CN113482671A - Construction method for restraining sinking amount of primary support of tunnel based on step method excavation - Google Patents
Construction method for restraining sinking amount of primary support of tunnel based on step method excavation Download PDFInfo
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- CN113482671A CN113482671A CN202110973601.0A CN202110973601A CN113482671A CN 113482671 A CN113482671 A CN 113482671A CN 202110973601 A CN202110973601 A CN 202110973601A CN 113482671 A CN113482671 A CN 113482671A
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- 238000010276 construction Methods 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000009412 basement excavation Methods 0.000 title claims abstract description 26
- 230000000452 restraining effect Effects 0.000 title claims abstract description 19
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 131
- 239000010959 steel Substances 0.000 claims abstract description 131
- 230000002787 reinforcement Effects 0.000 claims abstract description 42
- 239000011435 rock Substances 0.000 claims abstract description 28
- 238000009415 formwork Methods 0.000 claims abstract description 18
- 230000003014 reinforcing effect Effects 0.000 claims description 141
- 239000007788 liquid Substances 0.000 claims description 9
- 239000002002 slurry Substances 0.000 claims description 8
- 230000001681 protective effect Effects 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims 1
- 238000000465 moulding Methods 0.000 claims 1
- 230000002829 reductive effect Effects 0.000 abstract description 10
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 25
- 230000000670 limiting effect Effects 0.000 description 13
- 238000009434 installation Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 239000012530 fluid Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 241001391944 Commicarpus scandens Species 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 235000019353 potassium silicate Nutrition 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000003756 stirring 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
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
- E21D11/183—Supporting means for arch members, not provided for in E21D11/22
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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
- 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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- 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
- E21D21/008—Anchoring or tensioning means
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Abstract
本发明公开了一种基于台阶法开挖的抑制隧道初期支护下沉量的施工方法，该方法包括：一、安装定位钢拱架；二、安装锁脚锚杆并注浆；三、扩挖；四、安装并固定连接垫板；五、搭设加固层支撑模板体系并浇筑。本发明在所述加固层支撑模板体系浇筑完成后，在所述钢拱架的底部形成加固层结构，可将加固层结构作为加强型底纵梁，将拱架间有效连接起来，用以提高初期支护纵向刚度及整体性，提高上部衬砌结构的承载能力。利用所述锁脚锚杆在所述围岩内加固块，对所述钢拱架的外侧面进行加固；抑制了隧道初期支护竖向沉降及收敛，进而控制了围岩松动圈的规模，减少了衬砌结构所承担的围岩荷载，降低工程建设成本。
The invention discloses a construction method for restraining the initial support subsidence of a tunnel based on excavation by a step method. The method includes: first, installing a positioning steel arch; second, installing a locking anchor rod and grouting; third, expanding Dig; 4. Install and fix the connecting backing plate; 5. Set up the reinforcement layer to support the formwork system and pour it. In the present invention, after the reinforced layer supporting formwork system is poured, a reinforced layer structure is formed at the bottom of the steel arch frame, and the reinforced layer structure can be used as a reinforced bottom longitudinal beam to effectively connect the arch frames to improve the The longitudinal stiffness and integrity of the initial support improve the bearing capacity of the upper lining structure. The outer side of the steel arch frame is reinforced by using the locking foot bolt to reinforce the block in the surrounding rock; the vertical settlement and convergence of the initial support of the tunnel are suppressed, and the scale of the loose circle of the surrounding rock is controlled. The surrounding rock load borne by the lining structure is reduced, and the engineering construction cost is reduced.
Description
Technical Field
The invention belongs to the technical field of supporting of tunnels and underground engineering, and particularly relates to a construction method for restraining sinking of primary supporting of a tunnel based on step excavation.
