CN106498950A - Anchor head is placed in the Pile-Anchor Supporting for Deep Excavation system and its implementation of pile body - Google Patents

Abstract

The invention discloses a deep foundation pit pile-anchor support system with an anchor head placed on the pile body and an implementation method thereof. The support system includes a retaining pile, an anchor rod, a saddle-shaped pad, an anchor, a PVC pipe, Inclined iron and locking beam; the PVC pipe is preset in the retaining pile, the inner end of the anchor rod is inserted into the wall of the foundation pit through the PVC pipe, and the outer end of the anchor rod is fixedly connected with the anchorage. The tool axis has an included angle of 15° to 25° with the horizontal plane, and is consistent with the inclination angle of the anchor rod. The invention cancels the waist beam in the traditional pile-anchor system and avoids the loss of prestress caused by the deformation of the waist beam. The invention directly transmits the force of the anchor rod to the wall-protecting pile, and the anchor rod and the wall-protecting pile can better cooperate with force as a whole, and the integrity of the supporting structure is better, and it is safe and reliable. The invention cancels a large number of connecting panels and welding rods, which greatly saves profiled steel materials and electricity consumption. The invention avoids the heavy and dangerous waist beam installation work, simplifies the process and shortens the construction period.

Description

Deep foundation pit pile anchor support system with anchor head placed on pile body and its implementation method

technical field

The invention belongs to the field of geotechnical engineering, and relates to a deep foundation pit engineering constructed with a pile-anchor support system, in particular to a deep foundation pit pile-anchor support system with an anchor head placed on a pile body and an implementation method thereof.

Background technique

At present, in deep foundation pit projects using pile-anchor support system construction, the connection between wall retaining piles and anchor rods (cables) generally adopts waist beams made of I-beam or channel steel to anchor the anchor rods (cables) On the waist beam, it is connected with the retaining wall pile through certain structural measures to ensure the overall coordinated force of the entire pile-anchor support system. Therefore, the waist beam plays an important role in the entire support system as a force-transmitting structure for the pre-stressing of anchor rods (cables). Waist beams are generally welded by section steel. Since the length of the waist beams is generally very long, the slenderness ratio is very large, and the deformation of the waist beams is difficult to control. Especially when the prestress is applied to the anchor rods (cables), the deformation of the waist beams will be greater. The deformation of the beam directly causes the loss of the prestress, making it difficult to reach the design value, which makes it difficult to guarantee the safety factor of the support system; the construction and operation conditions of the waist beam welding are poor, the quality of the weld is difficult to guarantee, and weak parts are easily formed, which often occurs The overall instability or fall of the waist beam makes the support system lose its function, resulting in the instability and collapse of the deep foundation pit. In addition, this method not only requires a large amount of steel materials, but also requires multiple construction procedures such as the positioning and installation of the waist beam, making the construction difficult and cumbersome. Therefore need to develop a kind of supporting system that can solve the shortcomings such as poor safety, high cost, many procedures and long construction period that exist in the existing pile-anchor supporting system.

Contents of the invention

The technical problem to be solved by the present invention is to provide a deep foundation pit pile-anchor support system and its implementation method in which the anchor head is placed on the pile body, so as to solve the prestress loss caused by the deformation of the waist beam existing in the pile-anchor support system Problems, as well as shortcomings such as poor safety, high cost, many processes, and long construction period, achieve the purpose of improving the overall safety of the pile-anchor support system, reducing cost, simplifying the construction process and shortening the construction period.

