CN112983461A - Construction method for bias tunnel portal in slope volume - Google Patents
Construction method for bias tunnel portal in slope volume Download PDFInfo
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- CN112983461A CN112983461A CN202110302778.8A CN202110302778A CN112983461A CN 112983461 A CN112983461 A CN 112983461A CN 202110302778 A CN202110302778 A CN 202110302778A CN 112983461 A CN112983461 A CN 112983461A
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- 238000010276 construction Methods 0.000 title claims abstract description 65
- 239000002689 soil Substances 0.000 claims abstract description 61
- 239000004575 stone Substances 0.000 claims abstract description 48
- 238000009412 basement excavation Methods 0.000 claims abstract description 42
- 239000004927 clay Substances 0.000 claims abstract description 32
- 239000004746 geotextile Substances 0.000 claims abstract description 26
- 239000002002 slurry Substances 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims description 23
- 238000005507 spraying Methods 0.000 claims description 9
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 230000001681 protective effect Effects 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- 239000011435 rock Substances 0.000 claims description 5
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- 238000004873 anchoring Methods 0.000 claims description 3
- 239000007921 spray Substances 0.000 claims description 3
- 230000005641 tunneling Effects 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 230000003014 reinforcing effect Effects 0.000 abstract description 4
- 238000007796 conventional method Methods 0.000 abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 239000011440 grout Substances 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002787 reinforcement Effects 0.000 description 2
- 239000002352 surface water Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
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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
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/18—Making embankments, e.g. dikes, dams
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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
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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
- E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
- E21D11/152—Laggings made of grids or nettings
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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
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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
-
- 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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Abstract
The invention discloses a construction method of a bias tunnel portal in a slope volume, which comprises the following steps: constructing anti-slide piles which are sequentially arranged at intervals along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line; grouting in soil above a tunnel excavation contour line to form grouting body, and backfilling soil and stones on one side of the tunnel with less bias soil covering; laying geotextile, covering slurry and covering clay on the side slope and the backfill soil stone to form a waterproof stable layer covering the surface of the side slope; and (5) excavating and constructing the opening. The construction method of the bias tunnel portal in the slope volume carries out corresponding construction by utilizing the relevant terrain of the slope volume, and further can effectively solve the technical problems of high engineering cost, no utilization of relevant terrain, complex construction operation and low construction and operation safety existing in the conventional method for reinforcing the bias tunnel portal with the small span and the large section.
Description
Technical Field
The invention relates to the technical field of tunnel construction, in particular to a construction method of a bias tunnel portal in a slope volume.
Background
Along with the improvement of living standard, the travel quality demand of people is also continuously improved, so the requirement on the line type of the route is also continuously increased, tunnel structures are arranged on both highway lines and railway lines, the number of the tunnel structures is also increased year by year, and small-span large-section tunnels are rare. However, due to the restrictions of geological conditions, routes and surrounding environments, the situation of the tunnel encountering bias voltage is more and more, the bias voltage is generated at the opening, and the opening of the slope volume is accompanied with the problem of slope treatment, and how to solve the problems is the key point for ensuring the safety of tunnel construction and operation.
There are generally two methods for reinforcing the bias tunnel entrance of the small-span large-section tunnel: the first is to improve the strength or rigidity of the supporting structure, mostly apply advance support at the tunnel portal section, and increase the supporting parameters of the primary support and increase the thickness of the secondary lining at the same time; the other method is to apply a retaining wall on one side of the bias voltage or backfill the soil body, and the methods have the disadvantages of high construction cost, no utilization of relevant terrains, complex construction operation and low safety of construction and operation.
Disclosure of Invention
The invention provides a construction method of a bias tunnel portal in a slope volume, which aims to solve the technical problems of complex construction operation and low construction and operation safety of the existing reinforcement method of the bias tunnel portal with a small span and a large section.
The technical scheme adopted by the invention is as follows:
a construction method for a bias tunnel portal in a slope volume comprises the following steps: constructing anti-slide piles which are sequentially arranged at intervals along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line; grouting in soil above a tunnel excavation contour line to form grouting body, and backfilling soil and stones on one side of the tunnel with less bias soil covering; laying geotextile, covering slurry and covering clay on the side slope and the backfill soil stone to form a waterproof stable layer covering the surface of the side slope; and (5) excavating and constructing the opening.
