed above the steel reinforcement framework according to the concrete pouring progress, so that the arch of inverted arch concrete is ensured;
constructing arch wall steel bars, connecting reserved steel bars at the end wall with the end wall steel bars of the tunnel portal, adopting a secondary lining trolley as an inner mould for open cut tunnel lining, adopting a combined steel mould for outer mould, and performing one-time pouring on arch wall lining concrete;
after all the open cut tunnel lining is constructed, waterproof layer construction, tunnel gate end wall construction and retaining wall construction are carried out; after the construction of the tunnel portal is completed and the concrete strength reaches the design strength, backfilling the open cut tunnel; after the open cut tunnel backfilling is completed, greening and protecting work of the tunnel opening and the tunnel roof are timely carried out, so that rain wash is avoided;
the method comprises the steps of performing underground hole digging by adopting a drilling and blasting mode, performing blasting design before construction, performing smooth blasting on a tunnel, and timely adjusting blasting parameters according to blasting effects, wherein the construction safety step distance is controlled within an allowable range in the construction process; the method comprises the steps of respectively adopting a full-face excavation method, a step excavation method and a step subsection excavation method to excavate a hole body according to surrounding rock grades; for the fault fracture zone, after excavation, spraying concrete in time to seal the tunnel face, and applying advanced small-conduit support;
after excavation and advanced geological forecast are completed, constructing an initial support, wherein the initial support consists of initial shotcrete, grouting anchor pipes, hollow grouting anchor rods, mortar anchor rods, reinforcing steel meshes and I-steel arches; after the steel arch is installed, the wet spraying concrete is completed as soon as possible, the steel support is covered completely, the spraying thickness is H-shaped steel thickness plus 2cm, the steel support and the sprayed concrete are stressed together, and the deflection of surrounding rock is restrained;
constructing a composite waterproof layer consisting of an EVA waterproof board with the thickness of 1.2mm and a geotextile with the square meter of 350 g/m between the primary support and the secondary lining; a buried rubber water stop is arranged at the circumferential and longitudinal construction joint; setting a settlement joint at a fault, a bright-dark junction, different surrounding rock grades and geological change positions, setting a settlement joint every 10m of the same lining type, and additionally setting a back-attached rubber water stop belt on the settlement joint;
constructing a tunnel drainage ditch and a drainage pipe; the drainage ditch comprises a cable groove and a central drainage ditch; the drainage pipe comprises a longitudinal drainage pipe, a circumferential drainage pipe and a transverse water guide pipe;
the inverted arch is constructed in full width, the sectional whole pouring is carried out, and the inverted arch is utilized to automatically move the trestle to keep passing; after the mechanical bottom cleaning and the full section construction of the shotcrete support are completed, inverted arch concrete is poured in time, the concrete is poured in full width, and the concrete is tamped by using an inserted vibrator and leveled by using a flat vibrator; the inverted arch is filled after the inverted arch concrete is finally set, so that the support is closed into a ring as early as possible;
constructing secondary lining by adopting an integral hydraulic lining trolley; the concrete is intensively stirred by adopting an automatic metering concrete mixing station, and silica powder or fly ash is added into the concrete; the mixing transport vehicle transports concrete, pumps the concrete into a mould, and uses an attached vibrator and an inserted vibrator for tamping; adopting forward construction, namely sequentially pouring the wall and the arch;
and constructing a tunnel pavement, wherein the pavement structure is a composite pavement structure, and the interior of the tunnel is decorated by adopting fireproof paint.
In one embodiment, advanced geological forecast is required in the open cut tunnel excavation and the underground tunnel excavation construction process; and acquiring surrounding rock state parameters in front of the face through the advanced geological forecast, and timely feeding back information to guide construction through analysis and processing of data.
In one embodiment, the drainage of the hole adopts a mode of combining a hole top intercepting ditch, an end wall longitudinal broken stone blind ditch and a hole top backfilling transverse drainage ditch.
In one embodiment, the tunnel construction advanced long pipe shed support comprises the following construction steps: excavating a sleeve arch foundation, erecting a mould, pouring, manufacturing a sleeve arch steel frame, installing, welding a guide pipe, erecting a sleeve arch support and an installation template, pouring a sleeve arch body, removing the health maintenance, drilling a down-the-hole drill along the guide pipe, machining and installing a steel flower pipe, machining and installing a reinforcement cage, and grouting.
In one embodiment, the full face excavation method is applicable to class iii surrounding rock, and specifically comprises the following construction steps: and excavating a full section, carrying out anchor spraying support and carrying out secondary lining construction.
In one embodiment, the step excavation method is applicable to IV-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central part of the lower half part is excavated, the side wall is subjected to primary support, and secondary lining construction is performed; the step length of the step excavation method is 1 time of the span of the hole.
In one embodiment, the step division excavation method is applicable to V-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central core part is excavated, the lower part is excavated, the side wall is subjected to anchor spraying support, the inverted arch is poured, and secondary lining construction is carried out; the step length of the step subsection excavation method is 1.5-2 times of the hole span.
In one embodiment, the reinforcing mesh is hung on the excavated surface after the primary spraying of concrete, the thickness of the reinforcing protection layer is not less than 2cm, the reinforcing mesh is paved along with the fluctuation of the primary spraying of concrete surface, the gap between the reinforcing mesh and the sprayed surface is not more than 3cm, the reinforcing mesh is fixed on the anchor rod which is constructed in advance, the reinforcing mesh is welded into a mesh, and the lap joint length of the reinforcing mesh is not less than 50mm.