The technical solution of the present invention is: a deep foundation pit pile-anchor support system in which the anchor head is placed on the pile body, at least including retaining piles, anchor rods, saddle-shaped pads, anchors, PVC pipes, inclined irons and locking beams;

The PVC pipe is preset in the wall retaining pile, the inner end of the anchor rod is inserted into the wall of the foundation pit through the PVC pipe, the outer end of the anchor rod is fixedly connected with the anchorage, and an inclined iron is arranged between the anchorage and the retaining wall pile. and saddle-shaped pads; the sprayed concrete surface layer of the foundation pit wall, and soil nails and drainage holes are set in the foundation pit wall between two adjacent retaining piles; between two adjacent retaining piles The reinforcement mesh is arranged on the wall of the foundation pit; the axis of the anchorage has an included angle of 15°-25° with the horizontal plane, and is consistent with the inclination angle of the anchor rod.

Further, the axis of the anchor rod is in a vertical plane with the center line of the retaining pile.

Further, the anchor rod is replaced by an anchor cable.

Further, the vertical spacing of the soil nails in the wall of the foundation pit between two adjacent retaining piles is 1.4-1.6m, and the horizontal spacing and vertical spacing of the drainage holes are 1.4-1.6m.

Further, the inner diameter of the PVC pipe is consistent with the diameter of the anchor hole.

Further, a locking beam is arranged on the top of the retaining pile.

Further, there are multiple anchor rods, and multiple preset PVC pipes along the vertical direction of the retaining pile are respectively inserted into the wall of the foundation pit.

The implementation method of the deep foundation pit pile-anchor support system with the anchor head placed on the pile body comprises the following steps:

A. Making reinforcement cages for retaining piles

When making reinforcement cages for wall retaining piles, PVC pipes sealed at both ends with wooden plugs are preset in the reinforcement cages at the design depth of the anchor rods. The PVC pipes are reliably connected to the reinforcement cages through iron wires to ensure that the design angles of the PVC pipes and the anchor rods are consistent; The pre-installed PVC pipes should be treated with stirrup encryption, and the reinforcement of the wall protection piles has directionality. When placing the reinforcement cage, it should be constructed strictly according to the direction marked on the drawing.

B. Prefabricated saddle block

The saddle-shaped pad is obtained through prefabrication, and its material is steel or concrete. During prefabrication, the curvature of the saddle is guaranteed to be consistent with the curvature of the arc of the retaining pile used to ensure a perfect fit between the two. When the geological conditions are poor and a large prestress is required for the anchor bolt, the saddle block made of concrete should be prefabricated with high-grade cement and steel bars.

C. to clean up

Clean up the site, excavate the loose soil layer on the surface, measure, position and set out the pile holes of the retaining piles.

D. Digging pile holes

Excavate the holes to the design depth according to the hole position of the retaining pile determined in step C.

E. Hoisting reinforcement cage

When hoisting the reinforcement cage, the reinforcement of the retaining wall pile has directionality, and the reinforcement cage should be placed in strict accordance with the direction marked on the drawing.

F. Pouring concrete for wall retaining piles

Pour concrete into the pile holes where the reinforcement cages have been installed, and maintain them in time.

G. Make lock beam

After the construction conditions of the lock beam are met, the soil between the retaining piles and the head of the retaining pile are excavated, and the construction work surface of the lock beam is provided in time, the binding, the placement of the steel cage, the formwork, the pouring of concrete, and timely maintenance.

H. Install the anchor rod

After the foundation pit excavation construction conditions are met, excavate the foundation pit along the retaining piles to a certain depth below the design depth of the anchor rod, find the preset PVC pipe to get through the wooden plug and drill the anchor hole; install the anchor rod in the anchor hole and inject grout, Maintenance: After the cement mortar reaches the design strength, install saddle-shaped pads and inclined irons to tension and lock the anchor rod.

I. Treatment of the surface of the foundation pit wall

In order to prevent the soil between the piles from falling off and collapsing, soil nails are drilled into the soil between the piles, steel mesh is hung, and the concrete surface is sprayed; drainage holes are set on the surface of the foundation pit wall, and a gravel filter layer is made behind the holes.

J. end

Repeat steps H-J until the construction of the pile-anchor support system is completed.

