CN102797254B - Construction method for bottom-expanded pile casting by long-spiral drilling and compacted half soil sampling - Google Patents

Abstract

The invention relates to a construction method of long helical drilling compacting half-borrowed soil-borrowing bottom expansion grouting piles. The soil is backfilled into the pile hole, and the long auger drill equipped with a special rock drill bit is used to squeeze the hole to the predetermined depth again; replace the upper reamer at the bottom of the drill pipe, put it into the bottom of the pile hole for reaming construction; reaming After the end, put forward the long auger drilling rig, replace the multi-functional slag-cleaning tube at the bottom of the drill pipe, put it into the bottom of the pile hole for slag-clearing construction; after cleaning the residue at the bottom of the pile hole, open the concrete output valve at the bottom of the multi-functional slag-clearing The concrete pump pours concrete into the bottom of the pile hole; the steel cage is hoisted in, and the steel cage is vibrated into position by the vibrator and the self-weight of the steel cage. The perforated hole pile of the present invention has the advantages of large stress-bearing area at the bottom of the pile, high load-bearing capacity of the single pile, and strong anti-seismic ability at the bottom of the single pile.

Description

A Construction Method of Bottom Expansion Grouting Pile with Long Spiral Drilling and Compacting Semi-borrowed Soil

technical field

The invention relates to a construction method of reinforced concrete cast-in-place piles, in particular to a construction method of long auger drilled compacted semi-borrowed cast-in-place piles with bottom expansion.

Background technique

At present, under the geological conditions where the non-bedrock is the bearing layer, the high-rise and super-high-rise construction projects with extremely large upper loads generally increase the pile diameter and the length of the pile body to increase the bearing capacity of the single pile in order to ensure that the bearing capacity of the foundation is not exceeded. However, lengthening and increasing the diameter of the pile body will inevitably lead to a huge increase in the amount of concrete. Moreover, when the ratio of the length to diameter of the pile body is too large, the bearing capacity and shear resistance of the pile body will be significantly reduced. However, at present, the drilling, bottom expansion, pouring, pile forming and other processes in the construction process of bottom expansion grouting piles require the cooperation of multiple mechanical equipment to complete, the construction efficiency is low, the operation is complicated, and the maintenance cost is high. Therefore, the existing The construction method and equipment of the bottom-expanding cast-in-situ pile have seriously restricted the development of the pile foundation industry.

Contents of the invention

The technical problem to be solved by the present invention is to provide a construction method of a long auger bored compacted half-borrowed soil and bottom-expanded cast-in-place pile with fast construction speed and high bearing capacity.

In order to solve the above technical problems, the technical solution of the present invention is: a construction method of long auger bored compacted half-borrowed soil and bottom expansion grouting pile, which is characterized in that it comprises the following steps:

Step 1: Use a long auger drill equipped with a special rock drill bit to construct to the predetermined depth of the pile hole, and then put out the long auger drill;

Step 2: Backfill the rock and soil discharged by the long auger drill into the pile hole, squeeze the hole to the predetermined depth again with the long auger drill equipped with a special rock drilling bit, and finally lift out the long auger drill;

Step 3: Replace the upper reamer at the bottom of the drill pipe, put it into the bottom of the pile hole for reaming construction;

Step 4: After reaming, take out the long auger drill pipe, replace the multi-functional slag removal tube at the bottom of the drill pipe, and put it into the bottom of the pile hole for slag removal construction;

Step 5: After clearing the residue at the bottom of the pile hole, open the concrete output valve at the bottom of the multi-functional slag removal cylinder, and pour concrete into the pile pipe through the concrete pump;

Step 6: Hang into the reinforcement cage, use the vibrator and the self-weight of the reinforcement cage to vibrate the reinforcement cage into position.

The structure of the special rock drilling bit is as follows: it includes a double-screw double-ended drill bit, the cutting teeth and slag cleaning knives are symmetrically arranged on the double-screw double-ended drill bit, and a drill tip is arranged on the top of the double-screw double-ended drill bit.

The cutting tooth is composed of a bullet bit and a base, the base is welded on the helical piece, and the bullet bit is clamped in the base.

