CN216765988U - Retaining wall structure at open cut storey-adding vertical shaft position for underground excavation construction - Google Patents

Abstract

The utility model discloses a retaining wall structure at an open-cut storey-adding vertical shaft for underground excavation construction, which comprises a first layer plate support, a plurality of lower layer plate supports and a plate wall, wherein the plate supports and the plate wall are formed by binding steel bars and pouring concrete; each layer of plate support corresponds to one layer of inner support in the foundation pit. The utility model provides reference for the construction of a future rail transit transfer hub and is applied to the projects of the future underground excavation construction and open excavation storey addition; the problem that the underground excavation engineering vertical shaft at the position of the foundation pit fender pile cannot form a pile during underground excavation construction and open excavation storey addition is effectively solved: the construction of the slab supports, the slab walls and the backfill soil is simple to operate, the labor intensity is low, and the construction cost is low; the foundation pit inner support is connected with the plate support, the plate support is connected with the wall of the vertical shaft to form a force transmission system, and the formed retaining wall structure can bear the force of the inner support and resist soil pressure and has a good stress effect; not only protects the foundation pit, but also reduces the influence of construction on surrounding buildings and other facilities.

Description

Retaining wall structure at open cut storey-adding vertical shaft position for underground excavation construction

Technical Field

The utility model belongs to the technical field of underground structure construction, relates to shaft backfill, and particularly relates to a retaining wall structure at a shaft of an open cut storey-adding constructed by subsurface excavation.

Background

At present, underground engineering storey addition mainly focuses on the downward storey addition and reconstruction of existing houses, construction processes and related researches in the aspect are relatively complete, and cases and researches for vertical storey addition of underground buildings are few. In the future, the utilization of underground space begins to develop towards three-dimensional and multi-dimensional, including subway engineering, the increase of lines enables rail transit to develop in a network manner, and more traffic transfer hubs are operated while the rail transit lines are formed into a network. The transfer station can inevitably meet the problem of vertical storey addition, and the construction of the upward storey addition of the underground excavation engineering by adopting an open excavation method is simple and convenient. At present, the construction method combining the light excavation and the dark excavation of the subway station comprises the following steps: open digging at two ends (or cover digging), middle open digging, both-end open digging, middle open digging, left line open digging, right line open digging, side station hall open digging, left line open digging and right line open digging. The research of adopting the underground excavation construction and the open excavation layer-increasing is not developed. After the construction by the underground excavation method is finished, when open excavation layer increasing is adopted, some underground excavation engineering vertical shafts are located at the position of the foundation pit retaining pile, and part of the vertical shafts cannot be formed into piles within the range, so that the foundation pit retaining pile cannot be built, and the conventional vertical shaft backfilling far cannot achieve the effect of the foundation pit retaining pile. If reinforced concrete is adopted for backfilling, the manufacturing cost is high; if one side of a foundation pit in the shaft is used for constructing the concrete retaining wall or other parts of the enclosing and protecting column are filled with backfill, although the manufacturing cost can be reduced, an effective force transmission system is not formed among the concrete retaining wall, the backfill, the shaft wall and the soil layer, and the strength of the backfill in the shaft cannot bear the force of the support in the foundation pit on the concrete retaining wall or the enclosing and protecting column, so that the concrete retaining wall or the column can be toppled, and safety accidents are caused.

Disclosure of Invention

In view of the above, the utility model provides a retaining wall structure at a shaft for building an open cut storey adding by underground excavation, so as to solve the problem that a shaft cannot be formed when the shaft is built by underground excavation and the shaft is built by open cut storey adding.

The technical scheme of the utility model is as follows:

a retaining wall structure for an open-cut storey-adding vertical shaft during underground excavation construction is characterized in that the vertical shaft is located at a fender pile of an open-cut foundation pit, mutual anchoring reinforcing steel bars are reserved, the retaining wall structure comprises a first layer plate support and a plurality of lower layer plate supports which are arranged in the vertical shaft, one side, close to the foundation pit, of the lower portion of each layer plate support in the vertical shaft is provided with a plate wall, and the plate supports and the plate walls are of reinforced concrete structures and are formed by binding reinforcing steel bars and pouring concrete; each layer of plate support corresponds to one layer of inner support in the foundation pit and has the same elevation with the inner support, a steel bar connector is reserved at one side of each layer of plate support close to the foundation pit, the other sides of each layer of plate support are connected with the wall of the vertical shaft through steel bars reserved in the vertical shaft, the first layer of plate support is connected with the crown beam through the reserved steel bar connector and is cast into a whole, and the lower layer of plate support is connected with the inner side plate support of the lower layer of foundation pit through the reserved steel bar connector and is cast into a whole; the other part in the shaft is filled with backfill soil.

