A deep foundation pit support structure and construction method

Abstract

The present invention relates to the technical field of building engineering, and specifically to a deep foundation pit support structure and construction method; the technical scheme adopted is: comprising a plurality of vertically arranged support piles and anchor piles, a retaining body is built between two adjacent support piles, the anchor piles are fixedly connected to the support piles by anchor rods, and the length of the anchor piles is greater than the depth of the deep foundation pit. The present invention builds anchor piles in the earthwork around the deep foundation pit, and then connects the anchor piles with the support piles in the deep foundation pit by anchor rods, and the two sides of the retaining body are connected to the support piles, so that the pressure of the earthwork and groundwater on the support piles and the retaining body is transmitted to the anchor piles, which can prevent the earthwork of the deep foundation pit wall from collapsing and ensure construction safety; there is no need to build support beams in the deep foundation pit, avoid affecting the foundation layout of the building, earthwork excavation and transportation, and ensure construction efficiency; and there is no need to dismantle after the construction is completed, avoiding wasting working hours and the potential safety hazards caused by dismantling the support structure.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a deep foundation pit supporting structure and a construction method. Background Art

[0002] Deep foundation pit refers to a project with an excavation depth of more than 5 meters (including 5 meters), or a project with a depth of less than 5 meters but with particularly complex geological conditions, surrounding environment and underground pipelines. In the field of industrial and civil construction, the support of deep foundation pits generally uses conventional bored concrete cast-in-place piles as support piles, or is treated by the method of concrete continuous wall. At present, the support system of supporting beams and columns in deep foundation pits (cross-bracing system) is widely used for support. Although it can provide good support for the slope of the foundation pit, the large number of supporting beams and columns in the deep foundation pit seriously affects the layout of the foundation of the building to be built, and often conflicts with the building structure, occupying the operating space for subsequent construction, bringing great inconvenience to subsequent construction, and seriously affecting the construction efficiency. That is, the large number of internal support beams and steel lattice columns arranged in the foundation pit affect the excavation and transportation of earthwork, and the construction and removal of the internal support beams will cause a lot of waste and construction hazards, and at the same time affect the construction of the basement. Summary of the invention

[0003] In view of the technical problems that the above-mentioned existing deep foundation pit support system seriously affects the foundation layout of the building, affects the excavation and transportation of earth, is time-consuming and labor-intensive to remove, and has safety hazards; the present invention provides a deep foundation pit support structure, which does not require the installation of cross beams inside the foundation pit and will not affect the foundation layout of the building and subsequent construction.

[0004] The present invention is achieved through the following technical solutions:

[0005] A deep foundation pit support structure comprises a plurality of vertically arranged support piles, a retaining body is built between two adjacent support piles, and a plurality of vertically arranged anchor piles, wherein the anchor piles are fixedly connected to the support piles by anchor rods, and the length of the anchor piles is greater than the depth of the deep foundation pit.

[0006] The present invention builds anchor piles in the earth around the deep foundation pit so that the length of the anchor piles is greater than the depth of the deep foundation pit, and then connects the anchor piles and the supporting piles in the deep foundation pit through anchor rods, and the two sides of the retaining body are connected to the supporting piles, so that the pressure of the earth and groundwater on the supporting piles and the retaining body is transmitted to the anchor piles, so as to tighten the retaining body through the joint action of the anchor piles and the supporting piles. Therefore, it is not necessary to build support beams in the deep foundation pit, avoiding the impact on the foundation layout of the building, earth excavation and transportation, and ensuring the construction efficiency; and it is not necessary to dismantle after the construction is completed, avoiding the waste of man-hours and the potential safety hazards caused by the removal of the supporting structure.

[0007] The existing anchor support is to transfer the pressure of earth and groundwater on the support piles and retaining bodies to the earth on the side walls of the deep foundation pit and the earth directly below the deep foundation pit through the anchor rod, which is easy to cause the earth on the wall of the deep foundation pit to collapse, posing a great safety hazard, and therefore safety accidents often occur. The present invention transfers the tension of the anchor rod to the anchor pile, and the anchor pile is vertically inserted in the earth around the foundation pit, and the length of the anchor pile is greater than the depth of the deep foundation pit, which can transfer the tension of the anchor rod to the earth around the bottom of the deep foundation pit, thereby preventing the earth on the wall of the deep foundation pit from collapsing and ensuring construction safety.

