Construction method of ground preset suspender underground excavation structure suitable for soft stratum

Abstract

The invention discloses a construction method of a ground preset suspender underground excavation structure suitable for a soft stratum, and relates to the technical field of ground construction. The construction method of the ground preset suspender underground excavation structure suitable for the soft stratum comprises the following steps that S1, geological exploration of the soft stratum is carried out, the range and the property of the soft stratum are determined, three-way and one-level construction is carried out on a site, and a fence is constructed; s2, a steel pipe pile is driven, the pile bottom enters the position below a structural bottom plate, and a ground cover plate is constructed; s3, a suspender is constructed through a suspender hole reserved in the ground cover plate, and an anchoring end is constructed above the ground cover plate; and S4, the clamped soil rock mass is reinforced through grouting holes reserved in the ground cover plate, then a ground covering layer is constructed, and road surface passing is restored. According to the method, the problems that heavy pipelines above a to-be-built project cannot be migrated and changed, the to-be-built structure is in an unconventional form, the upper portion of the to-be-built structure cannot be cut off for a long time or the surrounding environment of the to-be-built structure is complex, and no excavation space exists can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of ground construction, and in particular relates to a construction method of a ground preset hanger concealed excavation structure suitable for soft strata. Background Art

[0002] With the acceleration of urbanization, the development and utilization of tunnels and underground spaces is becoming increasingly widespread, leading to a corresponding increase in demand for large-span tunnels. However, due to the dense concentration of commercial, corporate, financial, and residential buildings in urban centers, heavy traffic, high land prices, and the dense presence of underground pipelines and structures, traditional bored tunnel construction methods are becoming increasingly difficult, and the demand for more diverse structural forms is increasing. Furthermore, when constructing bored tunnels in soft strata, the poor self-supporting capacity of the strata makes surface subsidence and tunnel collapse a frequent occurrence. Therefore, ensuring construction safety while avoiding pipeline relocation and effectively controlling surface subsidence has become a key issue in bored tunnel construction in soft strata. Summary of the Invention

[0003] The object of the present invention is to provide a construction method of a ground preset boom-dig structure suitable for soft strata, so as to solve the problems raised in the above-mentioned background technology.

[0004] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0005] The present invention provides a construction method for a ground preset boom-dig structure suitable for soft strata, comprising the following steps:

[0006] S1. Conduct geological survey of weak strata to determine the scope and nature of the weak strata, establish three connections and one leveling of the site, and install construction enclosures;

[0007] S2. Drive steel pipe piles with the bottom of the piles under the structural base plate and construct the ground cover plate;

[0008] S3. Use the holes reserved on the ground cover to install the hanger and install the anchor end above the ground cover;

[0009] S4. Use the grouting holes reserved on the ground cover to reinforce the clamped soil and rock mass, then apply the ground cover layer and restore the road to traffic;

[0010] S5. Excavate the soil and rock masses on both sides, erect the first-layer steel frames on both sides, pass the hangers through the first-layer steel frames on both sides to serve as anchor heads, and apply prestressing force;

[0011] S6. Construct the second layer of steel frames on both sides;

[0012] S7. Construct the two side structures, top longitudinal beams, bottom longitudinal beams, and center columns, and install steel bar connectors at the top and bottom beams;

[0013] S8. Excavate the middle soil and rock mass, cut out the middle steel pipe piles, erect the middle first-layer steel frame, cut out the first-layer steel frames on both sides, weld the middle first-layer steel frame to the first-layer steel frames on both sides, pass the hanger rod through the middle first-layer steel frame to serve as an anchor head, and apply prestressing force;

[0014] S9. Construct the second-layer steel frame in the middle;

[0015] S10. Construct the intermediate structure and connect the main reinforcement of the intermediate structure with the reserved reinforcement connectors in the top longitudinal beam and the bottom longitudinal beam.

[0016] As a preferred solution of the present invention, the ground covering layer of the soft stratum meets the requirements of the road surface layer, and the top is flush with the top of the surrounding road surface, meeting the vehicle load passage requirements.

