CN104452784B - Composite bolt pile used for slope strengthening and construction technique of composite bolt pile - Google Patents

Abstract

The invention discloses a composite anchor pile for slope reinforcement and its construction technology, which comprises an anchor and a grouting body, the grouting body is filled around the anchor, the anchor includes a free section and an anchoring section, and the anchor A grouting pipe is fixed on one side of the free section, and the grouting pipe is integrated with the anchor rod. A geotextile is arranged outside the free section of the anchor rod, and a reserved steel bar is fixed horizontally on the top of the anchoring section of the anchor rod. The reserved steel bar is connected with the main reinforcement of the beam. The phase is fixed, and the beam is erected on the outside of the main reinforcement of the beam. There are two types of vertical and oblique. By arranging 3 to 6 anchor rods in the borehole and changing the position of the anchor section in the borehole, the tensile prestress can be effectively improved. The invention has good overall stability, high bending and shear strength, and can be used for anti-sliding reinforcement of the slope top, slope toe and slope surface of the subgrade slope; Multiple steel bars can be placed in the hole at the same time, which can reduce the arrangement of anchor cables between the lateral sides of the subgrade, and at the same time achieve effective reinforcement of the slope.

Description

A Composite Anchor Pile for Slope Reinforcement and Its Construction Technology

technical field

The invention belongs to the field of roadbed reinforcement engineering, in particular to a roadbed slope anti-sliding reinforcement technology, in particular to a composite anchor pile used for the anti-sliding reinforcement of expressway roadbed slopes and its construction technology.

Background technique

Landslides, sideslips, and collapses of roadbed side slopes are common diseases of expressway filled roadbeds, especially high-filled roadbeds. The main causes of these disasters are heavy rainfall erosion, insufficient strength of supporting and retaining structures, and excessive load on the upper part, etc. . At present, the commonly used treatment measures in engineering mainly include steel pipe piles at the top or foot of the slope, and setting prestressed anchor rods on the slope surface through drilling and grouting technology. Steel pipe pile technology refers to placing steel pipes in small boreholes, then sealing the holes by pressure grouting or pouring concrete to form micro bored piles, and then setting cast-in-place beams on the top to form an integral row of piles. This technology has structural integrity. It has the advantages of high performance, simple process, and low cost. It has become a commonly used disposal technology in slope treatment. However, this technology only installs a steel pipe inside the borehole and does not install anchor rods. Therefore, prestress cannot be applied to the top of the structure, resulting in The structural strength is low, and it cannot be used for slope reinforcement. The prestressed anchor technology refers to drilling holes on the slope, implanting the anchor, and prestressing and anchoring after grouting. This technology is often used in slope reinforcement. Due to the prestressing force applied to the anchor rod, the embankment slope is in a compressed state and prevents the slope from slipping. However, the diameter of the borehole is small and the length of the prestressed anchor is large, resulting in low shear and bending strength, which cannot resist the bending moment and shear force of the anchor caused by the slide of the soil.

Chinese patent CN 101220597 A discloses a retaining structure for a rock-soil slope, which realizes reinforcement of a broken rock mass slope through drilling and grouting technology. However, this patent is only applicable to the reinforcement of rock cutting slopes. For soil slopes, this reinforcement technology is not applicable. At the same time, the micro piles in this reinforcement technology can only be arranged obliquely, not vertically on the road shoulder, and the scope of application is limited. During the construction process, the supporting and retaining structure needs to drill holes for each micro-pile, which is difficult to construct. Moreover, for severely broken rock mass, the collapse of the broken rock mass or even the slope collapse will often be caused by vibration during the construction process. , at the same time, the internal reinforcement of the retaining structure is not prestressed, the reinforcement effect is not obvious, and the side slope is prone to lateral slippage.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and provide a composite anchor pile for slope reinforcement, which can be divided into oblique and vertical forms. By changing the position of the anchor section in the borehole, it can The tension prestress is effectively improved. The composite anchor pile has good overall stability and high flexural and shear strength, and can be used for anti-sliding reinforcement of the slope top, slope foot and slope surface of the roadbed side slope.

To achieve the above object, the present invention adopts the following technical solutions:

A composite anchor pile for slope reinforcement, comprising an anchor and a grouting body, the grouting body is filled around the anchor, the anchor includes a free section and an anchor section, the free section of the anchor A grouting pipe is fixed on one side, and the grouting pipe is integrated with the anchor rod. A geotextile is arranged outside the free section of the anchor rod, and its function is to wrap the free section of the anchor rod so that the anchor rod Separated from the grouting material, it is easy to stretch, and the geotextile on the outside of the anchor should be set up 1 to 2 layers, and fixed with steel wires. The top end of the anchoring section of the anchor rod is laterally fixed with reserved steel bars.