In one embodiment, in the primary support construction process, when the tunnel excavation section meets the design requirement, immediately spraying a first layer of concrete for sealing, along with deformation of surrounding rock, generating cracks on the surface of the first layer of sprayed concrete for water leakage, arranging omega-shaped spring semicircular drainage pipes at the water leakage positions, smearing 1-2 cm of mortar on the surface of the first layer of sprayed concrete for fixation, spraying a second layer of concrete for sealing, observing the surface of the spraying layer, drilling water diversion holes at the water leakage positions if water leakage exists, adding omega-shaped spring semicircular drainage pipes, and introducing water into the longitudinal drainage pipes of the basement for drainage outside the holes.
In one embodiment, the EVA waterproof board is laid in a non-nail way, the welding mode is double-seam hot-melt welding, the waterproof board is 1m or more away from the lap seam, the deformation seam and the weak link of the construction seam, and the lap seam lap joint length is not less than 10cm; the waterproof layer is laid for 1-2 cycles in advance of the secondary lining.
The embodiment is constructed according to the original organization construction of a new Ottoman method, and the principles of weak blasting, short footage, strong support, early closure, duty measurement and tight lining are adhered to. When the tunnel construction passes through a structure to erode a low and medium mountain area, a fault structural belt, weak surrounding rock and a shallow buried section, advanced support is made, collapse is controlled, and construction safety is ensured; when tunnel construction passes through a fault fracture zone, advanced geological forecast work is performed, advanced grouting and water shutoff work is performed, and collapse, water flushing and water bursting are prevented; during drilling and blasting construction, smooth blasting is adopted, blasting design is carried out before construction, blasting parameters are timely adjusted according to blasting effects, super-undermining is controlled, construction safety steps are controlled within an allowable range in the construction process, and collapse is prevented.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is evident that the figures in the following description are only some embodiments of the application, from which other figures can be obtained without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a schematic cross-sectional view of a tunnel portal advanced long pipe shed in accordance with an embodiment of the present application;
FIG. 2 is a schematic installation view of a rubber water stop belt for a settlement joint and an earthquake joint of a tunnel in the embodiment of the application;
fig. 3 is a schematic view of construction of a tunnel water stop according to an embodiment of the present application.
Detailed Description
The present application will be further described with reference to examples for the convenience of those skilled in the art.
The embodiment of the application provides a construction method for constructing a corrosion and denudation medium and low mountain tunnel, which comprises the following steps:
according to the result of measuring and analyzing the natural geographical condition of the position of the tunnel, tunnel arrangement design and tunnel structure design are carried out, and an overall construction scheme is formulated;
retesting the topography and geology of the tunnel portal before construction, and dynamically adjusting the portal construction scheme according to retesting results;
the method comprises the steps of constructing a tunnel portal drainage project, excavating a tunnel portal side elevation slope, excavating a secondary slope and adopting a 1:0.75 slope rate above the secondary slope, excavating a primary slope by adopting a 1:0.5 slope rate, arranging the tunnel portal side slope according to 8m primary, and arranging a 2m platform on the top of the slope; the side-elevation slope of the opening is protected by adopting a hanging net and anchor spraying mode;
performing tunnel portal construction, advanced long pipe canopy support, surface grouting and arranging a tunnel top settlement observation point, then performing open cut tunnel excavation from top to bottom, performing layered support, excavating soil layers by using an excavator, and excavating rock layers by using the excavator or weak blasting; the open cut tunnel inverted arch construction adopts a full-width construction technology, a water stop belt and a water stop bar are arranged at a longitudinal annular construction joint, and in the inverted arch concrete pouring process, the assembled steel forms are fixed above the steel reinforcement framework according to the concrete pouring progress, so that the arch of inverted arch concrete is ensured;
constructing arch wall steel bars, connecting reserved steel bars at the end wall with the end wall steel bars of the tunnel portal, adopting a secondary lining trolley as an inner mould for open cut tunnel lining, adopting a combined steel mould for outer mould, and performing one-time pouring on arch wall lining concrete;
after all the open cut tunnel lining is constructed, waterproof layer construction, tunnel gate end wall construction and retaining wall construction are carried out; after the construction of the tunnel portal is completed and the concrete strength reaches the design strength, backfilling the open cut tunnel; after the open cut tunnel backfilling is completed, greening and protecting work of the tunnel opening and the tunnel roof are timely carried out, so that rain wash is avoided;
the method comprises the steps of performing underground hole digging by adopting a drilling and blasting mode, performing blasting design before construction, performing smooth blasting on a tunnel, and timely adjusting blasting parameters according to blasting effects, wherein the construction safety step distance is controlled within an allowable range in the construction process; the method comprises the steps of respectively adopting a full-face excavation method, a step excavation method and a step subsection excavation method to excavate a hole body according to surrounding rock grades; for the fault fracture zone, after excavation, spraying concrete in time to seal the tunnel face, and applying advanced small-conduit support;