Further, in the step of constructing anti-slide piles which are sequentially arranged at intervals along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line, the anti-slide piles at least extend into a stable stratum below the potential sliding surface; the arrangement form and the distance of the slide-resistant piles are set according to the safety factor of the side slope, and if the safety factor of the side slope is larger, the distance between two adjacent slide-resistant piles is reduced.
Further, after the step of constructing the anti-slide piles sequentially arranged at intervals along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line is completed, the method further comprises the following steps: and side drainage ditches arranged along the extending direction of the tunnel are constructed between the mountain body and the anti-slide piles.
Further, the steps of grouting in the soil body above the tunnel excavation contour line to form grouting body and backfilling soil and stones on the side with less bias earth covering of the tunnel comprise the following steps: grouting in soil above a tunnel excavation contour line to form grouting body; arranging an advanced pipe shed at the tunnel portal section of the tunnel to be excavated, and constructing a protective arch and a sidewalk; and backfilling the excavated soil and stones formed by the protective arch and the pavement to the side of the tunnel with less bias earth covering.
Further, when the step of grouting to form grouting body in the soil body above the tunnel excavation contour line is carried out, the grouting body is set according to the stability and the biasing force of the side slope stratum, and when the stratum stability is poor and the biasing force is large, the grouting range and the grouting depth in the side slope are expanded.
Further, when the step of arranging an advanced pipe shed at the tunnel entrance section of the tunnel to be excavated and constructing an arch protection and a sidewalk is carried out, the tunnel entrance is supported in advance by adopting a large pipe shed with the diameter of more than 100mm, the length of the large pipe shed is not less than 30m, the large pipe shed is a hot-rolled seamless steel pipe, the circumferential distance of the steel pipes is 30 cm-50 cm, and the longitudinal external insertion angle is 1-2 degrees; when the large pipe shed is constructed, the concrete is matched for arch protection construction, and meanwhile, the construction of an access way is carried out.
And further, when the soil and stones excavated by the arch protection and the sidewalk are backfilled to the side with less biased soil covering of the tunnel, the soil and stone backfilling needs to be backfilled layer by layer, and manual and mechanical combination is adopted for tamping.
Further, the steps of geotextile laying, slurry covering and clay covering on the side slope and the backfill earth to form a waterproof stable layer covering the surface of the side slope specifically comprise the following steps: laying geotextile on the surface of the side slope and the backfill soil stone; covering the geotextile with the slurry to form a concrete layer; backfilling the soil on the concrete layer; covering clay on the concrete layer and the backfill soil stone to form a clay layer.
Further, when carrying out the concrete operation of step "carry out geotechnological cloth laying, slurry covering, clay covering in order to form the water proof stabilizer layer that covers the side slope surface on side slope and backfill earth's," still include the step: when geotextile is laid on the surface of the side slope and the backfill stone, a central drainage ditch template is built on the backfill stone; before backfilling the earth stones on the concrete layer again, building a central drainage ditch distributed along the extending direction of the tunnel by using a central drainage ditch template; when the concrete layer and the backfill soil stone are covered with clay, the height of the clay layer is equal to or higher than that of the central drainage ditch.
Further, the step of 'opening excavation construction' specifically comprises the following steps: excavating and tunneling by adopting a half-part CD method, which comprises the following steps: excavating a left upper step, erecting a permanent arch frame and a temporary arch frame, constructing a small advanced conduit, and carrying out net hanging, spray anchoring and supporting; excavating the right upper step, erecting a permanent arch, driving a small advanced conduit, and carrying out net hanging and anchor spraying support; excavating a left lower step, erecting a permanent arch frame, and carrying out net hanging and anchor spraying support; excavating a right lower step, erecting a permanent arch, and carrying out net hanging and anchor spraying support; excavating a core soil inverted arch, erecting a permanent arch frame, and constructing the inverted arch in a closed manner.
The invention has the following beneficial effects:
in the construction method of the bias tunnel portal in the slope volume, the anti-slide piles are arranged to be beneficial to the stability of the side slope and prevent the safety problem of tunnel construction and operation caused by the slide of the side slope; grouting is carried out in a certain range of the stratum above the tunnel, and soil and stone backfilling is carried out on the side, less in bias voltage earthing, of the tunnel, so that the influence of bias voltage on the tunnel is reduced, and the stability of the tunnel in the excavation and operation processes is improved; the geotextile is laid above the tunnel, and the slurry and the clay are covered to form a water-proof stable layer, so that the stability of the tunnel under normal conditions and rainfall conditions is facilitated; the construction method of the bias tunnel portal in the slope volume carries out corresponding construction by utilizing the relevant terrain of the slope volume, and further can effectively solve the technical problems of high engineering cost, no utilization of relevant terrain, complex construction operation and low construction and operation safety existing in the conventional method for reinforcing the bias tunnel portal with the small span and the large section.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic cross-sectional view of a structure constructed by the method of construction of a biased tunnel portal in a slope volume according to the preferred embodiment of the present invention.
