阅读说明：本技术 一种避免河道开挖引起下卧隧道上浮的结构及方法 (Structure and method for preventing downward-lying tunnel from floating upwards due to river channel excavation ) 是由 赵豫鄂 成怡冲 许冠 王洁栋 吴才德 龚迪快 沈俊杰 于 2021-01-08 设计创作，主要内容包括：本发明公开了一种避免河道开挖引起下卧隧道上浮的结构,包括设置在下卧隧道上方的预制混凝土抗浮板,预制混凝土抗浮板上固连有若干个分布在下卧隧道两侧的浆囊带锚杆,浆囊带锚杆的锚固段伸入到下卧隧道下部的土体中；浆囊带锚杆包括杆体、注浆管和设置在杆体的锚固段的浆囊袋,浆囊袋每隔2m设置一个束腰段；预制混凝土抗浮板上设置有载重。还公开一种避免下卧隧道上浮的方法：(1)将河道划分成多个施工段；(2)生产预制混凝土抗浮板；(3)间隔开挖施工段挖；(4)吊放预制混凝土抗浮板,并放置临时载重；(5)设置浆囊带锚杆；(6)移除临时压载,河道通水。本发明能够有效避免上方河道开挖引起下卧隧道上浮。(The invention discloses a structure for preventing a lower horizontal tunnel from floating up due to river channel excavation, which comprises a precast concrete anti-floating plate arranged above the lower horizontal tunnel, wherein a plurality of slurry bag belt anchor rods distributed on two sides of the lower horizontal tunnel are fixedly connected to the precast concrete anti-floating plate, and an anchoring section of each slurry bag belt anchor rod extends into a soil body at the lower part of the lower horizontal tunnel; the slurry bag belt anchor rod comprises a rod body, a grouting pipe and slurry bag bags arranged at the anchoring section of the rod body, wherein the slurry bag bags are provided with a waist restraining section every 2 m; and the precast concrete floating-resistant plate is provided with a load. Also discloses a method for avoiding the downward tunnel from floating upwards, which comprises the following steps: (1) dividing the river channel into a plurality of construction sections; (2) producing a precast concrete anti-floating plate; (3) excavating at intervals of excavation construction sections; (4) hoisting the precast concrete anti-floating plate and placing a temporary load; (5) arranging a slurry bag with an anchor rod; (6) and removing the temporary ballast and introducing water into the river channel. The method can effectively avoid the floating of the lower horizontal tunnel caused by the excavation of the upper river channel.)

1. The utility model provides an avoid river course excavation to cause tunnel that crouches down to go up structure floating which characterized in that: the device comprises a precast concrete anti-floating plate arranged above a lower horizontal tunnel, wherein the precast concrete anti-floating plate is fixedly connected with a plurality of slurry bag belt anchor rods distributed on two sides of the lower horizontal tunnel, and anchoring sections of the slurry bag belt anchor rods extend into soil on the lower part of the lower horizontal tunnel; the grouting bag belt anchor rod comprises a rod body, grouting pipes and a grouting bag arranged at the anchoring section of the rod body, wherein a waist restraining section is arranged at the interval of 2 meters of the grouting bag, cement slurry can be injected into the grouting bag through the grouting pipes, and the cement slurry injected into the grouting bag is formed into grouting body; and the precast concrete anti-floating plate is provided with a load.

2. The structure for preventing the river channel excavation from causing the downward-lying tunnel to float up according to claim 1, wherein: the precast concrete anti-floating plate is provided with a preformed hole corresponding to the slurry bag belt anchor rod; the prepared holes are vertical or inclined.

3. The structure for preventing the river channel excavation from causing the downward-lying tunnel to float up according to claim 1, wherein: the top of the rod body is connected with a nut, the nut and the precast concrete anti-floating plate are clamped and provided with a gasket sleeved on the rod body.

4. The structure for preventing the river channel excavation from causing the downward-lying tunnel to float up according to claim 1, wherein: the load is temporary load or river water.