Background
With the continuous expansion of the quantity and scale of tunnel projects in China, excavated tunnels mainly penetrate through soil, weak surrounding rocks, fault broken zones and other sections with poor foundation bearing capacity, and when tunnel construction is carried out under the geological condition, the defects of longitudinal cracks, longitudinal cracks of lining structures and the like caused by the fact that an inverted arch fills a top surface and bulges can be caused, and even major safety accidents such as instability of an inverted slope at a tunnel opening can be caused. The reason is caused by excessive vertical settlement of primary support, so that the research and development of stability of arch springing and wall feet and settlement control measures are gradually paid attention to by people.
In order to solve the problem, the arrangement of a locking anchor pipe at an arch springing or a wall footing is one of effective measures for controlling vertical settlement. Due to the difference of the on-site construction level, the construction angle of the lock pin anchor pipe and the connection reliability of the lock pin anchor pipe and the profile steel arch pin cannot be guaranteed. In addition, the steel arch frame and the lock leg anchor pipe are welded together by adopting the straight connecting ribs, and the contact area between the connecting ribs and the lock leg anchor pipe is small, the wall of the lock leg anchor pipe is thin, the steel pipe is easy to break down during welding, and the welding part of the connecting ribs and the lock leg anchor pipe is easy to break during stress, so that the effect of the anchor pipe is ineffective. Therefore, a construction method capable of effectively suppressing the sinking amount of the preliminary bracing of the tunnel is provided.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a construction method for restraining sinking of a primary support of a tunnel based on a step-wise excavation method, after the pouring of the reinforcing layer supporting template system is completed, a reinforcing layer structure is formed at the bottom of the steel arch frame, the reinforcing layer structure can be used as a reinforced bottom longitudinal beam, and the arch frames are effectively connected together to improve the longitudinal rigidity and integrity of the primary support and improve the bearing capacity of an upper lining structure. Reinforcing the outer side surface of the steel arch frame by using the foot locking anchor rod reinforcing block in the surrounding rock; vertical settlement and convergence of primary support of the tunnel are inhibited, the scale of the surrounding rock loosening ring is further controlled, the surrounding rock load borne by the lining structure is reduced, and the engineering construction cost is reduced.
In order to solve the technical problems, the invention adopts the technical scheme that: the construction method for restraining the sinking amount of the primary support of the tunnel based on the step method comprises the steps of excavating and supporting the tunnel, constructing the tunnel from back to front along the longitudinal extension direction of the tunnel, and enabling a transverse channel of the tunnel to comprise an upper step, a middle step arranged below the upper step and a lower step arranged at the bottom of the tunnel and below the middle step; when the transverse channel of the tunnel is excavated, firstly excavating and supporting the upper step, then excavating and supporting the middle step, and finally excavating and supporting the lower step, wherein the supporting structure of each step forms a primary supporting structure for supporting the tunnel;
the method is characterized in that the supporting method of each step is the same, and the method for supporting any step comprises the following steps:
step one, installing and positioning a steel arch frame: erecting a plurality of groups of positioning steel arches along the longitudinal extension direction of the tunnel, wherein the plurality of groups of positioning steel arches are uniformly distributed along the longitudinal extension direction of the tunnel;
the positioning steel arch comprises a steel arch erected on the inner side surface of the step and two groups of directional pipe groups obliquely arranged at the bottom of the steel arch, and the steel arch and the two groups of directional pipe groups are integrally formed; the longitudinal section shape of the steel arch is matched with that of the step;
the directional guide pipe group comprises two directional guide pipes which are symmetrically arranged on the same side of the steel arch frame, the two directional guide pipes are obliquely arranged on the front side and the rear side of the bottom of the steel arch frame, the directional guide pipes are fixed on the steel arch frame through a plurality of limiting reinforcing steel bars, the directional guide pipes are of a hollow structure, and the directional guide pipes are gradually inclined downwards along the direction far away from the central axis of the tunnel;
step two, installing a foot locking anchor rod and grouting: inserting a foot locking anchor rod into the directional guide pipe, wherein the end part of the foot locking anchor rod extending into the directional guide pipe penetrates through the directional guide pipe and then extends into the surrounding rock, and the other end of the foot locking anchor rod extends to the inner side of the step;
a grouting mechanism is arranged at the end part of the foot locking anchor rod positioned on the inner side of the tunnel, the grouting mechanism is utilized to perform grouting on the foot locking anchor rod, and a reinforcing block is formed at the end part of the foot locking anchor rod positioned in the surrounding rock;