The slag cleaning knife is composed of a shovel and a bracket, the bracket is welded on the spiral piece, and the shovel is fixed on the bracket by a bolt.

The drill tip is preferably twist-shaped.

The structure of the multifunctional slag cleaning cylinder is as follows: it includes a cylinder body, the top of the cylinder body is provided with a connecting part connected with the long auger rod, the bottom is provided with a fan-shaped bottom plate concentric with the cylinder body, and the cylinder body is provided with a hollow The steel pipe of the flow channel, the lower end of the steel pipe is fixedly connected to the fan-shaped bottom plate, the lower part of the fan-shaped bottom plate is provided with a soil collecting plate that can rotate around the steel pipe, the bottom of the steel pipe is provided with a valve, and the fan-shaped bottom plate is provided with a stopper.

A shovel board inclined downward is arranged on the edge of the soil collecting board.

The valve is composed of two half-moon baffles, and the half-moon baffle is provided with a crescent-shaped channel, one end of the baffle is fixed on the bottom of the steel pipe through a pin, and the other end passes through the crescent-shaped channel through a pin Restricted to the soil plate.

The fan-shaped bottom plate is connected with the bottom of the cylinder through a hinge.

This method is applicable to rock formations such as fill, silt, silt, clay, sand, pebbles, and moderate weathering, as well as foundation piles of various buildings (structures). No need to add steel formwork casings when constructing in groundwater formations And the mud retaining wall can complete the underwater injection with one machine. In the unsaturated soil layer, there is almost no need to take soil. In the saturated soil layer, the amount of soil taken into piles is only about 70% of the traditional process. The compactness of the soil around the pile and the side resistance of the pile body are greatly improved. The pile diameter can generally reach 600-1000mm, the pile length can reach within 30 meters deep, and the maximum diameter of the expanded bottom can reach 1600mm.

The drill bit used in this method is a special rock drill bit improved on the basis of the traditional drill bit. It uses the torsion and pressure of the long helical drilling machine to make the cutting teeth on the drill bit cut and break the geological rock formation. The broken slag is cleaned up, and finally the helical piece of the long auger drilling machine clears the excess slag out of the hole, which effectively solves the problem of drilling the drill bit into the rock and preventing the settlement of the pile foundation.

The slag cleaning cylinder used in this method is equipped with a steel pipe with a hollow flow channel for pouring concrete inside the original slag cleaning cylinder, so that it is connected to the hollow flow channel of the long auger drill pipe, and at the same time, a concrete outlet valve is designed at the bottom of the slag cleaning cylinder steel pipe , when the long auger rod rotates clockwise, the concrete outlet is automatically closed, and the slag removal cylinder is used for slag removal through the shovel, and when the long auger rod is rotated counterclockwise, the concrete outlet is opened for concrete pouring, which effectively solves the problem of cleaning The slag drum can only be cleaned of slag and cannot be poured into the technical problem of concrete.

The invention has advanced technology, simple operation, wide application range, fast pile forming speed, good bottom expansion effect, no mud discharge, no need for wall protection, one-machine operation, and slag removal, which are incomparable to other mechanical bored piles and manual digging piles. The latter has the advantages of one-gas pile formation, high degree of mechanization, safety and reliability, greatly reduced engineering cost, and greatly improved pile bearing capacity. This difficult problem that has plagued the pile foundation industry has filled a gap in my country's pile foundation industry.

Description of drawings

Fig. 1 is construction steps figure of the present invention;

Fig. 2 is a schematic diagram of a special rock drilling bit of the present invention;

Fig. 3 is the front view of the multifunctional slag cleaning cylinder of the present invention;

Fig. 4 is a bottom view of the multifunctional slag removal cylinder of the present invention when performing slag removal operations;

Fig. 5 is a bottom view of the multifunctional slag cleaning cylinder of the present invention when performing concrete pouring operation;

1. Drill tip, 2. Double screw double-headed drill bit, 3. Cutting teeth, 4. Slag cleaning knife, 5. Bullet drill bit, 6. Base, 7. Shovel knife, 8. Bracket. 9. Cylinder body, 10. Connecting parts, 11. Fan-shaped bottom plate, 12. Soil collecting board, 13. Valve, 14. Steel pipe, 15. Hinge, 16. Block, 17. Shoveling board, 18. Pin shaft, 19 , bearing pin, 20, hollow runner, 21, baffle plate, 22, crescent-shaped through groove.