5. A method for preventing a lower horizontal tunnel from floating up due to river channel excavation is characterized by comprising the following steps:

(1) arranging a river channel along the length direction of a lower horizontal tunnel and dividing the river channel into a plurality of construction sections;

(2) producing a precast concrete anti-floating plate, wherein the length of the precast concrete anti-floating plate is equal to the width of a riverbed, the width of the precast concrete anti-floating plate is equal to the length of the construction section, and the thickness and the reinforcing bars of the precast concrete anti-floating plate are determined according to anti-floating calculation in a use stage;

(3) excavating the construction sections at intervals, wherein the adjacent construction sections cannot be excavated simultaneously;

(4) after each construction section is excavated to the elevation of the river channel bottom, hoisting the precast concrete anti-floating plate, and placing a temporary load on the precast concrete anti-floating plate;

(5) placing a slurry bag belt anchor rod through preformed holes on two side edges of the precast concrete anti-floating plate, grouting slurry bags in the slurry bag belt anchor rod through a grouting pipe, and applying prestress to a rod body and locking after the strength of cement slurry meets the design requirement;

(6) after the locking of the grout bag with the anchor rod is finished, performing waterproof treatment on the locking port of the grout bag with the anchor rod; removing the temporary ballast and introducing water into the river channel; the temporary ballast is converted into a slurry bag with an anchor rod for resisting buoyancy and river water load;

(7) if tunnel upward floating trend appears in the tunnel operation process, need at last floating zone section, carry out interim damming to the river course, the root is pursued again to appearing tunnel upward floating trend on the precast concrete anti-floating plate thick liquid bag area stock carries out the stretch-draw locking, or thick liquid bag area stock is add in the reservation hole department of precast concrete anti-floating plate.

6. The method for avoiding ascent of a descending tunnel according to claim 5, wherein: the length of the construction section and the disposable unloading amount are determined according to the safety protection level of the rail transit structure and the soil condition, and the length of the construction section should not exceed 15 m.

7. The method for avoiding ascent of a descending tunnel according to claim 5, wherein: and when the precast concrete anti-floating plate is hoisted, a steel wire rope penetrates through the precast hole to assist the digging machine or the hoisting machine in hoisting.

8. The method for avoiding ascent of a descending tunnel according to claim 5, wherein: the weight of the temporary load is the same as that of the unloading soil body in the river channel region, so that the purpose of balancing the floating force and the ballast caused by unloading is achieved; dynamically increasing or decreasing ballast weights of corresponding sections according to the monitoring data of the upward floating of the lower horizontal tunnel in the construction process; preferably, a water bag is used as the temporary load.

9. The method for avoiding ascent of a descending tunnel according to claim 5, wherein: the precast concrete anti-floating plate is provided with a groove for installing a gasket, and the depth of the groove is matched with the thickness of the gasket; in the depth range of the tunnel, the hole of the slurry bag with the anchor rod is formed by adopting a casing pipe wall protection process, so that the influence of hole collapse on the tunnel is prevented; the minimum distance between the anchoring section of the pulp bag with the anchor rod and the lower horizontal tunnel is not less than 15m, and the minimum safety distance is controlled by controlling the angle of the pulp bag with the anchor rod and adjusting the lengths of the free section and the anchoring section of the pulp bag with the anchor rod; the top end of the pulp bag with the anchor rod is provided with a waterproof protection device.

Technical Field

The invention relates to the technical field of civil engineering, in particular to a structure and a method for preventing a downward tunnel from floating upwards due to river channel excavation.

