CN110836121A - Anti-floating reinforcing structure of operated subway tunnel and construction method - Google Patents
Anti-floating reinforcing structure of operated subway tunnel and construction method Download PDFInfo
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- 238000007667 floating Methods 0.000 title claims abstract description 127
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 57
- 238000010276 construction Methods 0.000 title claims abstract description 35
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 167
- 239000010959 steel Substances 0.000 claims abstract description 167
- 239000002689 soil Substances 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000004873 anchoring Methods 0.000 claims description 32
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 30
- 230000002787 reinforcement Effects 0.000 claims description 27
- 238000003466 welding Methods 0.000 claims description 22
- 239000004567 concrete Substances 0.000 claims description 21
- 238000005553 drilling Methods 0.000 claims description 20
- 239000002002 slurry Substances 0.000 claims description 19
- 239000004568 cement Substances 0.000 claims description 16
- 238000013461 design Methods 0.000 claims description 11
- 238000004364 calculation method Methods 0.000 claims description 10
- 239000003566 sealing material Substances 0.000 claims description 10
- 238000009412 basement excavation Methods 0.000 claims description 8
- 230000000630 rising effect Effects 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- 229920006333 epoxy cement Polymers 0.000 claims description 4
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 239000011372 high-strength concrete Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
- 230000009467 reduction Effects 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 3
- 239000011440 grout Substances 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
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- 229920005989 resin Polymers 0.000 description 2
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- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
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- 238000009435 building construction 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
- 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
- E21D11/08—Lining with building materials with preformed concrete slabs
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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
- E21D11/38—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
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/021—Grouting with inorganic components, e.g. cement
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
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Abstract
The invention relates to an anti-floating reinforcing structure of an operated subway tunnel and a construction method, which are characterized in that an inner reinforcing structure is arranged inside a tunnel lining, and an outer reinforcing structure and an anti-floating structure are arranged outside the tunnel lining; the inner reinforcing structure comprises steel sleeves and stiffening plates which are arranged at intervals, the stiffening plates are welded with the steel sleeves, and the steel sleeves are fixed with the tunnel lining through wall-mounted expansion bolts; the outer reinforcing structure comprises grouting reinforcing soil bodies, and the grouting reinforcing soil bodies are symmetrically arranged at the upper parts of the two sides of the tunnel lining; the anti-floating structure comprises an anchor rod, the anchor rod is arranged at the bottom of the tunnel lining, the top end of the anchor rod is anchored into the ballast bed, and grouting bodies are arranged around the anchor rod at the part below the tunnel lining. The invention can reduce the influence of the disturbance of the surrounding soil body on the subway tunnel, increase the anti-floating performance and the tunnel rigidity of the subway tunnel, and reduce the floating amount and the section deformation of the tunnel when the underground water level rises or the soil body on the tunnel is excavated.
Description
Technical Field
The invention relates to the technical field of subway tunnel anti-floating, in particular to an operated subway tunnel anti-floating reinforcing structure and a construction method.
Background
With the increasing of traffic flow, the traffic pressure of ground roads is gradually increased, so that the development and construction of underground spaces are also rising climax all over the country, cross traffic flows are separated in the space of the urban underpass tunnel, the traffic smoothness is improved, and the traffic pressure of cities is greatly relieved. In the subway operation stage, because groundwater level changes or peripheral construction activity, the shield tunnel can take place the come-up phenomenon, and the section of jurisdiction come-up can produce adverse effect to train operating speed, operation safety, passenger's comfort level.
The subway tunnel is used as an important urban traffic lifeline, and has extremely strict deformation requirements. According to the existing relevant regulations, the absolute maximum displacement of the tunnel cannot exceed 20mm, the tunnel rebound deformation does not exceed 15mm, the tunnel deformation curvature radius must be larger than 15000m, and the relative deformation must be smaller than 1/2500.
At present, the most common method for resisting the floating of the tunnel structure is to utilize the self weight of soil bodies which are deeply buried under the ground and are positioned above the top of the subway tunnel in the design stage, so that the weight of the soil bodies can resist the buoyancy possibly received by the subway tunnel underground. However, the perennial underground water level in coastal cities is high, the geological conditions are poor, the underground water level can also change greatly along with seasonal changes, and when the dead weight effect generated by the earth covering above the underground tunnel structure cannot resist the buoyancy of underground water, the structure can float upwards, and shield segments are cracked in a connecting manner seriously, so that the structure safety is endangered. In addition, the activity day that the existing subway tunnel is adjacent to the building construction is increased, when the top of the subway tunnel needs to carry out soil unloading engineering such as foundation pit excavation, the foundation pit excavation can cause the resilience of soil in the pit, additional displacement can be built (constructed) to the proximity underground, the upward floating deformation of the proximity subway tunnel is caused, the vertical diameter of the tunnel is caused to be reduced, the horizontal diameter is increased, the cross section shape of the tunnel is changed, if the anti-floating reinforcement treatment is not carried out on the subway tunnel in time, the upward floating displacement of the tunnel is out of limit, and then the tunnel segment is damaged, even the tunnel gushes water, collapses and other problems, and the life and property safety is damaged.
Along with the rapid increase of urban rail transit operating mileage and the increase of operating time, the adjacent side area of the shield tunnel is always a hot building area, the upward floating diseases of the tunnel in the subway operating stage are more and more expected, and it is necessary to research the upward floating disease treatment measures of shield tunnel segments in the operating stage, reasonably select the anti-floating reinforcement measures and means of the tunnel, and ensure the normal use of the subway tunnel.
Disclosure of Invention
The invention aims to solve the problems of anti-floating reinforcement of an operated subway tunnel, insufficient bearing capacity of a construction structure, weak construction integrity and the like due to the lack of effective measures in the prior art, and provides an anti-floating reinforcement structure of a subway tunnel and a construction method, which aim at the combination of the operated subway, anti-floating and reinforcement, simple steps, reasonable design, simple and convenient construction, good construction structure integrity and suitability for construction of a subway outage window period.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
the invention relates to an anti-floating reinforcing structure of an operated subway tunnel, which comprises a tunnel lining, wherein a ballast bed is arranged in the tunnel lining, and bearing platforms are arranged on two sides of the ballast bed, and the anti-floating reinforcing structure is characterized in that: an inner reinforcing structure is arranged inside the tunnel lining, and an outer reinforcing structure and an anti-floating structure are arranged outside the tunnel lining; the inner reinforcing structure comprises a steel sleeve ring and a stiffening plate which are arranged at intervals, the stiffening plate is welded with the steel sleeve ring, the steel sleeve ring is tightly attached to the inner surface of the tunnel lining and is fixed with the tunnel lining through a wall-mounted expansion bolt, two sides of the steel sleeve ring are plugged by epoxy cement, and a gap between the steel sleeve ring and the tunnel lining is filled by epoxy resin; the outer reinforcing structure comprises grouting reinforcing soil bodies, and the grouting reinforcing soil bodies are symmetrically arranged at the upper parts of the two sides of the tunnel lining; the anti-floating structure comprises a plurality of anchor rods, the anchor rods are arranged at the bottom of the tunnel lining, the top ends of the anchor rods are anchored into the ballast bed, and grouting bodies are arranged around the anchor rods at the part below the tunnel lining.