after excavation and advanced geological forecast are completed, constructing an initial support, wherein the initial support consists of initial shotcrete, grouting anchor pipes, hollow grouting anchor rods, mortar anchor rods, reinforcing steel meshes and I-steel arches; after the steel arch is installed, the wet spraying concrete is completed as soon as possible, the steel support is covered completely, the spraying thickness is H-shaped steel thickness plus 2cm, the steel support and the sprayed concrete are stressed together, and the deflection of surrounding rock is restrained;
constructing a composite waterproof layer consisting of an EVA waterproof board with the thickness of 1.2mm and a geotextile with the square meter of 350 g/m between the primary support and the secondary lining; a buried rubber water stop is arranged at the circumferential and longitudinal construction joint; setting a settlement joint at a fault, a bright-dark junction, different surrounding rock grades and geological change positions, setting a settlement joint every 10m of the same lining type, and additionally setting a back-attached rubber water stop belt on the settlement joint;
constructing a tunnel drainage ditch and a drainage pipe; the drainage ditch comprises a cable groove and a central drainage ditch; the drainage pipe comprises a longitudinal drainage pipe, a circumferential drainage pipe and a transverse water guide pipe;
the inverted arch is constructed in full width, the sectional whole pouring is carried out, and the inverted arch is utilized to automatically move the trestle to keep passing; after the mechanical bottom cleaning and the full section construction of the shotcrete support are completed, inverted arch concrete is poured in time, the concrete is poured in full width, and the concrete is tamped by using an inserted vibrator and leveled by using a flat vibrator; the inverted arch is filled after the inverted arch concrete is finally set, so that the support is closed into a ring as early as possible;
constructing secondary lining by adopting an integral hydraulic lining trolley; the concrete is intensively stirred by adopting an automatic metering concrete mixing station, and silica powder or fly ash is added into the concrete; the mixing transport vehicle transports concrete, pumps the concrete into a mould, and uses an attached vibrator and an inserted vibrator for tamping; adopting forward construction, namely sequentially pouring the wall and the arch;
and constructing a tunnel pavement, wherein the pavement structure is a composite pavement structure, and the interior of the tunnel is decorated by adopting fireproof paint.
Preferably, in the open cut tunnel excavation and the underground tunnel excavation construction process, advanced geological forecast is required; and acquiring surrounding rock state parameters in front of the face through the advanced geological forecast, and timely feeding back information to guide construction through analysis and processing of data.
Preferably, the drainage of the hole adopts a mode of combining a hole top intercepting ditch, an end wall longitudinal crushed stone blind ditch and a hole top backfilling transverse drainage ditch.
Preferably, the tunnel portal construction advanced long pipe shed support comprises the following construction steps: excavating a sleeve arch foundation, erecting a mould, pouring, manufacturing a sleeve arch steel frame, installing, welding a guide pipe, erecting a sleeve arch support and an installation template, pouring a sleeve arch body, removing the health maintenance, drilling a down-the-hole drill along the guide pipe, machining and installing a steel flower pipe, machining and installing a reinforcement cage, and grouting.
Preferably, the full section excavation method is suitable for class III surrounding rock, and specifically comprises the following construction steps: and excavating a full section, carrying out anchor spraying support and carrying out secondary lining construction.
Preferably, the step excavation method is suitable for IV-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central part of the lower half part is excavated, the side wall is subjected to primary support, and secondary lining construction is performed; the step length of the step excavation method is 1 time of the span of the hole.
Preferably, the step subsection excavation method is suitable for V-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central core part is excavated, the lower part is excavated, the side wall is subjected to anchor spraying support, the inverted arch is poured, and secondary lining construction is carried out; the step length of the step subsection excavation method is 1.5-2 times of the hole span.
Preferably, the reinforcing mesh is hung on the excavated surface after the primary spraying of concrete, the thickness of the reinforcing protection layer is not less than 2cm, the reinforcing mesh is paved along with the fluctuation of the primary spraying of concrete surface, the gap between the reinforcing mesh and the sprayed surface is not more than 3cm, the reinforcing mesh is fixed on the anchor rod which is constructed in advance, the reinforcing mesh is welded into a mesh, and the lap joint length of the reinforcing mesh is not less than 50mm.
Preferably, in the primary support construction process, when the tunnel excavation section meets the design requirement, immediately spraying a first layer of concrete for sealing, along with deformation of surrounding rock, generating cracks on the surface of the first layer of sprayed concrete, leaking water, arranging omega-shaped spring semicircular drainage pipes at the leaking positions, smearing 1-2 cm of setting mortar on the surface of the first layer of sprayed concrete for fixation, spraying a second layer of concrete for sealing, observing the surface of the spraying layer, if water leakage exists, drilling water diversion holes at the leaking positions, adding omega-shaped spring semicircular drainage pipes, and introducing water into the longitudinal drainage pipes of the basement to drain outside the holes.
Preferably, the EVA waterproof board is laid in a non-nail way, the welding mode is double-seam hot-melt welding, the distance between the waterproof board and the lap seam is more than 1m from the weak links of the deformation seam and the construction seam, and the lap seam lap length is not less than 10cm; the waterproof layer is laid for 1-2 cycles in advance of the secondary lining.
