CN110616715A - Construction method of foundation pit supporting soil nailing wall - Google Patents
Construction method of foundation pit supporting soil nailing wall Download PDFInfo
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- CN110616715A CN110616715A CN201910869596.1A CN201910869596A CN110616715A CN 110616715 A CN110616715 A CN 110616715A CN 201910869596 A CN201910869596 A CN 201910869596A CN 110616715 A CN110616715 A CN 110616715A
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- soil
- foundation pit
- side plate
- hole
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/76—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Piles And Underground Anchors (AREA)
Abstract
The invention provides a construction method of a foundation pit supporting soil nailing wall, and relates to the technical field of in-situ soil body reinforcement. According to the invention, the pore channel is subjected to reaming treatment, the part with the enlarged local inner diameter in the pore channel is filled with cement slurry after grouting, the local inner diameter of the column body formed after grouting is larger, the part with the larger local inner diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the local column body embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, and the pulling resistance of the column body formed after grouting is improved.
Description
Technical Field
The invention relates to the technical field of in-situ soil body reinforcement, in particular to a foundation pit supporting soil nailing wall construction method.
Background
The soil nailing wall is an in-situ soil body reinforcement technology, and is a slope reinforcement type support construction method which is characterized in that a foundation pit slope is reinforced through soil nails made of reinforcing steel bars, a reinforcing mesh is laid on the surface of the slope, and then a layer of concrete surface layer and an earthwork slope are sprayed.
At present, in practical use, the reinforced concrete retaining wall is constructed into a composite body formed by firmly bonding a reinforced rod piece (namely a soil nail or an anchor rod) arranged in a slope body and a surrounding soil body, and a supporting structure similar to a gravity retaining wall formed by a surface layer, wherein a common reinforced rod piece (namely the soil nail or the anchor rod) has a rough cylindrical hole channel.
However, the rough cylindrical hole has smaller pulling resistance when the column is formed by grouting.
Disclosure of Invention
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides a construction method of a foundation pit supporting multi-section extruded broad soil nailing wall, and solves the problem of small pulling resistance of a grouting formed column.
(II) technical scheme
In order to achieve the purpose, the invention is realized by the following technical scheme:
a foundation pit supporting soil nailing wall construction method comprises the following steps:
s100: excavating a foundation pit;
s200: drilling holes on the side wall of the foundation pit to form soil nail holes;
s300: selecting a hole expansion node in the soil nail hole, and expanding the hole expansion node to form a widening part;
s400: placing the soil nails into the soil nail holes after reaming;
s500: grouting the soil nail hole in which the soil nail is placed;
s600: fixedly paving a reinforcing mesh on the side wall of the foundation pit after grouting, and spraying concrete at the position where the reinforcing mesh is paved to form a concrete surface layer;
wherein the distance between the reaming nodes is 0.5-1 m.
Preferably, after step S600, the foundation pit at the lower layer is excavated.
Preferably, in step S100, the depth of the foundation pit is 0.5m below the aperture position of the soil nail hole.
Preferably, in step S300, the reaming node is reamed using an extruder.
Preferably, the spreader includes;
a body having a cavity along a length direction;
a core positioned within the body cavity, the core being movably connected to the body cavity, and the core first end extending from the body first end;
an extruded wide portion comprising:
an extrusion having a first end connected to the core first end and a second end connected to the body first end; and, the widening member can be bent outward.
Preferably, the spreader comprises:
a first side plate connected at a first end to the body first end;
a second side plate, the second side plate second end connected with the core first end; and the second end of the first side plate is flexibly connected with the first end of the second side plate.
Preferably, the spreader comprises:
a first side plate, the first side plate first end being hingedly connected to the body first end;
a second side panel having a second end hingedly connected to the core first end; and the second end of the first side plate is hinged with the first end of the second side plate.
Preferably, the body comprises:
the pipe portion, two are no less than to the pipe portion, just, two are adjacent the pipe portion passes through threaded fixed connection.
The core includes:
the number of the rod parts is not less than two, and the two adjacent rod parts are fixedly connected through threads.
Preferably, in step S300, the distance between the reamer node and the side wall of the foundation pit is greater than 1.5 m.
Preferably, in step S300, the diameter of the widened portion is 1.5 to 2 times of the diameter of the hole of the soil nail hole.