Preferably, the steel sleeve comprises a left arc-shaped steel plate and a right arc-shaped steel plate, and the stiffening plates comprise a left stiffening plate and a right stiffening plate; the radian of the left arc-shaped steel plate and the right arc-shaped steel plate is the same as that of the inner side of the tunnel lining, the inner surface of the tunnel lining is provided with screw holes, the corresponding positions of the left arc-shaped steel plate and the right arc-shaped steel plate are provided with screw holes, the left arc-shaped steel plate and the right arc-shaped steel plate are arranged in a manner of being tightly attached to the inner surface of the tunnel lining, and the left arc-shaped steel plate and the right arc-shaped steel plate are; the left stiffening plate is welded and connected along the central axis of the left arc-shaped steel plate, the right stiffening plate is welded and connected along the central axis of the right arc-shaped steel plate, connecting top plates are arranged at the top ends of the left stiffening plate and the right stiffening plate, and the connecting top plates at the two sides are mutually connected through split bolts; bottom connecting plates are welded at the bottoms of the left arc-shaped steel plate and the right arc-shaped steel plate, and the bottom connecting plates are fixed on the upper surfaces of the bearing platforms on the two sides through foundation bolts and nuts.
Preferably, a plurality of grouting pipes are arranged in the grouting reinforced soil body, the grouting pipes in the grouting reinforced soil body on two sides are bilaterally symmetrical, grouting holes are formed in the positions, corresponding to the grouting pipes, of the left side and the right side of the tunnel lining, the grouting pipes penetrate through the grouting holes and are inserted into the reinforced soil body on two sides of the tunnel lining, and the grouting holes are filled with sealing materials to block the grouting holes.
Preferably, the anchor rod comprises an anchor rod main rib, a plurality of anti-floating reinforcing ribs, a water stop steel plate and a steel bar positioner; the anchor rod main rib penetrates through the water stop steel plate, the bottom end of the anti-floating reinforcing rib is welded at the junction of the anchor rod main rib and the water stop steel plate, the water stop steel plate is buried in the ballast bed and is welded with the ballast bed reinforcing steel bar, and the reinforcing steel bar positioner is welded on the anchor rod main rib below the tunnel lining; stock owner muscle and anti-floating reinforcement's top all be equipped with the part of buckling, anti-floating reinforcement's bottom is equipped with the overlap joint part to the parallel with stock owner muscle, the length of the part of buckling is 15 times of stock owner muscle or anti-floating reinforcement diameter at least, the length of overlap joint part is 55 times of anti-floating reinforcement diameter at least.
The bearing platform is connected with the tunnel lining through a plurality of expansion bolts.
The invention also relates to a construction method of the operated subway tunnel anti-floating reinforcing structure, which is characterized by comprising the following steps: which comprises the following steps:
1) cutting and chiseling the ballast beds and the ditches on the two sides of the subway track until shield segments are exposed;
2) constructing bearing platforms at the cutting and chiseling positions of the track beds on the two sides of the subway track;
3) drilling grouting holes at the upper parts of two sides of a tunnel lining, driving a grouting perforated pipe along the grouting holes immediately after each drilling hole forms one grouting hole, injecting cement slurry, forming a grouting reinforced soil body after hardening, and then injecting waterproof concrete at the grouting hole to form a sealing material;
4) judging the reason causing the tunnel to float upwards, and calculating the anti-floating force F required by the single-ring tunnel segmentAnti-floating；
5) According to the buoyancy F borne by the single-ring tunnel segmentFloating bodyCalculating the designed axial tension value of a single anchor rod, the reinforcement of the anchor rod, the length of the anchor rod and the anchoring length of an anchoring body and the anchor rod;
6) drilling a track bed at the subway tunnel and setting an anchor rod according to the parameters calculated in the step 5;
7) and installing the steel ferrule and the stiffening plate.
Preferably, the step 4) is the floating resistance F required by the single-ring tunnel segment due to the tunnel floating caused by the rising of underground waterAnti-floatingThe calculation steps are as follows:
4.1) calculating the effective weight G of the overlying soil column of the single-ring tunnel segmentSoil for soil，
4.2) calculating the dead weight G of the single-ring tunnel segmentFrom，
GFrom＝δπ(R2-r2)γc；
4.3) calculating the underground water buoyancy F suffered by the single-ring tunnel segmentFloating body，
FFloating body＝δπR2γw；
4.4) calculating the required anti-buoyancy FAnti-floating，
Wherein, γaIs the saturated volume weight of the soil body, gammawThe volume weight of water is shown, R is the outer diameter of the shield tunnel, h is the thickness of a soil layer on the pipeline, delta is the width of a single-ring segment, and R is the inner diameter of the shield tunnel; gamma rayfTaking 1.2 as the safe anti-floating coefficient of the shield tunnel in the using stage; gamma raySoil for soilTaking the weight coefficient of the overburden layer on the tunnel as 1.0; gamma rayFromTaking 1.0 as the self-weight item coefficient of the tunnel structure; gamma rayAnti-floatingTaking the coefficient of the anti-floating component of the anchor rod as 1.0.
Preferably. The step 4) causes the tunnel to float up for the unloading above the tunnel, and the anti-floating force F required by the single-ring tunnel segmentAnti-floatingThe calculation steps are as follows:
4.1) unloading load pd according to the coordinate (ξ) of any point at the bottom of the foundation pitξdηCalculating (x, y, z) at the tunnel axis0) Additional stress σ ofz，
In the formula (I), the compound is shown in the specification,
upsilon is Poisson's ratio; z is a radical of0The distance between the central line of the tunnel and the earth surface is taken as the distance; h is the excavation depth of the foundation pit;
4.2) for each ring of shield segments, assuming that the additional stress of each point at the axis is the same, the additional load F borne by each ring of shield segments due to excavation of the foundation pit is added as
FAttachment(s)＝δRσz；
4.3) taking F according to the balance relation of forcesAnti-floating＝FAttachment(s)。
Preferably, the specific steps of step 5) are as follows:
5.1) F calculated according to step 4Anti-floatingCalculating the axial tension standard value N of the anchor rodak，
Nak＝FAnti-floating；
5.2) according to the axial tension standard value NakCalculating the design value N of the axial tension of a single anchor rodt，
Nt＝γQNak，
In the formula, gammaQTaking the load element coefficient as 1.3;
5.3) calculating the section area A of the reinforcing steel bar of the anchor rods，
In the formula, KtThe safety factor of the tensile strength of the anchor rod body is increased; f. ofykThe standard value of the tensile strength of the steel bar is;
and according to the calculated sectional area A of the anchor rod reinforcing steel barsDetermining the number of actual matching anchor rod reinforcing steel bars;
5.4) calculating the length L between the formation and the anchora1And L between anchor body and anchor rod steel bara2，
Selecting La1And La2The larger value is used as the anchoring length L between the anchoring body and the anchor rod (8)a；
In the formula (f)mgThe standard value of the bonding strength between the stratum and the anchoring grouting body is obtained; f. ofmsThe standard value of the bonding strength between the steel bar and the anchoring grouting body is obtained; k is the anti-pulling safety coefficient of the anchor rod, and 2.0 is taken; d is an anchor rodTaking the drilling diameter of the anchoring section as 150 mm; d is the diameter of the anchor rod steel bar and is determined according to actual reinforcement; n is the number of anchor rod reinforcing steel bars and is determined according to the actual reinforcing steel bars of each ring pipe sheet;
the coefficient is the reduction coefficient of the bonding strength of the section of the steel bar, and the value range is between 0.6 and 0.85; psi is the influence coefficient of anchor rod anchoring length to bonding strength, takes 1.0.