Further, the inside concrete foundation that is equipped with of shaft, the inside siding wall in basis that is equipped with of concrete foundation, the inside siding wall in basis and the lower floor first slab brace lower siding wall structure pour as an organic whole.

Furthermore, mutual anchoring steel bars are reserved on the upper portion of the plate wall below the first plate support and connected with the crown beam.

If the designed position of the inner support of the foundation pit is located at the retaining wall structure, construction is carried out according to the inner support construction process and the retaining wall structure (the inner side plate support and the crown beam of the lower-layer foundation pit) is connected.

The beneficial results of the utility model are:

(1) at present, the engineering of open cut added layers built by underground excavation is few, and for the engineering with shallow top plate burial depth, deeper bottom plate burial depth and large engineering section, the influence of geological conditions on full-section underground excavation construction is large, and the engineering risk of large excavation section is high; the open cut method belongs to deep and large foundation pit engineering, the engineering risk is high, the influence on the ground environment is large, and the construction space is limited for the engineering located in the urban area; if the underground excavation is adopted to increase the layer downwards, secondary disturbance can be caused to the open excavation structure and the surrounding environment, and the risk control is not favorable; therefore, for the construction method of building the open-cut added layer by adopting the underground cutting in the engineering, the advantages of the underground cutting method and the open-cut method can be combined, the defects of the two separate working methods can be weakened, the construction risk is reduced, and the construction is more flexible; the method can provide reference for the construction of a future rail transit transfer hub, and is applied to future underground excavation construction and open excavation storey-adding projects;

(2) the problem that the underground excavation engineering vertical shaft positioned at the position of the foundation pit fender pile cannot form a pile when underground excavation construction and open excavation storey addition are carried out is effectively solved, the vertical shaft backfilling and the construction of the plate wall and plate support structure are simple to operate, the labor intensity is low compared with that of a manual hole digging pile, and the construction cost is low;

(3) the foundation pit inner support is connected with the plate support, and the other sides of the plate support are connected with the wall of the vertical shaft, so that a force transmission system can be formed. The formed retaining wall structure can bear the force of the inner support and resist the soil pressure, and the stress effect is good;

(4) the shaft often loses the function after the construction of the underground excavation engineering is finished, and the retaining wall structure is connected with the enclosure structure of the shaft, so that the enclosure structure of the shaft is effectively utilized;

(5) the retaining wall structure that forms can enough protect the foundation ditch, can reduce the influence of construction to building (structure) and other facilities on every side again.

Drawings

Fig. 1 is a schematic view of a retaining wall structure at a position of an open-cut storey-added vertical shaft built by underground excavation in one embodiment of the utility model.

Fig. 2 is a schematic diagram of reinforcing bars of a plate support structure in an embodiment of the utility model.

Fig. 3 is a floor plan of a first floor enclosure of a foundation pit according to an embodiment of the present invention.

Fig. 4 is a plan layout view of two or three layers of building envelopes of a foundation pit in an embodiment of the utility model.

Description of reference numerals:

the foundation comprises a foundation pit 1, a vertical shaft 2, primary backfill plain soil 3, a plate wall concrete foundation 4, a foundation internal plate wall 5, a plate wall structure 6 below a lower layer first road plate support, secondary backfill plain soil 7, a lower layer first road plate support 8, a lower layer first road plate support steel bar connector 9, a lower layer second road plate support lower plate wall structure 10, tertiary backfill plain soil 11, a lower layer second road plate support 12, a lower layer second road plate support steel bar connector 13, a first layer plate support lower plate wall structure 14, fourth backfill plain soil 15, a first layer plate support 16, a first layer plate support steel bar connector 17, a crown beam 18, a lower layer second road pit inner plate support 19, a lower layer first foundation pit inner plate support 20, a foundation pit first layer inner support 21, a foundation pit second layer inner support 22 and a foundation pit third layer inner support 23.