The construction method for the construction of the corrosion and denudation medium and low mountain tunnel is constructed according to the original organization construction of a new Ottoman method, and the construction is carried out according to the principles of weak blasting, short footage, strong support, early closure, logistic measurement and tight lining. When the tunnel construction passes through a structure to erode a low and medium mountain area, a fault structural belt, weak surrounding rock and a shallow buried section, advanced support is made, collapse is controlled, and construction safety is ensured; when tunnel construction passes through a fault fracture zone, advanced geological forecast work is performed, advanced grouting and water shutoff work is performed, and collapse, water flushing and water bursting are prevented; during drilling and blasting construction, smooth blasting is adopted, blasting design is carried out before construction, blasting parameters are timely adjusted according to blasting effects, super-undermining is controlled, construction safety steps are controlled within an allowable range in the construction process, and collapse is prevented.
The construction method of the corrosion and degradation medium and low mountain tunnel constructed as described above is described in further detail below with reference to specific engineering examples.
And a tunnel engineering with the whole length of 650m is a single-hole double-row section tunnel. The tunnel address area is located in the Tai mountain area, and belongs to the areas of low and medium mountain areas with corrosion and ablation, and the fluctuation of topography is large, and is influenced by the effects of construction and wind, so that the mountains and the mountains are fluctuated, the ravines are vertical and horizontal, the topography is severely cut, the joints and the cracks of the rock mass develop, the rock mass is broken, the body section of the tunnel is mainly composed of oolitic limestone in the cold and the armed system, and the stability of surrounding rock is poor. Along the trend of the tunnel, the middle part of the topography is high, the two ends are low, the altitude of the tunnel address area is 1138.6-1332.5 meters, and the relative altitude difference is 193.3 meters.
The tunnel passes through the fault structural band, the weak surrounding rock and the shallow buried section, collapse needs to be controlled, and water burst are prevented; because of special geology, arching is difficult during tunnel drilling and blasting construction, and the blasting design needs to be optimized to improve the blasting arching effect in the construction process.
The construction method for constructing the corrosion and ablation medium and low mountain tunnel specifically comprises the following steps:
1) And carrying out tunnel arrangement design and tunnel structure design according to the result of measuring and analyzing the natural geographical condition of the position of the tunnel, and making an overall construction scheme.
The tunnel engineering passes through a fault construction zone, weak surrounding rock and a shallow buried section, open cut holes with different lengths are respectively arranged at the hidden tunnel openings of the tunnel for ensuring driving safety and mountain stability, and the open cut holes are lined by adopting reinforced concrete structures and have the thickness of 60 cm; the tunnel dark hole adopts a composite lining support structure, and the primary support adopts an anchor spraying support; the secondary lining structure of the tunnel adopts C30 molding (reinforced concrete); and when the overall stability of the surrounding rock is slightly poor, an advance anchor rod is adopted, when the overall stability of the surrounding rock is poor, a small guide pipe is adopted for grouting, and when the overall stability of the surrounding rock is poor, an advance pipe shed is adopted for grouting. The entrance and exit end wall type tunnel portal 2 seats are arranged on the tunnel, the entrance end is provided with an open cut tunnel with the length of 10m, the exit end is provided with an open cut tunnel with the length of 12m, class III surrounding rock 113m, class IV surrounding rock 360m and class V surrounding rock 155m, a fire extinguisher box chamber is provided with 12 positions, and 5 positions are treated by the karst cave.
2) And retesting the topography and geology of the tunnel portal before construction, and dynamically adjusting the portal construction scheme according to retesting results.
3) The method comprises the steps of constructing a tunnel portal drainage project, excavating a tunnel portal side elevation slope, excavating a secondary slope and adopting a 1:0.75 slope rate above the secondary slope, excavating a primary slope by adopting a 1:0.5 slope rate, arranging the tunnel portal side slope according to 8m primary, and arranging a 2m platform on the top of the slope; the side-elevation slope of the opening is protected by adopting a hanging net and anchor spraying mode.
The drainage of the tunnel portal adopts a mode of combining a tunnel top intercepting ditch, an end wall longitudinal crushed stone blind ditch and a tunnel top backfilling transverse drainage ditch for drainage; a water intercepting ditch is arranged above the tunnel portal, and surface water is led to the roadbed side ditch or natural gullies outside the tunnel portal; the protection of the side elevation slope of the tunnel portal adopts a hanging net and anchor spraying mode for protection, the steel bar net sheet adopts phi 8 round steel, the mesh size of the steel bar net is 25cm x 25cm, the anchor rods adopt phi 22 mortar anchor rods, the length of the anchor rods is 2.0m, the spacing is 150cm x 150cm, and the anchor rods are distributed in a plum blossom shape; the sprayed concrete adopts C25 sprayed concrete, and the thickness is 10cm; the protection construction process of the side elevation slope of the opening comprises the following steps: clearing loose dangerous stones on a side slope, drilling, controlling the depth of the holes according to the length of a designed anchor rod by +/-5 cm, enabling the drilling direction to be perpendicular to a rock surface, cleaning the holes by using high-pressure air, grouting the holes by using a grouting machine, controlling grouting pressure to be 0.5-1 MPa, ensuring that grouting liquid fills the hole body, using an air drill to send a rod, ensuring that nut gaskets are installed after the anchor rod is installed at the bottom of the hole, installing reinforcing steel meshes, constructing step by step from top to bottom, carrying out quincuncial binding on each mesh, and spraying concrete.