Description of the figures
10. Anti-slide piles; 20. grouting; 30. a side drainage ditch; 40. geotextile; 50. a concrete layer; 60. a clay layer; 70. a central drainage ditch; 80. and backfilling a soil stone layer.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.
Referring to fig. 1, a preferred embodiment of the present invention provides a construction method of a biased tunnel portal in a slope volume, comprising the steps of:
constructing anti-slide piles 10 which are sequentially arranged at intervals along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line;
grouting in soil above a tunnel excavation contour line to form a grouting body 20, and backfilling soil and stones on one side of the tunnel with less bias soil covering;
laying geotextile 40, covering slurry and covering clay on the side slope and the backfill soil stone to form a waterproof stable layer covering the surface of the side slope;
and (5) excavating and constructing the opening.
Specifically, when the construction method is adopted for construction of a bias tunnel opening in a slope volume, firstly, anti-slide piles 10 which are sequentially arranged at intervals along the extending direction of a tunnel are constructed between a potential sliding surface of a side slope and a tunnel excavation contour line, and the arrangement of the anti-slide piles 10 is used for reducing the gliding force on the tunnel and preventing the tunnel from sliding damage in the tunnel excavation or operation process; grouting in a soil body above a tunnel excavation contour line to form a grouting body 20, and backfilling soil and stones on one side of the tunnel with less bias soil covering, wherein the grouting body 20 and the backfilling soil and stones have a matching effect to reduce the influence of bias on the tunnel and improve the stability of the tunnel excavation and operation processes; then, geotextile 40 laying, slurry covering and clay covering are carried out on the side slope and the backfill soil stone to form a water-proof stable layer covering the surface of the side slope, the geotextile 40 is used for preventing the damage to the tunnel caused by surface water infiltration, the slurry covering is used for keeping the stability of the integral structure of the slope body, the clay covering plays a water-proof role, in addition, greening treatment can also be carried out on a clay layer, and the geotextile 40 laying, slurry covering and clay covering are matched for forming the water-proof stable layer with stable structure and good waterproof performance, so that the stability of the integral structure of the slope body is enhanced; and finally, carrying out opening excavation construction.
In the construction method of the bias tunnel portal in the slope volume, the anti-slide pile 10 is arranged to be beneficial to the stability of the side slope and prevent the safety problem of tunnel construction and operation caused by the slide of the side slope; grouting is carried out in a certain range of the stratum above the tunnel, and soil and stone backfilling is carried out on the side, less in bias voltage earthing, of the tunnel, so that the influence of bias voltage on the tunnel is reduced, and the stability of the tunnel in the excavation and operation processes is improved; the geotextile is laid above the tunnel, and the slurry and the clay are covered to form a water-proof stable layer, so that the stability of the tunnel under normal conditions and rainfall conditions is facilitated; the construction method of the bias tunnel portal in the slope volume carries out corresponding construction by utilizing the relevant terrain of the slope volume, and further can effectively solve the technical problems of high engineering cost, no utilization of relevant terrain, complex construction operation and low construction and operation safety existing in the conventional method for reinforcing the bias tunnel portal with the small span and the large section.
Alternatively, as shown in fig. 1, in the step of constructing anti-slide piles 10 arranged at intervals in sequence along the extending direction of the tunnel between the potential sliding surface of the slope and the contour line of the tunnel excavation,
the slide resistant piles 10 extend at least into the stable formation below the potential sliding surface;
the arrangement form and the distance between the anti-slide piles 10 are set according to the slope safety factor, and if the slope safety factor is larger, the distance between two adjacent anti-slide piles 10 is reduced.
