CN216586567U - Pit-in-pit miniature pile supporting structure - Google Patents
Pit-in-pit miniature pile supporting structure Download PDFInfo
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- CN216586567U CN216586567U CN202122804232.0U CN202122804232U CN216586567U CN 216586567 U CN216586567 U CN 216586567U CN 202122804232 U CN202122804232 U CN 202122804232U CN 216586567 U CN216586567 U CN 216586567U
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Abstract
The utility model discloses a pit-in-pit miniature pile supporting structure, which comprises: a plurality of miniature piles, spray anchors, crown beams and inner supports which are driven into the soil body; inserting a steel pipe into the pile body of the miniature pile and pouring pure cement slurry, arranging a crown beam at the top of the miniature pile in a circle, arranging an embedded steel plate in the crown beam, and welding the inner support on the embedded steel plate to form an angle brace and a counter support; after excavation of earth in the pit, carrying out spray anchoring reinforcement on the exposed miniature pile surface, and arranging drainage ditches and protective railings around the slope top; the utility model has high support strength, high rigidity, high bearing capacity, good stability and high anti-overturning capacity, can resist the side pressure of the micro pile soil, reduces displacement and reduces the influence on the surrounding environment; the utility model has fast construction speed, and the micro pile structure can be used as a pit-in-pit brick moulding bed, thereby saving the construction period and the cost.
Description
Technical Field
The utility model belongs to the technical field of construction engineering construction, and particularly provides a pit-in-pit miniature pile supporting structure.
Background
Along with the diversification of building structures, the popularization of main and auxiliary skirt building buildings, particularly elevator shafts, water collecting shafts, foundation equipment and the like of high-rise structures, leads to the fact that the bottoms of most foundation pits are not simple planes, but the foundation pit forms of pits in a large number of foundation pits appear. In foundation pit engineering, people usually care about the stability and safety of a foundation pit in the process of excavating the common foundation pit, and neglect the influence of a pit in the pit on the whole foundation pit. A large number of engineering practices show that the pit-in-pit supporting design is one of the key links in the foundation pit enclosure engineering, and if the pit-in-pit treatment measures are improper, the side wall of the pit is easy to generate landslide and collapse. Particularly, when the pit-in-pit is close to the inner edge line of the external foundation pit, the calculation of the foundation pit needs to consider the influence of the pit-in-pit, and the stress analysis of the whole model of the pit-in-pit and the external foundation pit is established. Usually, the supporting structures need to be reinforced to avoid instability and overturning of the whole foundation pit supporting system caused by pits in pits, so that the engineering piles of the main structure can be displaced, and particularly when the engineering piles are PHC tubular piles, the displacement of a large soil body can cause shearing and cracking damage of the tubular piles, and serious consequences are brought to the whole engineering. Therefore, the design of pit-in-pit support is crucial to the whole foundation pit engineering.
Pit-in-pit supporting modes comprise slope setting, gravity type retaining walls, steel sheet pile supporting, cement mixing piles, high-pressure jet grouting piles, SMW construction method piles and the like, wherein the slope setting is the most common. Generally, the overall stability of foundation pit construction is ensured by comprehensively considering various factors such as excavation depth, site construction conditions and geological conditions. However, when the foundation pit is complex, the excavation depth is large, and the construction operation space is limited, how to improve and innovate the pit-in-pit support so as to achieve the effects of increasing the rigidity of the support system, controlling the displacement of the foundation pit and integrally stabilizing the excavated pit-in-pit, which is a difficult problem.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a pit-in-pit micro pile supporting structure which is used for solving the difficult problems of pit-in-pit supporting when the surrounding environment of a foundation pit is complex, the excavation depth is large and the pit-in-pit distance is close under the soft soil geological condition.
The technical scheme of the utility model is as follows: a pit-in-pit micropile support structure comprising: a plurality of micro piles 1, spray anchors 2, crown beams 3 and inner supports 4 which are driven into a soil body 5; inserting a steel pipe 6 into the body of the miniature pile 1 and pouring pure cement slurry 7, arranging a crown beam 3 on the top of the miniature pile 1 in a circle, arranging an embedded steel plate 8 in the crown beam 3, and welding the inner support 4 on the embedded steel plate 8 to form an angle support and a counter support; after pit-in-pit earthwork 9 is excavated, spray anchors 2 are used for reinforcing the surface of the exposed micro-piles 1, and drainage ditches 10 and protective railings 11 are arranged on the periphery of the top of the slope.
Furthermore, the diameter of the hole formed by the micro-pile 1 is 200mm, the distance is 200mm, the pile length is 8m, the pile end enters the strongly weathered rock stratum for at least 3m, enters the medium weathered rock stratum for at least 2m and enters the slightly weathered rock stratum for at least 1.5 m.