The reserved reinforcement is fixed to the main reinforcement of the crossbeam, and a crossbeam is erected outside the main reinforcement of the crossbeam, and the crossbeam connects at least two composite anchor piles.

The number of the anchor rods is at least three.

The anchor rod is anchored through a concrete anchor pier and an anchor plate.

The diameter of the anchor rod is Set 3 to 6 per hole according to the size of the drilled hole.

The lengths of the free sections of the anchor rods are the same, so that the anchor rods are located at the same depth underground.

The free sections of the anchor rods have different lengths and gradually increase, so that the anchor rods are located at different depths underground. For slopes with a greater degree of damage, anchor rods with different free sections should be used, the purpose of which is to make the anchoring force uniform and increase the anchoring force at different depths of the anchoring section. The construction of this structure is more complicated than that of the free section, and it is only used on slopes with greater damage.

A construction technique for composite anchor piles for slope reinforcement, comprising the following steps:

Step 1: Survey the site, determine the anchor pile depth, aperture and inclination angle of the slope anchor pile, and determine the specific position of the composite anchor pile in the reinforcement area and the size of the pile spacing beam;

Step 2: Carry out drilling, the drilling of vertical anchor piles should be perpendicular to the road surface, and the inclination angle should not exceed 1 degree;

Step 3: Wrap the free section of the anchor rod with geotextile and place the anchor rod to the bottom of the borehole;

Step 4: After placing the anchor rod, grout the anchoring section of the anchor rod, connect the grouting pipe to the grouting machine, and stop grouting when the grouting body reaches the free section;

Step 5: Grout the free section of the anchor rod, and then perform prestressed tensioning, first perform preliminary tensioning and then lock tensioning, and anchor after tensioning is completed;

Step 6: After the grouting body of the free section of the anchor rod reaches the preset strength, the beam pit is excavated, the formwork is erected, the main reinforcement and the reserved steel bar are welded, and the concrete is poured to complete the production of the beam.

The beneficial effects of the present invention are:

1. Compared with the existing steel pipe pile technology, the present invention can realize the prestress tension of the composite anchor pile by setting the anchor rod, effectively improving the strength of the pile body, and can be used for anti-sliding reinforcement of the slope position, expanding range of application of this technology. At the same time, a horizontal reserved steel bar is set at the top of the pile, which can be lapped and welded with the main reinforcement of the beam, which ensures the stability of the connection between the pile body and the beam, and enhances the overall strength and stability of the structure.

2. Compared with the existing prestressed anchor technology, the pile body of the present invention has a large diameter, and multiple prestressed anchors are arranged inside, which has high strength and can effectively solve the problem that the prestressed anchor technology cannot resist the anchor bending caused by the soil sliding. The shortcomings of moment and shear force can effectively enhance the stability of the slope.

3. Compared with the existing prestressed anchor technology, the positions of the anchor sections of the prestressed anchor are staggered from each other, which can avoid the anchor being pulled out due to the insufficient strength of the anchor section during tension, which improves the tension prestress and strengthens the pile body. stiffness. The present invention has different anchoring positions of the anchor bars, which can realize effective anchoring of the anchor bars and increase the overall strength.

4. The bolt hole diameter of the present invention is large, and the number of drilled holes arranged in the lateral position is small, and each drilled hole can place multiple steel bars at the same time, which can reduce the arrangement of anchor cables between the lateral sides of the subgrade, and at the same time realize effective reinforcement of the slope; The steel bars are prestressed, and the overall rigidity is large, which can be used as a support at the shoulder of the road, and plays a role similar to steel pipe piles.