after grouting, the grouting mechanism is dismantled;
step three, expanding and digging: manually carrying out expanding excavation on the outer side of the bottom of the step, forming a reinforcing cavity with a right trapezoid longitudinal section at the bottom of the step, wherein the reinforcing cavity is distributed along the longitudinal extension direction of the tunnel; the bottom surface of the reinforcing cavity and the bottom surface of the steel arch in the step are distributed in the same horizontal plane;
step four, mounting and fixedly connecting the base plate: horizontally installing a connecting base plate on the bottom surface of the reinforcing cavity, wherein the connecting base plate is arranged at the bottom of the steel arch frame, the cross section area of the connecting base plate is larger than that of the steel arch frame, and the connecting base plate is fixed at the bottom of the reinforcing cavity through a plurality of fixing pieces;
step five, building a reinforcing layer supporting template system and pouring: and erecting a reinforcing layer supporting template system in the reinforcing cavity, pouring concrete in the reinforcing layer supporting template system after the erection is finished, and forming a reinforcing layer structure after the concrete is solidified.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: in the first step, the end part of the directional guide pipe extending into the surrounding rock is flush with the bottom of the step; the inner diameter of the directional guide pipe is larger than the outer diameter of the foot locking anchor rod.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: in the first step, the number of the limiting reinforcing steel bars is two, the two directional guide pipes are sleeved in the limiting reinforcing steel bars, and one limiting reinforcing steel bar is arranged on the inner side of the tunnel and fixed at the connecting part of the directional guide pipes and the steel arch frame; and the other limiting steel bar is arranged on one side of the steel arch frame far away from the tunnel and is fixed at the joint of the directional guide pipe and the steel arch frame.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: in the fifth step, the reinforcing layer supporting template system comprises a reinforcing layer template structure arranged in the reinforcing cavity and a reinforcing layer supporting structure vertically arranged in the reinforcing layer template structure;
the reinforcing layer template structure comprises a plurality of reinforcing bottom plates which are horizontally arranged at the bottoms of the reinforcing cavities and reinforcing side plates which are vertically arranged on one sides of the reinforcing bottom plates and are arranged on the inner sides of the tunnels, and the reinforcing bottom plates and the reinforcing side plates are integrally formed; the reinforced bottom plate, the reinforced side plates and the inner wall of the tunnel are enclosed into a concrete forming cavity with a right trapezoid longitudinal section.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: the plurality of reinforcing bottom plates and the connecting gasket plates are uniformly arranged in the same horizontal plane; one side of the reinforcing side plate, which is far away from the concrete forming cavity, is vertically provided with a plurality of reinforcing rods, and the plurality of reinforcing rods are uniformly distributed along the longitudinal extension direction of the tunnel.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: the reinforcing layer supporting structure is arranged in the concrete forming cavity and comprises a longitudinal steel bar group arranged at the bottom of the steel arch frame and arranged in the reinforcing cavity and a circumferential steel bar group sleeved on the longitudinal steel bar group, and the longitudinal steel bar group and the circumferential steel bar group are integrally formed;
the longitudinal reinforcing steel bar group comprises a plurality of reinforcing layer longitudinal reinforcing steel bars which are arranged along the longitudinal extension direction of the tunnel, and the plurality of reinforcing layer longitudinal reinforcing steel bars are uniformly distributed on the inner side and the outer side of the steel arch frame;
the circumferential reinforcing steel bar group comprises a plurality of reinforcing layer circumferential reinforcing steel bars sleeved on the longitudinal reinforcing steel bar group, and the plurality of reinforcing layer circumferential reinforcing steel bars are distributed along the extending direction of the reinforcing layer longitudinal reinforcing steel bars; the reinforcing layer hoop reinforcing steel bars are of a right-angle trapezoid structure, and the reinforcing layer longitudinal reinforcing steel bars are arranged at four top corners of the reinforcing layer hoop reinforcing steel bars.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: the grouting mechanism comprises a stop valve, a three-way pipe, a double-liquid grouting machine and a grouting pipe, wherein the stop valve is arranged on the inner side of the tunnel and is arranged at the end part of the foot locking anchor rod, the three-way pipe is communicated with the stop valve, the double-liquid grouting machine is arranged in the tunnel and is used for grouting into the foot locking anchor rod, and the grouting pipe is connected with the three-way pipe and the double-liquid grouting machine.