[0008] As a specific embodiment of the anchor pile, the anchor pile is a hollow pipe pile, and the side wall of the anchor pile is provided with a plurality of through holes, and the through holes are distributed along the length direction of the anchor pile. The through holes are provided on the side wall of the hollow pipe pile as an anchor pile, so that the groundwater in the earth around the foundation pit can be introduced into the pipe pile, and the water infiltrated into the pipe pile can be pumped out by a water pump to reduce the pressure of the groundwater in the earth on the support pile and the retaining body, and further ensure the support safety of the deep foundation pit.

[0009] As a specific implementation of the support pile, the side wall of the support pile is provided with a plurality of anchor holes, the anchor holes are distributed along the length direction of the support pile, and the anchor holes are used to insert anchor rods. The anchor holes are provided on the side wall of the support pile to provide guidance when drilling and laying holes for the anchor rods, ensuring that the anchor rods can be inserted into the through holes.

[0010] As a specific embodiment of the anchor rod, a clamping rod is hinged at one end of the anchor rod, the middle part of the clamping rod is hinged to the end of the anchor rod, and a counterweight is provided at one end of the clamping rod, so that the clamping rod is vertically clamped at the end of the through hole by the gravity of the counterweight. Therefore, when constructing the support structure, one end of the anchor rod can be directly inserted into the through hole, and the other end of the anchor rod can be fixedly connected to the support pile, which is simple and convenient to connect.

[0011] Furthermore, it also includes an anchor rod hole, which connects the through hole and the anchoring hole, and is used to insert the anchor rod, thereby further improving the deployment efficiency of the anchor rod.

[0012] Furthermore, a grout stop ring is provided in the middle of the anchor rod, an anchor ring is provided at one end of the anchor rod away from the clamping rod, and a grouting hole is axially provided in the anchor ring. Grouting is performed through the grouting hole to form a grouting body between the grout stop ring and the anchor ring, so as to prevent groundwater infiltrating into the pipe pile from flowing back between the earthwork and the retaining body and increasing the load of the retaining body.

[0013] As a specific implementation of the retaining body, the cross-section of the retaining body is an arch convex toward the foundation pit slope, so as to utilize the horizontal arch structure similar to the arch dam of a hydropower station to transfer the pressure of earth and groundwater on the retaining body to the supporting piles, thereby further preventing landslides.

[0014] Furthermore, it also includes a supporting beam, the end of which is fixedly connected to the supporting pile, and the supporting beam is an arched beam adapted to the retaining body to enhance the structural strength of the retaining body.

[0015] The present invention also provides a method for constructing a deep foundation pit support structure, comprising the above-mentioned deep foundation pit support structure, comprising the following steps:

[0016] Anchor piles are built vertically in the earth around the foundation pit to be excavated;

[0017] After excavating the foundation pit, support piles are built on the pit wall, and anchor holes are reserved on the support piles;

[0018] Drilling anchor holes along the length direction of the anchor hole to connect the through hole and the anchor hole;

[0019] Insert one end of the anchor rod clamping rod into the through hole from the anchor rod hole so that the clamping rod is clamped at the end of the through hole;

[0020] After tightening the anchor rod, construct the grouting body;

[0021] After the grouting body is constructed, the retaining body and supporting beams are constructed to complete the support of the deep foundation pit.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. The present invention builds anchor piles with a length greater than the depth of the foundation pit in the earth around the deep foundation pit, and then connects the anchor piles and the supporting piles in the deep foundation pit through anchor rods, so as to transmit the pressure of the earth and groundwater on the supporting piles and the retaining body to the anchor piles, so as to tighten the retaining body through the joint action of the anchor piles and the supporting piles. Therefore, it is not necessary to build support beams in the deep foundation pit, avoiding the impact on the foundation layout of the building, earth excavation and transportation, and ensuring the construction efficiency; and it is not necessary to dismantle after the construction is completed, avoiding the waste of man-hours and the potential safety hazards caused by the dismantling of the supporting structure.

[0024] 2. The present invention transfers the tension of the anchor rod to the anchor piles, and the anchor piles are vertically inserted in the earth around the foundation pit. The length of the anchor piles is greater than the depth of the deep foundation pit, and the tension of the anchor rod can be transferred to the earth around the bottom of the deep foundation pit, thereby preventing the earth collapse of the deep foundation pit wall and ensuring construction safety.