[0017] As a preferred embodiment of the present invention, in said S3, the method for reinforcing the clamped soil and rock mass by using the grouting holes reserved on the ground cover plate is the sleeve valve tube grouting method, the stirring method or the membrane bag method.

[0018] As a preferred solution of the present invention, four steel pipe piles in a plane form a vertical support system, steel sections are inserted into the steel pipe piles on both sides, and the interior of the steel pipe piles is filled with cement mortar.

[0019] Wherein, overflow holes are reserved on the side walls of the steel pipe piles to reinforce the strata.

[0020] As a preferred embodiment of the present invention, the anchor end, the hanger and the anchor head constitute a hanger system. The hanger drilling construction of the hanger system adopts a drilling diameter of 150 mm. The hanger adopts multiple bundles of steel strands, and the standard strength value of the steel strands is 1860 MPa.

[0021] The length of the boom entering the dark tunnel is 200 mm.

[0022] As a preferred solution of the present invention, the ground cover is a top support structure, and the top support structure adopts a C30 concrete structure, and the thickness of the C30 concrete structure is 500 mm.

[0023] The ground cover plate is provided with grouting holes, the horizontal distance of which is determined by the tunnel width, and the longitudinal distance is 1.5m.

[0024] As a preferred solution of the present invention, the horizontal inward spacing of the boom system is 1.5m to 2m, and the longitudinal spacing of the boom system is 1.5m.

[0025] As a preferred solution of the present invention, the second-layer steel frames on both sides, the first-layer steel frames on both sides, the middle first-layer steel frame and the middle second-layer steel frame constitute an excavation support structure, and the longitudinal direction of the excavation support structure is connected by steel bars.

[0026] The steel bars are made of The connecting bars have a unilateral circumferential spacing of 2m, and the connecting bars are arranged in a staggered manner inside and outside.

[0027] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0028] The purpose of this invention is to address projects that cannot be constructed using conventional open-cut, concealed, or covered excavation methods. Compared to traditional construction methods, this invention can effectively address issues such as the presence of critical pipelines above the proposed project that cannot be relocated, unconventional structures, the inability to interrupt the flow of water above the proposed structure for extended periods, or complex surroundings with no excavation space.

[0029] 1. Shallow buried large-span tunnel structures have a poor arching effect due to their shallow burial depth, weak cover layer, and poor arching effect. The traditional shallow buried tunnel block excavation method is used, which results in a large number of temporary supports, a large amount of abandoned projects, and low construction efficiency. At the same time, the ground is repeatedly disturbed, which has an adverse effect on controlling ground settlement and protecting underground pipelines.

[0030] 2. A construction method of ground-preset boom-type underground excavation structure suitable for diverse structural forms in soft strata is adopted. The ground grouting and other auxiliary measures such as booms can be used to reinforce the stratum, improve the strength of the clamped rock mass and the geotechnical properties, reduce the number of underground excavation blocks, reduce the number of supports, and improve construction efficiency.

[0031] 3. When used appropriately under suitable conditions, it can reduce the amount of large underground pipeline relocation and road occupancy time, and serve as a supplementary solution to the shallow buried tunnel method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1 It is a structural schematic diagram of the underground excavation structure after the construction of the present invention is completed. DETAILED DESCRIPTION

[0034] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0035] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0036] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0037] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0038] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0039] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0040] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0041] See also Figure 1 The present invention discloses a construction method for a ground preset boom-dig structure suitable for soft strata, comprising the following steps: first, the ground covering layer of the soft stratum meets the requirements of the road surface layer, and the top is flush with the surrounding road top to meet the vehicle load passage requirements.

[0042] S1. Conduct geological survey of weak strata to determine the scope and nature of the weak strata, establish three connections and one leveling of the site, and install construction enclosures;

[0043] S2. Drive steel pipe piles with the bottom of the piles extending below the structural base plate. Construct a ground cover plate. Four steel pipe piles form a vertical support system. Section steel is inserted into the steel pipe piles on both sides. Cement mortar is filled inside the steel pipe piles. Grout holes are reserved on the side walls of the steel pipe piles to reinforce the ground.