The construction method for restraining the sinking amount of the primary support of the tunnel based on the step excavation is characterized by comprising the following steps of: the outside cover of connecting the backing plate is equipped with the safety cover, connect the backing plate with the safety cover encloses into confined cuboid region.
Compared with the prior art, the invention has the following advantages:
1. the directional guide pipe is arranged for subsequent installation of the foot-locking anchor rod, the directional guide pipe and the steel arch frame are fixedly connected into a whole, the installation position of the foot-locking anchor rod is determined in advance, the deviation of the position of the foot-locking anchor rod caused in construction is avoided, the construction angle of the foot-locking anchor rod is ensured, the function of the foot-locking anchor rod is better exerted, and the function of inhibiting the vertical settlement of the tunnel is better exerted.
2. According to the invention, the bottom bearing area of the lining structure can be increased by digging the reinforcing cavity at the bottom of the steel arch frame, and the sinking amount of the primary support of the tunnel can be inhibited.
3. The invention can control early settlement by utilizing the connecting backing plate arranged at the bottom of the steel arch frame, and the connecting backing plate can be repeatedly used; meanwhile, the mounting position of the lower first-layer step steel arch can be accurately positioned by utilizing the connecting base plate, so that the connection and fixation of the steel arches in the upper and lower steps are facilitated.
4. After the reinforcing layer supporting template system is poured, a reinforcing layer structure is formed at the bottom of the steel arch frame, the reinforcing layer structure can be used as a reinforced bottom longitudinal beam, and the arch frames are effectively connected together, so that the longitudinal rigidity and integrity of the primary support are improved, and the bearing capacity of the upper lining structure is improved.
5. The construction method is simple, and the outer side surface of the steel arch is reinforced by the reinforcing blocks of the foot-locking anchor rods in the surrounding rock; the reinforcing layer supporting formwork system is utilized to pour at the bottom of the steel arch frame, a reinforcing layer structure is formed, the bottom of the steel arch frame is reinforced, vertical settlement and convergence of primary tunnel support are restrained, the scale of a surrounding rock loosening ring is controlled, surrounding rock load borne by a lining structure is reduced, and engineering construction cost is reduced.
In summary, after the reinforcing layer supporting template system is poured, a reinforcing layer structure is formed at the bottom of the steel arch frame, and the reinforcing layer structure can be used as a reinforced bottom longitudinal beam to effectively connect the arch frames, so that the longitudinal rigidity and integrity of the primary support are improved, and the bearing capacity of the upper lining structure is improved. Reinforcing the outer side surface of the steel arch frame by using the foot locking anchor rod reinforcing block in the surrounding rock; vertical settlement and convergence of primary support of the tunnel are inhibited, the scale of the surrounding rock loosening ring is further controlled, the surrounding rock load borne by the lining structure is reduced, and the engineering construction cost is reduced.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic view of the construction state of installing and positioning steel arch frames and foot-locking anchor rods during the construction of an upper step.
Fig. 2 is a schematic view of the construction state of the foot-locking anchor rod during pouring of the foot-locking anchor rod during upper step construction.
FIG. 3 is a schematic view of a construction state of a reinforcing layer structure poured during the construction of an upper step.
FIG. 4 is a schematic view of the construction effect forming of the present invention.