(III) advantageous effects
The invention provides a construction method of a foundation pit supporting soil nailing wall. Compared with the prior art, the method has the following beneficial effects:
according to the foundation pit supporting soil nailing wall construction method provided by the invention, hole expansion treatment is carried out on the hole, cement slurry is filled in the part with the enlarged local inner diameter in the hole after grouting, the local inner diameter of a cylinder formed after grouting is larger, and the part with the larger local inner diameter of the cylinder is embedded into the soil body, so that the stress state of the soil around the cylinder is changed, the local cylinder embedded into the soil body provides larger resistance, the cylinder has soil body friction force, cohesive force and multi-end fulcrum bearing force, and the pulling resistance of the cylinder formed after grouting is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic cross-sectional view of a foundation pit supporting soil nailing wall;
FIG. 2 is a schematic view of the expanding device in an expanded state;
FIG. 3 is a schematic view of the spreader in a contracted state;
FIG. 4 is a schematic view of the expanding portion of the expanding device;
FIG. 5 is a schematic of the core of the expressor;
the foundation pit comprises a foundation pit 1, a foundation pit side wall 11, a soil nail hole 2, an extrusion part 21, a soil nail 3, a reinforcing mesh 4, a body part 100, a boss 101, a pipe part 110, a core part 200, a handle 202, a groove 203, a rod part 210, an extrusion part 300, an extrusion part 310, a first side plate 320, a first concave part 321, a first convex part 322, a second side plate 330, a second concave part 331 and a second convex part 332.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the application provides a foundation pit supporting soil nailing wall construction method, and solves the problem that a column formed by grouting is small in pulling resistance.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to the construction method of the foundation pit supporting soil nailing wall, provided by the invention, through carrying out reaming treatment on the hole, after grouting, the soil nail has soil body friction force, cohesive force and multi-end fulcrum bearing force, the stress state of the soil around the rod piece is changed, and thus the pulling resistance of a column body formed after grouting is improved.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
A construction method of a foundation pit supporting soil nailing wall is shown in figure 1 and comprises the following steps:
s100: excavating a foundation pit 1;
s200: drilling a hole on the side wall 11 of the foundation pit 1 to form a soil nail hole 2;
s300: a hole expansion node is selected in the soil nail hole, and hole expansion is carried out on the hole expansion node to form a widening part 21;
s400: placing the soil nails 3 into the soil nail holes 2 after reaming;
s500: grouting the soil nail hole 2 in which the soil nail 3 is placed;
s600: fixedly paving the reinforcing mesh 4 on the side wall 11 of the foundation pit after grouting, and spraying concrete at the position where the reinforcing mesh 4 is paved to form a concrete surface layer;
wherein the distance between the reaming nodes is 0.5-1 m.
Specifically, in step S100, the excavation work of the foundation pit 1 is performed while ensuring the flatness of the foundation pit side wall 11. When stagnant water and residual interlaminar diving occur, the foundation pit needs to be drained, and the stagnant water on the upper layer can be dredged by measures such as drainage tubes and the like; after the excavation work of the foundation pit 1 is completed, soil nail hole sites are marked at the position of the side wall 11 of the foundation pit, and when the soil nail hole sites are marked on the side wall 11 of the foundation pit according to the gradient of the soil texture of the construction site and the side wall 11 of the foundation pit, the horizontal distance between the soil nail hole sites is 1-2 m, the vertical distance between the soil nail hole sites is 1-2 m, and the soil nail hole sites on the upper layer and the lower layer are arranged in a quincunx shape.
In step S200, performing hole forming construction on the marked soil nail hole site, wherein hole forming construction can be performed by using a luoyang shovel or other jumbolter equipment according to the longitudinal dimension, the transverse dimension and the horizontal plane included angle of a set scheme during construction;
in step S300, when the distance between the reaming nodes is small, the resultant resistance force provided by the soil body between the extruded and widened parts 21 is small, and when the distance between the reaming nodes is large, the passive soil pressure of the soil body between the extruded and widened parts 21 cannot be fully utilized, so that the distance between the reaming nodes is 0.5-1 m;
in step S400, before the soil nails 3 are placed, the soil nails 3 are subjected to rust and oil removal treatment, and strength inspection is performed; in order to position the soil nails 3 at the center of the soil nail holes 2, positioning brackets are arranged every 2.0m along the length direction of the soil nails 3 and fixed on the soil nails 3, and the diameters of the positioning brackets are the same as the diameter of the pore passages of the soil nail holes 2.
