阅读说明：本技术 一种地铁矿山法建成区间扩建成渡线段的结构及其施工方法 (Structure for expanding subway section in subway mine method construction interval and construction method thereof ) 是由 孔恒 彭明玉 史磊磊 梁静宇 王渭 张仲宇 贾硕 戴建伟 鲍宇 王胜奇 于 2019-09-16 设计创作，主要内容包括：一种地铁矿山法建成区间扩建成渡线段的结构及其施工方法。所述结构包括建成在利用矿山法建成的既有左线区间结构(4)和既有右线区间结构(5)之间的新建区间结构(6),所述新建区间结构(6)为变截面矩形结构,其主体结构包括结构底板、侧墙及顶板结构,所述新建区间结构(6)沿地铁线路走向成渐变形式；所述新建区间结构(6)采用不规则基坑围护体系进行支护,所述基坑是利用明挖法扩建而成,所述不规则基坑围护体系选用双排围护桩(7)+预应力锚固缆索(10)与单排围护桩(8)+钢支撑(9)的结合方式。本发明提供了一种合理、可行的设计方案,实现了已建成的矿山法地铁区间通过明挖法进行改造,扩建成带有渡线段的区间结构。(A structure for expanding a metro section in a metro mine construction interval and a construction method thereof. The structure comprises a newly-built interval structure (6) built between an existing left line interval structure (4) and an existing right line interval structure (5) built by a mine method, wherein the newly-built interval structure (6) is a variable-section rectangular structure, a main structure of the newly-built interval structure comprises a structure bottom plate, a side wall and a top plate structure, and the newly-built interval structure (6) is in a gradual change form along the direction of a subway line; the newly-built interval structure (6) is supported by an irregular foundation pit enclosure system, the foundation pit is formed by expanding by an open cut method, and the irregular foundation pit enclosure system adopts a combination mode of double-row enclosure piles (7) + prestressed anchoring cables (10) and single-row enclosure piles (8) + steel supports (9). The invention provides a reasonable and feasible design scheme, and realizes the reconstruction of the established subway interval of the mine method through an open cut method and the extension of an interval structure with a transition line segment.)

1. A structure for expanding a subway section between a subway mine method-built section is characterized by comprising a newly-built section structure (6) built between an existing left line section structure (4) and an existing right line section structure (5) built by a mine method, wherein the newly-built section structure (6) is a variable-section rectangular structure, the main structure of the newly-built section structure comprises a structure bottom plate, a side wall and a top plate structure, and the newly-built section structure (6) is in a gradual change form along the subway line;

the newly-built interval structure (6) is supported by an irregular foundation pit enclosure system, the foundation pit is expanded by an open cut method, the irregular foundation pit bracing system adopts a combination mode of double rows of fender piles (7), prestressed anchoring cables (10), single rows of fender piles (8) and steel supports (9), and specifically comprises the steps that the left side and the right side of the foundation pit along the subway line trend are respectively braced by the single rows of fender piles (8), the single row of fender posts (8) at the left side and the right side are connected by steel supports (9), two rows of fender posts (7) and prestressed anchoring cables (10) are arranged on the soil body at two ends of the foundation pit along the trend of the subway line for reinforcement, the lower parts of the double rows of fender piles (7) are reinforced by adopting a soil nailing wall reinforcing embedded structure (16), and the upper parts of the double rows of fender piles (7) are provided with crown beams (13);

the number of the single row of fender piles (8) is multiple, a crown beam (13) is arranged above each single row of fender piles (8), and the top ends of the multiple single row of fender piles (8) are fixedly connected with the crown beam (13) into a whole; the steel supports (9) are arranged in parallel from top to bottom, the uppermost steel support (9) is connected with the crown beam (13), and the rest steel supports (9) are connected with the single-row fender post (8) through the waist beam; each group of steel supports (9) is provided with a plurality of steel supports (9) which are arranged in parallel from front to back and are uniformly distributed on the same horizontal plane, and two ends of each steel support (9) are respectively fixed on the inner side wall of the waist beam on the same horizontal plane; the steel support (9) is supported by a plurality of temporary upright columns (11), and the temporary upright columns (11) are fixed on a base (12) of the foundation pit; a retaining wall (15) is arranged at the upper edge of the foundation pit, and a catch drain (14) is arranged on the outer side of the retaining wall (15); an L-shaped crown beam (17) is arranged on a soil slope 3-5m away from the pile bottom of the double-row fender pile (7) at two ends of the foundation pit, and a soil nailing wall reinforcing and embedding structure (16) is arranged at the lower part of the L-shaped crown beam (17).