Compared with the prior art, the present invention has the following beneficial effects:

1. Safe and reliable. The invention cancels the waist beam in the traditional pile anchor system, and avoids the loss of prestress caused by the deformation of the waist beam. The present invention directly transmits the force of the anchor rod (cable) to the retaining wall pile, and the anchor rod (cable) and the retaining wall pile can better cooperate with force as a whole, and the integrity of the supporting structure is better, and it is safe and reliable. However, in the traditional pile-anchor support system, the force of the anchor rod (cable) must be transmitted to the retaining wall pile through the steel waist beam. Destruction of the supporting structure system.

2. Low cost. The connection structure of the present invention cancels the waist beam connection method used in the traditional pile-anchor support system, cancels a large number of connecting panels and welding rods, and greatly saves steel materials and electricity consumption.

3. Few processes and short construction period. Because the invention cancels the waist beam in the traditional pile anchor system, it saves a lot of complicated welding work, and more importantly, it avoids the heavy and dangerous installation work of the waist beam, simplifies the construction process, and shortens the construction period.

Description of drawings

Fig. 1 is a schematic plan view of the connection structure of the present invention.

Fig. 2 is a detailed diagram of the connection structure of the present invention.

Fig. 3 is a schematic diagram of pre-installed PVC pipes in steel cages of the present invention.

Fig. 4 is the vertical view of soil support between piles of the present invention.

Fig. 5 is a plan view of soil support between piles of the present invention.

Fig. 6 is a schematic cross-sectional view of the foundation pit of the example of the present invention.

Fig. 7 is an elevation view of the foundation pit of the present invention.

In the figure: 1. Retaining pile; 2. Anchor rod; 3. Saddle pad; 4. Anchorage; 5. PVC pipe; 6. Slanted iron; 7. Lock beam; 8. Concrete surface; Nails; 10, steel mesh; 11, planting bars; 12, drainage holes; 13, steel cages.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, feature of the present invention is further described:

As shown in Figure 1-7, the deep foundation pit pile anchor support system with the anchor head placed on the pile body includes at least wall retaining pile 1, anchor rod 2, saddle-shaped pad 3, anchorage 4, PVC pipe 5, and inclined iron 6 and lock beam 7;

The PVC pipe 5 is preset in the wall retaining pile 1, the inner end of the anchor rod 2 is inserted into the wall of the foundation pit through the PVC pipe 5, the outer end of the anchor rod 2 is fixedly connected with the anchorage 4, and the anchorage 4 and the Slant iron 6 and saddle-shaped spacer 3 are arranged between the retaining piles 1; the sprayed concrete surface layer 8 on the wall of the foundation pit is set, and soil nails 9 and Drain holes 12; steel mesh 10 is set on the wall of the foundation pit between two adjacent retaining piles 1; the axis of the anchor 4 has an included angle of 15° to 25° with the horizontal plane, and has an angle of inclination with the anchor rod 2 be consistent.

Further, the axis of the anchor rod 2 and the centerline of the retaining pile 1 are in a vertical plane.

Further, the anchor rod 2 is replaced by an anchor cable.

Further, the vertical distance between the soil nails 9 in the foundation pit wall between two adjacent retaining piles 1 is 1.4-1.6m, and the horizontal and vertical distances between the drainage holes 12 are 1.4-1.6m.

Further, the inner diameter of the PVC pipe 5 is consistent with the diameter of the anchor hole.

Further, a locking beam 7 is arranged on the top of the wall retaining pile 1 .

Further, there are multiple anchor rods 2, and multiple preset PVC pipes 5 along the vertical direction of the retaining pile 1 are respectively inserted into the wall of the foundation pit.