[0025] 3. Through holes are set on the side walls of the hollow pipe piles as anchor piles, which can lead the groundwater in the surrounding soil of the foundation pit into the pipe piles. The water that has seeped into the pipe piles can be pumped out by a water pump to reduce the pressure of the groundwater in the soil on the support piles and retaining bodies, further ensuring the support safety of the deep foundation pit.

[0026] 4. A grouting ring is provided in the middle of the anchor rod, and an anchoring ring is provided at one end of the anchor rod away from the clamping rod, and a grouting hole is provided in the axial direction of the anchoring ring. Grouting is performed through the grouting hole to form a grouting body between the grouting ring and the anchoring ring, which can prevent the groundwater infiltrated into the pipe pile from flowing back between the earthwork and the retaining body and increasing the load of the retaining body.

[0027] 5. The horizontal cross-section of the retaining body is an arch convex toward the foundation pit slope, so as to utilize the horizontal arch structure similar to the arch dam of a hydroelectric power station to transfer the pressure of earth and groundwater on the retaining body to the supporting piles, thereby further preventing landslides. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0029] Figure 1 It is a vertical cross-sectional schematic diagram of a support unit of the present invention;

[0030] Figure 2 for Figure 1 A magnified schematic diagram of part A;

[0031] Figure 3 It is a horizontal cross-sectional schematic diagram of a support unit of the present invention.

[0032] Marks and corresponding parts names in the attached drawings:

[0033] 1-support pile, 2-retaining body, 3-anchor pile, 4-anchor rod, 5-through hole, 6-anchor hole, 7-clamping rod, 8-counterweight part, 9-anchor rod hole, 10-stop grouting ring, 11-anchor ring, 12-grouting body, 13-support beam, 14-foundation pit, 15-earthwork. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. Example

[0035] A deep foundation pit support structure includes a plurality of vertically arranged support piles 1, and a retaining body 2 is built between two adjacent support piles 1. It can be understood that the support piles 1 are arranged along the circumference of the pit wall of the deep foundation pit, and the number and spacing of the support piles 1 are determined according to the composition of the earthwork and the depth of the foundation pit; and the sides of the retaining body 2 built between the two support piles 1 are fixedly connected to the support piles 1 to form a closed shape, thereby supporting the side wall of the deep foundation pit. The retaining body 2 can be formed by pouring concrete, a mixture of cement and sand, or spliced ​​by a plurality of channel steels or steel piles. In this example, it is poured by a mixture of cement and sand. It also includes a plurality of vertically arranged anchor piles 3, and the anchor piles 3 are fixedly connected to the support piles 1 by anchor rods 4, and the length of the anchor piles 3 is greater than the depth of the deep foundation pit. The present invention builds anchor piles 3 in the earth around the deep foundation pit so that the length of the anchor piles 3 is greater than the depth of the deep foundation pit, and then connects the anchor piles 3 and the supporting piles 1 in the deep foundation pit through anchor rods 4, and the two sides of the retaining body 2 are connected to the supporting piles 1, so that the pressure of the earth and groundwater on the supporting piles 1 and the retaining body 2 is transmitted to the anchor piles 3, so as to tighten the retaining body 2 through the joint action of the anchor piles 3 and the supporting piles 1. Therefore, it is not necessary to build support beams in the deep foundation pit, avoid affecting the foundation layout of the building, earth excavation and transportation, and ensure construction efficiency; and it is not necessary to dismantle after the construction is completed, avoiding wasting man-hours and potential safety hazards caused by dismantling the supporting structure.

[0036] The existing anchor support transmits the pressure of earth and groundwater on the support pile 1 and the retaining body 2 to the earth on the side wall of the deep foundation pit and the earth directly below the deep foundation pit through the anchor rod 4, which is easy to cause the earth on the wall of the deep foundation pit to collapse, posing a great safety hazard, and therefore safety accidents occur from time to time. The present invention transmits the tension of the anchor rod 4 to the anchor pile 3, and the anchor pile 3 is vertically inserted in the earth around the foundation pit, and the length of the anchor pile 3 is greater than the depth of the deep foundation pit, which can transmit the tension of the anchor rod 4 to the earth around the bottom of the deep foundation pit, thereby preventing the earth on the wall of the deep foundation pit from collapsing and ensuring construction safety.