Background

With the formation of urban rail transit network and the development of urban water area environment construction, the situation that a river channel passes through or is adjacent to the existing subway tunnel is more and more. On one hand, the stress of the soil body at the bottom of the river channel is released by excavating and unloading the river channel, the pit bottom generates uplift deformation, the stress of the upper part of the lower horizontal tunnel is reduced at the moment, and the tunnel is subjected to inevitable additional internal force and additional deformation. On the other hand, along with the excavation of the river channel, the height difference between the inside and the outside of the river channel is continuously increased, so that the deformation of the surrounding soil body from the outside of the river channel to the inside of the river channel is caused, the uplift deformation of the soil body at the bottom of the river channel is increased, and the uplift deformation of the lower lying tunnel is also increased. The excavation of the river channel is light, so that the built tunnel generates large longitudinal deformation, and diseases such as water seepage, cracks and the like occur; the use of the built tunnel is influenced, the speed of the train in the affected section is limited, and even the tunnel is stopped, so that great economic loss and social adverse effect are caused.

The current common method for controlling the floating of the tunnel comprises the following steps: foundation reinforcement (grouting reinforcement, high-pressure jet grouting reinforcement and deep stirring reinforcement), uplift pile arrangement, layered and partitioned excavation and the like. However, the process of large-area foundation reinforcement and uplift pile construction often has great influence on the existing downward lying tunnel, the construction speed is relatively slow, the economy is relatively poor, and meanwhile, mud pollution can be caused to the soil body and water quality around the river channel.

Disclosure of Invention

The invention aims to provide a structure and a method for preventing a lower horizontal tunnel from floating up due to river channel excavation, which are used for solving the problems in the prior art and preventing the lower horizontal tunnel from floating up due to upper river channel excavation.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a structure for preventing a lower horizontal tunnel from floating up due to river channel excavation, which comprises a precast concrete anti-floating plate arranged above the lower horizontal tunnel, wherein the precast concrete anti-floating plate is fixedly connected with a plurality of slurry bag belt anchor rods distributed on two sides of the lower horizontal tunnel, and anchoring sections of the slurry bag belt anchor rods extend into a soil body at the lower part of the lower horizontal tunnel; the grouting bag belt anchor rod comprises a rod body, grouting pipes and a grouting bag arranged at the anchoring section of the rod body, wherein a waist restraining section is arranged at the interval of 2 meters of the grouting bag, cement slurry can be injected into the grouting bag through the grouting pipes, and the cement slurry injected into the grouting bag is formed into grouting body; and the precast concrete anti-floating plate is provided with a load.

Preferably, the precast concrete anti-floating plate is provided with a preformed hole corresponding to the slurry bag belt anchor rod; the prepared holes are vertical or inclined.

Preferably, the top end of the rod body is connected with a nut, the nut and the precast concrete anti-floating plate are clamped and sleeved with a gasket on the rod body.

Preferably, the load is a temporary load or river water.

The invention also provides a method for preventing the downward tunnel from floating upwards caused by river channel excavation, which comprises the following steps:

(1) arranging a river channel along the length direction of a lower horizontal tunnel and dividing the river channel into a plurality of construction sections;

(2) producing a precast concrete anti-floating plate, wherein the length of the precast concrete anti-floating plate is equal to the width of a riverbed, the width of the precast concrete anti-floating plate is equal to the length of the construction section, and the thickness and the reinforcing bars of the precast concrete anti-floating plate are determined according to anti-floating calculation in a use stage;

(3) excavating the construction sections at intervals, wherein the adjacent construction sections cannot be excavated simultaneously;

(4) after each construction section is excavated to the elevation of the river channel bottom, hoisting the precast concrete anti-floating plate, and placing a temporary load on the precast concrete anti-floating plate;

(5) placing a slurry bag belt anchor rod through preformed holes on two side edges of the precast concrete anti-floating plate, grouting slurry bags in the slurry bag belt anchor rod through a grouting pipe, and applying prestress to a rod body and locking after the strength of cement slurry meets the design requirement;

(6) after the locking of the grout bag with the anchor rod is finished, performing waterproof treatment on the locking port of the grout bag with the anchor rod; removing the temporary ballast and introducing water into the river channel; the temporary ballast is converted into a slurry bag with an anchor rod for resisting buoyancy and river water load;

(7) if tunnel upward floating trend appears in the tunnel operation process, need at last floating zone section, carry out interim damming to the river course, the root is pursued again to appearing tunnel upward floating trend on the precast concrete anti-floating plate thick liquid bag area stock carries out the stretch-draw locking, or thick liquid bag area stock is add in the reservation hole department of precast concrete anti-floating plate.