Specifically, when the slide-resistant piles 10 are arranged, the position of the slide-resistant piles 10 is generally set to be about 3m to 5m away from the horizontal distance of the tunnel excavation contour line, but must be set between the potential sliding surface and the tunnel excavation contour line; the specific length of the slide-resistant pile 10 is specifically set according to the stratum conditions, but the slide-resistant pile 10 is required to be arranged to at least extend into a stable stratum below the potential sliding surface; the arrangement form and the distance of the anti-slide piles 10 are set according to the safety coefficient of the side slope, the pile diameter of the anti-slide piles 10 can be generally set to be 1.5 m-3 m, the pile distance can be generally about 4 m-6 m, if the safety coefficient of the side slope is large, the distance between two adjacent anti-slide piles 10 can be properly reduced, but the anti-slide piles must be set between a potential sliding surface and a tunnel excavation contour line, otherwise, the anti-slide piles 10 cannot achieve the preset effect.
Specifically, the excavation and pouring of the slide-resistant pile 10 includes the following steps: firstly, digging a hole at a set position, and discharging dregs in the hole; then pouring concrete dado, and cleaning the hole bottom; then placing a reinforcement cage in the hole; and finally, pouring concrete and curing. The construction steps of the slide-resistant pile 10 are simple and easy to implement.
Optionally, after the step of "constructing the anti-slide piles 10 arranged at intervals in sequence along the extending direction of the tunnel between the potential sliding surface of the side slope and the tunnel excavation contour line" is completed, the method further includes the steps of:
Optionally, the step of grouting in the soil body above the tunnel excavation contour line to form a grouting body 20, and backfilling soil and stones on the side with less bias earth covering of the tunnel specifically includes the following steps:
grouting in soil above a tunnel excavation contour line to form grouting body 20;
arranging an advanced pipe shed at the tunnel portal section of the tunnel to be excavated, and constructing a protective arch and a sidewalk;
and backfilling the excavated soil and stones formed by the protective arch and the pavement to the side of the tunnel with less bias earth covering.
In this alternative, as shown in fig. 1, when the step "forming a grouting body 20 by grouting in a soil body above a tunnel excavation contour line" is performed, the setting is performed according to the stability and the biasing force of a side slope stratum, and when the stratum stability is poor and the biasing force is large, the grouting range and the grouting depth in the side slope are expanded. In a specific embodiment of this alternative, the concrete steps of forming the grout 20 are: firstly, positioning a position in a side slope, then drilling holes at the positioning positions of the holes, cleaning the holes after the drilling is finished, then placing floral tubes and fillers into the holes, and finally performing open-loop grouting. The forming step of the grout 20 is simple and easy to implement. The grouting body 20 is arranged, so that the stability of a side slope soil body can be improved, the influence of bias voltage on the tunnel is reduced, and the stability of the tunnel in the excavation and operation processes is improved.
In the alternative, as shown in fig. 1, when the steps of arranging the advanced pipe shed at the tunnel opening section of the tunnel to be excavated and constructing the protective arch and the sidewalk are carried out,
adopting a large pipe shed with the diameter of more than 100mm to support the tunnel portal in advance, wherein the length of the large pipe shed is not less than 30m, the large pipe shed is a hot-rolled seamless steel pipe, the circumferential distance of the steel pipe is 30-50 cm, and the longitudinal external insertion angle is 1-2 degrees;
when the large pipe shed is constructed, the concrete is matched for arch protection construction, and meanwhile, the construction of an access way is carried out.
Specifically, the advanced large pipe shed is arranged at the tunnel portal section, so that the self-bearing capacity of surrounding rocks can be improved through grouting, the elastic resistance of rock bodies to the structure is improved, and the stress condition of the structure is further improved; in the concrete construction, a large pipe shed with the diameter of phi 108mm is used for advance support, the length of the pipe shed is not less than 30m in one-step driving, a hot-rolled seamless steel pipe with the outer diameter of 108mm and the wall thickness of 6mm is used for the long pipe shed, the circumferential distance of the steel pipe is 30-50 cm, and the longitudinal external insertion angle is 1-2 degrees. When the large pipe shed is constructed, the C30 concrete is matched for arch protection construction, and meanwhile, as the construction needs a passage and the concrete and slurry are solidified for requiring time, the construction of the passage is also carried out at the arch protection construction stage, so that the construction time is saved, and the construction efficiency is improved. The pipe shed grouting is designed according to soil mass in a limited range around a consolidation pipe shed, the diffusion radius of the slurry is not less than 0.5m, and the grouting adopts sectional grouting; grouting parameters: water-cement ratio is 0.5: 1, grouting pressure: and the total station is adopted for positioning in the construction of the tunnel portal pipe shed under the pressure of 0.5-1 MPa, the construction angle and the joint quality are strictly controlled, the construction is completed in one step, and the construction quality and the construction efficiency are improved.