4) Performing tunnel construction, advanced long pipe shed support, surface grouting and arranging a tunnel top settlement observation point, then performing open cut excavation from top to bottom, performing layered support, excavating soil layers by using an excavator, and excavating rock strata by weak blasting if necessary; the inverted arch construction adopts full-width construction technology, and water stop strips are arranged at the longitudinal annular construction joint, and in the inverted arch concrete pouring process, the assembled steel forms are fixed above the steel reinforcement framework according to the concrete pouring progress, so that the arch shape of the inverted arch concrete is ensured.
Wherein, the leading long pipe shed is provided with a guide sleeve arch, the longitudinal length of the sleeve arch foundation is 200cm, the transverse width is 110cm, and the depth is 100cm; the sleeve arch is made of C30 concrete, the longitudinal length is 200cm, the thickness is 60cm, 4I 18I-shaped steel frames are arranged in the sleeve arch, 108 x 6mm hot-rolled seamless steel tubes are adopted in a tube shed, the annular tube distance is between the middle and the middle 35cm, the grouting hole diameter of the steel tubes is 10mm, the hole spacing is 20cm, the steel bar cages phi 20 are arranged in the tubes, cement slurry with the water-cement ratio of 1:1 is adopted for grouting, the initial pressure of grouting is 0.5-1.0 MPa, and the end pressure of grouting is 2.0MPa; the advanced long pipe shed support comprises the following construction steps: excavating a sleeve arch foundation, erecting a mould, pouring, manufacturing a sleeve arch steel frame, installing, welding a guide pipe, erecting a sleeve arch support and an installation template, pouring a sleeve arch body, removing the health maintenance, drilling a down-the-hole drill along the guide pipe, machining and installing a steel flower pipe, machining and installing a reinforcement cage, and grouting.
5) And constructing arch wall steel bars, connecting reserved steel bars at the end wall with the end wall steel bars of the tunnel portal, adopting a secondary lining trolley as an inner mould for open cut tunnel lining, adopting a combined steel mould for outer mould, and performing one-time pouring on arch wall lining concrete.
6) Carrying out waterproof layer construction and tunnel gate end wall and retaining wall construction after all open cut tunnel lining construction is completed; after the construction of the tunnel portal is completed and the concrete strength reaches the design strength, backfilling the open cut tunnel; after the open cut tunnel is backfilled, greening and protection work of the tunnel opening and the tunnel roof are timely carried out, and rain wash is avoided.
7) And the underground tunnel is dug by adopting a drilling and blasting mode, blasting design is carried out before construction, smooth blasting is adopted for the tunnel, blasting parameters are timely adjusted according to blasting effects, and the construction safety step distance is controlled within an allowable range in the construction process.
In the open cut tunnel excavation and hidden tunnel excavation construction processes, advanced geological forecast is needed; and acquiring surrounding rock state parameters in front of the face through the advanced geological forecast, and timely feeding back information to guide construction through analysis and processing of data.
The method comprises the steps of respectively adopting a full-face excavation method, a step excavation method and a step subsection excavation method to excavate a hole body according to surrounding rock grades; for the fault fracture zone, after excavation, spraying concrete in time to seal the tunnel face, and applying advanced small-conduit support;
the III type surrounding rock adopts a full section excavation method, and specifically comprises the following construction steps: full section excavation, anchor spraying support and secondary lining construction are carried out; the IV-class surrounding rock adopts a step excavation method, and specifically comprises the following construction steps: the method comprises the steps of excavating an upper half part, carrying out anchor spraying support on an arch part, excavating a central part of a lower half part, excavating a side wall part, carrying out primary support on the side wall, carrying out secondary lining construction, and carrying out step length of a step excavation method to form a hole span with the length of 1 time; the V-class surrounding rock adopts a step subsection excavation method, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central core part is excavated, the lower part is excavated, the side wall is subjected to anchor spraying support, the inverted arch is poured, secondary lining construction is carried out, the step length of the step subsection excavation method is 1.5-2 times of the step span, the step length and the number of steps can be properly adjusted according to the stability condition of surrounding rock in construction, and meanwhile, long and short horse mouth combination and staggered construction are adopted according to the primary supporting construction condition.
8) After excavation and advanced geological forecast are completed, performing primary support, wherein the primary support consists of primary sprayed concrete, grouting anchor pipes, hollow grouting anchor rods, mortar anchor rods, reinforcing steel meshes and I-steel arch frames; after the steel arch is installed, wet spraying concrete is completed as soon as possible, the steel support is covered completely, the spraying thickness is H-shaped steel thickness +2cm, the steel support and the sprayed concrete are stressed together, and surrounding rock deflection is restrained.
The construction process of the primary support comprises the following steps: preparing construction, excavating, advanced geological prediction, preparing sprayed concrete, primary spraying concrete, measuring and lofting, drilling, clearing holes, processing system anchor rods, installing the system anchor rods, grouting, processing reinforcing steel bar meshes, installing steel bar arches, locking foot anchor rods, processing small guide pipes, installing locking foot anchor rods, installing small guide pipes, grouting, installing arches, installing two layers of reinforcing steel bar meshes and re-spraying concrete; the system anchor rod is a phi 22 mortar anchor rod and a phi 25 hollow anchor rod, the small guide pipe is a phi 42 guide pipe, the external insertion angle of the advanced small guide pipe is controlled to be 5-7 degrees, the foot-shrinking anchor pipe adopts a seamless steel pipe, and the radial anchor pipe adopts a perforated steel pipe; before grouting a small guide pipe, plugging a gap between a steel pipe and a drilling hole by using early strength cement mortar, controlling the grouting pressure to be 0.5-1.0 MPa, and plugging a guide pipe opening by using cement mortar not smaller than M20 after grouting is finished; the weak surrounding rock section is provided with a foot locking anchor rod at the foot of the steel arch frame so as to increase the bearing capacity of the base; in order to enhance the overall stability of the steel arch, the arch is connected with the anchor rods, and longitudinal connecting steel bars with the diameter phi of 20mm are arranged along the steel arch; the re-spraying concrete is carried out after the anchor rods, the hanging net and the steel arch are installed, so that the whole stress of the sprayed anchor support is formed as soon as possible, and the deflection of surrounding rock is restrained; silica fume or fly ash is added into the concrete to increase the workability of the concrete and reduce the rebound.
