CN218933931U

CN218933931U - Reinforcing structure for deep foundation pit adjacent to existing building

Info

Publication number: CN218933931U
Application number: CN202223541198.3U
Authority: CN
Inventors: 刘金桥; 李雪; 王竞翔; 栗尚明; 黄广锴; 王安楚; 赵卫星; 王博
Original assignee: Southwest Petroleum University; China Railway Construction Kunlun Metro Investment Construction Management Co Ltd; Municipal Engineering Co Ltd of China Railway 18th Bureau Group Co Ltd; China Railway Construction Kunlun Investment Group Co Ltd
Current assignee: Southwest Petroleum University; China Railway Construction Kunlun Metro Investment Construction Management Co Ltd; Municipal Engineering Co Ltd of China Railway 18th Bureau Group Co Ltd; China Railway Construction Kunlun Investment Group Co Ltd
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-04-28
Anticipated expiration: 2032-12-29

Abstract

The utility model discloses a reinforcing structure of a deep foundation pit adjacent to an existing building, which comprises an L-shaped grouting reinforcing region, wherein the L-shaped grouting reinforcing region comprises a vertical isolation section and a horizontal isolation section, the vertical isolation section is positioned between an enclosure structure of the foundation pit and an enclosure structure of the existing building, the position of the horizontal isolation section is lower than the bottom surface of the existing building and higher than the bottom surface of the foundation pit, and one side of the vertical isolation section, which is close to the foundation pit, is also provided with a continuous wall. The structure can simultaneously prevent the deformation of the existing structure and the settlement of stratum, effectively improve the self-stabilizing capacity and bearing capacity of soil bodies close to the enclosure structure, reduce the risk of further deformation in the process of excavation of the foundation pit, reduce the influence on surrounding buildings, ensure the normal propulsion of foundation pit construction, and have small disturbance on surrounding environment and good application prospect and economic benefit.

Description

Reinforcing structure for deep foundation pit adjacent to existing building

Technical Field

The utility model relates to the technical field of building reinforcement, in particular to a reinforcement structure of a deep foundation pit adjacent to an existing building.

Background

In recent years, along with the rapid development of modern economy and urban development, the scale of rail transit in China is continuously enlarged, urban land resources are short, and the construction land is focused on longitudinal development in order to relieve the shortage of land. Correspondingly, the scale of the subway foundation pit engineering adjacent to the existing building is gradually enlarged, and the foundation pit engineering has the characteristics of large, tight and deep. The subway station construction scheme directly relates to engineering cost and construction period, and relates to whether construction safety can be ensured.

Due to the shortage of urban land, more foundation pit engineering inevitably needs to be constructed nearby existing rail transit, the influence of the foundation pit engineering on nearby buildings, ground traffic and subway tunnels is not negligible, a subway system is taken as an example, deep foundation pit excavation unloading can break the stress balance of the nearby areas of the nearby subway tunnels, the ground stress field is redistributed, the subway tunnels are further influenced, the existing tunnel structure is deformed in a controllable manner, tunnel duct pieces are cracked in a heavy manner, the daily operation of the subways is influenced, and serious safety accidents are further caused to cause bad social influence; for residential and ancient buildings, foundation pit excavation may cause uneven settlement of surrounding earth surfaces, thereby causing larger cracks in the building and even affecting the safety and stability of the structure.

Disclosure of Invention

The utility model aims to overcome the defect that a deep foundation pit excavated adjacent to an existing subway station is easy to deform in the prior art, and provides a reinforcing structure of the deep foundation pit adjacent to an existing building.

In order to achieve the above object, the present utility model provides the following technical solutions:

the utility model provides a deep basal pit is adjacent the reinforced structure of existing building, contains L type slip casting reinforced region, L type slip casting reinforced region contains vertical isolation section and horizontal isolation section, vertical isolation section is located between the envelope of basal pit and the envelope of existing building, horizontal isolation section's position is less than the bottom surface of existing building, is higher than the bottom surface of basal pit, vertical isolation section is close to basal pit one side still is equipped with the continuous wall.

The deep foundation pit is adjacent to the reinforcing structure of the existing building, the L-shaped isolation area is formed by grouting, larger gaps in the stratum can be effectively filled, particularly, the stratum can be well stabilized for pebble strata, then the cement soil reinforcing body of the continuous wall can be used as a vertically-loaded composite foundation and a large-volume cement stabilized soil body, disturbance to the existing building caused by excavation of the foundation pit is further reduced, the structure can simultaneously prevent deformation of the existing structure and avoid settlement of the stratum, the self-stabilizing capacity and bearing capacity of the soil body adjacent to the building envelope are effectively improved, the risk of further deformation in the excavation process of the foundation pit is reduced, the influence on surrounding buildings is reduced, the disturbance to the surrounding environment is small while the normal propulsion of the foundation pit is ensured, the structure can be applied to stratum reinforcing engineering with poor stability after the pebble layer is precipitated, and the structure has good application prospect and economic benefit.