FIG. 5 is a schematic view showing the connection relationship between the reinforcing layer supporting formwork system and the positioning steel arch according to the present invention.
FIG. 6 is a schematic view showing the connection relationship between the reinforcing rods, the reinforcing layer supporting formwork system and the positioning steel arch according to the present invention
FIG. 7 is a flow chart of the present invention.
Description of reference numerals:
1, going up a step; 2-middle step; 3, descending a step;
4-steel arch centering; 5-reinforcing blocks;
6, locking the anchor rod; 7-double-fluid grouting machine; 8, grouting pipes;
9-a directional catheter; 10-limiting steel bars; 11-connecting the backing plate;
12-reinforcing the side plates; 13-a fixing member; 14-reinforcing the bottom plate;
15-reinforcing layer longitudinal steel bars; 16-reinforcing layer circumferential reinforcing steel bars; 17-a protective cover;
18-a reinforcement bar; 19-a stop valve; 20-surrounding rock;
21-reinforcing layer structure; 22-cement mixing tank; 23-a water glass grouting tank;
24-three-way pipe.
Detailed Description
As shown in fig. 1 to 7, the construction method for restraining the sinking amount of the primary support of the tunnel based on the step-wise excavation adopts the step-wise excavation and support of the tunnel, the tunnel is constructed from back to front along the longitudinal extension direction of the tunnel, and the transverse channel of the tunnel comprises an upper step 1, a middle step 2 arranged below the upper step 1, and a lower step 3 arranged at the bottom of the tunnel and arranged below the middle step 2; when a transverse channel of the tunnel is excavated, firstly excavating and supporting an upper step 1, then excavating and supporting a middle step 2, and finally excavating and supporting a lower step 3, wherein the supporting structure of each step forms a primary supporting structure for supporting the tunnel;
the supporting method of each step is the same, and the method for supporting any step comprises the following steps:
step one, installing and positioning a steel arch frame: erecting a plurality of groups of positioning steel arches along the longitudinal extension direction of the tunnel, wherein the plurality of groups of positioning steel arches are uniformly distributed along the longitudinal extension direction of the tunnel;
the positioning steel arch comprises a steel arch 4 erected on the inner side surface of the step and two groups of directional pipe tube groups obliquely arranged at the bottom of the steel arch 4, and the steel arch 4 and the two groups of directional pipe tube groups are integrally formed; the longitudinal section shape of the steel arch frame 4 is matched with that of the step;
the directional conduit pipe group comprises two directional conduits 9 symmetrically arranged on the same side of the steel arch frame 4, the two directional conduits 9 are obliquely arranged on the front side and the rear side of the bottom of the steel arch frame 4, the directional conduits 9 are fixed on the steel arch frame 4 through a plurality of limiting reinforcing steel bars 10, the directional conduits 9 are of a hollow structure, and the directional conduits 9 gradually incline downwards along the direction far away from the central axis of the tunnel;
step two, installing a foot locking anchor rod and grouting: a foot-locking anchor rod 6 is inserted into the directional guide pipe 9, the end part of the foot-locking anchor rod 6, which extends into the directional guide pipe 9, passes through the directional guide pipe 9 and then extends into the surrounding rock 20, and the other end of the foot-locking anchor rod 6 extends to the inner side of the step;
installing a grouting mechanism on the end part of the foot-locking anchor rod 6 positioned on the inner side of the tunnel, grouting into the foot-locking anchor rod 6 by using the grouting mechanism, and forming a reinforcing block 5 at the end part of the foot-locking anchor rod 6 positioned in the surrounding rock 20;
after grouting, the grouting mechanism is dismantled;
step three, expanding and digging: manually carrying out expanding excavation on the outer side of the bottom of the step, forming a reinforcing cavity with a right trapezoid longitudinal section at the bottom of the step, wherein the reinforcing cavity is distributed along the longitudinal extension direction of the tunnel; the bottom surface of the reinforcing cavity and the bottom surface of the steel arch frame 4 in the step are arranged in the same horizontal plane;
step four, mounting and fixedly connecting the base plate: a connecting backing plate 11 is horizontally arranged on the bottom surface of the reinforcing cavity, the connecting backing plate 11 is arranged at the bottom of the steel arch frame 4, the cross section area of the connecting backing plate 11 is larger than that of the steel arch frame 4, and the connecting backing plate 11 is fixed at the bottom of the reinforcing cavity through a plurality of fixing pieces 13;
step five, building a reinforcing layer supporting template system and pouring: and erecting a reinforcing layer supporting template system in the reinforcing cavity, pouring concrete in the reinforcing layer supporting template system after the erection is finished, and forming a reinforcing layer structure 21 after the concrete is solidified.