In addition, in the primary support construction process, when the tunnel excavation section meets the design requirement, immediately spraying a first layer of concrete for sealing, wherein the spraying thickness is 4cm; along with deformation of surrounding rock, cracks are generated on the surface of the first layer of sprayed concrete to leak water, omega-shaped semicircular drainage pipes are arranged at the leaking positions, 1-2 cm of mortar is smeared on the surface of the first layer of sprayed concrete to wrap and fix the first layer of sprayed concrete, then a second layer of sprayed concrete is sprayed to seal the first layer of sprayed concrete, if water leakage exists, water diversion holes are drilled at the leaking positions, and then omega-shaped semicircular drainage pipes are added to introduce water into the longitudinal drainage pipes of the basement to drain out of the holes; the reinforcing mesh is hung on the excavated surface after the primary spraying of concrete, the thickness of the reinforcing protection layer is not less than 2cm, the reinforcing mesh is paved along with the fluctuation of the primary spraying of concrete surface, the gap between the reinforcing mesh and the sprayed surface is not more than 3cm, the reinforcing mesh is fixed on an anchor rod which is constructed in advance, the reinforcing mesh is welded into a net, and the lap joint length of the reinforcing mesh is not less than 50mm.
9) Constructing a composite waterproof layer consisting of an EVA waterproof plate with the thickness of 1.2mm and geotextile with the square meter of 350 g/m between the primary support and the secondary lining; a buried rubber water stop is arranged at the circumferential and longitudinal construction joint; setting a settlement joint at the fault, the bright-dark junction, the surrounding rock grades and the geological change positions, setting a settlement joint every 10m of the same lining type, and additionally arranging a back-attached rubber water stop belt on the settlement joint.
The construction method comprises the steps of firstly carrying out basal surface treatment during waterproof layer construction, utilizing a multifunctional waterproof plate operation trolley to cut off exposed steel bars, anchor rod heads and other sharp objects on the sprayed concrete surface, then trowelling the uneven surface and the cut iron piece heads by using mortar, and trowelling the anchor rod heads into circular arcs by using mortar, wherein the radius of the circular arcs is larger than 30cm; fixing a half non-woven fabric to a preset position by using a rack, then fixing the non-woven fabric on sprayed concrete by using special hot-melt gaskets and shooting nails, wherein the special hot-melt gaskets and the shooting nails are arranged in a quincuncial manner, the arch part spacing is 0.5-0.8 m, the side wall is 0.8-1.0 m, and the overlapping width between the non-woven fabrics is more than or equal to 5cm; the EVA waterproof board is laid in a non-nail way, the welding mode is double-seam hot-melt welding, the distance between the waterproof board and the lap seam is more than 1m from the weak links of the deformation seam and the construction seam, and the lap seam lap length is not less than 10cm; the waterproof layer is laid for 1-2 cycles of advanced secondary lining;
10 A construction tunnel drainage ditch and a drainage pipe; the drainage ditch comprises a cable groove and a central drainage ditch; the drain pipe comprises a longitudinal drain pipe, a circumferential drain pipe and a transverse water guide pipe.
The horizontal water guide pipe is used for leading open cut tunnel backfill back water and dark tunnel lining back water into the central drainage ditch to drain out of the tunnel; the annular drain pipe discharges the rock surface seepage water into the longitudinal drain pipe, and a drain ditch is arranged at the whole length in the tunnel, so that the transverse drain pipe is communicated with the longitudinal drain pipe to guide the water out of the tunnel; the tunnel drainage outlet adopts a heat preservation drainage outlet, so that smoothness of tunnel drainage is ensured, and the drainage at the tunnel portal is prevented from being frozen and blocked.
11 Full-width construction of an inverted arch and sectional integral pouring, and the inverted arch is utilized to automatically move the trestle to keep passing; after the mechanical bottom cleaning and the full section construction of the shotcrete support are completed, inverted arch concrete is poured in time, the concrete is poured in full width, and the concrete is tamped by using an inserted vibrator and leveled by using a flat vibrator; the inverted arch is filled after the inverted arch concrete is finally set, so that the support is closed into a ring as early as possible.
Wherein, the end of the inverted arch adopts a wood plate, concrete is symmetrically poured from the center to two sides, and the joint of the inverted arch and the side wall is compacted by tamping; the primary construction length of the inverted arch is controlled to be 6m, inverted arch filling construction is carried out after the lining of the two-die inverted arch is completed, an inverted arch large sample is manufactured, and filled concrete is ensured not to invade the section of the inverted arch; and (3) roughening the upper circulating concrete inverted arch joint, and connecting the upper circulating concrete inverted arch joint with side wall lining steel bars.