Detailed Description

For the convenience of understanding the technical solution of the present invention, the following description is further explained with reference to the accompanying drawings and specific examples, which are not to be construed as limiting the scope of the present invention.

Example 1

In the embodiment of the utility model, the underground excavation is adopted to build the open excavation storey-adding structure to be the subway transfer station. The method comprises the steps of firstly building a vertical shaft and constructing a transverse passage, reserving mutual anchoring reinforcing steel bars of plate supports of a retaining wall structure for subsequent construction during construction of a vertical shaft enclosure structure, constructing an underground platform layer and a station hall layer by adopting a hole-pile method, then additionally arranging a transfer hall layer on the upper side of a subsurface excavated station by adopting an open excavation method, arranging an enclosure pile in an open excavated foundation pit 1 in a subsurface excavation engineering vertical shaft 2, and forming a pile in the range of the vertical shaft when the enclosure pile is arranged before excavation of the foundation pit, wherein conventional foundation pit enclosure pile construction cannot be carried out.

As shown in fig. 1-4, the wall structure at the position of the open-cut storey-adding shaft is built by subsurface excavation in the embodiment of the utility model, and comprises a first layer plate support 16, a first lower layer plate support 8 and a second lower layer plate support 12 which are arranged in the shaft, each layer plate support corresponds to one layer of inner support in the foundation pit and has the same elevation with the inner support, a steel bar connector is reserved at one side of each layer plate support close to the foundation pit 1, the other sides are connected with the shaft wall through mutual anchoring steel bars reserved in the shaft 2, a plate wall is arranged at one side of the lower part of each layer plate support close to the foundation pit 1, the plate supports and the plate wall are of a reinforced concrete structure and are formed by binding and pouring concrete, a plate wall concrete foundation 4 is arranged in the shaft 1, a foundation inner plate wall 5 is arranged in the plate wall concrete foundation 4, and the foundation inner plate wall 5 and the plate wall structure 6 below the first lower layer plate support are poured into a whole; the upper part of a lower plate wall structure 14 below a first plate support 16 is reserved with mutual anchoring reinforcing steel bars connected with a crown beam 18, the first plate support 16 is connected with the crown beam 18 in a reinforcement penetrating mode through a reserved reinforcing steel bar connector, the first plate support is connected with the crown beam 18 through the reserved mutual anchoring reinforcing steel bars through a lower plate wall structure 14 and poured into a whole, a lower layer first foundation pit inner plate support 20 and a lower layer second foundation pit inner plate support 19 are respectively connected with the lower layer first plate support 8 and the lower layer second plate support 12 in a reinforcement penetrating mode through a reinforcing steel bar connector reserved for constructing a lower layer first plate support 8 and a lower layer second plate support 12, and poured into a whole; the remaining part in the shaft 2 is filled with backfill soil.

The construction method for constructing the retaining wall structure at the open-cut storey-adding vertical shaft by using the underground excavation comprises the following steps:

s1: backfilling plain soil to the bottom of the concrete foundation: after the construction of the underground excavation structure at the lower part is finished, backfilling plain soil 3 to the bottom elevation position of a backfilling layer of a plate wall concrete foundation 4 for the first time in the vertical shaft according to design requirements, wherein the backfilling plain soil is 12.7m high, adopting layered backfilling and layered tamping, and adopting a handheld tamping machine to tamp, wherein the backfilling height of each layer is not more than 1 m;

s2: pouring a concrete foundation of the plate wall: backfilling and pouring the panel wall concrete foundation 4 in layers, wherein the height is 3m, C20 concrete is adopted, the thickness of each layer is not more than 0.5m, a vibrating rod is adopted to vibrate in time, the panel wall concrete foundation is backfilled to the designed elevation in sequence, a panel wall 5 structure positioned in the foundation is constructed, and panel wall reinforcing steel bars are reserved when the last layer is poured so as to be convenient for continuously constructing the panel wall structure in the later period;

s3: constructing a lower plate support and a plate wall: the lower layer first slab brace 8 corresponds to the foundation pit third layer inner support 20, and the lower layer second slab brace 12 corresponds to the foundation pit second layer inner support 19 and has the same elevation with the corresponding inner support.