Preferably, the step of installing the anchor rod in the step 6) comprises the following steps:
6.1) chiseling concrete according to the chiseling trace of the ballast bed concrete, and then forming holes by using a down-the-hole hammer;
6.2) placing the anchor rod which is manufactured in advance into the drilled hole, and grouting in a secondary grouting mode;
6.3) after the slurry is initially set, recharging the high-strength concrete and filling the chiseling part of the ballast bed concrete.
Preferably, the step 7) of installing the steel ferrule and the stiffening plate comprises the following steps:
7.1) arranging corresponding screw holes on the tunnel lining according to the positions of the screw holes of the steel sleeve ring;
7.2) welding the left stiffening plate on the left arc-shaped steel plate, welding the right stiffening plate on the right arc-shaped steel plate, hoisting the left arc-shaped steel plate and the right arc-shaped steel plate to specified positions, and anchoring the left arc-shaped steel plate and the right stiffening plate on the tunnel lining by using wall-mounted expansion bolts;
7.3) connecting the connecting top plates of the arc-shaped steel plates at the two sides with each other by using split bolts;
7.4) fixing the left arc-shaped steel plate and the left stiffening plate and fixing the right arc-shaped steel plate and the right stiffening plate on the bearing platforms at two sides by adopting foundation bolts respectively.
Compared with the prior art, the scheme of the invention has the following beneficial effects:
(1) according to the invention, the inner reinforcing structure consisting of the steel sleeve and the stiffening plate is arranged inside the tunnel lining, and the left side and the right side of the outer part of the tunnel lining are respectively provided with the grouting reinforcing soil body, so that the upward floating trend of the tunnel can be quickly inhibited, and the quick-acting effect is achieved.
(2) According to the invention, the anti-floating structure is arranged at the bottom of the tunnel lining, the anti-floating structure is matched with the tunnel upper earthing to counteract the buoyancy of underground water to the tunnel, when the water level changes or the overlying soil is excavated, the anti-floating structure plays a role in preventing the tunnel from floating upwards, the structural damage caused by the floating upwards of the tunnel is avoided, and the displacement value of the tunnel can be controlled in a long term in a load period.
(3) The construction method for arranging the anti-floating structure at the bottom of the tunnel lining has simple steps, mainly takes the assembled structure as a main structure, improves the construction efficiency, is suitable for the engineering characteristics of the operated tunnel in a short construction window period, and provides a new active anti-floating idea for the upward floating deformation of the operated tunnel.
(4) The invention solves two tunnel structure disasters of tunnel floating deformation and tunnel section deformation, greatly reduces the construction cost, improves the anti-deformation capability of the tunnel, prolongs the service life of the tunnel, and has high practical value and good use effect.
(5) The technology disclosed by the invention can be used for correcting the floating deformation of the operated subway tunnels with different diameters and different areas, is particularly suitable for protecting and reinforcing the tunnels in dangerous stratums which are easy to generate lining diseases, such as water-rich weak areas and the like, and has wide application range.
Drawings
Fig. 1 is a schematic structural diagram of an anti-floating reinforcing structure of a subway tunnel according to the present invention;
fig. 2 is a sectional view a-a of the anti-floating reinforcing structure of the subway tunnel shown in fig. 1;
FIG. 3 is a sectional view taken along line A-A of the grouting hole, anchor rod hole and screw hole forming structure;
FIG. 4 is a sectional view taken along line A-A of the structure after the placement of the anchor rods;
FIG. 5 is a diagrammatic view of a bolt joint;
FIG. 6 is a cross-sectional view taken generally along line 1-1 of the anchor node;
FIG. 7 is a somewhat diagrammatic view of the anchor rod;
FIG. 8 is a reinforcement view of the anchor rod;
FIG. 9 is a diagram illustrating the tunnel floating calculation caused by the rising of water level;
FIG. 10 is a schematic illustration of the tunnel ascent calculation caused by the unloading above the tunnel;
fig. 11 is a tunnel segment displacement monitoring diagram.
Description of the labeling: the method comprises the following steps of 1-tunnel lining, 2-ballast bed, 3-bearing platform, 4-steel sleeve, 5-stiffening plate, 6-wall-hanging expansion bolt, 7-grouting reinforced soil body, 8-anchor rod, 9-grouting body, 10-grouting flower tube, 11-left arc-shaped steel plate, 12-right arc-shaped steel plate, 13-left stiffening plate, 14-right stiffening plate, 15-connecting top plate, 16-sealing material, 17-foundation bolt, 18-bottom connecting plate, 19-split bolt, 20-ballast bed steel bar, 21-grouting hole, 22-anchor rod hole, 23-expansion bolt, 24-screw hole, 25-anchor rod main bar, 26-anti-floating reinforcing bar, 27-water stop steel plate, 28-ballast steel bar positioner and 29-ballast bed concrete chiseling trace.
Detailed Description
For further understanding of the present invention, the present invention will be described in detail with reference to examples, which are provided for illustration of the present invention but are not intended to limit the scope of the present invention.
Example 1
The invention relates to an anti-floating reinforcing structure of an operated subway tunnel, which is shown by combining accompanying drawings 1-4 and used for solving the problem of tunnel floating caused by rising of water level or tunnel floating caused by unloading above the tunnel, and comprises a tunnel lining 1, wherein a ballast bed 2 and an inner reinforcing structure are arranged inside the tunnel lining 1, an outer reinforcing structure and an anti-floating structure are arranged outside the tunnel lining 1, bearing platforms 3 are arranged on two sides of the ballast bed 2, and the bearing platforms 3 are connected with the tunnel lining 1 through a plurality of expansion bolts 23.