In step S500, during grouting, a gravity grouting method may be adopted, and grouting is performed until the orifice overflows, and grouting is supplemented for 2-3 times before initial setting until the grout is full. Plugging the hole in the weak position by filling soil or spraying concrete; the slurry should be stirred uniformly and used immediately, and the pipeline needs to be flushed by water before the grouting is started, and the pipeline is stopped in the middle or after the operation is finished. After grouting is finished, arranging a hook at the exposed end part of the main reinforcement of the soil nail, and fixedly connecting the hook with the end part of the through long reinforcing rib of the adjacent soil nail; and in the grouting process, cement paste is adopted, the water-cement ratio of the cement paste is 0.5, and the strength grade of the cement paste is not lower than M20.
In step S600, the reinforcing mesh 4 is fixedly laid on the side wall 11 of the foundation pit after grouting, concrete is sprayed at the position where the reinforcing mesh 4 is laid to form a concrete surface layer, the thickness of the concrete surface layer is not less than 10cm, the selected concrete strength is not lower than C20, and the spraying sequence of the working surface is from bottom to top; and curing the concrete surface layer after the spraying is finished.
According to the construction method provided by the embodiment, the part of the internal diameter of the hole of the soil nail hole 2 which is expanded after grouting is filled with cement slurry, the part of the internal diameter of the column body which is formed after grouting is larger, the part of the larger part of the internal diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the part of the column body which is embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, and the pulling resistance of the column body formed after grouting is improved.
In the implementation process of the embodiment, after the step S600, the foundation pit (1) at the lower layer is excavated.
Specifically, during the construction of the soil nailing wall, in order to prevent collapse, a layered construction method is adopted, wherein the foundation pit 1 is excavated in layers according to the arrangement of the soil nailing holes, and the lower layer can be excavated after the strength of the upper concrete surface layer reaches 70% of the design strength, so after the step S600 is completed and the strength of the upper concrete surface layer reaches 70% of the design strength, the excavation work of the foundation pit 1 of the next layer is carried out, and the steps S100-S600 are repeated until the soil nailing wall reaches the expected set requirement.
In the implementation process of the above embodiment, in step S100, the depth of the foundation pit 1 is 0.5m below the aperture position of the soil nail hole 2.
During the construction, in order to facilitate the operation of constructors, the depth of the foundation pit 1 is not too deep or too shallow, and according to the actual construction condition, when the depth of the foundation pit 1 is 0.5m below the hole opening position of the soil nail hole 2, the construction is most convenient.
In one embodiment, as shown in fig. 2-5, in step S300, a reamer is used to ream the reamed node.
In the implementation of the above embodiment, the spreader includes a body 100, a core 200, and a spreader 300; the body 100 has a cavity along a length direction; the core 200 is located in the cavity of the body 100, the core 200 is movably connected with the cavity of the body 100, and a first end of the core 200 extends out of the first end of the body 100; the widening 300 comprises a widening 310, a first end of the widening 310 being connected to a first end of the core 200, a second end of the widening 310 being connected to a first end of the body 100; and the widening 310 can be bent to the outside.
Specifically, in order to ensure that the widening member 310 is bent outward, the widening member 310 has a length greater than the distance that the first end of the core 200 extends from the first end of the body 100 when it is straightened, the widening member 310 maintains the outward bent state when it is not in use, and the diameter of the widened portion 300 after bending is smaller than the diameter of the hole. The second end of the core 200 is provided with a handle 202
In the using process, after the hole expanding node is selected, the extruding and widening device extends into the hole expanding node in the soil nail hole channel, the body part 100 is fixed, the core part 200 is moved backwards, and at the moment, one end part of the extruding and widening part 310 moves backwards under the driving of the core part 200; since one end of the widening member 310 is connected to the first end of the core 200, the other end of the widening portion 300 is connected to the first end of the body 100, and the widening portion 300 can be bent outward; when one end of the broad extrusion part 300 moves backwards, the broad extrusion part 300 bends outwards to extrude the soil layer in the pore canal, so that the partial inner diameter of the common cylindrical pore canal is enlarged; the column body is characterized in that the expanded part of the local inner diameter in the pore channel after grouting is filled with cement slurry, the local inner diameter of the column body formed after grouting is larger, the larger part of the local inner diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the local column body embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, and the pulling resistance of the column body formed after grouting is improved.