During actual use, the directional guide pipe 9 is arranged for subsequent installation of the foot locking anchor rod 6, the directional guide pipe 9 and the steel arch frame 4 are fixedly connected into a whole, the installation position of the foot locking anchor rod 6 is determined in advance, the deviation of the position of the foot locking anchor rod 6 caused in construction is avoided, the construction angle of the foot locking anchor rod 6 is guaranteed, the effect of the foot locking anchor rod 6 is better played, and the effect of inhibiting the vertical settlement of a tunnel is better played.
And a reinforcing cavity is expanded and dug at the bottom of the steel arch frame 4, so that the bearing area of the bottom of the lining structure can be increased, and the sinking amount of the primary support of the tunnel can be inhibited.
In addition, the early settlement can be controlled by using the connecting backing plate 11 arranged at the bottom of the steel arch frame 4, and the connecting backing plate 11 can be repeatedly used; as shown in fig. 6, the connecting pad 11 can be used to accurately position the mounting position of the lower first-layer step steel arch 4, so as to facilitate the connection and fixation of the steel arch 4 in the upper and lower steps.
According to the invention, after the reinforcing layer supporting template system is poured, the reinforcing layer structure 21 is formed at the bottom of the steel arch frame 4, the reinforcing layer structure 21 can be used as a reinforced bottom longitudinal beam, and the arch frames are effectively connected together, so that the longitudinal rigidity and integrity of the primary support are improved, and the bearing capacity of the upper lining structure is improved.
The construction method is simple, and the outer side surface of the steel arch frame 4 is reinforced by the reinforcing blocks 5 in the surrounding rock 20 through the foot locking anchor rods 6; the reinforcing layer supporting template system is utilized to pour at the bottom of the steel arch frame 4, the reinforcing layer structure 21 is formed, the bottom of the steel arch frame 4 is reinforced, vertical settlement and convergence of primary tunnel support are inhibited, the scale of the loose circle of the surrounding rock 20 is controlled, the surrounding rock load borne by the lining structure is reduced, and the engineering construction cost is reduced.
It should be noted that an included angle exists between the central axis of the directional duct 9 and the vertical central line of the steel arch frame 4, and the included angle is determined according to the field construction condition in the construction process of each step, as shown in fig. 1 to 4, in the construction process of the upper step 1, the included angle between the central axis of the directional duct 9 and the vertical central line of the steel arch frame 4 is 30 degrees; in the construction process of the middle step 2, an included angle between the central axis of the directional conduit 9 and the vertical central line of the steel arch frame 4 is 45 degrees; in the construction process of the lower step 3, the included angle between the central axis of the directional conduit 9 and the vertical central line of the steel arch frame 4 is 30 degrees. During the in-service use, connecting backing plate 11 can select strong plastic slab, steel sheet or plank to make, connecting backing plate 11 is last to be seted up a plurality of confessions the through-hole of mounting 13 installation.