[0037] As a specific implementation of the anchor pile 3, the anchor pile 3 is a hollow pipe pile, and the side wall of the anchor pile 3 is provided with a plurality of through holes 5, and the through holes 5 are distributed along the length direction of the anchor pile 3. It can be seen that the through holes 5 are pre-opened before the anchor pile 3 is driven into the earth. In this embodiment, the through holes 5 are provided on the side wall of the hollow pipe pile as the anchor pile 3, so that the groundwater in the earth around the foundation pit can be introduced into the pipe pile, and the water infiltrated into the pipe pile can be pumped out by a water pump to reduce the pressure of the groundwater in the earth on the support pile 1 and the retaining body 2, and further ensure the support safety of the deep foundation pit.

[0038] As a specific embodiment of the support pile 1, the side wall of the support pile 1 is provided with a plurality of anchor holes 6, and the anchor holes 6 are distributed along the length direction of the support pile 1, and the anchor holes 6 are used to insert the anchor rod 4. It should be understood that the through hole 5 and the anchor hole 6 are collinear in the length direction during support. The anchor holes 6 are provided on the side wall of the support pile 1 to provide guidance for the anchor rod 4 when drilling and laying holes, so that the drill rod is inserted into the anchor hole 6 to excavate into the through hole 5 to form the anchor rod hole 9. That is, it also includes the anchor rod hole 9, which connects the through hole 5 and the anchor hole 6, and the anchor rod hole 9 is used to insert the anchor rod 4 to ensure that the anchor rod 4 can be inserted into the through hole 5.

[0039] As a specific embodiment of the anchor rod 4, a clamping rod 7 is hinged at one end of the anchor rod 4, and the middle part of the clamping rod 7 is hinged with the end of the anchor rod 4. A counterweight part 8 is provided at one end of the clamping rod 7, and the gravity of the counterweight part 8 makes the clamping rod 7 vertically clamped at the end of the through hole 5. Therefore, when constructing the support structure, one end of the anchor rod 4 is directly inserted into the through hole 5, and the other end of the anchor rod 4 is fixedly connected to the support pile 1, and the connection is simple and convenient. It should be noted that when the anchor rod 4 is inserted into the anchor rod hole 9, the clamping rod 7 is parallel to the anchor rod 4. When the clamping rod 7 is fully inserted into the middle cavity of the anchor pile 3, the clamping rod 7 is driven by the gravity of the counterweight part 8 to rotate downward and remain vertical; at this time, the anchor rod 4 will be pulled so that the clamping rod 7 is close to the side wall of the cavity of the anchor pile 3, and the anchor rod 4 is fixedly connected to the support pile 1, thereby realizing the connection between the anchor pile 3 and the support pile 1.

[0040] Furthermore, a grout stop ring 10 is provided in the middle of the anchor rod 4, and an anchor ring 11 is provided at one end of the anchor rod 4 away from the clamping rod 7, and a grouting hole is axially provided in the anchor ring 11. Grouting is performed through the grouting hole to form a grouting body 12 between the grout stop ring 10 and the anchor ring 11, so as to prevent the groundwater infiltrated into the pipe pile from flowing back between the earthwork and the retaining body 2 and increasing the load of the retaining body 2.

[0041] As a specific implementation of the retaining body 2, the cross-section of the retaining body 2 is an arch convex toward the slope of the foundation pit, so as to utilize the horizontal arch structure similar to the arch dam of a hydropower station to transfer the pressure of earth and groundwater on the retaining body 2 to the supporting piles 1. The retaining bodies 2 are connected to both sides of the supporting piles 1 to offset most of the pressure, and the component force is borne jointly by the supporting piles 1 and the anchor piles 3, which can further prevent landslides.

[0042] Furthermore, it also includes a supporting beam 13 , the end of which is fixedly connected to the supporting pile 1 . The supporting beam 13 is an arched beam adapted to the retaining body 2 to enhance the structural strength of the retaining body 2 .