From supreme construction in proper order down, set up below the first slab props high 5m die carrier support system, die carrier support system adopts die carrier + bamboo offset plate + fastener formula scaffold combination construction. Wherein the parameters of the die carrier are as follows: the concrete wall adopts 6012 mould frame, bamboo plywood with thickness of 20mm is adopted at the corner part, and the inner edge adopts mining10 x 10cm square timber is used, and one timber is vertically arranged at a distance of 0.6 m; the outer edge is made of 10 multiplied by 10cm square wood, one square wood (which can be finely adjusted according to the field and is not more than 10cm) is arranged at a transverse distance of 0.9m, and the U-shaped jacking and 10 multiplied by 10cm square wood are adopted to jack the initial support of the vertical shaft. The construction parameters of the scaffold supporting system are as follows: support system adopts

The fastener type scaffold has a vertical step distance of 90cm, a transverse distance of 90cm and a longitudinal distance of 90 cm. The bottom end of the vertical rod of the scaffold is uniformly provided with longitudinal and transverse ground sweeping rods at the position which is not more than 200mm, the vertical rod is firmly connected with the vertical rod, and a horizontal cross brace is arranged along the longitudinal direction. And constructing a lower-layer first slab support lower slab wall structure 6. The vertical main rib of the plate wall is C22@150, and the double layers are arranged in a two-way manner; the longitudinal distribution ribs are C20@150 and are arranged in a double-layer and bidirectional mode, the structural size is (the length is 15.2m, the width is 6.7m, the height is 0.8m), and the draw hook is arranged in a quincunx shape of A10@300 mm. And after the panel wall reaches the strength, dismantling the formwork support system, and backfilling plain soil 7 to the bottom of the lower-layer first slab support 8 for the second time. And (3) backfilling in layers, wherein the backfilling height of each layer is not more than 1m, horizontally compacting, and tamping by using a handheld tamping machine. Pouring a lower layer first slab support 8 after backfilling, wherein the transverse main rib of the slab support is C22@150, the longitudinal distribution rib is C20@150, the double layers are arranged in a two-way mode, the drag hooks are arranged in a quincunx shape of A10@300 multiplied by 300mm, a lower layer first slab support steel bar connector 9 is reserved at one side close to the foundation pit, and the other sides are connected with the wall of the foundation pit through mutual anchoring steel bars reserved for constructing the underground excavation engineering shaft 2;

erecting a formwork support system with the height of 2.2m below a second slab support, constructing a lower slab wall structure 10 of a lower-layer second slab support by adopting a formwork, a bamboo plywood and a fastener type scaffold, constructing parameters in the same manner, removing the formwork support system after the slab wall reaches the strength, backfilling plain soil 11 to the bottom of the lower-layer second slab support 12 for the third time, backfilling in layers, wherein the backfilling height of each layer is not more than 1m, horizontally compacting, tamping by adopting a handheld tamping machine, pouring the lower-layer second slab support 12 after backfilling is finished, reserving a lower-layer second slab support steel bar connector 13 at one side close to a foundation pit, connecting mutually anchored steel bars reserved at other sides of the underground excavation engineering shaft 2 with the shaft wall, and binding the slab wall and the slab support steel bars;

s4: constructing a first-layer plate to support the following plate walls: erecting a formwork support system with the height of 4.4m below a first-layer formwork support, constructing the formwork support system by combining a formwork, a bamboo plywood and a fastener type scaffold, constructing the plate-wall structure 14 below the first-layer formwork support according to the same parameters as the step S3, constructing the plate-wall reinforcing steel bar binding method according to the step S3, constructing the plate-wall reinforcing steel bar binding method to the bottom of the crown beam 18, dismantling the formwork support system, and reserving mutual anchoring reinforcing steel bars connected with the crown beam 18;