In particular, the inner diameter of the directional guide tube 9 is larger than the inner diameter of the locking pin anchor rod 6, and the inner diameter of the directional guide tube 9 only needs to be capable of inserting the locking pin anchor rod 6. The installation position of the foot-locking anchor rod 6 is determined in advance according to the directional guide pipe 9, the construction angle of the foot-locking anchor rod 6 is ensured, and the function of the foot-locking anchor rod 6 is better exerted. And reinforcing the outer side surface of the steel arch frame 4 by using the foot-locking anchor rod 6 and the reinforcing block 5 in the surrounding rock 20.
As shown in fig. 6, the connecting pad 11 can accurately position the installation position of the lower first-layer step steel arch 4, connect the steel arches 4 in the upper and lower two-layer steps, and remove the connecting pad 11 after the positioning steel arches in the lower step are installed.
In the present embodiment, as shown in fig. 1 to 5, in step one, the end of the guiding pipe 9 extending into the surrounding rock 20 is flush with the bottom of the step; the inner diameter of the directional guide pipe 9 is larger than the outer diameter of the locking pin anchor rod 6.
During the in-service use, directional pipe 9's main effect is for follow-up installation lock foot stock 6, will directional pipe 9 and steel bow member 4 fixed connection are as an organic whole, confirm in advance equivalently the mounted position of lock foot stock 6 avoids installing lock foot stock 6 in the construction, causes the skew of lock foot stock 6 position, has played its effect that restraines the vertical settlement of tunnel better.
In this embodiment, in the first step, the number of the limiting steel bars 10 is two, the two directional guide tubes 9 are both sleeved in the limiting steel bars 10, and one limiting steel bar 10 is arranged on the inner side of the tunnel and fixed at the connection position of the directional guide tube 9 and the steel arch frame 4; the other limiting steel bar 10 is arranged on one side of the steel arch frame 4 far away from the tunnel and is fixed at the joint of the directional guide pipe 9 and the steel arch frame 4.
In actual use, the limiting steel bars 10 fix the two directional guide pipes 9 on the front side and the rear side of the steel arch frame 4; the limiting steel bars 10 and the directional guide pipes 9 are integrally processed with the steel arch frame 4 through welding. In addition, the directional guide pipe 9 and the steel arch frame 4 are pre-welded in a steel bar processing factory in advance through the limiting steel bars 10, the quality is controllable, the construction and installation are simple and convenient, and the field construction time in the tunnel is shortened.
As shown in fig. 5 and 6, in the fifth embodiment, in step five, the reinforcement layer supporting formwork system includes a reinforcement layer formwork structure disposed in the reinforcement cavity and a reinforcement layer supporting structure vertically disposed in the reinforcement layer formwork structure;
the reinforcing layer template structure comprises a plurality of reinforcing bottom plates 14 which are horizontally arranged at the bottoms of the reinforcing cavities and reinforcing side plates 12 which are vertically arranged on one sides of the reinforcing bottom plates 14 and are arranged on the inner sides of the tunnels, and the reinforcing bottom plates 14 and the reinforcing side plates 12 are integrally formed; the reinforced bottom plate 14, the reinforced side plates 12 and the inner wall of the tunnel are enclosed to form a concrete forming cavity with a right trapezoid longitudinal section.
During actual use, the reinforcing layer template structure is arranged at the bottom of the steel arch frame 4, and the reinforcing layer supporting structure is arranged in the reinforcing layer template structure to strengthen the stability of the steel arch frame 4, strengthen the longitudinal rigidity and integrity of primary support, effectively control the generation of ground surface annular cracks and primary support inclined cracks of a shallow buried section of the cave opening and improve the stability of the upward slope of the cave opening. The reinforcing cavity is plugged by the reinforcing bottom plate 14 and the reinforcing side plates 12, and the bottom of the steel arch frame 4 is reinforced by a concrete forming cavity which is right-angled trapezoid in longitudinal section and is used for pouring concrete, which is enclosed by the inner wall of the tunnel. In addition, after the reinforcing layer structure 21 is poured, the reinforcing layer formwork structure is dismantled, so that the construction of the next step is not influenced, and the dismantled reinforcing layer formwork structure can be reused.