Preferably, the L-shaped grouting reinforcement area performs grouting through a sleeve valve pipe.

Further preferably, the sleeve valve tube comprises a pvc tube, a plurality of grouting holes are formed in the lower section of the pvc tube, rubber sleeves are arranged on the grouting holes, grouting core tubes are arranged in the pvc tube, plungers are arranged at two ends of each grouting core tube, and the grouting core tubes are used for being communicated with the grouting tubes.

Further preferably, the sleeve valve pipe for constructing the vertical isolation section comprises a pipeline which is arranged obliquely upwards and a pipeline which is arranged horizontally, and the pipeline which is arranged obliquely upwards is positioned above the pipeline which is arranged horizontally.

Further preferably, the sleeve valve pipe for constructing the transverse isolation section is arranged obliquely downwards, and the included angle between the sleeve valve pipe for constructing the transverse isolation section and the horizontal direction is 10-15 degrees.

Further preferably, the distance between the uppermost row of pipelines of the sleeve valve pipe for constructing the transverse isolation section and the bottom surface of the enclosure structure of the existing building is more than or equal to 10cm.

The disturbance to the surrounding environment can be effectively reduced.

Preferably, the continuous wall comprises a plurality of cement stirring piles, and profile steel is arranged in the cement stirring piles.

Further preferably, the section steel is arranged at intervals of one cement mixing pile.

Preferably, the distance between the top surface of the transverse isolation section and the bottom surface of the bottom plate of the existing building is greater than or equal to 4m.

The disturbance to the existing building stratum is reduced, and the settlement can be avoided.

Preferably, the length of the L-shaped grouting reinforcement area is adapted to the length of a standard section of the foundation pit, which coincides with the existing building, and the width of the transverse isolation section is larger than or equal to 15m.

In summary, compared with the prior art, the utility model has the following beneficial effects:

1. the reinforcement structure of the deep foundation pit adjacent to the existing building can simultaneously prevent the existing structure from deforming and prevent stratum from settling, effectively improve the self-stabilizing capacity and bearing capacity of soil bodies adjacent to the enclosure structure, reduce the risk of further deformation in the process of excavation of the foundation pit, reduce the influence on surrounding buildings, ensure normal propulsion of foundation pit construction, have small disturbance on surrounding environment, do not have adverse effect, can be applied to stratum reinforcement engineering with poor stability after precipitation of pebble layers, and have good application prospect and economic benefit.

Description of the drawings:

FIG. 1 is a cross-sectional view of a deep foundation pit adjacent to a reinforcing structure of an existing building in accordance with embodiment 1;

FIG. 2 is a schematic plan view of a deep foundation pit adjacent to a reinforcing structure of an existing building in accordance with embodiment 1;

FIG. 3 is a schematic view of the continuous wall of example 1;

fig. 4 is a schematic view of the structure of the sleeve in embodiment 1.

The marks in the figure: 1-foundation pit, 2-existing building, 3-vertical isolation section, 4-horizontal isolation section, 5-sleeve valve pipe, 61-cement stirring pile, 62-section steel, 7-grouting hole, 8-grouting core pipe and 9-rubber sleeve.

Detailed Description

The utility model is described in further detail below with reference to the accompanying drawings and specific examples. It should not be construed that the scope of the above subject matter of the present utility model is limited to the following embodiments, and all techniques realized based on the present utility model are within the scope of the present utility model.

Example 1

As shown in fig. 1-3, the deep foundation pit adjacent to the reinforcing structure of the existing building comprises an L-shaped grouting reinforcing region, the L-shaped grouting reinforcing region comprises a vertical isolation section 3 and a horizontal isolation section 4, the vertical isolation section 3 is positioned between the enclosure structure of the foundation pit 1 and the enclosure structure of the existing building 2, the position of the horizontal isolation section 4 is lower than the bottom surface of the existing building 2 and higher than the bottom surface of the foundation pit 1, and a continuous wall is arranged on one side of the vertical isolation section 3 close to the foundation pit 1.