With reference to the attached drawings 1-4, the inner reinforcing structure comprises a steel sleeve 4 and a stiffening plate 5 which are arranged at intervals, the stiffening plate 5 is welded with the steel sleeve 4, the steel sleeve 4 comprises a left arc-shaped steel plate 11 and a right arc-shaped steel plate 12, and the stiffening plate 5 comprises a left stiffening plate 13 and a right stiffening plate 14; the radian of the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12 is the same as the inner side radian of the tunnel lining 1, the inner surface of the tunnel lining 1 is provided with a screw hole 24, screw holes are arranged at corresponding positions on the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12, the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12 are arranged close to the inner surface of the tunnel lining 1, the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12 are connected with the tunnel lining 1 through wall-mounted expansion bolts 6 penetrating through the screw holes 24, so that the steel sleeve 4 is close to the inner surface of the tunnel lining 1, two sides of the steel sleeve 4 are plugged by epoxy; the left stiffening plate 13 is welded and connected along the central axis of the left arc-shaped steel plate 11, the right stiffening plate 14 is welded and connected along the central axis of the right arc-shaped steel plate 12, the top ends of the left stiffening plate 13 and the right stiffening plate 14 are respectively provided with a connecting top plate 15, and the connecting top plates 15 at the two sides are mutually connected through split bolts 19; bottom connecting plates 18 are welded at the bottoms of the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12, and the bottom connecting plates 18 are fixed on the upper surfaces of the bearing platforms 3 on the two sides through anchor bolts 17 matched with nuts.
The external reinforcing structure described with reference to fig. 1, 2 and 4 comprises grouting reinforcing soil 7, the grouting reinforcing soil 7 is symmetrically arranged at the upper part of the two sides of the tunnel lining 1, the grouting reinforcing body 7 is formed by injecting cement slurry into soil at the two sides through a plurality of grouting floral tubes 10, the cement slurry is hardened, and the grouting floral tubes 10 are not pulled out; the grouting floral tubes 10 in the grouting reinforced soil bodies 7 on the two sides are bilaterally symmetrical, grouting holes 21 are formed in the positions, corresponding to the grouting floral tubes 10, of the left side and the right side of the tunnel lining 1, the grouting floral tubes 10 penetrate through the grouting holes 21 and are inserted into soil on the two sides of the tunnel lining 1, cement slurry is injected into the soil through the grouting floral tubes 10, the reinforced soil bodies 7 are formed after the cement slurry is hardened, concrete is poured into the grouting holes 21 after the cement slurry is injected, and filling sealing materials 16 are formed and used for plugging the grouting holes 21 and preventing the cement slurry from flowing backwards from the grouting holes 21.
With reference to fig. 1 to 4, the anti-floating structure includes a plurality of anchor rods 8, and with reference to fig. 5 to 7, the anchor rods 8 include anchor rod main ribs 25, a plurality of anti-floating reinforcing ribs 26, a water stop steel plate 27 and a steel bar positioner 28; the anchor rod main rib 25 penetrates through the water stop steel plate 27, the bottom end of the anti-floating reinforcing rib 26 is welded at the junction of the anchor rod main rib 25 and the water stop steel plate 27, the water stop steel plate 27 is buried in the ballast bed 2 and is welded with ballast bed reinforcing steel bars 20, and the reinforcing steel bar positioner 28 is welded on the anchor rod main rib 25 below the tunnel lining 1; referring to fig. 5, 7 and 8, the anchor rod main rib 25 and the anti-floating reinforcing rib 26 are provided at their top ends with bent portions, the anti-floating reinforcing rib 26 is provided at its bottom end with an overlapping portion parallel to the anchor rod main rib 25, the length of the bent portion is at least 15 times the diameter of the anchor rod main rib 25 or the anti-floating reinforcing rib 26, the length of the overlapping portion is at least 55 times the diameter of the anti-floating reinforcing rib 26, the anchor rod 8 is inserted into the soil at the bottom of the tunnel lining 1, the steel bar locator 28 is located in the anchor rod hole 22, the outer diameter of the steel bar locator 28 is slightly smaller than the aperture of the anchor rod hole 22, so that the cement slurry can penetrate through the gap between the steel bar locator 28 and the anchor rod hole 22, the top end of the anchor rod 8 is anchored in the ballast 2, and the cement slurry is injected around the anchor.
Example 2
When the tunnel floats upwards due to rising of the water level of the operated subway tunnel, the following steps are adopted for construction:
1) selecting a manipulator and a flat car for construction according to construction environments such as a limit of an operation line, a minimum radius of the line, a maximum gradient and the like; then, moving and modifying the internal pipeline of the shield tunnel, mainly shifting side brackets of strong and weak current, reforming lines and the like, and providing an effective action field for construction; then, the track bed 2 and the ditch on the two sides of the subway track are cut and chiseled until the shield segment is exposed, the side face of the track bed 2 is chiseled after cutting, the surface of the tunnel lining 1 is cleaned by a high-pressure water gun, and loose objects such as broken blocks, calcifications and the like on the surface of the segment are treated.
2) Constructing a bearing platform 3 at the cutting and chiseling positions of the track beds on the two sides of the subway track: the bearing platform 3 is lofted and processed on site according to the cutting size of the track bed 2, the bearing platform 3 is transported to the site by using a special flat car, the bearing platform 3 is hoisted in place, the 100mmM16 stainless steel expansion bolts 23 are anchored on the pipe sheets by using implanted concrete, the bearing platform 3 is further fixed, slurry is poured back at the joints, and the bearing platform 3 and the track bed 2 form a whole.
3) Drilling grouting holes 21 at the upper parts of two sides of the tunnel lining 1, arranging two rows of holes at each side, drilling 3 holes in each row, immediately driving a grouting perforated pipe 10 along the grouting holes 21 after each drilling hole forms a grouting hole 21, wherein the driving depth of the grouting perforated pipe 10 is 2m, injecting cement slurry, the grouting pressure is 0.3-0.5 Mpa, forming a grouting reinforced soil body 7 after the cement slurry is hardened, then injecting waterproof concrete at the position of the grouting hole 21 to form a sealing material 16, and the sealing material 16 has the function of preventing underground water from entering the tunnel lining 1 and preventing the cement slurry from leaking outwards.
4) Judging the reason causing the tunnel to float upwards, and calculating the anti-floating force F required by the single-ring tunnel segmentAnti-floatingIn this embodiment, the tunnel floats upwards due to the rising of the water level, and as shown in fig. 9, the calculation method is as follows:
4.1) calculating the effective weight G of the overlying soil column of the single-ring tunnel segmentSoil for soil，
4.2) calculating the dead weight G of the single-ring tunnel segmentFrom，
GFrom＝δπ(R2-r2)γc；
4.3) calculating the underground water buoyancy F suffered by the single-ring tunnel segmentFloating body，
FFloating body＝δπR2γw；
4.4) calculating the required anti-buoyancy FAnti-floating，
Wherein, γaIs the saturated volume weight of the soil body, gammawThe volume weight of water is shown, R is the outer diameter of the shield tunnel, h is the thickness of a soil layer on the pipeline, delta is the width of a single-ring segment, and R is the inner diameter of the shield tunnel; gamma rayfTaking 1.2 as the safe anti-floating coefficient of the shield tunnel in the using stage; gamma raySoil for soilTaking the weight coefficient of the overburden layer on the tunnel as 1.0; gamma rayFromTaking 1.0 as the self-weight item coefficient of the tunnel structure; gamma rayAnti-floatingTaking the coefficient of the anti-floating component of the anchor rod as 1.0.