In the alternative, as shown in fig. 1, when the step of backfilling the excavated earth and stones by the protective arches and the sidewalks to the side with less bias earth covering of the tunnel is carried out, the earth and stone backfilling needs to be backfilled layer by layer, and tamping is carried out by adopting manual and mechanical combination.
Optionally, as shown in fig. 1, the step of "laying geotextile 40, covering slurry, and covering clay on the side slope and the backfill rock to form a waterproof stable layer covering the surface of the side slope" specifically includes the following steps:
the geotextile 40 is laid on the surface of the side slope and the backfill soil stone, and the geotextile 40 is used for preventing the damage of the surface water infiltration to the tunnel;
covering the geotextile 40 with the slurry to form a concrete layer 50, wherein the concrete layer 50 is used for keeping the stability of the integral structure of the slope volume;
backfilling the concrete layer 50 with earth stones, which is beneficial to further reducing the effect of bias voltage on the tunnel;
the concrete layer 50 and the backfill soil stone are covered with clay to form a clay layer 60, the clay layer 60 plays a role of water isolation, and in addition, greening treatment can be carried out on the clay layer.
In the alternative, the geotextile 40, the backfill stone layer 80, the concrete layer 50, the clay layer 60 and the like are matched for forming a waterproof stable layer with stable structure and good waterproof performance, so that the stability of the integral structure of the slope volume is enhanced.
Optionally, as shown in fig. 1, when performing the specific operations of "laying geotextile 40, covering slurry, and covering clay on the slope and the backfill rock to form a water-proof stable layer covering the surface of the slope", the method further includes the steps of:
when the geotextile 40 is laid on the surface of the side slope and the backfill stone, a central drainage ditch template is built on the backfill stone;
before backfilling the soil stone on the concrete layer 50 again, building a central drainage ditch 70 arranged along the extending direction of the tunnel by using a central drainage ditch template;
when the concrete layer 50 and the backfill stones are covered with clay, the clay layer 60 is made to have a height equal to or higher than that of the center drain 70.
Specifically, the size of the central drainage ditch 70 is determined according to local meteorological conditions, and the cross section of the central drainage ditch 70 is rectangular, so that the central drainage ditch has the advantages of small excavation surface and controllable depth; the center drain 70 is disposed at the center of the two tunnels and also at the lowest position of one tunnel, and the center drain 70 is disposed at such a position that the water on both sides can be merged at this position or the water on one side of the tunnel can be merged at this position, thereby preventing the tunnel from being damaged and reducing the risk of slope slippage.
Optionally, the step of "opening excavation construction" specifically includes the following steps:
excavating and tunneling by adopting a half-part CD method, which comprises the following steps:
excavating a left upper step, erecting a permanent arch frame and a temporary arch frame, constructing a small advanced conduit, and carrying out net hanging, spray anchoring and supporting;
excavating the right upper step, erecting a permanent arch, driving a small advanced conduit, and carrying out net hanging and anchor spraying support;
excavating a left lower step, erecting a permanent arch frame, and carrying out net hanging and anchor spraying support;
excavating a right lower step, erecting a permanent arch, and carrying out net hanging and anchor spraying support;
excavating a core soil inverted arch, erecting a permanent arch frame, and constructing the inverted arch in a closed manner.
Specifically, this construction step of entrance to a cave excavation is favorable to the stability of the integrated body of excavation in-process slope, prevents the tunnel unstability or the phenomenon of collapsing, and whole work progress easy operation, constructor's working strength is low, and the efficiency of construction is high. During actual excavation, the distance of each step is 5-10 m, and other processes such as timely transport stone ballast, roof support are convenient for.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A construction method for a bias tunnel portal in a slope volume is characterized by comprising the following steps:
anti-slide piles (10) which are sequentially arranged at intervals along the extending direction of the tunnel are constructed between the potential sliding surface of the side slope and the tunnel excavation contour line;
grouting in soil above a tunnel excavation contour line to form a grouting body (20), and backfilling soil and stones on one side of the tunnel with less bias soil covering;
laying geotextile (40), covering slurry and covering clay on the side slope and the backfill soil stone to form a waterproof stable layer covering the surface of the side slope;
and (5) excavating and constructing the opening.
2. The method for constructing a biased tunnel opening in a sloping volume according to claim 1, characterized by the steps of building slide resistant piles (10) arranged at intervals in sequence in the tunnel extension direction between the potential sliding surface of the slope and the tunnel excavation contour line,
the anti-slide pile (10) extends at least into the stable ground formation below the potential sliding surface;
the arrangement form and the distance of the anti-slide piles (10) are set according to the safety coefficient of the side slope, and if the safety coefficient of the side slope is larger, the distance between two adjacent anti-slide piles (10) is reduced.