[0044] S3. Use the holes reserved on the ground cover to install the hangers and construct the anchor ends above the ground cover. The ground cover serves as the top support structure, which is made of C30 concrete with a thickness of 500 mm. Grouting holes are reserved on the ground cover. The horizontal spacing of the grouting holes is determined by the tunnel width, and the vertical spacing is 1.5 m.

[0045] S4. Use the grouting holes reserved on the ground cover to reinforce the clamped soil and rock mass, then apply the ground cover layer and restore the road to traffic. The method for reinforcing the clamped soil and rock mass using the grouting holes reserved on the ground cover is sleeve valve pipe grouting method, mixing method or film bag method;

[0046] S5. Excavate the soil and rock masses on both sides, erect the first-layer steel frames on both sides, pass the hangers through the first-layer steel frames on both sides to serve as anchor heads, and apply prestressing force;

[0047] S6. Construct the second layer of steel frames on both sides;

[0048] S7. Construct the two side structures, top longitudinal beams, bottom longitudinal beams, and center columns, and install steel bar connectors at the top and bottom beams;

[0049] S8. Excavate the middle soil and rock mass, cut out the middle steel pipe piles, erect the middle first-layer steel frame, cut out the first-layer steel frames on both sides, weld the middle first-layer steel frame to the first-layer steel frames on both sides, pass the hanger rod through the middle first-layer steel frame to serve as an anchor head, and apply prestressing force;

[0050] S9. Construct the second-layer steel frame in the middle;

[0051] S10. Construct the intermediate structure and connect the main reinforcement of the intermediate structure with the reserved reinforcement connectors in the top longitudinal beam and the bottom longitudinal beam.

[0052] Furthermore, the anchor end, the suspender and the anchor head constitute a suspender system. The suspender drilling construction of the suspender system adopts a drilling diameter of 150mm. The suspender adopts multiple strands of steel wire, and the standard strength value of the steel strand is 1860MPa.

[0053] Among them, the length of the boom entering the dark tunnel is 200mm, the horizontal inward spacing of the boom system is 1.5m to 2m, and the longitudinal spacing of the boom system is 1.5m.

[0054] Furthermore, the second-layer steel frames on both sides, the first-layer steel frames on both sides, the first-layer steel frame in the middle and the second-layer steel frame in the middle constitute an excavation support structure, and the longitudinal direction of the excavation support structure is connected by steel bars, wherein the steel bars are Connecting reinforcement: the unilateral circumferential spacing of the connecting reinforcement is 2m, and the connecting reinforcement is staggered inside and outside.

[0055] Furthermore, the bottom of the steel pipe pile is located no less than 1.5m below the bottom plates of the structure on both sides.

[0056] Furthermore, the booms are arranged in a horizontal and vertical rectangular configuration.

[0057] Furthermore, the top of the anchoring end is located on the upper part of the ground cover plate, the bottom of the anchoring end is flush with the top of the ground cover plate, and the anchoring end is buried in the ground covering layer.

[0058] Furthermore, the anchor head is preferably a specially made wedge-shaped anchor head.

[0059] Furthermore, when tying the first-layer steel frames on both sides to the first-layer steel frame in the middle, beard bars are welded to the steel frame stirrups. The length of the steel bars should be about 200mm longer than the lower plane of the first-layer primary support. At the same time, when the second-layer steel frames on both sides and the second-layer steel frame in the middle are erected, the reserved steel bar joints are welded to the stirrups of the second-layer steel frames.

[0060] Furthermore, the first-layer steel frames on both sides and the second-layer steel frames on both sides, as well as the first-layer steel frame in the middle and the second-layer steel frame in the middle should be staggered.

[0061] Furthermore, the skipping method should be used when cutting the steel pipe piles.