Preferably, the length of the construction section and the disposable unloading amount are determined according to the safety protection level of the rail transit structure and the soil condition, and the length of the construction section should not exceed 15 m.

Preferably, when the precast concrete anti-floating plate is hoisted, a steel wire rope penetrates through the precast hole to assist the digging machine or the hoisting machine in hoisting.

Preferably, the weight of the temporary load is equal to the weight of the unloading soil body in the river channel region, so that the purpose of balancing the floating force caused by unloading and the ballast is achieved; dynamically increasing or decreasing ballast weights of corresponding sections according to the monitoring data of the upward floating of the lower horizontal tunnel in the construction process; preferably, a water bag is used as the temporary load.

Preferably, the precast concrete anti-floating plate is provided with a groove for installing a gasket, and the depth of the groove is matched with the thickness of the gasket; in the depth range of the tunnel, the hole of the slurry bag with the anchor rod is formed by adopting a casing pipe wall protection process, so that the influence of hole collapse on the tunnel is prevented; the minimum distance between the anchoring section of the pulp bag with the anchor rod and the lower horizontal tunnel is not less than 15m, and the minimum safety distance is controlled by controlling the angle of the pulp bag with the anchor rod and adjusting the lengths of the free section and the anchoring section of the pulp bag with the anchor rod; the top end of the pulp bag with the anchor rod is provided with a waterproof protection device.

Compared with the prior art, the invention has the following technical effects:

the structure and the method for preventing the lower horizontal tunnel from floating up due to river channel excavation can effectively prevent the lower horizontal tunnel from floating up due to upper river channel excavation. According to the structure and the method for preventing the downward-lying tunnel from floating due to river channel excavation, the construction of the excavation of the river channel above the existing tunnel through sectional strip-drawing excavation is avoided, and the subway tunnel from floating due to one-time large-area excavation unloading is avoided; rapidly compensating the soil body weight unloaded by excavation through a precast concrete anti-floating plate and temporary weight; by adopting the construction process of the slurry bag with the anchor rod, the influence of slurry flowing to the tunnel and the environment is reduced, and the cement soil quality of the anchor body is ensured; by combining real-time monitoring and control, the problem that the anchor rod of the pulp bag is loosened or failed gradually is solved by re-tensioning and locking the anchor rod of the pulp bag or additionally arranging the anchor rod of the pulp bag in the long-term operation process of the tunnel. Compared with the prior art, the method has the advantages of construction progress block, short effective time, small influence of the construction process on the tunnel, environmental friendliness and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a load space relationship diagram of river channel excavation;

FIG. 2 is a first schematic layout diagram of the method for preventing a downward tunnel from floating up due to river channel excavation according to the present invention;

FIG. 3 is a schematic layout diagram II of the method for preventing a downward tunnel from floating up due to river channel excavation according to the invention;

FIG. 4 is a third schematic layout diagram of the method for preventing a downward tunnel from floating up due to river channel excavation according to the present invention;

FIG. 5 is a fourth schematic layout diagram of the method for preventing a downward tunnel from floating up due to river channel excavation according to the present invention;

FIG. 6 is a structural schematic diagram I of a structure for preventing a downward tunnel from floating due to river channel excavation;

FIG. 7 is a partial structural schematic view of a structure for preventing a downward tunnel from floating due to river channel excavation according to the present invention;

FIG. 8 is a structural schematic diagram II of a structure for preventing a downward tunnel from floating due to river channel excavation according to the invention;

FIG. 9 is a first structural schematic diagram of a precast concrete anti-floating plate in a structure for preventing a lower horizontal tunnel from floating upwards due to river channel excavation according to the invention;