3. The construction method for biasing a tunnel opening in a sloping volume according to claim 1, wherein after the step of constructing the slide piles (10) arranged at intervals in sequence in the extending direction of the tunnel between the potential sliding surface of the side slope and the excavation contour line of the tunnel is completed, the method further comprises the steps of:
and side drainage ditches (30) arranged along the extending direction of the tunnel are constructed between the mountain body and the anti-slide piles (10).
4. The construction method of the bias tunnel portal in the sloping volume according to claim 1, characterized in that the steps of grouting in the soil body above the tunnel excavation contour line to form a grouting body (20) and backfilling the soil and stones on the side with less bias soil covering of the tunnel comprise the following steps:
grouting in soil above a tunnel excavation contour line to form grouting body (20);
arranging an advanced pipe shed at the tunnel portal section of the tunnel to be excavated, and constructing a protective arch and a sidewalk;
and backfilling the excavated soil and stones formed by the protective arch and the pavement to the side of the tunnel with less bias earth covering.
5. The method of claim 4, wherein when the step of grouting the soil above the excavation contour line of the tunnel to form a grouting body (20) is performed,
and (4) according to the stability and the biasing force of the stratum of the side slope, when the stratum is poor in stability and large in biasing force, the grouting range and the grouting depth in the side slope are expanded.
6. The construction method for biasing the tunnel opening in the sloping volume according to claim 4, wherein in the step of arranging a leading pipe shed at the opening section of the tunnel to be excavated and constructing an arch protection and a sidewalk,
adopting a large pipe shed with the diameter of more than 100mm to support the tunnel portal in advance, wherein the length of the large pipe shed is not less than 30m, the large pipe shed is a hot-rolled seamless steel pipe, the circumferential distance of the steel pipe is 30-50 cm, and the longitudinal external insertion angle is 1-2 degrees;
when the large pipe shed is constructed, the concrete is matched for arch protection construction, and meanwhile, the construction of an access way is carried out.
7. The construction method of the bias tunnel opening in the sloping volume according to claim 4, wherein when the step of backfilling the excavated soil and stones from the arch protection and the sidewalk to the side with less bias soil covering of the tunnel is performed,
the earth and stone backfill is carried out by layering and tamping by manual and mechanical combination.
8. The construction method of a biased tunnel portal in a sloping volume according to claim 1, characterized in that the steps of "laying geotextile (40), slurry covering, clay covering on the slope and backfill rock to form a water-proof stable layer covering the surface of the slope" specifically comprise the following steps:
laying geotextile (40) on the surface of the side slope and the backfill soil stone;
covering the geotextile (40) with the slurry to form a concrete layer (50);
backfilling the concrete layer (50) with earth stones;
and covering clay on the concrete layer (50) and the backfill soil stone to form a clay layer (60).
9. The method of claim 8, wherein the concrete operations of laying geotextile (40), covering slurry and covering clay on the side slope and backfill earth to form a water-proof stable layer covering the surface of the side slope are carried out, and the method further comprises the following steps:
when the geotextile (40) is laid on the surface of the side slope and the backfill stone, a central drainage ditch template is built on the backfill stone;
before backfilling the earth stones on the concrete layer (50), building a central drainage ditch (70) arranged along the extending direction of the tunnel by using a central drainage ditch template;
when the concrete layer (50) and the backfill soil stone are covered with clay, the height of the clay layer (60) is equal to or higher than that of the central drainage ditch (70).
10. The construction method for biasing the tunnel portal in the sloping volume according to claim 1, wherein the step of portal excavation construction comprises the following steps:
excavating and tunneling by adopting a half-part CD method, which comprises the following steps:
excavating a left upper step, erecting a permanent arch frame and a temporary arch frame, constructing a small advanced conduit, and carrying out net hanging, spray anchoring and supporting;
excavating the right upper step, erecting a permanent arch, driving a small advanced conduit, and carrying out net hanging and anchor spraying support;
excavating a left lower step, erecting a permanent arch frame, and carrying out net hanging and anchor spraying support;
excavating a right lower step, erecting a permanent arch, and carrying out net hanging and anchor spraying support;
excavating a core soil inverted arch, erecting a permanent arch frame, and constructing the inverted arch in a closed manner.
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