2. The structure for expanding a section into a transition line section according to a subway mine method built section, which is characterized in that pile bodies of the single-row fender pile (8) and the double-row fender pile (7) are both made of slurry and pile body reinforcing members, the pile body reinforcing members are prefabricated steel members and are provided with connecting ends, the connecting ends are composed of high-strength connecting steel rods and plug-in connectors, and joints of the connecting ends are sealed by epoxy resin; and a crown beam (13) is arranged at the top of the pile body reinforcing piece.

3. A structure of a metro mine construction interval expanded into a transition line section according to claims 1-2, wherein the slurry is cement mortar formed by mixing and mixing pile position undisturbed soil of the fender pile through drilling and pouring and mixing with a curing agent, so as to form an independent pile body with a cylindrical or rectangular cross section.

4. A structure for extension of a metro section according to the subway mine method, as claimed in claim 3, wherein a retaining structure having the same height as the fender is arranged between the single row of fender posts (8) and the adjacent single fender posts of the row of fender posts close to the inner side of the foundation pit in the double row of fender posts (7) and on the surface of the fender posts facing the inner side of the foundation pit, the retaining structure is made of concrete, a reinforcing mesh is arranged in the concrete, and the reinforcing mesh is connected with the fender posts through a plurality of connectors; the connecting piece is a reinforcing steel bar with the diameter of 12-15mm, and the reinforcing mesh is of a reticular structure made of phi 8 round steel with the size of 150mm multiplied by 150 mm.

5. A key technical construction method for expanding a transition line segment structure in a subway mine construction interval according to claims 1-4, characterized by comprising the following steps:

a. constructing a plurality of dewatering wells on the stratum of the designed foundation pit excavation construction area by adopting the dewatering wells, and performing dewatering construction on the stratum by adopting a water suction pump;

b. side lines are excavated along the periphery of a designed foundation pit area, double rows of fender piles (7) and single rows of fender piles (8) are successively constructed at related design positions of the foundation pit, and cement mortar is formed on the pile positions of the fender piles by adopting a drilling and pouring method to form an independent pile body with a cylindrical or rectangular cross section; hoisting the pile body reinforcement to a pile position, overcoming resistance through a high-frequency vibration hammer and implanting the pile body reinforcement into the formed slurry, splicing the pile body reinforcement through a connecting end, continuously and repeatedly hoisting after splicing, splicing to the bottom of the slurry, and adjusting the plane position and elevation of the pile body reinforcement through a pile top positioning adjusting bolt; then constructing a crown beam (13) at the pile top of the fender pile, and sequentially constructing a retaining wall (15) and a catch basin (14) around the designed excavation position of the foundation pit;

c. excavating downwards in sequence, and arranging the steel supports (9) among the single row of fender piles (8); then, arranging a prestressed anchoring cable (10) at the position where the double-row fender post (7) is arranged on the excavated foundation pit wall; excavating a soil body to a position 3-5m away from the pile bottom of the double-row fender pile (7), reserving a part of soil slope, constructing an L-shaped crown beam (17) on the soil slope, and immediately arranging a prestressed anchoring cable 10 after the design strength is reached; and a fence structure is constructed above the L-shaped crown beam (17) and between the adjacent single fender piles of the row of piles close to the inner side of the foundation pit in the double rows of fender piles (7);

d. continuously excavating the soil body downwards, spraying concrete (18) to the soil slope construction hanging net, immediately drilling 2 anchor rods (19), and forming a soil nailing wall reinforcing embedded structure (16) after the design strength is reached;

e. continuously excavating the soil body downwards to the position of the design height of the newly-built interval structure (6), and dismantling the existing structure (20) at the position; then constructing a fence structure between the adjacent single fender piles of the single row of fender piles (8);

f. and finally, sequentially completing construction of the structure bottom plate, the side wall and the top plate structure of the main structure of the newly-built interval structure (6) according to a sequential construction method, and effectively connecting the main structure with the existing interval structure to ensure the communication of the whole interval.