5) According to the buoyancy F borne by the single-ring tunnel segmentFloating bodyValue calculation axial tension design value of single anchor rod 8, reinforcement of anchor rod 8 and anchorThe length of the rod 8 and the anchoring length of the anchoring body and the anchor rod 8 are as follows:
5.1) F calculated according to step 4Anti-floatingCalculating the axial tension standard value N of the anchor rodak，
Nak＝FAnti-floating；
5.2) according to the axial tension standard value NakCalculating the design value N of the axial tension of a single anchor rodt，
Nt＝γQNak，
In the formula, gammaQTaking the load element coefficient as 1.3;
5.3) calculating the section area A of the reinforcing steel bar of the anchor rods，
In the formula, KtThe safety factor of the tensile strength of the anchor rod body is increased; f. ofykThe standard value of the tensile strength of the steel bar is;
and according to the calculated sectional area A of the anchor rod reinforcing steel barsDetermining the number of actual matching anchor rod reinforcing steel bars;
5.4) calculating the length L between the formation and the anchora1And L between anchor body and anchor rod steel bara2，
Selecting La1And La2The larger value is used as the anchoring length L between the anchoring body and the anchor rod (8)a；
In the formula (f)mgThe standard value of the bonding strength between the stratum and the anchoring grouting body is obtained; f. ofmsThe standard value of the bonding strength between the steel bar and the anchoring grouting body is obtained; k is the anti-pulling safety coefficient of the anchor rod, and 2.0 is taken; d is the drilling diameter of the anchor rod anchoring section, and is taken as 150 mm; d is the diameter of the anchor rod steel bar and is determined according to actual reinforcement; n is the number of anchor rod reinforcing steel bars and is determined according to the actual reinforcing steel bars of each ring pipe sheet;
the coefficient is the reduction coefficient of the bonding strength of the section of the steel bar, and the value range is between 0.6 and 0.85; psi is the influence coefficient of anchor rod anchoring length to bonding strength, takes 1.0.
6) Drilling a track bed at the subway tunnel and setting an anchor rod 8 according to the parameters calculated in the step 5), wherein the specific method comprises the following steps:
6.1) paying off, positioning and respectively arranging at four corner points of a square with the side length of 60cm according to a planar arrangement principle, marking the position of an anchor rod, chiseling concrete according to a track bed concrete chiseling trace 29 to form a circular truncated cone-shaped groove, reducing the damage to a track bed reinforcing steel bar as much as possible during chiseling, forming a hole by using a down-the-hole hammer, wherein the aperture deviation is not more than 2cm, the depth deviation is not more than 1% of the designed depth, the positions of the track bed 2 and the tunnel lining 1 reinforcing steel bar are avoided during drilling, and the structure after hole forming is shown in an attached figure;
6.2) placing the anchor rod 8 which is manufactured in advance into the drilled hole, and performing grouting operation by adopting a secondary grouting mode and the grouting pressure of more than 1.0 Mpa;
6.3) after the grout is initially set to form grouting body 9, high-strength concrete is grouted back above the welding water stop steel plate 27 to fill the chiseling part of the ballast bed concrete, and the structure shown in the attached drawing 4 is formed.
7) Installing the steel ferrule 4 and the stiffening plate 5, wherein the installation method of the steel ferrule 4 and the stiffening plate 5 comprises the following steps:
7.1) arranging corresponding screw holes 24 on the tunnel lining 1 according to the positions of the screw holes of the steel sleeve, arranging 2 rows of screw holes on the duct piece of the tunnel lining 1 on the left side in a circumferential direction, wherein 6 screw holes are arranged in each row, and the same is true for the duct piece of the tunnel lining 1 on the right side;
7.2) selecting steel braces with the cross-sectional dimension of 20mm multiplied by 150mm from left and right arc-shaped steel plates, wherein the radian is consistent with that of the inner wall of the tunnel lining 1, selecting steel bars with the cross-sectional dimension of 20mm multiplied by 80mm from left and right stiffening plates, wherein the radian is consistent with that of the arc-shaped steel plates, welding the left stiffening plate 13 on the left arc-shaped steel plate 11, welding the right stiffening plate 14 on the right arc-shaped steel plate 12, and integrally welding the steel plates to ensure that a good stress system is formed, wherein the welding seams are subjected to groove welding and gas shielded welding simultaneously, the welding seam grade requires three grades (the surface of the steel before entering the field is subjected to anti-corrosion treatment, and the welding seams are subjected to anti-corrosion treatment again), hoisting the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12 to a specified position by using a manipulator, and anchoring the left arc-shaped steel;
7.3) connecting the connecting top plates 15 of the arc-shaped steel plates at two sides with each other by using split bolts 19;
7.4) fixing the left arc-shaped steel plate 11 and the left stiffening plate 13, and the right arc-shaped steel plate 12 and the right stiffening plate 14 on the bearing platforms 3 at two sides by adopting foundation bolts 17 respectively to form an inner reinforcing structure, as shown in the attached figure 2; after the left and right arc-shaped steel plates 11 and 12 form a complete rigid sleeve ring 4, the joints of the two sides of the rigid sleeve ring 4 and the segments of the tunnel lining 1 are plugged by epoxy cement, grouting holes and air outlet holes are reserved for plugging the two sides of the rigid sleeve ring 4, no less than 4 segments are arranged on each side, then a small electric grouting pump is used for injecting epoxy resin from bottom to top until the top reserved hole overflows resin to serve as a construction end mark, the grouting is repeatedly carried out, and finally facilities such as pipelines and drainage ditches are recovered.
With reference to the attached drawing 11, in the construction process, the deformation conditions of the tunnel, such as settlement, horizontal displacement, ovality, convergence and the like, are comprehensively monitored in real time, if sudden deformation change is found, a countermeasure is immediately taken, the positive value of the settlement amount represents upward floating, and the negative value represents settlement.
Example 3
When the operated subway tunnel floats upwards due to the unloading above the tunnel, the following steps are adopted for construction:
1) selecting a manipulator and a flat car for construction according to construction environments such as a limit of an operation line, a minimum radius of the line, a maximum gradient and the like; then, moving and modifying the internal pipeline of the shield tunnel, mainly shifting side brackets of strong and weak current, reforming lines and the like, and providing an effective action field for construction; then, the track bed 2 and the ditch on the two sides of the subway track are cut and chiseled until the shield segment is exposed, the side face of the track bed 2 is chiseled after cutting, the surface of the tunnel lining 1 is cleaned by a high-pressure water gun, and loose objects such as broken blocks, calcifications and the like on the surface of the segment are treated.