12 Constructing secondary lining by adopting an integral hydraulic lining trolley; the concrete is intensively stirred by adopting an automatic metering concrete mixing station, and silica powder or fly ash is added into the concrete; the mixing transport vehicle transports concrete, pumps the concrete into a mould, and uses an attached vibrator and an inserted vibrator for tamping; and (3) adopting forward construction, namely sequentially pouring the wall and the arch.
According to the surrounding rock grade, the secondary lining is not more than 90 m from the IV grade of the tunnel face, and the V grade is not more than 70 m; after the hole section is excavated for 70 meters, secondary lining and open cut tunnel mould building lining construction are required, the secondary lining of the hole and the soft rock section in the hole is constructed as early as possible, and other sections are constructed timely according to monitoring and measuring results and meet the requirement of safe step distance; demolding by using a hydraulic system of the full-hydraulic lining trolley, wherein the time required for the concrete to reach the demolding control strength is determined through a test, the concrete strength is required to reach 5MPa, and the surface of the lining is required to be prevented from being collided after demolding; the concrete prepared from silicate cement, ordinary silicate cement and slag silicate cement is cured for not less than 7 days, and the impervious concrete is cured for not less than 14 days.
13 And constructing a tunnel pavement, wherein the pavement structure is a composite pavement structure, and the interior of the tunnel is decorated by adopting fireproof paint.
The tunnel composite pavement structure is composed of 5cm medium-grain asphalt concrete, 22cm lean concrete base layer and 10cm lean concrete base layer (without inverted arch section), and the total thickness is 37cm; after the construction of the lean concrete slab with the length of 22cm is finished, sundries are removed from expansion joints and construction joints of the lean concrete slab, and then joint filling materials are filled.
The embodiment is constructed according to the original organization construction of a new Ottoman method, and the principles of weak blasting, short footage, strong support, early closure, duty measurement and tight lining are adhered to. When the tunnel construction passes through a structure to erode a low and medium mountain area, a fault structural belt, weak surrounding rock and a shallow buried section, advanced support is made, collapse is controlled, and construction safety is ensured; when tunnel construction passes through a fault fracture zone, advanced geological forecast work is performed, advanced grouting and water shutoff work is performed, and collapse, water flushing and water bursting are prevented; during drilling and blasting construction, smooth blasting is adopted, blasting design is carried out before construction, blasting parameters are timely adjusted according to blasting effects, super-undermining is controlled, construction safety steps are controlled within an allowable range in the construction process, and collapse is prevented.
The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (10)
1. The construction method for constructing the corrosion and denudation medium and low mountain tunnel is characterized by comprising the following steps of:
according to the result of measuring and analyzing the natural geographical condition of the position of the tunnel, tunnel arrangement design and tunnel structure design are carried out, and an overall construction scheme is formulated;
retesting the topography and geology of the tunnel portal before construction, and dynamically adjusting the portal construction scheme according to retesting results;
the method comprises the steps of constructing a tunnel portal drainage project, excavating a tunnel portal side elevation slope, excavating a secondary slope and adopting a 1:0.75 slope rate above the secondary slope, excavating a primary slope by adopting a 1:0.5 slope rate, arranging the tunnel portal side slope according to 8m primary, and arranging a 2m platform on the top of the slope; the side-elevation slope of the opening is protected by adopting a hanging net and anchor spraying mode;
performing tunnel portal construction, advanced long pipe canopy support, surface grouting and arranging a tunnel top settlement observation point, then performing open cut tunnel excavation from top to bottom, performing layered support, excavating soil layers by using an excavator, and excavating rock layers by using the excavator or weak blasting; the open cut tunnel inverted arch construction adopts a full-width construction technology, a water stop belt and a water stop bar are arranged at a longitudinal annular construction joint, and in the inverted arch concrete pouring process, the assembled steel forms are fixed above the steel reinforcement framework according to the concrete pouring progress, so that the arch of inverted arch concrete is ensured;
constructing arch wall steel bars, connecting reserved steel bars at the end wall with the end wall steel bars of the tunnel portal, adopting a secondary lining trolley as an inner mould for open cut tunnel lining, adopting a combined steel mould for outer mould, and performing one-time pouring on arch wall lining concrete;
after all the open cut tunnel lining is constructed, waterproof layer construction, tunnel gate end wall construction and retaining wall construction are carried out; after the construction of the tunnel portal is completed and the concrete strength reaches the design strength, backfilling the open cut tunnel; after the open cut tunnel backfilling is completed, greening and protecting work of the tunnel opening and the tunnel roof are timely carried out, so that rain wash is avoided;
the method comprises the steps of performing underground hole digging by adopting a drilling and blasting mode, performing blasting design before construction, performing smooth blasting on a tunnel, and timely adjusting blasting parameters according to blasting effects, wherein the construction safety step distance is controlled within an allowable range in the construction process; the method comprises the steps of respectively adopting a full-face excavation method, a step excavation method and a step subsection excavation method to excavate a hole body according to surrounding rock grades; for the fault fracture zone, after excavation, spraying concrete in time to seal the tunnel face, and applying advanced small-conduit support;