6. The method according to claim 5, characterized in that the step c of arranging the steel struts (9) between the single row of fender posts (8) is carried out by the steps of: excavating a first layer of soil body of the excavated foundation pit until the first layer of soil body is excavated to the bottom elevation of the group of steel supports (9) on the uppermost layer; then connecting the group of steel supports (9) at the uppermost layer with the crown beams (13) of the single row of fender piles (8); excavating a second layer of soil body of the excavated foundation pit until the second layer of soil body is excavated to the bottom elevation of a group of steel supports (9) with the second height; then connecting the steel support (9) with the single row of fender posts (8) through the wale; and repeating the construction sequence until a group of steel supports (9) at the lowest layer are connected with the single-row fender piles (8) through the wale.

7. The method as claimed in claims 5 to 6, wherein the construction steps of the enclosure structure are as follows: manually cleaning soil on the surface of the fender pile and soil between any two adjacent fender piles; preparing a plurality of connecting pieces, drilling holes in the cleaned fender post, and placing one end of each connecting piece into the fender post; manufacturing a steel bar mesh with a mesh structure by using a plurality of steel bars, and penetrating the other end of the connector through the steel bar mesh; and laying templates on two sides of the reinforcing mesh, pouring concrete between the templates and the fender post, and removing the templates after the concrete is solidified.

8. The method of claim 7, wherein in step d, the soil is excavated downwards continuously, the slope of the soil is 1:0.2, and double layers are hung@150X150 reinforcing mesh, spraying C25 concrete (18) with the thickness of 150mm, and then drilling 2 anchor rods (19); and e, removing the existing structure (20) by adopting a static force breaking method.

Technical Field

The invention belongs to the field of underground structures, and particularly relates to a structure for expanding a metro section in a metro mine method construction interval and a key technical construction method thereof, which are beneficial to solving the metro operation problem and bring better social benefits to the society.

Background

In recent years, the problem of traffic jam in large and medium-sized cities is particularly prominent, so that the development of public traffic is promoted, and more cities begin to build urban rail transit to meet the urban traffic demand. However, subway lines are generally long, and some stations may not be completely communicated due to the reason of a certain station because of the limitation of conditions such as occupied area removal, integrated development or restriction factors encountered during construction. Aiming at the situation, a mode of additionally arranging a single crossover line in front of a station of a checkpoint can be adopted to meet the requirement of operation organization and achieve the purpose of full-line segmented operation. However, the design is usually improved immediately, the reserved crossover condition is not considered during the design, and the construction of the section is completed, so that the vehicle cannot turn back in the section, and only the crossover at the previous section can turn back, and the station between the checkpoint station and the crossover at the previous section cannot be opened for operation. Therefore, it is necessary to provide a structure and a method for opening the station in this area.

Disclosure of Invention

In order to solve the problems, the invention provides a structure for expanding a metro section in a metro mine method construction interval into a transition line section and a key technical construction method thereof. The invention provides a reasonable and feasible design scheme, and realizes the reconstruction of the established subway interval of the mine method through an open cut method and the extension of an interval structure with a transition line segment.

The technical scheme adopted by the invention for solving the technical problems is that a structure for expanding a subway construction interval into a transition line section by a subway mine method comprises a newly-built interval structure between an existing left line interval structure and an existing right line interval structure which are built by the mine method, wherein the newly-built interval structure is a variable-section rectangular structure, the main structure of the newly-built interval structure comprises a structure bottom plate, a side wall and a top plate structure, and the newly-built interval structure is in a gradual change form along the subway line;

the newly-built interval structure is supported by an irregular foundation pit enclosure system, the foundation pit is formed by expanding by an open cut method, the irregular foundation pit enclosure system adopts a combination mode of double-row enclosure piles, prestressed anchoring cables and single-row enclosure piles and steel supports, the concrete structure comprises that the left side and the right side of the foundation pit along the trend of the subway line are supported by the single-row enclosure piles, the single-row enclosure piles on the left side and the right side are connected by the steel supports, the soil bodies at two ends of the foundation pit along the trend of the subway line are provided with the double-row enclosure piles and the prestressed anchoring cables for reinforcement, the lower parts of the double-row enclosure piles are reinforced by a soil nailing wall reinforcing embedded structure, and the upper parts of the double-row enclosure piles are provided with crown beams;