2) Constructing a bearing platform 3 at the cutting and chiseling positions of the track beds on the two sides of the subway track: the bearing platform 3 is lofted and processed on site according to the cutting size of the track bed 2, the bearing platform 3 is transported to the site by using a special flat car, the bearing platform 3 is hoisted in place, the 100mmM16 stainless steel expansion bolts 23 are anchored on the pipe sheets by using implanted concrete, the bearing platform 3 is further fixed, slurry is poured back at the joints, and the bearing platform 3 and the track bed 2 form a whole.
3) Drilling grouting holes 21 at the upper parts of two sides of the tunnel lining 1, arranging two rows of holes at each side, drilling 3 holes in each row, immediately driving a grouting perforated pipe 10 along the grouting holes 21 after each drilling hole forms a grouting hole 21, wherein the driving depth of the grouting perforated pipe 10 is 2m, injecting cement slurry, the grouting pressure is 0.3-0.5 Mpa, forming a grouting reinforced soil body 7 after the cement slurry is hardened, then injecting waterproof concrete at the position of the grouting hole 21 to form a sealing material 16, and the sealing material 16 has the function of preventing underground water from entering the tunnel lining 1 and preventing the cement slurry from leaking outwards.
4) Judging the reason causing the tunnel to float upwards, and calculating the anti-floating force F required by the single-ring tunnel segmentAnti-floatingIn this embodiment, the tunnel floats upwards due to the unloading above the tunnel, and as shown in fig. 10, the calculation method is as follows:
4.1) unloading load pd according to the coordinate (ξ) of any point at the bottom of the foundation pitξdηCalculating (x, y, z) at the tunnel axis0) Additional stress σ ofz，
In the formula (I), the compound is shown in the specification,
upsilon is Poisson's ratio; z is a radical of0The distance between the central line of the tunnel and the earth surface is taken as the distance; h is the excavation depth of the foundation pit;
4.2) for each ring of shield segments, assuming that the additional stress of each point at the axis is the same, the additional load F borne by each ring of shield segments due to foundation pit excavationAttachment(s)Is composed of
FAttachment(s)＝δRσz；
4.3) according to the balance relation of the force and the design specification of the tunnel,
Fanti-floating≥FAttachment(s)
Then take FAnti-floating＝FAttachment(s)。
5) According to the buoyancy F borne by the single-ring tunnel segmentFloating bodyThe value calculates the axial tension design value of single stock 8, 8 arrangement of reinforcement of stock, 8 length of stock, the anchor length of anchor body and stock 8, and concrete step is:
5.1) F calculated according to step 4Anti-floatingCalculating the axial tension standard value N of the anchor rodak，
Nak＝FAnti-floating；
5.2) according to the axial tension standard value NakCalculating the design value N of the axial tension of a single anchor rodt，
Nt＝γQNak，
In the formula, gammaQTaking the load element coefficient as 1.3;
5.3) calculating the section area A of the reinforcing steel bar of the anchor rods，
In the formula, KtThe safety factor of the tensile strength of the anchor rod body is increased; f. ofykThe standard value of the tensile strength of the steel bar is;
and according to the calculated sectional area A of the anchor rod reinforcing steel barsDetermining the number of actual matching anchor rod reinforcing steel bars;
5.4) calculating the length L between the formation and the anchora1And L between anchor body and anchor rod steel bara2，
Selecting La1And La2The larger value of the length L of the anchor body and the anchor rod 8a；
In the formula (f)mgThe standard value of the bonding strength between the stratum and the anchoring grouting body is obtained; f. ofmsThe standard value of the bonding strength between the steel bar and the anchoring grouting body is obtained; k is the anti-pulling safety coefficient of the anchor rod, and 2.0 is taken; d is the drilling diameter of the anchor rod anchoring section, and is taken as 150 mm; d is the diameter of the anchor rod steel bar and is determined according to actual reinforcement; n is the number of anchor rod reinforcing steel bars and is determined according to the actual reinforcing steel bars of each ring pipe sheet;
the coefficient is the reduction coefficient of the bonding strength of the section of the steel bar, and the value range is between 0.6 and 0.85; psi is the influence coefficient of anchor rod anchoring length to bonding strength, takes 1.0.
6) Drilling a track bed at the subway tunnel and setting an anchor rod 8 according to the parameters calculated in the step 5), wherein the specific method comprises the following steps:
6.1) paying off, positioning and respectively arranging at four corner points of a square with the side length of 60cm according to a planar arrangement principle, marking the position of an anchor rod, chiseling concrete according to a track bed concrete chiseling trace 29 to form a circular truncated cone-shaped groove, reducing the damage to a track bed reinforcing steel bar as much as possible during chiseling, forming a hole by using a down-the-hole hammer, wherein the aperture deviation is not more than 2cm, the depth deviation is not more than 1% of the designed depth, the positions of the track bed 2 and the tunnel lining 1 reinforcing steel bar are avoided during drilling, and the structure after hole forming is shown in an attached figure;
6.2) placing the anchor rod 8 which is manufactured in advance into the drilled hole, and performing grouting operation by adopting a secondary grouting mode and the grouting pressure of more than 1.0 Mpa;
6.3) after the grout is initially set to form grouting body 9, high-strength concrete is grouted back above the welding water stop steel plate 27 to fill the chiseling part of the ballast bed concrete, and the structure shown in the attached drawing 4 is formed.
7) Installing the steel ferrule 4 and the stiffening plate 5, wherein the installation method of the steel ferrule 4 and the stiffening plate 5 comprises the following steps:
7.1) arranging corresponding screw holes 24 on the tunnel lining 1 according to the positions of the screw holes of the steel sleeve, arranging 2 rows of screw holes on the duct piece of the tunnel lining 1 on the left side in a circumferential direction, wherein 6 screw holes are arranged in each row, and the same is true for the duct piece of the tunnel lining 1 on the right side;
7.2) selecting steel braces with the cross-sectional dimension of 20mm multiplied by 150mm from left and right arc-shaped steel plates, wherein the radian is consistent with that of the inner wall of the tunnel lining 1, selecting steel bars with the cross-sectional dimension of 20mm multiplied by 80mm from left and right stiffening plates, wherein the radian is consistent with that of the arc-shaped steel plates, welding the left stiffening plate 13 on the left arc-shaped steel plate 11, welding the right stiffening plate 14 on the right arc-shaped steel plate 12, and integrally welding the steel plates to ensure that a good stress system is formed, wherein the welding seams are subjected to groove welding and gas shielded welding simultaneously, the welding seam grade requires three grades (the surface of the steel before entering the field is subjected to anti-corrosion treatment, and the welding seams are subjected to anti-corrosion treatment again), hoisting the left arc-shaped steel plate 11 and the right arc-shaped steel plate 12 to a specified position by using a manipulator, and anchoring the left arc-shaped steel;
7.3) connecting the connecting top plates 15 of the arc-shaped steel plates at two sides with each other by using split bolts 19;
7.4) fixing the left arc-shaped steel plate 11 and the left stiffening plate 13, and the right arc-shaped steel plate 12 and the right stiffening plate 14 on the bearing platforms 3 at two sides by adopting foundation bolts 17 respectively to form an inner reinforcing structure, as shown in the attached figure 2; after the left and right arc-shaped steel plates 11 and 12 form a complete rigid sleeve ring 4, the joints of the two sides of the rigid sleeve ring 4 and the segments of the tunnel lining 1 are plugged by epoxy cement, grouting holes and air outlet holes are reserved for plugging the two sides of the rigid sleeve ring 4, no less than 4 segments are arranged on each side, then a small electric grouting pump is used for injecting epoxy resin from bottom to top until the top reserved hole overflows resin to serve as a construction end mark, the grouting is repeatedly carried out, and finally facilities such as pipelines and drainage ditches are recovered.