In one embodiment, the spreader 310 shown in fig. 2-5 includes a first side plate 320 and a second side plate 330; the first side plate 320 is connected at a first end thereof to the first end of the body 100; the second end of the second side plate 330 is connected to the first end of the core 200; and the second end of the first side plate 320 is flexibly connected to the first end of the second side plate 330.
Specifically, after the hole expansion joint is selected, the extruding device extends into the hole expansion joint in the soil nail hole channel, the body part 100 is fixed, the core part 200 is moved backwards, and the second end part of the second side plate 330 is connected with the first end part of the core part 200; the second side plate 330 moves backward by the core 200; the first side plate 320 is connected at a first end thereof to the first end of the body 100; moreover, the flexible connection portion between the second end of the first side plate 320 and the first end of the second side plate 330 is bent outwards; when the second side plate 330 moves backwards, the flexible connection part between the second end of the first side plate 320 and the first end of the second side plate 330 bends outwards to squeeze the soil layer in the hole, so that the partial inner diameter of the common cylindrical hole is enlarged; the column body is characterized in that the expanded part of the local inner diameter in the pore channel after grouting is filled with cement slurry, the local inner diameter of the column body formed after grouting is larger, the larger part of the local inner diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the local column body embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, and the pulling resistance of the column body formed after grouting is improved.
In one embodiment, as shown in fig. 2-5, the spreader 310 includes a first side plate 320 and a second side plate 330; a first side plate 320 is hinged at a first end to the body 100; the second end of the second side plate 330 is hinged with the first end of the core 200; and a second end of the first side plate 320 is hingedly connected to a first end of the second side plate 330.
Specifically, the present embodiment provides a hinge manner:
the first end of the first side plate 320 has a first concave portion 321, and the second end of the first side plate 320 has a first convex portion 322; the first end of the second side plate 330 has a second concave portion 33l, and the second end of the second side plate 330 has a second convex portion 332;
the first concave portion 321 is provided with a first hole, and the first convex portion 322 is provided with a first shaft pin; the second recess 331 is provided with a second hole, and the second protrusion 332 is provided with a second shaft pin; when in use, the first shaft bolt of the first side plate 320 is hinged with the second hole of the second side plate 330;
the first end of the body 100 is provided with a boss 101, and the boss 101 is provided with a third shaft bolt; the first end of the core 200 has a groove 203, and a third hole is provided on the groove 203;
the first hole of the first side plate 320 is hinged with the third shaft bolt, and the second shaft bolt of the second side plate 330 is hinged with the third hole;
it should be noted that the present embodiment may also be hinged in other ways, and is not limited to the solution provided above.
Specifically, after the hole expansion joint is selected, the expanding device extends into the hole expansion joint in the soil nail hole channel, the body part 100 is fixed, the core part 200 is moved backwards, and the second side plate 330 is driven by the core part 200 to move backwards; the first side plate 320 is hinged to the first end of the body 100; the second side panel 330 is hinged to the first end of the core 200; moreover, the hinged part of the first side plate 320 and the second side plate 330 is bent outwards; when the second side plate 330 moves backwards, the hinged part of the first side plate 320 and the second side plate 330 bends outwards to extrude the soil layer in the hole, so that the partial inner diameter of the common cylindrical hole is enlarged; the column body is characterized in that the expanded part of the local inner diameter in the pore channel after grouting is filled with cement slurry, the local inner diameter of the column body formed after grouting is larger, the larger part of the local inner diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the local column body embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, and the pulling resistance of the column body formed after grouting is improved.
In one embodiment, as shown in fig. 2 to 5, the body 100 includes tube parts 110, the number of the tube parts 110 is not less than two, and two adjacent tube parts 110 are fixedly connected by a screw thread.
The core 200 includes the rod parts 210, the number of the rod parts 210 is not less than two, and two adjacent rod parts 210 are fixedly connected by a screw thread.
The invention provides a preferable thread fixing connection mode: the first end of the pipe part 110 is provided with an internal thread, the first end of the pipe part 110 is also provided with a first pin hole, the second end of the pipe part 110 is provided with an external thread, and the second end of the pipe part 110 is also provided with a second pin hole; the two adjacent pipe parts 110 are fixedly connected through threads, and after the threads are fixed, the first pin hole corresponds to the second pin hole, and the pin shaft is inserted for fixation.