Furthermore, the steel pipe 6 is a seamless steel pipe with the diameter of 150mm, the wall thickness of 4.5mm and the length of 8 m.
Further, the spray anchor 2 is a net hanging spray concrete, the net sheets are formed by welding phi 6mm steel bars, the welding distance is 150 x 150mm, and the spray concrete is C20 concrete with the thickness of 100 mm.
Further, the cross section of the crown beam 3 is 300 × 400mm, 7 HRB 400-grade phi 25mm main ribs 12 are arranged in the crown beam, and phi 8@200mm stirrups 13 are arranged; the strength of the concrete of the crown beam 3 is C30, an embedded steel plate 8 is embedded in advance at the position where the inner support 4 is arranged, and a hanging rib 14 is arranged at the position of the embedded steel plate 8.
Furthermore, the inner support 4 comprises 4 corner supports and 3 opposite supports, 32C I-shaped steel is adopted, two ends of the I-shaped steel are respectively welded with the steel plates 15, the size of each steel plate is 400 x 20mm, and the peripheries of the steel plates 15 and the embedded steel plates 8 are fully welded to form a support structure.
Further, the pure cement slurry 7 is prepared from P.O.42.5 cement by mixing cement slurry: water 1: 0.50 and the grouting pressure is 0.4 MPa.
Furthermore, the specification and size of the embedded steel plate 8 are 400 × 20mm, 3 HRB 400-grade phi 25mm U-shaped steel bars 16 are vertically arranged on the back face, the distance is 150mm, and the embedded steel plates are welded with the embedded steel plate 8 and anchored into the crown beam 3 by 300 mm.
Furthermore, the drainage ditch 10 is built by sand-lime bricks, the size is 500 × 300mm, and the surfaces of the two sides within 50mm are protected by fine aggregate concrete.
Furthermore, the height of the guard rail 11 is 1200mm, a skirting board is arranged in the range of 300mm at the bottom, the guard rail 11 is made of a steel pipe, and the cross section is phi 48.3 x 3.6 mm; the vertical interval is 600mm one, and the horizontal interval is 1500mm one.
Furthermore, the hanging ribs 14 are HRB 400-grade steel bars with the diameter of 25mm, the length of the steel bars is 800mm, and the steel bars are bent into trapezoids.
The utility model has the following beneficial effects:
the utility model mainly comprises a micro pile, a steel pipe, a spray anchor, a crown beam and an inner support, wherein the steel pipe is inserted after the micro pile is formed into a hole, pure cement slurry is poured inside and outside the steel pipe, a reinforced concrete crown beam is constructed on the top of the micro pile, a steel plate embedded in the crown beam is connected with the inner support to form a stressed structure, and when the earthwork is excavated, concrete is sprayed on the micro pile surface on the excavated side, and the concrete is sprayed along with the excavation; the utility model has high support strength, high rigidity, high bearing capacity, good stability and high anti-overturning capacity, can resist the side pressure of the micro pile soil, reduces displacement and reduces the influence on the surrounding environment; the utility model has fast construction speed, and the micro pile structure can be used as a pit-in-pit brick moulding bed, thereby saving the construction period and the cost; the construction process is simple and clear, and the operation is not difficult; the utility model has small pile spacing, the excavation surface is provided with the spray anchor, the water stop effect is good, the soil layer in the excavation range can be ensured to be dry, and the water lowering and discharging equipment and the labor input are reduced; the utility model can adjust the size, parameters and the like according to geological conditions, site conditions, construction working faces and the like, and has stronger flexibility and applicability.
Drawings
FIG. 1 is a plan view of a pit-in-pit micropile support structure of the present invention;
FIG. 2 is a vertical cross-sectional view of the micro-pile supporting structure of the pit-in-pit of the present invention;
FIG. 3 is a transverse cross-sectional view of a micro-pile support structure for a pit-in-pit of the present invention;
FIG. 4 is a schematic view of a micropile according to the present invention;
FIG. 5 is a schematic view showing the connection between the micro-piles and the crown beams according to the present invention;
FIG. 6 is a schematic view of the connection of the inner support to the crown beam in the present invention;
FIG. 7 is a plan view of a pre-buried steel plate according to the present invention;
FIG. 8 is a cross-sectional view of a pre-buried steel plate according to the present invention;
in the figure: 1. micro-piles; 2. spraying an anchor; 3. a crown beam; 4. an inner support; 5. a soil body; 6. a steel pipe; 7. pure cement slurry; 8. pre-burying a steel plate; 9. pit-in-pit earthwork; 10. a drainage ditch; 11. a guard rail; 12. a main rib; 13. hooping; 14. hanging the ribs; 15. a steel plate; 16. u-shaped steel bars.