With reference to the attached drawing 11, in the construction process, the deformation conditions of the tunnel, such as settlement, horizontal displacement, ovality, convergence and the like, are comprehensively monitored in real time, if sudden deformation change is found, a countermeasure is immediately taken, the positive value of the settlement amount represents upward floating, and the negative value represents settlement.
The present invention has been described in detail with reference to the embodiments, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (10)
1. The utility model provides an anti reinforced structure that floats of operation subway tunnel, includes tunnel lining (1), and tunnel lining is inside to be equipped with ballast bed (2), and ballast bed (2) both sides are equipped with cushion cap (3), its characterized in that: an inner reinforcing structure is arranged inside the tunnel lining (1), and an outer reinforcing structure and an anti-floating structure are arranged outside the tunnel lining; the inner reinforcing structure comprises steel sleeves (4) and reinforcing plates (5) which are arranged at intervals, the reinforcing plates (5) are welded with the steel sleeves (4), the steel sleeves (4) are tightly attached to the inner surface of the tunnel lining (1) and are fixed with the tunnel lining (1) through wall-mounted expansion bolts (6), two sides of the steel sleeves (4) are plugged by epoxy cement, and a gap between the steel sleeves (4) and the tunnel lining (1) is filled by epoxy resin; the outer reinforcing structure comprises grouting reinforcing soil bodies (7), and the grouting reinforcing soil bodies (7) are symmetrically arranged at the upper parts of the two sides of the tunnel lining (1); anti floating structure include a plurality of stock (8), establish in tunnel lining (1) bottom stock (8), inside stock (8) top anchor income railway roadbed (2), be equipped with grout body (9) around stock (8) of the following part of tunnel lining (1).
2. The operated subway tunnel anti-floating reinforcement structure according to claim 1, characterized in that: the steel sleeve (4) comprises a left arc-shaped steel plate (11) and a right arc-shaped steel plate (12), and the stiffening plate (5) comprises a left stiffening plate (13) and a right stiffening plate (14); the radian of the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12) is the same as that of the inner side of the tunnel lining (1), the inner surface of the tunnel lining (1) is provided with a screw hole (24), the corresponding positions of the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12) are provided with screw holes, the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12) are arranged close to the inner surface of the tunnel lining (1), and the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12) are connected with the tunnel lining (1) through wall-hanging expansion bolts (6) penetrating through the; the left stiffening plate (13) is welded and connected along the central axis of the left arc-shaped steel plate (11), the right stiffening plate (14) is welded and connected along the central axis of the right arc-shaped steel plate (12), the top ends of the left stiffening plate (13) and the right stiffening plate (14) are respectively provided with a connecting top plate (15), and the connecting top plates (15) at the two sides are mutually connected through split bolts (19); bottom connecting plates (18) are welded at the bottoms of the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12), and the bottom connecting plates (18) are fixed on the upper surfaces of the bearing platforms (3) on the two sides through foundation bolts (17) matched with nuts.
3. The operated subway tunnel anti-floating reinforcement structure according to claim 1, characterized in that: the tunnel lining is characterized in that a plurality of grouting floral tubes (10) are arranged in the grouting reinforced soil body (7), the grouting floral tubes (10) in the grouting reinforced soil body (7) on two sides are bilaterally symmetrical, grouting holes (21) are formed in the positions, corresponding to the grouting floral tubes (10), on the left side and the right side of the tunnel lining (1), the grouting floral tubes (10) penetrate through the grouting holes (21) and are inserted into the reinforced soil body (7) on two sides of the tunnel lining (1), and the grouting holes (21) are filled with sealing materials (16) for plugging the grouting holes (21).
4. The operated subway tunnel anti-floating reinforcement structure according to claim 1, characterized in that: the anchor rod (8) comprises anchor rod main ribs (25), a plurality of anti-floating reinforcing ribs (26), a water stop steel plate (27) and a steel bar positioner (28); the anchor rod main rib (25) penetrates through the water stop steel plate (27), the bottom end of the anti-floating reinforcing rib (26) is welded at the junction of the anchor rod main rib (25) and the water stop steel plate (27), the water stop steel plate (27) is buried in the ballast bed (2) and is welded with ballast bed reinforcing steel bars (20), and the reinforcing steel bar positioner (28) is welded on the anchor rod main rib (25) of the part below the tunnel lining (1); the anchor rod main rib (25) and the anti-floating reinforcing rib (26) are respectively provided with a bending part at the top end, the bottom end of the anti-floating reinforcing rib (26) is provided with an overlap joint part parallel to the anchor rod main rib (25), the length of the bending part is at least 15 times of the diameter of the anchor rod main rib (25) or the anti-floating reinforcing rib (26), and the length of the overlap joint part is at least 55 times of the diameter of the anti-floating reinforcing rib (26).
5. A construction method of the operated subway tunnel anti-floating reinforcement structure of claim 1, characterized in that: which comprises the following steps:
1) cutting and chiseling the ballast beds and the ditches on the two sides of the subway track until shield segments are exposed;
2) constructing bearing platforms (3) at the cutting and chiseling positions of the track beds on the two sides of the subway track;
3) drilling grouting holes (21) at the upper positions of the two sides of the tunnel lining (1), driving a grouting perforated pipe (10) along the grouting holes (21) immediately after each drilling hole forms one grouting hole (21), injecting cement paste, forming a grouting reinforced soil body (7) after hardening, and then injecting waterproof concrete at the grouting hole positions to form a sealing material (16);
4) judging the reason causing the tunnel to float upwards, and calculating the anti-floating force F required by the single-ring tunnel segmentAnti-floating；
5) According to the buoyancy F borne by the single-ring tunnel segmentFloating bodyCalculating the axial tension design value of a single anchor rod (8), the reinforcement of the anchor rod (8), the length of the anchor rod (8) and the anchoring length of an anchoring body and the anchor rod (8);
6) drilling a track bed at the subway tunnel and setting an anchor rod (8) according to the parameters calculated in the step 5);
7) and (5) installing the steel ferrule (4) and the stiffening plate.