Detailed ways

The construction method of the long auger bored compacted half-borrowed soil and bottom-expanded cast-in-place pile comprises the following steps:

Step 1: Use a long auger drill equipped with a special rock drill bit to construct to the predetermined depth of the pile hole, and then put out the long auger drill;

Step 2: Backfill the rock and soil discharged by the long auger drill into the pile hole, squeeze the hole to the predetermined depth again with the long auger drill equipped with a special rock drilling bit, and finally lift out the long auger drill;

Step 3: Replace the upper reamer at the bottom of the drill pipe, put it into the bottom of the pile hole for reaming construction;

Step 4: After reaming, put out the long auger drilling rig, replace the multi-functional slag cleaning tube at the bottom of the drill pipe, and put it into the bottom of the pile hole for slag cleaning construction;

Step 5: After the residue at the bottom of the pile hole is cleared, open the concrete output valve at the bottom of the multifunctional slag removal cylinder, and while lifting the drill pipe, pour concrete into the bottom of the pile hole through the concrete pump;

Step 6: Hang into the reinforcement cage, use the vibrator and the self-weight of the reinforcement cage to vibrate the reinforcement cage into position.

As shown in accompanying drawing 1, the detailed construction steps of the present invention are as follows:

Leveling the site→pile position setting out→assembling equipment→drilling machine in place→drilling to the design depth and stopping drilling→lifting the drill pipe→backfilling the remaining soil in the pile hole→squeezing the drill hole→lifting the drill pipe and removing the auger Drill → replace the reamer → use the drill pipe to send the reamer to the bottom of the hole → turn on the drilling rig, carry out bottom reaming and cutting, and stop when it meets the design requirements → lift the drill pipe → remove the reamer and replace it with a slag cleaning cylinder to clean the bottom of the hole Muck → pump concrete to the design elevation → use the self-equipped hoist of the pile driver to lift the reinforcement cage and vibrator, and vibrate the reinforcement cage into the concrete → pile formation → pile head treatment → pile top protection measures.

As shown in accompanying drawing 2, the structure of the special rock drilling bit includes a threaded long helical drill rod and a double-screw double-ended drill bit 2, and the double-screw double-ended drill bit 2 is provided with two symmetrical cutting teeth 3 and cleaning teeth. The slag cutter 4 is provided with a twist-shaped drill tip 1 on the top, the cutting teeth 3 are composed of a bullet bit 5 and a base 6, and the plurality of bases 6 are welded side by side on the spiral piece, and the bullet bit 5 is clamped on the base 6 can rotate freely; the slag-cleaning knife 4 is made up of a shovel 7 and a support 8, the support 8 is welded on the helical piece, the shovel 7 is fixed on the support 8 by a latch, and the bullet bit 5 and The quantity and length size and the position of the spatula 7 can be adjusted according to the size of the borehole diameter.

As shown in Figure 3, the structure of the multi-functional slag cleaning cylinder includes a cylinder body 9, the top of the cylinder body 9 is provided with a connecting part 10 connected to the long auger rod, and the bottom is connected by a hinge 15 concentric with the cylinder body 9. The fan-shaped bottom plate 11, the cylinder body 9 is provided with a steel pipe 14 with a hollow flow channel 20, its upper end is fixedly connected to the connecting part 10, and its lower end is fixedly connected to the fan-shaped bottom plate 11, and the lower part of the fan-shaped bottom plate 11 is provided with A soil collection plate 12 that can rotate around a steel pipe 14, and a concrete outlet valve 13 is provided at the bottom of the steel pipe 14.

As shown in accompanying drawing 4, on the edge of described earth collecting plate 12, be provided with the shovel plate 17 that slopes downward, and described valve 13 is made up of two half-moon baffles 21, and one end of described baffle 21 passes pin Axle 18 is fixed on central shaft 14 bottoms, and the other end passes through crescent-shaped through groove 22 and is limited on the soil collection plate 12 by bearing pin 19, and two half-moon baffle plates 21 rotate clockwise to In the closed state, the concrete outlet valve 13 is closed, and at the same time, the earth collecting plate 12 rotates clockwise around the steel pipe 14 to the position of the stopper 16, and the earth shoveling plate 17 starts to carry out the slag removal operation.