[0043] The method for supporting a deep foundation pit using the above-mentioned deep foundation pit supporting structure comprises the following steps:

[0044] Drill anchor pile foundation holes in the earth around the foundation pit to be excavated to facilitate the insertion of anchor piles 3, the hole diameter of the anchor pile foundation hole is smaller than the outer diameter of the anchor pile 3, and then insert the anchor pile 3 into the anchor pile foundation hole to vertically build the anchor pile 3, and the distance between the anchor pile 3 and the pit wall of the deep foundation pit is determined according to the rock layer structure of the earth to be excavated, which is usually greater than 10m;

[0045] After the foundation pit is excavated, support piles 1 are built on the foundation pit wall. The lower end of the support piles is inserted into the earth and is a reinforced concrete structure. Anchor holes 6 are reserved on the support piles 1.

[0046] Anchor holes 9 are drilled along the length direction of the anchor holes 6 to connect the through holes 5 and the anchor holes 6;

[0047] Insert one end of the anchor rod 4 provided with the clamping rod 7 into the through hole 5 from the anchor rod hole 9, so that the clamping rod 7 is clamped at the end of the through hole 5, and the other end of the anchor rod 4 is fixedly connected to the supporting pile 1 to tighten the anchor rod 4;

[0048] After the anchor rod 4 is tightened, grout is poured through the grouting holes on the anchor ring 11 to build the grouting body 12;

[0049] After the grouting body 12 is constructed, the retaining body 2 and the supporting beam 13 are constructed to complete the support of the deep foundation pit.

[0050] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A deep foundation pit support structure, comprising a plurality of vertically arranged support piles (1), a retaining body (2) being constructed between two adjacent support piles (1), characterized in that: It also comprises a plurality of vertically arranged anchor piles (3), wherein the anchor piles (3) are fixedly connected to the support piles (1) via anchor rods (4), and the length of the anchor piles (3) is greater than the depth of the deep foundation pit; The anchor pile (3) is a hollow pipe pile, and a plurality of through holes (5) are provided on the side wall of the anchor pile (3), wherein the through holes (5) are distributed along the length direction of the anchor pile (3); The side wall of the support pile (1) is provided with a plurality of anchor holes (6), the anchor holes (6) are distributed along the length direction of the support pile (1), and the anchor holes (6) are used for inserting anchor rods (4); It also comprises an anchor rod hole (9), the anchor rod hole (9) being connected to the through hole (5) and the anchor hole (6), and the anchor rod hole (9) being used for inserting the anchor rod (4); A clamping rod (7) is hingedly connected to one end of the anchor rod (4); the middle portion of the clamping rod (7) is hingedly connected to the end of the anchor rod (4); a counterweight portion (8) is provided at one end of the clamping rod (7); and the clamping rod (7) is vertically clamped at the end of the through hole (5) by the gravity of the counterweight portion (8); The cross section of the retaining body (2) is an arch convex toward the foundation pit slope.

2. The deep foundation pit support structure according to claim 1 is characterized in that: A grout-stopping ring (10) is provided in the middle of the anchor rod (4), an anchoring ring (11) is provided at one end of the anchor rod (4) away from the clamping rod (7), and a grouting hole is axially provided in the anchoring ring (11).

3. The deep foundation pit support structure according to claim 2 is characterized in that: A grouting body (12) is provided between the grout-stopping ring (10) and the anchoring ring (11).

4. The deep foundation pit support structure according to claim 1, characterized in that: It also comprises a supporting beam (13), the end of which is fixedly connected to the supporting pile (1), and the supporting beam (13) is an arched beam adapted to the retaining body (2).

5. A method for constructing a deep foundation pit support structure, characterized in that: The deep foundation pit support structure according to any one of claims 1 to 4 comprises the following steps: Anchor piles (3) are vertically constructed in the earth surrounding the foundation pit to be excavated; After excavating the foundation pit, support piles (1) are built on the pit wall, and anchor holes (6) are reserved on the support piles (1); Drilling an anchor hole (9) along the length direction of the anchor hole (6) to connect the through hole (5) and the anchor hole (6); Inserting one end of the anchor rod (4) provided with a clamping rod (7) into the through hole (5) from the anchor rod hole (9), so that the clamping rod (7) is clamped at the end of the through hole (5); After tightening the anchor rod (4), a grouting body (12) is constructed; After the grouting body (12) is constructed, the retaining body (2) and the supporting beam (13) are constructed to complete the support of the deep foundation pit.

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