the number of the single row of fender piles is multiple, a crown beam is arranged above each single row of fender piles, and the top ends of the multiple single row of fender piles are fixedly connected with the crown beam into a whole; the steel supports are arranged in parallel from top to bottom, the uppermost group of steel supports is connected with the crown beam, and the rest groups of steel supports are connected with the single row of fender posts through the waist beam; each group of steel supports is provided with a plurality of steel supports which are arranged in parallel from front to back and are uniformly distributed on the same horizontal plane, and two ends of each steel support are respectively fixed on the inner side wall of the waist beam on the same horizontal plane; the steel support is supported by a plurality of temporary stand columns, and the temporary stand columns are fixed on a base of the foundation pit; a retaining wall is arranged at the upper edge of the foundation pit, and a water intercepting ditch is arranged on the outer side of the retaining wall; and arranging an L-shaped crown beam on the soil slope 3-5m away from the pile bottom of the double-row fender pile at two ends of the foundation pit, and arranging a soil nail wall reinforcing and embedding structure at the lower part of the L-shaped crown beam.

Preferably, the pile bodies of the single-row fender pile and the double-row fender pile are both made of slurry and pile body reinforcements, each pile body reinforcement is a prefabricated steel member and is provided with a connecting end, each connecting end consists of a high-strength connecting steel rod and a plug, and the joints of the connecting ends are sealed by epoxy resin; and a crown beam is arranged at the top of the pile body reinforcing piece.

In any of the above solutions, preferably, the slurry is cement mortar formed by pouring and mixing the undisturbed soil of the pile position of the fender pile with a curing agent through a drill hole, so as to form an independent pile body with a cylindrical or rectangular cross section.

In any of the above schemes, preferably, between adjacent single fender piles of the row of piles close to the inner side of the foundation pit in the single row of fender piles and the double row of fender piles, and on the surface of the fender piles facing the inner side of the foundation pit, fender structures with the same height as the fender piles are arranged, the fender structures are made of concrete, reinforcing mesh is arranged in the concrete, and the reinforcing mesh is connected with the fender piles through a plurality of connectors; the connecting piece is a reinforcing steel bar with the diameter of 12-15mm, and the reinforcing mesh is of a reticular structure made of phi 8 round steel with the size of 150mm multiplied by 150 mm.

The invention adopts another technical scheme to solve the technical problems, and the key technical construction method for expanding a metro section into a transition line section structure by a metro mine method construction interval comprises the following steps:

a. constructing a plurality of dewatering wells on the stratum of the designed foundation pit excavation construction area by adopting the dewatering wells, and performing dewatering construction on the stratum by adopting a water suction pump;

b. side lines are excavated along the periphery of a designed foundation pit area, double rows of fender piles and single rows of fender piles are sequentially constructed at related design positions of the foundation pit, and cement mortar is formed on the pile positions of the fender piles by adopting a drilling and pouring method to form independent pile bodies with cylindrical or rectangular sections; hoisting the pile body reinforcement to a pile position, overcoming resistance through a high-frequency vibration hammer and implanting the pile body reinforcement into the formed slurry, splicing the pile body reinforcement through a connecting end, continuously and repeatedly hoisting after splicing, splicing to the bottom of the slurry, and adjusting the plane position and elevation of the pile body reinforcement through a pile top positioning adjusting bolt; then constructing a crown beam at the pile top of the fender pile, and sequentially constructing a retaining wall and a catch basin around the designed excavation position of the foundation pit;

c. sequentially and downwards excavating, and arranging the steel supports among the single row of fender piles; then, arranging a prestressed anchoring cable at the position where the double-row fender post is constructed on the excavated foundation pit wall; excavating a soil body to a position 3-5m away from the pile bottom of the double-row fender pile, reserving a part of soil slope, constructing an L-shaped crown beam on the soil slope, and immediately arranging a prestressed anchoring cable after the design strength is reached; and a fence structure is constructed above the L-shaped crown beam and between the adjacent single fender piles of the row of piles close to the inner side of the foundation pit in the double rows of fender piles;

d. continuously excavating a soil body downwards, spraying concrete to the soil slope construction hanging net, immediately drilling 2 anchor rods, and forming a soil nailing wall reinforced embedding structure after the design strength is reached;

e. continuously excavating the soil body downwards to the designed height position of the newly-built interval structure, and dismantling the existing structure; constructing a fence structure between adjacent single fender piles of the single row of fender piles;

f. and finally, sequentially completing construction of a structural bottom plate, a side wall and a top plate structure for the main structure of the newly-built interval structure according to a sequential construction method, and effectively connecting the main structure with the existing interval structure to ensure the communication of the whole interval.