As shown in Figure 5, when the long auger rod rotates counterclockwise, the soil collecting plate 12 rotates counterclockwise to the close state with the fan-shaped bottom plate 11, and at the same time, the two half-moon baffles 21 follow the crescent-shaped through groove 22. The internal pin shaft 19 rotates counterclockwise synchronously with the soil collecting plate 12, the concrete outlet valve 13 is opened, and the pouring operation of concrete begins.

This method is suitable for filling, silt, silt, clay, sand, pebbles, moderately weathered and slightly weathered geological rock formations in most provinces and cities in central China, and will make a great contribution to the express development of the pile foundation industry.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Equivalent replacements or changes based on the technical solutions of the present invention and their inventive concepts shall all be covered by the protection of the present invention. within range.

Claims (2)

1. A construction method of long auger bored compacting half-borrowed soil-borrowing bottom-expanding cast-in-situ piles, characterized in that it comprises the following steps: Step 1: Use a long auger drill equipped with a special rock drill bit to construct to the predetermined depth of the pile hole, and then put out the long auger drill; Step 2: Backfill the rock and soil discharged by the long auger drill into the pile hole, squeeze the hole to the predetermined depth again with the long auger drill equipped with a special rock drilling bit, and finally lift out the long auger drill; Step 3: Replace the upper reamer at the bottom of the drill pipe, put it into the bottom of the pile hole for reaming construction; Step 4: After reaming, take out the long auger drill pipe, replace the multi-functional slag removal tube at the bottom of the drill pipe, and put it into the bottom of the pile hole for slag removal construction; Step 5: After the residue at the bottom of the pile hole is cleared, open the concrete output valve at the bottom of the multifunctional slag removal cylinder, and while lifting the drill pipe, pour concrete into the bottom of the pile hole through the concrete pump; Step 6: Hang into the reinforcement cage, use the vibrator and the weight of the reinforcement cage to vibrate the reinforcement cage into position; The structure of the special rock drilling bit is as follows: it includes a double-screw double-ended drill bit (2), and the double-screw double-ended drill bit (2) is symmetrically equipped with cutting teeth (3) and slag cleaning knives (4). The top of the double-ended drill bit (2) is provided with a drill point (1); The cutting tooth (3) is composed of a bullet bit (5) and a base (6), the base (6) is welded on the spiral sheet, and the bullet bit (5) is clamped in the base (6); The slag cleaning knife (4) is composed of a shovel (7) and a bracket (8), the bracket (8) is welded on the spiral sheet, and the shovel (7) is fixed on the bracket (8) by a bolt; The structure of the multi-functional slag cleaning cylinder is: including a cylinder body (9), the top of the cylinder body (9) is provided with a connecting part (10) connected with the long auger rod, and the bottom is provided with a connecting part (10) concentric with the cylinder body (9). The fan-shaped bottom plate (11), the cylinder body (9) is provided with a steel pipe (14) with a hollow flow channel (20), the lower end of the steel pipe (14) is fixedly connected to the fan-shaped bottom plate (11), and the fan-shaped The lower part of the bottom plate (11) is provided with a soil collection plate (12) that can rotate around the steel pipe (14), the bottom of the steel pipe (14) is provided with a valve (13), and the fan-shaped bottom plate (11) is provided with a stopper (16 ); A shoveling board (17) inclined downward is arranged on the edge of the soil collecting board (12); The valve (13) is composed of two half-moon baffles (21), the half-moon baffles (21) are provided with a crescent-shaped through groove (22), and one end of the baffle (21) passes through a pin ( 18) It is fixed on the bottom of the steel pipe (14), and the other end passes through the crescent-shaped through groove (22) through the pin shaft (19) and is restricted on the soil collection plate (12); The fan-shaped bottom plate (11) is connected with the bottom of the cylinder (9) through a hinge (15). 2. The construction method according to claim 1, characterized in that: the drill tip (1) is twist-shaped.