[0062] Furthermore, when the first-layer steel frames on both sides and the second-layer steel frames on both sides are cut off, sufficient steel bar length should be reserved to facilitate welding with the middle first-layer steel frame and the middle second-layer steel frame.

[0063] Furthermore, the anchor head is located between the grilles of the second-layer steel frames on both sides and the middle second-layer steel frame, and is buried inside the second-layer primary support.

[0064] Without limitation, any person skilled in the art who is familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, and these changes should be covered by the protection scope of the present invention.

Claims

1. A construction method for a ground-preset suspension rod dark excavation structure suitable for soft strata, characterized in that: The following steps are involved: S1. Conduct geological survey of soft strata to determine the scope and nature of soft strata, level the site, and build enclosures; S2. Drive steel pipe piles, with the bottom of the piles entering under the structural bottom plate, and construct the ground cover plate; S3. Use the holes for the suspension rods reserved on the ground cover plate to construct the suspension rods, and construct the anchoring end above the ground cover plate; S4. Use the grouting holes reserved on the ground cover to reinforce the clamped soil and rock mass, then apply the ground cover layer and restore the road to traffic; S5. Excavate the soil and rock masses on both sides, erect the first layer of steel frames on both sides, pass the hangers through the first layer of steel frames on both sides to serve as anchor heads, and apply prestress; S6. Construct the second layer of steel frames on both sides; S7. Construct the structures on both sides, top longitudinal beams, bottom longitudinal beams and middle columns, and set steel bar connectors at the top and bottom beams; S8, excavate the middle soil and rock mass, cut off the middle steel pipe piles, erect the middle first-layer steel frame, cut off the first-layer steel frames on both sides, weld the middle first-layer steel frame with the first-layer steel frames on both sides, pass the hanger rod through the middle first-layer steel frame to serve as an anchor head, and apply prestress; S9, construct the second intermediate steel frame; S10. Construct the intermediate structure and connect the main reinforcement of the intermediate structure with the reserved reinforcement connectors in the top longitudinal beam and the bottom longitudinal beam.

2. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: The ground covering layer of the soft stratum meets the requirements of the road surface layer, and the top is flush with the surrounding road top, meeting the vehicle load passage requirements.

3. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: In S3, the method of reinforcing the clamped soil and rock mass by using the grouting holes reserved on the ground cover plate is the sleeve valve pipe grouting method, the mixing method or the membrane bag method.

4. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: Four steel pipe piles in the plane form a vertical support system, steel sections are inserted into the steel pipe piles on both sides, and cement mortar is filled inside the steel pipe piles. Wherein, overflow holes are reserved on the side walls of the steel pipe piles to reinforce the strata.

5. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: The anchor end, the hanger and the anchor head constitute a hanger system. The hanger drilling construction of the hanger system adopts a drilling diameter of 150 mm. The hanger adopts multiple bundles of steel strands, and the standard strength value of the steel strands is 1860 MPa. Among them, the length of the suspension rod entering the dark tunnel is 200mm.

6. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: The ground cover is a top support structure, and the top support structure adopts a C30 concrete structure, and the thickness of the C30 concrete structure is 500 mm. Among them, grouting holes are reserved on the plate of the ground cover plate, the horizontal distance of the grouting holes is determined according to the tunnel width, and the longitudinal distance is 1.5m.

7. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 5, characterized in that: The horizontal inward spacing of the suspension rod system is 1.5m to 2m, and the longitudinal spacing of the suspension rod system is 1.5m.

8. The construction method of a ground preset suspension rod dark excavation structure suitable for soft strata according to claim 1, characterized in that: The second-layer steel frames on both sides, the first-layer steel frames on both sides, the first-layer steel frames in the middle and the second-layer steel frames in the middle constitute an excavation support structure, and the longitudinal direction of the excavation support structure is connected by steel bars. The steel bars are made of The connecting bars have a unilateral circumferential spacing of 2m and are arranged staggered inside and outside.

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