FIG. 10 is a structural schematic diagram II of a precast concrete anti-floating plate in a structure for preventing a lower horizontal tunnel from floating upwards due to river channel excavation according to the invention;

wherein: 100. a structure that a lower horizontal tunnel floats upwards due to river channel excavation is avoided; 1. a lower horizontal tunnel; 2. a main soil covering area; 3. construction sections; 4. prefabricating a concrete anti-floating plate; 5. temporary load; 6. the slurry bag is provided with an anchor rod; 7. a rod body; 8. a first grouting pipe; 9. grouting; 10. a corset section; 11. a serous sac; 12. a gasket; 13. a nut; 14. adding ointment into the hemp thread; 15. reserving a hole; 16. river water; 17. a second grouting pipe; 18. and a reflux pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

The invention aims to provide a structure and a method for preventing a lower horizontal tunnel from floating up due to river channel excavation, which are used for solving the problems in the prior art and preventing the lower horizontal tunnel from floating up due to upper river channel excavation.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1 to 10: the embodiment provides a structure 100 for preventing a lower horizontal tunnel from floating up due to river channel excavation, wherein a precast concrete anti-floating plate 4 is fixedly connected with a plurality of slurry bag belt anchor rods 6 distributed on two sides of the lower horizontal tunnel, and anchoring sections of the slurry bag belt anchor rods 6 extend into soil on the lower portion of the lower horizontal tunnel 1; the slurry bag belt anchor rod 6 comprises a rod body 7, a grouting pipe and slurry bag bags 11 arranged at the anchoring section of the rod body, wherein the slurry bag bags are provided with a beam waist section 10 every 2m, the arrangement of the beam waist section 10 can enable the slurry bag bags 11 to form a concave-convex structure, and the shape of the grouting body 9 is ensured to be a plurality of cylinders which are uniformly arranged at intervals and are sequentially connected, so that the friction force between the slurry bag bags 11 and a soil body is increased. The top of slip casting pipe is located precast concrete anti-floating plate 4's reservation mouth department, injects grout through the top of slip casting pipe into the slip casting pipe, and during grout in the slip casting pipe flowed into thick liquid bag 11 again, slip casting pipe and the body of rod 7 homogeneous end were located the top of thick liquid bag area stock 6 (anti-floating plate reservation mouth department), and the other end is located the bottom of thick liquid bag area stock 6. In the present embodiment, two grouting pipes, namely a first grouting pipe 8 and a second grouting pipe 17, are provided, the first grouting pipe 8 adopts end grouting, that is, cement slurry is injected into the slurry bag 11 from the end of the first grouting pipe 8 and overflows upwards to fill the slurry bag 11, and a backflow pipe 18 is provided at the position of each corset section 10, and the backflow pipe 18 helps the cement slurry to flow back from the slurry bag 11 at the lower side of the corset section 10 to the slurry bag 11 at the upper side of the corset section 10. The second grouting pipe 17 adopts side grouting, that is, holes are drilled on the side surface of the second grouting pipe 17, the holes are firstly sealed by using adhesive tapes, and the second grouting pipe 17 is used for grouting during secondary grouting. The cement slurry poured in the slurry bag 11 is formed into a grouting body 9; the precast concrete anti-floating plate 4 is provided with a load.

In the embodiment, the slurry bag anchor rod 6 is inclined, the precast concrete anti-floating plate 4 is provided with a reserved hole 15 corresponding to the slurry bag anchor rod 6, the reserved hole 15 is inclined, and the slurry bag anchor rod 6 penetrates through the reserved hole 15. It should be noted that the slurry bag anchor rod 6 and the prepared hole 15 can be vertically inclined, and when the minimum distance between the tunnel and the anchor rod does not meet the specification requirement, the distance can be increased by increasing the inclination angle of the slurry bag anchor rod 6 and the prepared hole 15.