The first end of the rod part 210 is provided with internal threads, the first end of the rod part 210 is also provided with a third pin hole, the second end of the rod part 210 is provided with external threads, and the second end of the rod part 210 is also provided with a fourth pin hole; the two adjacent rod parts 210 are fixedly connected through threads, and after the threads are fixed, the third pin hole corresponds to the fourth pin hole and the pin shaft is inserted for fixation.
In the actual use process, because the length of pore is different to, the required position depth that crowds is different, the crowded device that widens of pore of fixed length can not satisfy actual construction demand. The body 100 is composed of a plurality of pipe parts 110, and two adjacent pipe parts 110 are fixedly connected in the above way; the core 200 is composed of a plurality of rod parts 210, and two adjacent rod parts 210 are fixedly connected in the above manner;
since the core 200 is rotated for expansion and contraction, if the core 200 is rotated with pure screw threads, the tube part 110 or the rod part 210 may be detached when the rotation direction is the unscrewing direction; the connection mode is fixed by using a pin shaft, so that the pipe part 110 or the rod part 210 can be prevented from being separated; when facing the crowded broad position of different degree of depth, only need the quantity of adjustment pipe portion 110 and pole portion 210, very big improvement the crowded broad device's of pore commonality.
In one embodiment, in step S300, the distance between the reamer node and the sidewall of the foundation pit is greater than 1.5 m.
Specifically, in order to avoid disturbing or damaging the side wall 11 of the foundation pit due to too close distance to the side wall 11 of the foundation pit during reaming, the distance between the reaming node and the side wall 11 of the foundation pit is greater than 1.5 m.
In one embodiment, in step S300, the diameter of the widened portion 21 is 1.5 to 2 times the diameter of the hole of the soil nail hole 2.
Specifically, in order to obtain better effect, the larger the diameter of the extruding and widening part 21 is, the better the effect is, but in actual use, the too large diameter of the extruding and widening part 21 influences adjacent soil nail holes and causes waste of cement paste, so the diameter of the extruding and widening part 21 is 1.5-2 times of the pore diameter of the soil nail hole 2.
In the concrete implementation process, the foundation pit 1 is excavated layer by layer, when the foundation pit 1 is excavated, the depth of the foundation pit 1 is 0.5m below the soil nail hole 2, and when the foundation pit 1 is excavated, the flatness of the side wall 11 of the foundation pit is ensured. When stagnant water and residual interlaminar diving occur, the foundation pit needs to be drained, and the stagnant water on the upper layer can be dredged by measures such as drainage tubes and the like; after the excavation work of the foundation pit 1 is completed, soil nail hole sites are marked at the positions of the side walls 11 of the foundation pit.
Carrying out pore-forming construction on the marked soil nail hole site, wherein during construction, pore-forming construction can be carried out by selecting a Luoyang shovel or other anchor rod drilling machine equipment according to the longitudinal dimension, the transverse dimension and the horizontal plane included angle of a set scheme; the diameter of the soil nail hole is controlled to be 70-120 mm.
The soil nail hole is reamed by using the extruding and widening device, the distance between the reaming nodes is 0.5-1 m in order to effectively utilize the soil body between the nodes to provide resistance, the distance between the reaming nodes and the side slope surface is not less than 1.5m, the diameter of the extruding and widening space is 1.5-2 times of the diameter of the hole channel, and soil and sundries in the hole channel are cleaned after the reaming is finished.
Extending the spreader into the hole-expanding node position in the soil nail hole channel, fixing the body 100, moving the core 200 backwards through the handle 202, and driving the second side plate 330 to move backwards through the core 200; the first side plate 320 is hinged to the first end of the body 100; the second side panel 330 is hinged to the first end of the core 200; moreover, the hinged part of the first side plate 320 and the second side plate 330 is bent outwards; when the second side plate 330 moves backwards, the hinged part of the first side plate 320 and the second side plate 330 bends outwards to squeeze the soil layer in the hole, so that the partial inner diameter of the common cylindrical hole is enlarged.
When the soil nails 3 are placed, the placed soil nails 3 are subjected to rust and oil removal treatment, and strength inspection is performed; in order to position the soil nails 3 at the center of the soil nail holes 2, positioning brackets are arranged every 2.0m along the length direction of the soil nails 3 and fixed on the soil nails 3, and the diameters of the positioning brackets are the same as the diameter of the pore passages of the soil nail holes 2.