Description of drawings

Fig. 1 is the structural representation of anchor piles at the same depth of anchorage section of the present invention;

Fig. 2 is the schematic diagram of the anchor pile structure of the anchor section of the present invention at different depths;

Fig. 3 is the anchor pile reinforced slope schematic diagram at the same depth of the anchor section of the present invention;

Fig. 4 is a partial enlarged view of place A in Fig. 3;

Fig. 5 is a partial enlarged view of place B in Fig. 3;

Fig. 6 is the schematic diagram of the slope reinforced by anchor piles at different depths in the anchor section of the present invention;

Fig. 7 is the schematic diagram of beam connection between two composite anchor piles of the present invention;

In the figure, 1. anchor rod, 2. free section, 3. anchor section, 4. grouting body, 5. grouting pipe, 6. geotextile, 7. concrete anchor pier, 8. anchor plate, 9. prefabricated Stay steel bar, 10, crossbeam, 11, main reinforcement of crossbeam.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1-7, the composite anchor pile used for slope reinforcement includes an anchor 1 and a grouting body 4, the grouting body 4 is filled around the anchor 1, and the anchor 1 includes a free section 2 and an anchoring section 3. A grouting pipe 5 is fixed on one side of the free section 2 of the anchor 1, and the grouting pipe 5 is integrated with the anchor 1. A geotextile 6 is arranged on the outside of the free section 2 of the anchor 1, and the distance between the anchor piles is 1.5 ～2m, the length of the anchoring section is 1.5～4m, and the reserved steel bar 9 is set on the top of the anchoring section 3, which is welded with the main reinforcement 11 of the beam. A crossbeam 10 is erected outside the main reinforcement 11 of the crossbeam, and the crossbeam 10 connects two composite anchor piles. Anchor rod 1 is HRB type threaded steel bar, the strength is not lower than HRB335, and the diameter is The length is the same as the drilling depth, and 3 to 6 are set in each hole according to the size of the drilling. The anchor rod 1 is anchored through the concrete anchor pier 7 and the anchor plate 8 .

The diameter of the borehole is 15-30cm, and its depth should exceed the sliding surface by 2-3m. After the borehole is completed, it should be cleaned. Pressure grouting is used in the borehole, and the grouting pressure is controlled at 0.4-1.0MPa. The grouting method should be single-pipe grouting or multi-pipe grouting. Single-pipe grouting refers to setting a grouting pipe in the center of the pile, and the sleeve-pipe grouting process can be used. Multi-pipe grouting means that each anchor rod is equipped with a grouting pipe of the same length for grouting.

Grouting pipe 5 is a steel pipe for sleeve valve pipe grouting, with a diameter of 2 to 4 cm, the same length as anchor rod 1, and is welded into one with anchor rod 1, and holes are punched at anchoring section 3 every 10 to 20 cm in length. 3~5mm. The grouting end of the grouting pipe 5 should be sealed before being connected with the grouting machine.

The grouting material is cement mortar, the mortar is made of fine sand or extra fine sand, the grade is not lower than M30, the water-cement ratio is 0.8-1.2, and the mass fraction of sand is not more than 30%.

Geotextile 6 is a geotextile for ordinary construction. Its function is to wrap the free section of the anchor rod, so that the anchor rod is separated from the grouting material during prestressed tension, which is convenient for stretching. And fixed with steel wire.

The crossbeam 10 is a reinforced concrete structure, and its function is to connect multiple anchor piles into a whole. After the anchor bolts are anchored, excavate pits along the longitudinal direction at the anchor ends, erect steel bars and weld them with reserved steel bars, and place formwork Pouring concrete, the concrete strength is greater than C40.

The construction technology of the composite anchor pile used for slope reinforcement includes the following steps:

The first step is to survey the site first, determine the anchor pile depth, aperture, and slope angle of the anchor pile according to the site conditions, landslide location, and damage area size, and then carry out site measurement and setting out to determine the composite anchor pile in the reinforcement area. Parameters such as the specific location of the pile, the size of the pile spacing, and the beam size.

The second step: the drilling rig is in place and drilling is carried out. The drilling of vertical anchor piles should be perpendicular to the road surface, and the inclination angle should not exceed 1 degree. Clean the holes after completion.

The third step is to place the prestressed anchor rod 1. The anchor rod 1 should reach the bottom of the drilled hole. Before placing the anchor rod 1, the free section 2 should be wrapped with geotextile 6, and the anchor rod 1 in the same hole should be installed at the same time. , Erecting steel bars can be set during installation to ensure the spacing between anchor rods.

Step 4: After placing the anchor rod 1, grout the anchor section 3, connect the grouting pipe 5 to the grouting machine, and stop grouting when the grouting body 4 reaches the free section 2.

Step 5: After the strength of the grouting body 4 of the anchorage section 3 reaches the design strength greater than 80%, grout the free section 2, and then perform prestressed tension. When the anchor is formally tensioned, it should be tensioned to the design load 105% to 110% of the specified value, and then anchored after the locking and tensioning is completed according to the specified value.