Preferably, the step c of arranging the steel supports among the single row of fender piles comprises the following construction steps: excavating a first layer of soil body of the excavated foundation pit until the first layer of soil body is excavated to the bottom elevation of the uppermost layer of the steel supports; then connecting the group of steel supports on the uppermost layer with the crown beams of the single row of fender piles; excavating a second layer of soil body of the excavated foundation pit until the second layer of soil body is excavated to the bottom elevation of the group of steel supports with the second height; then connecting the steel support with the single row of fender posts through the wale; and repeating the construction sequence until a group of steel supports at the lowermost layer are connected with the single-row fender piles through the wales.

In any of the above schemes, preferably, the construction steps of the enclosure structure are as follows: manually cleaning soil on the surface of the fender pile and soil between any two adjacent fender piles; preparing a plurality of connecting pieces, drilling holes in the cleaned fender post, and placing one end of each connecting piece into the fender post; manufacturing a steel bar mesh with a mesh structure by using a plurality of steel bars, and penetrating the other end of the connector through the steel bar mesh; and laying templates on two sides of the reinforcing mesh, pouring concrete between the templates and the fender post, and removing the templates after the concrete is solidified.

In any scheme, preferably, in the step d, soil bodies are continuously excavated downwards, the slope of the soil slope is 1:0.2, and double layers are hung@150X150 reinforcing mesh, spraying C25 concrete with the thickness of 150mm, and immediately drilling 2 anchor rods; and e, removing the existing structure by adopting a static force removing method.

The invention is obtained according to years of practical application practice and experience, adopts the best technical means and measures to carry out combined optimization, obtains the optimal technical effect, is not simple superposition and splicing of technical characteristics, and has obvious significance.

The invention has the beneficial effects that:

1. under the condition that a subway section is built, the structure of the subway section is improved by adopting an open cut method, the section structure of a cross section is completed, and conditions are provided for turning back of subway vehicles; the construction method of the invention provides a safe solution for the pile body with insufficient embedding depth, and the fender post is constructed above the existing interval structure, and the embedding depth of the pile body can not be met due to the existence of the lower structure, even under the condition that the base is positioned below the pile end, the soil body at the pile end is reinforced by adopting a mode of reinforcing the embedding structure by the soil nailing wall, so as to prevent the pile end from generating displacement to cause instability of the foundation pit, and the method can be used for solving the problems similar to the foundation pit.

2. The method has the advantages of simple steps, reasonable design, convenient construction, faster construction progress, good construction effect and lower input construction cost. The foundation pit support structure is optimized, combined measures such as construction pipe well dewatering, prestressed anchoring cables, fender piles, steel supports and soil nailing wall reinforcing embedment are fully utilized for supporting, and safety and reliability of the foundation pit support structure are guaranteed. The invention has high practical value, remarkable social benefit and economic benefit and great popularization and application value.

3. The invention inserts the vertically assembled body reinforcement into the slurry pre-formed into a pile on site, and forms the integral fender pile through the crown beam arranged at the top, thereby replacing the existing fender pile structure. The invention has strong field construction operability and high operation efficiency, can ensure the integrity and construction quality of the structure, reduces the construction cost and has good construction implementation effect.

4. By adopting the technical scheme provided by the invention, the enclosure piles, the reinforcing mesh and the concrete are connected into an integral structure, the poured concrete layer is smoother, the thickness of the concrete layer is easier to control, the enclosure piles are well sealed, the waterproof effect of the whole supporting system is ensured, and meanwhile, the reinforcing mesh is arranged between the enclosure piles and the inner wall of the foundation pit, so that the strength of the supporting structure is enhanced.

Drawings

FIG. 1 is a schematic structural plane view of a transition line segment expanded in a subway mine method construction interval according to the present invention;

FIG. 2 is a cross-sectional view of a foundation pit enclosure system of a structure for expanding a transition line section between metro and mine construction intervals according to the present invention;

fig. 3 is a side view of a foundation pit enclosure system of a structure for expanding a transition line section in a subway mine method construction interval.

Wherein, 1-existing left line interval structure central line, 2-existing right line interval structure central line and 3-crossover line central line.

Detailed Description

The invention is further described with reference to the following figures and specific examples, but the scope of the claims is not limited thereto.