Detailed Description
The utility model is described in detail below with reference to the figures and examples.
As shown in fig. 1 to 8, a micro pile supporting structure for pit-in-pit includes: a plurality of micro piles 1, spray anchors 2, crown beams 3 and inner supports 4 which are driven into a soil body 5; inserting a steel pipe 6 into the pile body of the micro pile 1 and pouring pure cement slurry 7, arranging a crown beam 3 on the top of the micro pile 1 in a circle, arranging an embedded steel plate 8 in the crown beam 3, and welding an inner support 4 on the embedded steel plate 8 to form a corner support and a counter support, thereby forming a complete pit-in-pit supporting stress system; after pit-in-pit earthwork 9 is excavated, spray anchors 2 are used for reinforcing the surface of the exposed micro-piles 1, and drainage ditches 10 and protective railings 11 are arranged on the periphery of the top of the slope.
In the embodiment of the utility model, the diameter of the hole formed by the micro-pile 1 is 200mm, the distance is 200mm, the pile length is 8m, the pile end enters the strongly weathered rock stratum for at least 3m, enters the medium weathered rock stratum for at least 2m and enters the slightly weathered rock stratum for at least 1.5 m.
In the embodiment of the utility model, the steel pipe 6 is a seamless steel pipe with the diameter of 150mm, the wall thickness of 4.5mm and the length of 8 m.
In the embodiment of the utility model, the spray anchor 2 is the hanging net sprayed concrete, the net sheets are welded by phi 6mm steel bars, the welding distance is 150 x 150mm, and the sprayed concrete is C20 concrete with the thickness of 100 mm.
In the embodiment of the utility model, the cross section of the crown beam 3 is 300 x 400mm, 7 HRB 400-grade phi 25mm main ribs 12 are arranged in the crown beam, and phi 8@200mm stirrups 13 are arranged; the strength of the concrete of the crown beam 3 is C30, an embedded steel plate 8 is embedded in advance at the position where the inner support 4 is arranged, and a hanging rib 14 is arranged at the embedded steel plate 8.
In the embodiment of the utility model, the inner support 4 comprises 4 corner supports and 3 opposite supports, 32C I-steel is adopted, two ends of the I-steel are respectively welded with steel plates 15, the size of the steel plates is 400 x 20mm, and the peripheries of the steel plates 15 and the embedded steel plates 8 are fully welded to form a support structure; the inner support 4 must take reliable welding measures to prevent support falling due to pile deformation and construction impact.
In the embodiment of the utility model, the pure cement slurry liquid 7 is prepared by selecting P.O.42.5 cement, and the mixing ratio of the cement slurry is cement: water 1: 0.50 and the grouting pressure is 0.4 MPa.
In the embodiment of the utility model, the specification and size of the embedded steel plate 8 are 400 × 20mm, 3 HRB 400-grade phi 25mm U-shaped steel bars 16 are vertically arranged on the back surface, the distance is 150mm, and the embedded steel plate 8 is welded and anchored into the crown beam 3 by 300 mm.
In the illustrated embodiment of the utility model, the gutters 10 are constructed of sand-lime bricks, 500 x 300mm in size, and are faced with fine aggregate concrete on both sides within 50 mm.
In the embodiment of the utility model, the height of the protective railing 11 is 1200mm, the range of the bottom 300mm is provided with a skirting board, the protective railing 11 is made of a steel pipe, and the cross section is phi 48.3 x 3.6 mm; the vertical interval is 600mm one, and the horizontal interval is 1500mm one.
In the embodiment of the utility model, the hanging ribs 14 are HRB 400-grade steel bars with the diameter of 25mm, the length of the steel bars is 800mm, and the steel bars are bent into trapezoids.
The utility model relates to a mini-pile 1, which is constructed by firstly setting out and positioning, adopting a geological drilling machine to form a hole, then hanging a steel pipe, enabling a grouting pipe and the steel pipe to enter the hole, enabling the lower end of the grouting pipe to extend into the bottom of the hole, pressing the grouting pipe upwards from the bottom of the hole in a reverse direction, pressing out water or mud at the bottom of the hole, and stopping when normal cement slurry returns from an orifice.
When the spray anchor 2 is constructed, the spraying is sequentially carried out in sections, the spray head is perpendicular to the wall surface, the distance between the spray head and the wall surface is preferably 0.6-1.0 m, the spraying in the same section is uniformly sprayed from bottom to top, and the once spraying thickness is preferably 30-80 mm.