s5: constructing a primary plate support and a crown beam: backfilling plain soil 15 to the bottom of a first-layer plate support 16 for the fourth time in a layered mode, wherein the backfilling height of each layer is not more than 1m, horizontally compacting, compacting by using a handheld tamping machine, the height of the first-layer plate support 16 is the same as that of an inner support 21 of the first layer of the foundation pit, pouring the first-layer plate support 16 after backfilling is finished, the steel bar binding method of the first-layer plate support is the same as that of the step S3, a first-layer plate support steel bar connector 17 is reserved on one side, close to the foundation pit 1, of the first-layer plate support, other sides are connected with a vertical shaft wall through mutually-anchored steel bars reserved in a construction vertical shaft 2, a crown beam 18 is constructed after construction of the first-layer plate support 16 is finished, the crown beam 18 is mutually anchored with the first-layer plate support 16 through the reserved first-layer plate support steel bar connector 17, and mutually-anchored with a plate wall structure 14 reserved under the first-plate support in S4;

s6: pouring an inner side plate support of the foundation pit: excavation foundation pit after concrete slab wall and board prop intensity reach design intensity in the shaft, when treating foundation pit excavation to lower floor's second guidance tape and prop 12, prop reinforcing bar connector 13 through the lower floor's second guidance tape that reserves, adopt and wear the muscle mode and connect 12 main muscle of lower floor's second guidance tape and prop 19 in the second guidance tape pit of lower floor of formwork pouring again. Treat that the foundation ditch excavates when 8 to the first slab of lower floor props, prop the reinforcing bar connector 9 through the first slab of lower floor of reserving, adopt and wear the muscle mode and connect the first slab of lower floor and prop 8 main muscle of lower floor and prop the mould and pour the first foundation ditch inside plate of lower floor and prop 20 again. The inner support 21 of the first layer of the foundation pit and the crown beam 18 are poured at the same time, the inner support 22 of the second layer of the foundation pit and the inner support 23 of the third layer of the foundation pit are constructed according to the inner support construction process and are connected with the inner side plate support 19 of the second foundation pit of the lower layer and the inner side plate support 20 of the first foundation pit of the lower layer of the retaining wall structure.

Claims (4)

1. The utility model provides a retaining wall structure of open cut build-up shaft department is built to undercut which characterized in that: the vertical shaft (2) is positioned at a fender post of the open cut foundation pit (1), mutual anchoring reinforcing steel bars are reserved, the retaining wall structure comprises a first layer plate support (16) and a plurality of lower layer plate supports which are arranged in the vertical shaft (2), a plate wall is arranged on one side, close to the foundation pit (1), of the lower portion of each layer plate support in the vertical shaft, the plate supports and the plate walls are of reinforced concrete structures, and the retaining wall is formed by binding reinforcing steel bars and pouring concrete; each layer of plate support corresponds to one layer of inner support in the foundation pit and has the same elevation with the support in the layer, a reinforcing steel bar connector is reserved at one side of each layer of plate support close to the foundation pit (1), the other sides are connected with the vertical shaft wall through reinforcing steel bars reserved in the vertical shaft (2), the first layer of plate support (16) is connected with the crown beam (18) through the reserved reinforcing steel bar connector and is poured into a whole, and the reinforcing steel bar connector reserved in the lower layer of plate support is connected with the inner side plate support of the lower layer of foundation pit and is poured into a whole; the other part in the vertical shaft (2) is filled with backfill soil.

2. The retaining wall structure at the position of the open-cut storey-adding vertical shaft built by underground excavation according to claim 1, wherein: the concrete wall structure is characterized in that a plate wall concrete foundation (4) is arranged in the vertical shaft (2), a foundation inner plate wall (5) is arranged in the concrete foundation (4), and the foundation inner plate wall (5) and the lower first plate support are cast integrally through the plate wall structure.

3. The retaining wall structure at the position of the open-cut storey-adding vertical shaft built by underground excavation according to claim 1, wherein: mutual anchoring reinforcing steel bars are reserved on the upper portion of the plate wall below the first plate support and connected with the crown beam (18).

4. The retaining wall structure at the position of the open-cut storey-adding vertical shaft built by underground excavation according to claim 1, wherein: if the designed position of the support in the foundation pit is located at the retaining wall structure, the support in the foundation pit is connected with the retaining wall structure.

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