Specifically, as shown in fig. 1, the underground structure of the newly-built foundation pit 1 exceeds the negative four layers, the L-shaped grouting reinforcement area is grouted through the sleeve valve pipe 5, during construction, the vertical isolation section 3 is preferably constructed firstly, then the horizontal isolation section 4 is constructed, and the vertical isolation section 3 is constructed along with the foundation pit 1 while being excavated. The hole is formed from the side wall 10/15/18/20m of the foundation pit 1 according to the position of the existing building 2, and the hole position can be properly adjusted according to the position of the dewatering well and the position of the pipeline on the construction site. The aperture can be phi 90mm, a down-the-hole drill is adopted for drilling, after the drilling is carried out to the designed depth, clear water is firstly used for flushing the hole, the sleeve valve pipe 5 is inserted to the designed depth, the sleeve valve pipe 5 is sealed, and the end head of the sleeve valve pipe 5 is exposed out of the enclosure pile arranging wall by 50cm.

The sleeve valve pipe 5 contains the pvc pipe, pvc pipe hypomere is equipped with a plurality of grouting holes 7, be equipped with rubber sleeve 9 on the grouting hole 7, be equipped with grout core pipe 8 in the pvc pipe, grout core pipe 8 both ends all are equipped with the plunger, grout core pipe 8 is used for the intercommunication grouting pipe, and as shown in fig. 4, every 30cm is equipped with grouting hole 7 on the pvc pipe, outsourcing rubber sleeve 9, inserts the drilling, and the pipe end seals, and the intraductal submarine pipe that is full of. Fine sand for the casing material of the pipe section and 1:1 cement slurry is mixed with mortar slurry for filling, the mixing ratio can be adjusted according to the construction condition, and the brittleness and the self-stability of the filling material are ensured. The casing is broken and opened during grouting, so that grouting slurry enters the stratum within the range of one grouting section, and the purpose of unidirectional grouting and no backflow is achieved. The sleeve shell material can seal the annular space between the sleeve valve pipe and the borehole wall, so that slurry flow and slurry leakage on the wall surface during grouting are prevented. The grouting material of the sleeve valve pipe 5 can be cement slurry with the water-cement ratio of 1:1, the water-cement ratio can be properly adjusted according to the actual condition of the site during grouting, and the slurry is preferably cement single slurry. If 3 sleeve valve pipes 5 which are inclined upwards are respectively arranged between each pile in the reinforcing range at the positions of the negative two layers to the negative three layers corresponding to the foundation pit 1, 6 horizontal sleeve valve pipes 5 are arranged at the positions of the negative three layers to the negative four layers, the sleeve valve pipes are arranged in a quincuncial shape, and the vertical spacing of grouting pipes is 1m.

And during grouting, a grouting core pipe 8 with double plugs is placed in the sleeve valve pipe 5 to perform sectional inclined grouting and horizontal grouting, the sleeve valve pipe 5 of the transverse isolation section 4 is constructed to be arranged obliquely downwards, the included angle between the sleeve valve pipe 5 of the transverse isolation section 4 and the horizontal direction is 10-15 degrees, and the distance between the uppermost row of pipelines of the sleeve valve pipe 5 of the transverse isolation section 4 and the bottom surface of the enclosure structure of the existing building 2 is greater than or equal to 10cm. When grouting is carried out in each section, the pressure is firstly increased to enable the slurry to prop open the rubber sleeve 9, the shell material is crushed, namely the ring is opened, and then the slurry enters the stratum. The grouting end standard is that grouting pressure is gradually increased, when the grouting reaches the design final pressure and continues grouting for more than 10min, a certain grouting amount is available, and the grouting amount at the end of grouting is generally below 20-30 min. When the surrounding stratum is inspected, and the cement slurry leaks out of the surface, the surrounding rainwater well and the sewage well, grouting should be suspended for a period of time. After grouting is restored, if grouting is continued, the formation gap is proved to be filled by cement slurry, grouting is immediately stopped, an L-shaped grouting reinforcement area is finally formed, the length (such as the length direction in fig. 2) of the L-shaped grouting reinforcement area is matched with the standard section length of the foundation pit, which is overlapped with the existing building 2, of the foundation pit 1, the width (such as the transverse direction in fig. 1) of the transverse isolation section 4 is larger than or equal to 15m, and the distance between the top surface of the transverse isolation section 4 and the bottom surface of the bottom plate of the existing building 2 is larger than or equal to 4m.

The vertical isolation section 3 is provided with a continuous wall which is constructed by adopting an SMW construction method and is close to the foundation pit 1, the continuous wall comprises a plurality of cement stirring piles 61, and section steel 62 is arranged in the cement stirring piles 61, as shown in figures 2-3. Before the actual construction of the SMW construction method pile, firstly, measuring and lofting is carried out on a construction site, and secondly, after the construction position is determined, the temporary control pile is required to be arranged. In the trench excavation construction, the center line of the cement-soil mixing pile 61 can be excavated by adopting an excavator, after the trench excavation construction is completed, channel steel can be arranged on two sides of the trench, and after the pile position is determined, the drill-down construction can be performed. In the process, the cement slurry is required to be continuously poured, and the stirring head can cut and stir soil according to the sequence from top to bottom and continuously sink to the designed elevation. The section steel can be arranged by adopting H-shaped steel 16 at intervals of one cement mixing pile 61. When the section steel is placed in the stirring pile, the section steel can be hung by a crane, the deviation of the hanging verticality is strictly controlled to be smaller than 1/200, the section steel can be measured by a theodolite, and the newly built foundation pit 1 is reinforced close to the existing building 2 after construction is finished.