6. The construction method of the operated subway tunnel anti-floating reinforcement structure according to claim 5, characterized in that: the step 4) is the floating of the tunnel caused by the rising of underground water and the anti-floating force F required by the single-ring tunnel segmentAnti-floatingThe calculation steps are as follows:
4.1) calculating the effective weight G of the overlying soil column of the single-ring tunnel segmentSoil for soil，
4.2) calculating the dead weight G of the single-ring tunnel segmentFrom，
GFrom＝δπ(R2-r2)γc；
4.3) calculation of Single Ring TunnelGroundwater buoyancy F suffered by pipe pieceFloating body，
FFloating body＝δπR2γw；
4.4) calculating the required anti-buoyancy FAnti-floating，
Wherein, γaIs the saturated volume weight of the soil body, gammawThe volume weight of water is shown, R is the outer diameter of the shield tunnel, h is the thickness of a soil layer on the pipeline, delta is the width of a single-ring segment, and R is the inner diameter of the shield tunnel; gamma rayfTaking 1.2 as the safe anti-floating coefficient of the shield tunnel in the using stage; gamma raySoil for soilTaking the weight coefficient of the overburden layer on the tunnel as 1.0; gamma rayFromTaking 1.0 as the self-weight item coefficient of the tunnel structure; gamma rayAnti-floatingTaking the coefficient of the anti-floating component of the anchor rod as 1.0.
7. The construction method of the operated subway tunnel anti-floating reinforcement structure according to claim 5, characterized in that: the step 4) causes the tunnel to float up for the unloading above the tunnel, and the anti-floating force F required by the single-ring tunnel segmentAnti-floatingThe calculation steps are as follows:
4.1) unloading load pd according to the coordinate (ξ) of any point at the bottom of the foundation pitξdηCalculating (x, y, z) at the tunnel axis0) Additional stress σ ofz，
In the formula (I), the compound is shown in the specification,
upsilon is Poisson's ratio; z is a radical of0The distance between the central line of the tunnel and the earth surface is taken as the distance; h is the excavation depth of the foundation pit;
4.2) for each ring of shield segments, assuming that the additional stress of each point at the axis is the same, the additional load F borne by each ring of shield segments due to foundation pit excavationAttachment(s)Is composed of
FAttachment(s)＝δRσz；
4.3) according to the balance relation of the forces and the design specification of the tunnel, taking FAnti-floating＝FAttachment(s)。
8. The construction method of the operated subway tunnel anti-floating reinforcement structure according to claim 5, characterized in that: the specific steps of the step 5) are as follows:
5.1) F calculated according to step 4Anti-floatingCalculating the axial tension standard value N of the anchor rodak，
Nak＝FAnti-floating；
5.2) according to the axial tension standard value NakCalculating the design value N of the axial tension of a single anchor rodt，
Nt＝γQNak，
In the formula, gammaQTaking the load element coefficient as 1.3;
5.3) calculating the section area A of the reinforcing steel bar of the anchor rods，
In the formula, KtThe safety factor of the tensile strength of the anchor rod body is increased; f. ofykThe standard value of the tensile strength of the steel bar is;
and according to the calculated sectional area A of the anchor rod reinforcing steel barsDetermining the number of actual matching anchor rod reinforcing steel bars;
5.4) calculating the length L between the formation and the anchora1And L between anchor body and anchor rod steel bara2，
Selecting La1And La2The larger value is used as the anchoring length L between the anchoring body and the anchor rod (8)a；
In the formula (f)mgThe standard value of the bonding strength between the stratum and the anchoring grouting body is obtained; f. ofmsThe standard value of the bonding strength between the steel bar and the anchoring grouting body is obtained; k is the anti-pulling safety coefficient of the anchor rod, and 2.0 is taken; d is the drilling diameter of the anchor rod anchoring section, and is taken as 150 mm; d is the diameter of the anchor rod steel bar and is determined according to actual reinforcement; n is the number of anchor rod reinforcing steel bars and is determined according to the actual reinforcing steel bars of each ring pipe sheet;the coefficient is the reduction coefficient of the bonding strength of the section of the steel bar, and the value range is between 0.6 and 0.85; psi is the influence coefficient of anchor rod anchoring length to bonding strength, takes 1.0.
9. The construction method of the operated subway tunnel anti-floating reinforcement structure according to claim 5, characterized in that: the installation steps of the anchor rod (8) in the step 6) are as follows:
6.1) chiseling concrete according to the track bed concrete chiseling trace (29), and then forming holes by using a down-the-hole hammer;
6.2) placing the anchor rod (8) which is manufactured in advance into the drilled hole, and grouting in a secondary grouting mode;
6.3) after the slurry is initially set, recharging the high-strength concrete and filling the chiseling part of the ballast bed concrete.
10. The construction method of the operated subway tunnel anti-floating reinforcement structure according to claim 5, characterized in that: the step 7) of mounting the steel ferrule (4) and the stiffening plate (5) comprises the following steps:
7.1) arranging corresponding screw holes (24) on the tunnel lining (1) according to the positions of the screw holes of the steel sleeve ring;
7.2) welding the left stiffening plate (13) on the left arc-shaped steel plate (11), welding the right stiffening plate (14) on the right arc-shaped steel plate (12), hoisting the left arc-shaped steel plate (11) and the right arc-shaped steel plate (12) to specified positions, and anchoring the left arc-shaped steel plate (11) and the right stiffening plate (14) on the tunnel lining (1) by using wall-hanging expansion bolts (6);
7.3) connecting the connecting top plates (15) of the arc-shaped steel plates at the two sides with each other by using split bolts (19);
7.4) fixing the left arc-shaped steel plate (11) and the left stiffening plate (13) and the right arc-shaped steel plate (12) and the right stiffening plate (14) on the bearing platforms (3) at two sides by adopting foundation bolts (17) respectively.
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| CN201911184264.6A CN110836121A (en) | 2019-11-27 | 2019-11-27 | Anti-floating reinforcing structure of operated subway tunnel and construction method |
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| CN111428304A (en) * | 2020-03-31 | 2020-07-17 | 浙江大学城市学院 | Displacement deformation prediction method for shield tunnel with anti-floating anchor rod under excavation of foundation pit |
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| CN113137273A (en) * | 2021-04-08 | 2021-07-20 | 苏州中车建设工程有限公司 | Large-diameter shield tunnel deformation control structure and construction method thereof |
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| CN113137273A (en) * | 2021-04-08 | 2021-07-20 | 苏州中车建设工程有限公司 | Large-diameter shield tunnel deformation control structure and construction method thereof |
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