The implementation method of the deep foundation pit pile-anchor support system with the anchor head placed on the pile body comprises the following steps:

A, make the reinforcement cage 13 of retaining pile 1

When making the reinforcing cage 13 of retaining wall pile 1, the PVC pipe 5 that both ends are sealed with wooden plugs is preset at the design depth of the anchor rod 2 in the reinforcing cage 13, and the PVC pipe 5 is reliably connected with the reinforcing cage 13 by iron wire, so as to ensure that the PVC pipe 5 and the reinforcing cage 13 are reliably connected. The design angles of the anchor rods 2 should be kept consistent; the 5 places where the PVC pipes are preset in the reinforcement cage 13 should be treated with stirrup encryption, and the reinforcement of the retaining wall pile 1 has directionality, and the reinforcement cage 13 should be placed in strict accordance with the direction marked on the drawing.

B. Prefabricated saddle block 3

The saddle-shaped spacer 3 is obtained through prefabrication, and its material is steel or concrete. During prefabrication, the curvature of the saddle is guaranteed to be consistent with the arc curvature of the retaining pile 1 adopted to ensure that the two can fit perfectly. When the geological conditions are poor and the anchor rod 2 needs to be applied with a large prestress, the concrete saddle block 3 is prefabricated with high-grade cement and reinforced.

C. to clean up

Clean up the site, excavate the loose soil layer on the surface, measure, position and set out the pile hole of the retaining pile 1.

D. Digging pile holes

According to step C, dig the hole position of retaining pile 1 to the design depth.

E. Hoisting reinforcement cage 13

When hoisting the reinforcement cage 13, the reinforcement of the wall retaining pile 1 has directionality. When the reinforcement cage 13 is placed, it should be constructed strictly according to the direction marked on the drawing.

F. Pouring concrete for wall retaining pile 1

Concrete is poured in the pile hole that steel cage 13 is installed, and maintenance in time.

G. Make lock beam 7

After the construction conditions of the locking beam 7 are met, excavate the soil between the retaining pile 1 and cut off the pile head of the retaining pile 1, provide the construction work surface of the locking beam 7 in time, bind and place the steel cage 13, set up the formwork, and pour concrete , and timely maintenance.

H. Install anchor rod 2

After the foundation pit excavation construction conditions are met, excavate the foundation pit along the retaining pile 1 to the design depth of the anchor rod 2, find the preset PVC pipe 5 to get through the wooden plug and drill the anchor hole; install the anchor rod 2 in the anchor hole and inject After the cement mortar reaches the design strength, install the saddle-shaped block 3 and the inclined iron 6 to tension and lock the anchor rod 2.

I. Treatment of the surface of the foundation pit wall

In order to prevent the soil between the piles from falling off and collapsing, soil nails 9 are drilled in the soil between the piles, steel mesh 10 is hung, and the surface layer of sprayed concrete is 8; drainage holes 12 are arranged on the surface of the foundation pit wall, and a gravel filter layer is made behind the holes.

J. end

Repeat steps H-J until the construction of the pile-anchor support system is completed.

Engineering example:

For deep foundation pit projects with poor geological conditions, pile-anchor support systems are usually used. As shown in Figure 6-7, the depth of the foundation pit in this example is 12.4m, and the wall retaining pile 1 used is 15m long, 0.8m in pile diameter, and 1.6m in pile spacing, and two rows are arranged at positions 5.0m and 7.5m away from the pile top Anchor rod 2, the inclination angle of anchor rod 2 is 15°.

Fully prepare for the construction, level the working surface, excavate the loose soil layer on the surface, and measure and position the 1 pile hole of the retaining pile.

As shown in Figure 3, carry out the digging operation after setting out the hole position, and carry out the making of reinforcement cage 13 at the same time, the main reinforcement of reinforcement cage 13 adopts HRB400 grade reinforcement, fy=400MPa; Stirrup adopts HPB300 grade reinforcement, Fy=300MPa; When making the reinforcement cage 13 of the retaining pile 1, the PVC pipe 5 with both ends sealed with wooden plugs is preset in the design depth of the anchor rod 2 in the reinforcement cage 13, and the used PVC pipe 5 has an inner diameter of 130mm, which is consistent with the design diameter of the anchor hole. The reliable connection between the iron wire and the reinforcement cage 13 ensures that the design angles of the PVC pipe 5 and the anchor rod 2 are consistent; After the above two steps are completed, the steel cage 13 is hoisted into the hole and used as the retaining pile 1. The reinforcement of the retaining pile 1 has directionality. When the reinforcement cage 13 is placed, it should be constructed strictly according to the direction marked on the drawing. Wall retaining pile 1 has a concrete strength grade of C30, and the thickness of the reinforcement protective layer is 35mm.