During grouting, as shown in fig. 1, a gravity grouting method can be adopted, and grouting is carried out until the grout overflows from the hole opening of the soil nail hole, and the grout is supplemented for 2-3 times before initial setting until the grout is full. And filling soil or spraying concrete and other methods are applied to the positions with weak openings to be plugged. The grouting material is selected from cement paste, the water-cement ratio of the selected cement paste is 0.5, and the strength grade is not lower than M20. The slurry should be stirred uniformly and used immediately, and the pipeline needs to be flushed by water before the grouting is started, and the pipeline is stopped in the middle or after the operation is finished. After grouting is finished, a hook is arranged at the exposed end part of the main rib of the soil nail 2, and the hook is fixedly connected with the end part of the through long reinforcing rib of the adjacent soil nail 2.
When the reinforcing mesh is laid and the concrete surface layer is sprayed, the thickness of the sprayed concrete surface layer is not less than 10cm, the spraying sequence of the operation surface is from bottom to top, and the concrete is sprayed upwards from the bottom of the excavation layer; curing the concrete surface layer after the spraying is finished; the strength of the selected concrete is not lower than C20.
After the concrete surface layer of one layer is finished and the strength of the concrete surface layer of the upper layer reaches 70% of the designed strength, a foundation pit 1 of the next layer is excavated, and the steps are repeated until the soil nailing wall reaches the expected set requirement.
By using the construction method of the embodiment, the part with the enlarged local inner diameter in the pore passage after grouting is filled with cement paste, the local inner diameter of the column body formed after grouting is larger, the part with the larger local inner diameter of the column body is embedded into the soil body, the stress state of the soil around the column body is changed, and the local column body embedded into the soil body provides larger resistance, so that the column body has soil body friction force, cohesive force and multi-end supporting point bearing force, thereby improving the drawing resistance of the column body formed after grouting. After practice tests show that the construction method has the advantages that the length of the hole channel of the soil nail hole is averagely shortened by about 20 percent under the condition of providing the same tensile resistance, the range of cement slurry pouring is reduced, and the pouring amount is saved by about 15 percent.
In summary, compared with the prior art, the method has the following beneficial effects:
1. according to the foundation pit supporting soil nailing wall construction method provided by the invention, hole expanding treatment is carried out on the pore channel of the soil nailing hole, after grouting, the soil nailing hole has soil body friction force, cohesive force and multi-end fulcrum bearing force, and the stress state of soil around the rod piece is changed, so that the drawing resistance of a column body formed after grouting is improved.
2. According to the construction method for the foundation pit supporting soil nailing wall, the length of the pore passage of the soil nailing hole is averagely shortened by about 20% under the condition of providing the same tensile resistance through practice tests, the range of cement slurry pouring is reduced, and the pouring amount is saved by about 15%. The construction method not only greatly reduces the cost investment of construction, but also can prevent the excessive waste of resources and the condition that cement slurry pollutes the surrounding soil body; the construction method can overcome and solve the working condition that the length of the pore passage is limited by the adjacent underground structure because the length of the pore passage of the soil nail hole is greatly shortened; therefore, compared with the traditional process, the construction method has the advantages of lower cost, better slope support stability, smaller construction influence range and better stress form of the reinforced rod (soil nails); and the construction quality is improved, the labor safety is guaranteed, the construction cost is saved, and the adjacent underground structures are protected.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A foundation pit supporting soil nailing wall construction method is characterized by comprising the following steps:
s100: excavating a foundation pit (1);
s200: drilling a hole on the side wall (11) of the foundation pit (1) to form a soil nail hole (2);
s300: a hole expansion node is selected in the soil nail hole, and hole expansion is carried out on the hole expansion node to form a widening part (21);
s400: placing the soil nails (3) into the reamed soil nail holes (2);
s500: grouting the soil nail hole (2) in which the soil nail (3) is placed;
s600: fixedly paving the reinforcing mesh (4) on the side wall (11) of the foundation pit after grouting, and spraying concrete at the position where the reinforcing mesh (4) is paved to form a concrete surface layer;
wherein the distance between the reaming nodes is 0.5-1 m.
2. A method of constructing a foundation pit supporting soil nailing wall according to claim 1, wherein after step S600, the underlying foundation pit (1) is excavated.