When the earthwork 9 in the pit is excavated, the earthwork is required to be excavated in a layered, segmented and symmetrical mode, over-excavation is strictly forbidden, the excavation depth is not more than the supporting elevation of the position, each path of support is completed, and the next layer of earthwork can be excavated and supported after the structural strength reaches 80%; the thickness of the excavated earth on each layer is not more than 3m, and the specific layering thickness and the segmentation length can be properly adjusted according to the field condition.
The utility model can be adjusted according to the actual situation of the site, and the embodiment only briefly describes the micro-pile supporting structure under specific conditions.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (10)
1. The utility model provides a little stake supporting construction in hole which characterized in that includes: a plurality of micro piles (1), spray anchors (2), crown beams (3) and inner supports (4) which are driven into a soil body (5); a steel pipe (6) is inserted into the pile body of the miniature pile (1) and pure cement slurry (7) is poured, a crown beam (3) is arranged on the top of the miniature pile (1) in a circle, an embedded steel plate (8) is arranged in the crown beam (3), and the inner support (4) is welded on the embedded steel plate (8) to form a corner support and a counter support; after pit earth (9) in the pit is excavated, the surface of the exposed micro-pile (1) is reinforced by the spray anchor (2), and drainage ditches (10) and protective railings (11) are arranged around the top of the slope.
2. A pit-in-pit micropile support structure according to claim 1, wherein said micropiles (1) have a bore diameter of 200mm, a pitch of 200mm, a pile length of 8m, a pile tip entering the strongly weathered rock formation of at least 3m, entering the moderately weathered rock formation of at least 2m, and entering the slightly weathered rock formation of at least 1.5 m.
3. A pit-in-pit micropile support structure according to claim 1, characterised in that the steel pipe (6) is a seamless steel pipe with a diameter of 150mm, a wall thickness of 4.5mm and a length of 8 m.
4. A micro-pile support structure in a pit according to claim 1, wherein the spray anchors (2) are mesh-hung shotcrete, the mesh sheets are welded by steel bars with a diameter of 6mm, the welding distance is 150 x 150mm, and the shotcrete is C20 concrete with a thickness of 100 mm.
5. A micro-pile support structure in a pit according to claim 1, characterized in that the cross-sectional dimension of the crown beam (3) is 300 x 400mm, 7 HRB 400-grade phi 25mm main bars (12) are built in, and phi 8@200mm stirrups (13) are provided; the concrete strength of the crown beam (3) is C30, an embedded steel plate (8) is embedded in advance at the position where the inner support (4) is arranged, and a lifting rib (14) is arranged at the position of the embedded steel plate (8).
6. A micro pile support structure in a pit according to claim 1, characterized in that the inner support (4) comprises 4 corner supports and 3 opposite supports, 32C i-steel is adopted, steel plates (15) are welded at two ends of the i-steel respectively, the size of the steel plates is 400 x 20mm, and the steel plates (15) and the embedded steel plates (8) are fully welded at the periphery to form the support structure.
7. A pit-in-pit micropile supporting structure as claimed in claim 1, wherein the size of the pre-buried steel plate (8) is 400 x 20mm, 3 HRB 400-grade phi 25mm U-shaped steel bars (16) are vertically arranged on the back side, the spacing is 150mm, and the pre-buried steel plate (8) is welded and anchored into the crown beam (3) by 300 mm.
8. A pit-in-pit micropile support structure as claimed in claim 1 in which the drainage gutters (10) are constructed from sand-lime bricks of 500 by 300mm size faced with fine concrete on both sides to 50 mm.
9. A pit-in-pit micropile supporting structure according to claim 1, wherein the height of the protective railing (11) is 1200mm, a base board is arranged within 300mm, the protective railing (11) is made of a steel pipe, and the cross-sectional dimension is phi 48.3 x 3.6 mm; the vertical interval is 600mm one, and the horizontal interval is 1500mm one.
10. A micro-pile support structure in pit according to claim 5, characterized in that the said hanging bars (14) are HRB400 grade 25mm steel bar with a diameter of 800mm, bent into trapezium shape.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122804232.0U CN216586567U (en) | 2021-11-16 | 2021-11-16 | Pit-in-pit miniature pile supporting structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202122804232.0U CN216586567U (en) | 2021-11-16 | 2021-11-16 | Pit-in-pit miniature pile supporting structure |
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| CN216586567U true CN216586567U (en) | 2022-05-24 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116716897A (en) * | 2023-06-12 | 2023-09-08 | 上海宝冶集团有限公司 | Groove supporting method under limited space working condition |
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2021
- 2021-11-16 CN CN202122804232.0U patent/CN216586567U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116716897A (en) * | 2023-06-12 | 2023-09-08 | 上海宝冶集团有限公司 | Groove supporting method under limited space working condition |
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