Step 6: After the grouting body 4 of the free section reaches a certain strength, excavate the concrete beam 10 pit, erect the formwork, weld the main reinforcement and the reserved steel bar 9, pour concrete, and complete the fabrication of the beam.

Example 1:

As shown in Figure 1, it is a vertical anchor pile. The parameters of the reinforcement design plan are determined according to the site. The anchor section is composite anchor pile at the same depth. After parameter drilling and hole clearing, anchor rods are placed, and the hole is grouted and sealed by sleeve valve grouting technology. After the free forging grout reaches a certain strength, the beam pit is excavated, the formwork is erected, the main reinforcement and reserved reinforcement are welded, and the concrete is poured. , to complete the fabrication of beams.

Example 2:

As shown in Fig. 3, the anchor piles in the vertical form and the prestressed anchor piles in the oblique form are determined according to the parameters of the reinforcement design scheme on site, and the anchorage section is combined with the anchor piles at the same depth. Determine the location of the drilling hole, drill the hole according to the parameters of the design plan, place the anchor rod after the hole cleaning is completed, and grout the anchoring section through the sleeve valve grouting technology. After the grouting body reaches 80% of the design strength, grout the free section, and then Prestressed tensioning and anchoring of anchor rods. After the free forging grouting body reaches a certain strength, the beam pit is excavated, the formwork is erected, the main reinforcement and reserved reinforcement are welded, and the concrete is poured to complete the beam.

Example 3:

As shown in Figure 6, it is an oblique form of prestressed anchor pile. The parameters of the reinforcement design scheme are determined according to the site. The anchor section is compounded with anchor piles at different depths. The design parameters are to drill the hole and place the anchor rod after the hole cleaning is completed, and grout the anchor section and the free section through the sleeve valve grouting technology. After the grout reaches 80% of the design strength, the anchor bolt is prestressed and anchored. Excavate the beam pit, erect the formwork, weld the main bars and reserved steel bars, pour concrete, and complete the beam.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (7)

1. a kind of Composite Bolt stake for slope reinforcement, is characterized in that, including anchor pole and injecting cement paste, described injecting cement paste is filled in Around anchor pole, described anchor pole includes free segment and anchoring section, and the free segment side of described anchor pole is fixed with Grouting Pipe, described slip casting Pipe is integral with anchor pole, is provided with geotextiles, the top of the anchoring section of described anchor pole is laterally fixed outside the free segment of described anchor pole There is reserved steel bar；

Described reserved steel bar is fixed with crossbeam cage bar phase, and setting up outside described crossbeam cage bar has crossbeam；Described crossbeam will at least two Individual Composite Bolt stake couples together.

2. Composite Bolt stake as claimed in claim 1, is characterized in that, described anchor pole quantity is at least three.

3. Composite Bolt stake as claimed in claim 1, is characterized in that, described anchor pole is carried out by concrete anchor pier and anchor plate Anchoring.

4. Composite Bolt stake as claimed in claim 1, is characterized in that, a diameter of φ 20 ~ φ 32 mm of described anchor pole.

5. Composite Bolt stake as claimed in claim 1, is characterized in that, the freedom length of described anchor pole is identical.

6. Composite Bolt stake as claimed in claim 1, is characterized in that, the freedom length of described anchor pole is different, and gradually passs Increase.

7. the construction technology of the Composite Bolt stake as described in any one of claim 1-6, is characterized in that, comprise the following steps:

Step 1: exploration place, determine the angle of inclination of anchor pile depth, aperture and domatic anchor pile, determine that reinforcing area is multiple Close particular location, the pile spacing crossbeam size of anchor pile；

Step 2: holed, vertical form anchor pile boring should be vertical with road surface, and angle of inclination not can exceed that 1 degree；

Step 3: the free segment of anchor pole is wrapped up with geotextiles, places anchor pole to foot of hole；

Step 4: after placing anchor pole, the anchoring section of anchor pole is in the milk, Grouting Pipe is connected with slip casting machine, reaches in injecting cement paste During free segment, stop slip casting；

Step 5: grouting treatment is carried out to the free segment of anchor pole, carries out prestressed tensioning afterwards, first carry out preliminary tensioning and enter again Row locking tensioning, tensioning is anchored after completing；

Step 6: after the free segment injecting cement paste of anchor pole reaches preset strength, excavate crossbeam pit, set up template, welding cage bar and pre- Stay reinforcing bar, casting concrete, complete the making of crossbeam.