The structure is suitable for foundation pits which are close to the existing building and require strict control of deformation of surrounding buildings, for example, the distance between the foundation pit 1 and the existing building 2 is smaller than 10m, the deformation of the enclosure structure of the existing building 2 is smaller than 10mm, differential settlement is smaller than 4mm, the application prospect is wide, the structure can be applied to stratum reinforcement engineering with poor stability after pebble layer precipitation, and the structure has good application prospect and economic benefit, so that the negative influence caused by deformation settlement of the building due to foundation pit excavation is effectively reduced, and the risk level is reduced. The normal pushing of foundation pit construction is ensured, and meanwhile, the disturbance to the surrounding environment is small, and adverse effects are not generated. The method can effectively prevent the settlement deformation damage of the building caused by the disturbance of the soil layer by excavation in the excavation process in time, thereby effectively ensuring the safe and efficient construction under a plurality of serious risk conditions, and reinforcing the targeted risk control of the existing station and the underground excavation region, and has excellent risk control effect. And the vibration noise is small, civilized construction and environmental protection measures are adopted, the influence on the surrounding environment is effectively reduced, and the green construction is achieved.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.

Claims

1. The utility model provides a reinforced structure of deep basal pit adjacent existing building, its characterized in that contains L type slip casting reinforced region, L type slip casting reinforced region contains vertical isolation section (3) and horizontal isolation section (4), vertical isolation section (3) are located between envelope of foundation ditch (1) and the envelope of existing building (2), the position of horizontal isolation section (4) is less than the bottom surface of existing building (2), be higher than the bottom surface of foundation ditch (1), vertical isolation section (3) are close to foundation ditch (1) one side still is equipped with the continuous wall.

2. A deep foundation pit adjacent to a reinforcing structure of an existing building according to claim 1, characterized in that the L-shaped grouting reinforcement zone is grouted by means of sleeve valve pipes (5).

3. The reinforced structure of the deep foundation pit adjacent to the existing building according to claim 2, wherein the sleeve valve pipe (5) comprises a pvc pipe, a plurality of grouting holes (7) are formed in the lower section of the pvc pipe, rubber sleeves (9) are arranged on the grouting holes (7), grouting core pipes (8) are arranged in the pvc pipe, plungers are arranged at two ends of the grouting core pipes (8), and the grouting core pipes (8) are used for communicating the grouting pipes.

4. A reinforcing structure for a deep foundation pit adjacent an existing building according to claim 2, characterized in that the sleeve valve pipe (5) for constructing the vertical isolation section (3) comprises a pipe arranged obliquely upwards and a pipe arranged horizontally, the pipe arranged obliquely upwards being located above the pipe arranged horizontally.

5. A reinforcing structure for a deep foundation pit adjacent to an existing building according to claim 2, characterized in that the sleeve valve pipes (5) constructing the lateral isolation section (4) are arranged obliquely downwards, and the angle between the sleeve valve pipes (5) constructing the lateral isolation section (4) and the horizontal direction is 10-15 °.

6. The reinforced structure of the deep foundation pit adjacent to the existing building according to claim 5, wherein the distance between the uppermost row of pipelines of the sleeve valve pipes (5) for constructing the transverse isolation section (4) and the bottom surface of the enclosure structure of the existing building (2) is greater than or equal to 10cm.

7. A deep foundation pit adjacent to a reinforcing structure of an existing building according to any one of claims 1-6, wherein the continuous wall comprises a plurality of cement mixing piles (61), and section steel (62) is arranged in the cement mixing piles (61).

8. A deep foundation pit adjacent to a reinforcing structure of an existing building according to claim 7, characterized in that said section steel (62) is arranged at intervals of one of said cement mixing piles (61).

9. A deep foundation pit adjacent to a reinforcing structure of an existing building according to any of claims 1-6, characterized in that the distance between the top surface of the lateral isolation section (4) and the bottom surface of the floor of the existing building (2) is greater than or equal to 4m.

10. A deep foundation pit adjacent to a reinforcing structure of an existing building according to any one of claims 1-6, characterized in that the length of the L-shaped grouting reinforcement zone is adapted to the length of a standard section of the foundation pit where the foundation pit (1) coincides with the existing building (2), and the width of the lateral isolation section (4) is greater than or equal to 15m.