3. The method of constructing a foundation pit support soil nailing wall according to claim 1, wherein in step S100, the depth of the foundation pit (1) is 0.5m below the aperture position of the soil nailing hole (2).
4. A method of constructing a foundation pit support soil nailing wall according to claim 1, wherein in step S300, a hole enlarging is performed at the hole enlarging node using an extruder.
5. A method of constructing a foundation pit supporting soil nailing wall according to claim 4, wherein the spreader comprises;
a body (100), the body (100) having a cavity along a length direction;
a core (200), said core (200) being located within said body (100) cavity, said core (200) being movably connected to said body (100) cavity, and a first end of said core (200) extending from a first end of said body (100);
an extrusion width (300), the extrusion width (300) comprising:
an extrusion member (310), a first end of the extrusion member (310) being connected to the first end of the core (200), a second end of the extrusion member (310) being connected to the first end of the body (100); the widening member (310) can be bent outward.
6. The spreader of claim 5, wherein the spreader member (310) comprises:
a first side plate (320), a first end of the first side plate (320) being connected to a first end of the body (100);
a second side plate (330), a second end of the second side plate (330) being connected to the first end of the core (200); and the second end of the first side plate (320) is flexibly connected with the first end of the second side plate (330).
7. The spreader of claim 5, wherein the spreader member (310) comprises:
a first side plate (320), a first end of the first side plate (320) being hinged to a first end of the body (100);
a second side plate (330), a second end of the second side plate (330) being hinged to the first end of the core (200); and the second end of the first side plate (320) is hinged with the first end of the second side plate (330).
8. The spreader of claim 1, wherein the body (100) comprises:
the pipe portion (110), pipe portion (110) are no less than two, just, two adjacent pipe portion (110) pass through screw thread fixed connection.
The core (200) comprises:
the number of the rod parts (210) is not less than two, and the two adjacent rod parts (210) are fixedly connected through threads.
9. A method of constructing a foundation pit support soil nailing wall according to claim 1, wherein in step S300, the distance of the reamer node from the side wall of the foundation pit is greater than 1.5 m.
10. The foundation pit support soil nailing wall construction method according to claim 1, wherein in step S300, the diameter of the widening part (21) is 1.5 to 2 times the diameter of the hole passage of the soil nailing hole (2).
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| CN201910869596.1A CN110616715A (en) | 2019-09-12 | 2019-09-12 | Construction method of foundation pit supporting soil nailing wall |
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| CN201910869596.1A CN110616715A (en) | 2019-09-12 | 2019-09-12 | Construction method of foundation pit supporting soil nailing wall |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111691429A (en) * | 2020-06-29 | 2020-09-22 | 福建江夏学院 | Soil nailing device for deep foundation pit support |
| CN114673143A (en) * | 2022-03-22 | 2022-06-28 | 浙江恒炜建设集团有限公司 | Municipal soft foundation road reinforcing method |
| CN114892676A (en) * | 2022-06-02 | 2022-08-12 | 中铁十五局集团第五工程有限公司 | Foundation pit soil nailing wall support and construction method thereof |
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| CN1786352A (en) * | 2004-12-09 | 2006-06-14 | 北京中阔科技有限责任公司 | Apparatus of anchoring capable of repeating use and its construction method |
| CN101748741A (en) * | 2009-12-18 | 2010-06-23 | 中冶交通工程技术有限公司 | Construction method of concrete supporting structure |
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| CN1786352A (en) * | 2004-12-09 | 2006-06-14 | 北京中阔科技有限责任公司 | Apparatus of anchoring capable of repeating use and its construction method |
| CN101748741A (en) * | 2009-12-18 | 2010-06-23 | 中冶交通工程技术有限公司 | Construction method of concrete supporting structure |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111691429A (en) * | 2020-06-29 | 2020-09-22 | 福建江夏学院 | Soil nailing device for deep foundation pit support |
| CN114673143A (en) * | 2022-03-22 | 2022-06-28 | 浙江恒炜建设集团有限公司 | Municipal soft foundation road reinforcing method |
| CN114673143B (en) * | 2022-03-22 | 2024-04-02 | 浙江恒炜建设集团有限公司 | Municipal soft foundation road reinforcement method |
| CN114892676A (en) * | 2022-06-02 | 2022-08-12 | 中铁十五局集团第五工程有限公司 | Foundation pit soil nailing wall support and construction method thereof |
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Application publication date: 20191227 |