As shown in fig. 6, in this embodiment, a plurality of the reinforcing bottom plates 14 and the connecting shim plates 11 are uniformly arranged in the same horizontal plane; a plurality of reinforcing rods 18 are vertically arranged on one side, away from the concrete forming cavity, of the reinforcing side plate 12, and the plurality of reinforcing rods 18 are uniformly distributed along the longitudinal extension direction of the tunnel.
In actual use, the main function of the reinforcing rods 18 is to prevent the reinforcing side plates 12 from tilting or falling off under the impact of concrete during the process of pouring concrete, which affects the pouring of concrete and the formation of the final reinforcing layer structure 21; the bottom of the reinforcing rod 18 extends into the surrounding rock 20 below the step, and the rod section of the reinforcing rod 18 extending out of the surrounding rock 20 is tightly attached to the side face of the reinforcing side plate 12. As shown in fig. 6, the area enclosed by the broken line and the reinforcing side plate 12 is the area of the reinforcing cavity.
As shown in fig. 5 and fig. 6, in this embodiment, the reinforcing layer supporting structure is disposed in the concrete forming cavity, the reinforcing layer supporting structure includes a longitudinal reinforcement set disposed at the bottom of the steel arch frame 4 and disposed in the reinforcing cavity, and a circumferential reinforcement set disposed on the longitudinal reinforcement set, and the longitudinal reinforcement set and the circumferential reinforcement set are integrally formed;
the longitudinal reinforcing steel bar group comprises a plurality of reinforcing layer longitudinal reinforcing steel bars 15 which are arranged along the longitudinal extension direction of the tunnel, and the plurality of reinforcing layer longitudinal reinforcing steel bars 15 are uniformly distributed on the inner side and the outer side of the steel arch frame 4;
the circumferential reinforcing steel bar group comprises a plurality of reinforcing layer circumferential reinforcing steel bars 16 sleeved on the longitudinal reinforcing steel bar group, and the plurality of reinforcing layer circumferential reinforcing steel bars 16 are distributed along the extending direction of the reinforcing layer longitudinal reinforcing steel bars 15; reinforcing layer hoop reinforcing bar 16 is the right trapezoid structure, reinforcing layer longitudinal reinforcement 15 sets up four apex angle departments of reinforcing layer hoop reinforcing bar 16.
During the in-service use, longitudinal reinforcement group with the hoop reinforcing bar group plays the reinforced effect of support, lays the concrete shaping intracavity has guaranteed the later stage and has pour the shaping the overall stability of back up coat structure 21.
As shown in fig. 2, in this embodiment, the grouting mechanism includes a stop valve 19 disposed inside the tunnel and disposed at an end of the anchor bolt 6, a tee pipe 24 communicated with the stop valve 19, a double-fluid grouting machine 7 disposed inside the tunnel for grouting into the anchor bolt 6, and a grouting pipe 8 connecting the tee pipe 24 and the double-fluid grouting machine 7.
In actual use, one port of the three-way pipe 24 is connected with the three-way pipe 24 stop valve 19, and the other two ports of the three-way pipe 24 are connected to the slurry outlet of the double-liquid slurry grouting machine 7 by using the grouting pipe 8; wherein, one slurry inlet of the double-liquid slurry grouting machine 7 is connected with a cement stirring tank 22, and the other slurry inlet of the double-liquid slurry grouting machine 7 is connected with a water glass grouting tank 23; and opening the stop valve 19, and starting the double-liquid grouting machine 7 to perform grouting on the foot locking anchor rod 6.
As shown in fig. 5 and 6, in this embodiment, a protective cover 17 is sleeved on an outer side of the connection pad 11, and the connection pad 11 and the protective cover 17 enclose a closed rectangular parallelepiped region.
In actual use, when the reinforcing cavity is concreted, the connecting pad 11 needs to be protected in order to prevent the connecting pad 11 from being concreted, and the protective cover 17 serves to protect the connecting pad 11.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (8)
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| CN113482671B (en) | 2024-03-15 |
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