after excavation and advanced geological forecast are completed, constructing an initial support, wherein the initial support consists of initial shotcrete, grouting anchor pipes, hollow grouting anchor rods, mortar anchor rods, reinforcing steel meshes and I-steel arches; after the steel arch is installed, the wet spraying concrete is completed as soon as possible, the steel support is covered completely, the spraying thickness is H-shaped steel thickness plus 2cm, the steel support and the sprayed concrete are stressed together, and the deflection of surrounding rock is restrained;
constructing a composite waterproof layer consisting of an EVA waterproof board with the thickness of 1.2mm and a geotextile with the square meter of 350 g/m between the primary support and the secondary lining; a buried rubber water stop is arranged at the circumferential and longitudinal construction joint; setting a settlement joint at a fault, a bright-dark junction, different surrounding rock grades and geological change positions, setting a settlement joint every 10m of the same lining type, and additionally setting a back-attached rubber water stop belt on the settlement joint;
constructing a tunnel drainage ditch and a drainage pipe; the drainage ditch comprises a cable groove and a central drainage ditch; the drainage pipe comprises a longitudinal drainage pipe, a circumferential drainage pipe and a transverse water guide pipe;
the inverted arch is constructed in full width, the sectional whole pouring is carried out, and the inverted arch is utilized to automatically move the trestle to keep passing; after the mechanical bottom cleaning and the full section construction of the shotcrete support are completed, inverted arch concrete is poured in time, the concrete is poured in full width, and the concrete is tamped by using an inserted vibrator and leveled by using a flat vibrator; the inverted arch is filled after the inverted arch concrete is finally set, so that the support is closed into a ring as early as possible;
constructing secondary lining by adopting an integral hydraulic lining trolley; the concrete is intensively stirred by adopting an automatic metering concrete mixing station, and silica powder or fly ash is added into the concrete; the mixing transport vehicle transports concrete, pumps the concrete into a mould, and uses an attached vibrator and an inserted vibrator for tamping; adopting forward construction, namely sequentially pouring the wall and the arch;
and constructing a tunnel pavement, wherein the pavement structure is a composite pavement structure, and the interior of the tunnel is decorated by adopting fireproof paint.
2. The construction method for constructing the corrosion-degraded low and medium mountain tunnels according to claim 1, wherein advanced geological forecast is required in the open cut tunnel excavation and the hidden tunnel excavation construction process; and acquiring surrounding rock state parameters in front of the face through the advanced geological forecast, and timely feeding back information to guide construction through analysis and processing of data.
3. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the drainage of the tunnel portal adopts a mode of combining a tunnel top intercepting ditch, an end wall longitudinal broken stone blind ditch and a tunnel top backfill transverse drainage ditch.
4. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the tunnel portal construction advanced long pipe shed support comprises the following construction steps: excavating a sleeve arch foundation, erecting a mould, pouring, manufacturing a sleeve arch steel frame, installing, welding a guide pipe, erecting a sleeve arch support and an installation template, pouring a sleeve arch body, removing the health maintenance, drilling a down-the-hole drill along the guide pipe, machining and installing a steel flower pipe, machining and installing a reinforcement cage, and grouting.
5. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the full-face excavation method is suitable for class iii surrounding rock, and specifically comprises the following construction steps: and excavating a full section, carrying out anchor spraying support and carrying out secondary lining construction.
6. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the step excavation method is suitable for IV-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central part of the lower half part is excavated, the side wall is subjected to primary support, and secondary lining construction is performed; the step length of the step excavation method is 1 time of the span of the hole.
7. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the step division excavation method is suitable for V-class surrounding rock, and specifically comprises the following construction steps: the upper half part is excavated, the arch part is subjected to anchor spraying support, the central core part is excavated, the lower part is excavated, the side wall is subjected to anchor spraying support, the inverted arch is poured, and secondary lining construction is carried out; the step length of the step subsection excavation method is 1.5-2 times of the hole span.
8. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the reinforcing mesh is hung on an excavated surface after primary spraying concrete, the thickness of the reinforcing protection layer is not less than 2cm, the reinforcing mesh is paved along with the fluctuation of the primary spraying concrete surface, the gap between the reinforcing mesh and the sprayed surface is not more than 3cm, the reinforcing mesh is fixed on an anchor rod which is constructed in advance, and the reinforcing mesh is welded into a mesh, wherein the lap joint length of the reinforcing mesh is not less than 50mm.
9. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein in the construction process of the primary support, when the tunnel excavation section meets the design requirement, immediately spraying a first layer of concrete for sealing, along with the deformation of surrounding rock, generating crack water leakage on the surface of the first layer of sprayed concrete, arranging omega-shaped spring semicircle drainage pipes at the water leakage positions, smearing 1-2 cm of condensed mortar on the surface for fixation, spraying a second layer of concrete for sealing, observing the surface of the sprayed layer, if water leakage exists, drilling water diversion holes at the water leakage positions, adding omega-shaped spring semicircle drainage pipes, and introducing water into the longitudinal drainage pipes of the basement for discharging outside the holes.
10. The construction method for constructing the corrosion-degraded low and medium mountain tunnel according to claim 1, wherein the EVA waterproof board is laid in a nailing-free manner, the welding mode is double-seam hot-melt welding, the waterproof board is 1m or more away from the lap joint, the deformation joint and the weak link of the construction joint, and the lap joint length of the lap joint is not less than 10cm; the waterproof layer is laid for 1-2 cycles in advance of the secondary lining.
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