After the construction conditions of the interlocking beam 7 are met, excavation of the soil between the retaining piles 1 and the cutting off of the pile head shall be carried out, and the construction work surface of the interlocking beam 7 shall be provided in time, and the binding, placement and pouring of the reinforcing cage 13 of the interlocking beam 7 shall be carried out. Concrete, concrete strength grade C30, steel bar cover thickness 35mm. Within 12 hours after concrete pouring, cover all exposed concrete surfaces with sacks and water them for curing. The number of waterings per day is appropriate to keep the concrete surface always in a wet state, and the curing time is not less than 7 days.

As shown in Figure 1-2, after the earthwork excavation conditions for the foundation pit are met, excavate the foundation pit along the retaining pile 1 to a place 0.5m below the design depth of the anchor rod 2, find the preset PVC pipe 5 to get through the wooden plug and drill the anchor hole , Install anchor rod 2, grouting, maintenance, install saddle-shaped block 3 and inclined iron 6 to tension and lock anchor rod 2 after the cement mortar reaches the design strength. The steel strand adopts 1×7 seven strands, the nominal diameter is 17.8mm, and the tensile strength is 1860MPa. Anchor holes are filled with cement mortar of strength grade M30.

As shown in Figure 4-5, after the installation of the anchor rod 2 is completed, the soil between the retaining pile 1 is supported. The soil between the piles uses soil nails 9 to hang 6.5@200×200 steel mesh 10, and the soil nails 9 use HRB400 steel bars , fy=400MPa, the surface layer is sprayed with C20 fine stone concrete, and the thickness is 50mm. Welding process should be preferred for mesh production. The overlap of steel mesh 10 should not be less than 300mm. The mesh should be planted with reinforcement 11, such as: expansion bolts or other methods are firmly connected with retaining pile 1; drainage holes 12 are set on the surface of the foundation pit wall, Drainage hole 12 adopts Φ100PVC pipe, the spacing is 1.5m×1.5m, and the outward slope is 4%, and the gravel reverse filter layer is used behind the hole.

Excavate and support downwards in the same way to the design depth.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the examples should be regarded in all points of view as exemplary and not restrictive, the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that the scope of the invention will fall within the scope of the claims. All changes within the meaning and range of equivalent elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

The above is only a preferred embodiment of the present invention, and does not limit the present invention. Any minor modifications, equivalent replacements and improvements made to the above embodiments according to the technical essence of the present invention should be included in the technical aspects of the present invention. within the scope of protection of the program.

Claims (8)

1. anchor head is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：At least include lagging pile (1), anchor pole (2), Shape of a saddle cushion block (3), anchorage (4), pvc pipe (5), wedge (6) and fore shaft beam (7)；

In described lagging pile (1) preset pvc pipe (5), the inner of anchor pole (2) is inserted in foundation ditch crater wall through pvc pipe (5), The outer end of anchor pole (2) is fixedly connected with anchorage (4), arranges wedge (6) and shape of a saddle pad between anchorage (4) and lagging pile (1) Block (3)；Arrange in described foundation ditch crater wall gunite concrete surface layer (8), the foundation ditch crater wall between two adjacent lagging piles (1) Soil nailing (9) and osculum (12)；Bar-mat reinforcement (10) is set in the foundation ditch crater wall between two adjacent lagging piles (1)；Described Anchorage (4) axis has 15 °～25 ° of angle with horizontal plane, and is consistent with anchor pole (2) inclination angle.

2. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described anchor Bar (2) axis is with lagging pile (1) centrage in a vertical.

3. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described anchor Bar (2) is replaced with anchor cable.

4. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described two Soil nailing (9) level interval in foundation ditch crater wall between individual adjacent lagging pile (1) is 1.4-1.6m, between osculum (12) is horizontal Away from level interval be 1.4-1.6m.

5. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described Pvc pipe (5) internal diameter is consistent with anchor hole aperture.

6. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described shield Fore shaft beam (7) is set at the top of wall stake (1).

7. anchor head according to claim 1 is placed in the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Described anchor Bar (2) has multiple, and the multiple preset pvc pipe (5) along lagging pile (1) vertical direction is inserted in foundation ditch crater wall respectively.

8. anchor head is placed in the implementation of the Pile-Anchor Supporting for Deep Excavation system of pile body, it is characterised in that：Comprise the following steps：

A, the steel reinforcement cage (13) for making lagging pile (1)

During steel reinforcement cage (13) of making lagging pile (1), at anchor pole (2) projected depth of steel reinforcement cage (13) inherence, preset two ends are with stopper The pvc pipe (5) of sealing, pvc pipe (5) are reliably connected with steel reinforcement cage (13) by iron wire, it is ensured that pvc pipe (5) is designed with anchor pole (2) Angle is consistent；In steel reinforcement cage (13), stirrup encryption should be done by preset pvc pipe (5) place, and lagging pile (1) arrangement of reinforcement has direction Property, steel reinforcement cage (13) should strictly press the direction construction of drawings marked when laying；

B, prefabricated shape of a saddle cushion block (3)

Shape of a saddle cushion block (3) by prefabricated acquisition, its material using steel or concrete, ensure when prefabricated at its saddle radian with Lagging pile (1) circular arc curvature for being adopted be consistent with ensure both can perfection agree with；When geological conditions poor, anchor pole (2) When needing to apply more high-prestressed, concrete material shape of a saddle cushion block (3) from high-mark cement and matches somebody with somebody reinforcing bar when prefabricated；

C, place cleaning

Place cleaning, excavates surface and loosens soil layer, measure positioning, setting-out to lagging pile (1) stake holes；

D, digging stake holes

Lagging pile (1) hole position that sets according to step C carries out borehole to projected depth；

E, lifting steel reinforcement cage (13)

There is directivity, steel reinforcement cage (13) should strictly press drawings marked when laying for lifting steel reinforcement cage (13), lagging pile (1) arrangement of reinforcement Construct in direction；

F, pour lagging pile (1) concrete

The casting concrete into the stake holes for install steel reinforcement cage (13), and conserve in time；

G, perform fore shaft beam (7)

After possessing fore shaft beam (7) execution conditions, carry out lagging pile (1) inter-pile soil and excavate and the amputation work of lagging pile (1) pile crown, and When fore shaft beam (7) construction working face is provided, colligation, lay steel reinforcement cage (13), formwork, casting concrete, and conserving in time；

H, installation anchor pole (2)

After possessing excavation condition, below lagging pile (1) excavation pit to anchor pole (2) projected depth, find preset Pvc pipe (5) is got through stopper and drills through anchor hole；Anchor pole (2) slip casting is installed in anchor hole, is conserved；Treat that cement mortar reaches design strong Installing shape of a saddle cushion block (3) and wedge (6) after degree carries out tensioning fixation to anchor pole (2)；

I, process Foundation Pit wall surface

For preventing inter-pile soil from coming off landslide, soil nailing (9) is beaten into inter-pile soil, hang bar-mat reinforcement (10), gunite concrete surface layer (8)； Foundation Pit wall surface arranges osculum (12), does rubble loaded filter behind hole；

J, end

Repeat step H-J, until complete the construction of pile-anchor supporting system.