The top of the body of rod 7 is connected with the nut 13, presss from both sides between nut 13 and the anti kickboard 4 of precast concrete and is equipped with the gasket 12 of cover on the body of rod 7, and the body of rod 7 adopts reinforcing bar or steel strand wires in this embodiment, but because of the steel strand wires can exert bigger prestressing force, so preferentially adopt the steel strand wires as the body of rod 7 in this embodiment, is provided with the recess that is used for installing gasket 12 on the anti kickboard 4 of precast concrete, and the degree of depth of recess matches with the thickness of gasket 12. The load is a temporary load 5 or river water 16.

The embodiment also provides a method for avoiding the floating of a downward tunnel caused by river channel excavation, which comprises the following steps:

(1) arranging a river channel along the length direction of a lower horizontal tunnel 1 and dividing the river channel into a plurality of construction sections 3; the length of the construction section 3 and the one-time unloading amount are determined according to the safety protection level of the rail transit structure and the soil condition, and the length of the construction section 3 should not exceed 15 m. The amount of the one-time unloading body should meet S₁≤ν₁And S. Wherein S₁The cross section area of the one-time unloading quantity is S is the cross section area of the main soil covering area 2 above the tunnel, v₁Is the unloading ratio (v)₁Not more than 0.3); the main overburden 2 has an effect spread angle of 45 + psi/2.

(2) Producing a precast concrete anti-floating plate 4, wherein the length of the precast concrete anti-floating plate 4 is equal to the width of a riverbed, the width of the precast concrete anti-floating plate 4 is equal to the length of the construction section 3, and the thickness and reinforcing bars of the precast concrete anti-floating plate 4 are determined according to anti-floating calculation in a use stage;

(3) excavating the construction sections 3 at intervals, wherein the adjacent construction sections 3 cannot be excavated at the same time;

(4) after each construction section 3 is excavated to the elevation of the river channel bottom, hoisting a precast concrete anti-floating plate 4, and placing a temporary load 5 on the precast concrete anti-floating plate 4;

when the precast concrete anti-floating plate 4 is hoisted, a steel wire rope penetrates through the precast hole to assist the digging machine or the hoisting machine in hoisting. The weight of the temporary load 5 is the same as that of the unloading soil body in the river channel region, so that the purpose of balancing the floating force caused by unloading and ballast is achieved; dynamically increasing or decreasing ballast weights of corresponding sections according to the floating monitoring data of the lower horizontal tunnel 1 in the construction process; the water bag is preferably used as the temporary load 5, and the water bag is broken during unloading and is discharged, so that the use is convenient.

(5) Placing a grout bag belt anchor rod 6 through preformed holes 15 on two side edges of the precast concrete anti-floating plate 4, grouting grout bag bags 11 in the grout bag belt anchor rod 6 through a grouting pipe, and smearing hemp fiber and factice 14 on the grout bag belt anchor rod 6; applying prestress and locking after the strength of the cement paste reaches the design requirement;

(6) after the locking of the slurry bag with the anchor rod 6 is finished, performing waterproof treatment on the locking port of the slurry bag with the anchor rod 6; removing the temporary ballast and introducing water into the river channel; the temporary ballast is converted into the anti-buoyancy of the slurry bag anchor rod 6 and the load of the river 16;

(7) if tunnel upward floating trend appears in the tunnel operation process, the river channel is temporarily intercepted in the upward floating section, the slurry bag belt anchor rods 6 on the precast concrete anti-floating plates 4 with the tunnel upward floating trend are tensioned and locked one by one, or the slurry bag belt anchor rods 6 are additionally arranged at the preformed holes 15 of the precast concrete anti-floating plates 4.

The hole of the slurry bag anchor rod 6 in the depth range of the tunnel is formed by a casing pipe wall protection process, so that the influence of hole collapse on the tunnel is prevented; the minimum distance between the anchoring section of the pulp bag anchor rod 6 and the lower horizontal tunnel 1 is not less than 15m, and the minimum safety distance is controlled by controlling the angle of the pulp bag anchor rod 6 and adjusting the length of the free section and the anchoring section of the pulp bag anchor rod 6; the top end of the pulp bag with the anchor rod 6 is provided with a waterproof protection device.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.