GB2147039A - Interconnected cast in situ piles - Google Patents

Abstract

A pile structure and construction method thereof are provided. This pile structure includes one or more than one connecting beam 148 which not only can increase the structure strength of a single pile, but also can improve the load-bearing capacity of the whole pile system underneath one construction work; further, the construction of the pile is done with a machine, which can make the construction work more efficient and accurate. <IMAGE>

Description

SPECIFICATION Apparatus and construction method for increasing bearing capacity of piles with connecting beams Generally, the load-bearing capacity and the sinking of a pile in a foundation work depend upon the point load-bearing and the friction between the pile and the soil. The structure strength of a pile depends upon the load of a construction and the resistance to compressive strength, and the tensile strength during earth-quake. Underneath a same building, the single pile in certain spot may be imposed on with different pressure as a result of earthquake and the soil structure; in that case, the building or a construction work might be caused a minor sag or deformation.

In order to eliminate the drawbacks in a construction work, the inventor has developed a new structure between or among the piles, i.e. a connecting beam (similar to a prop or shoring means), so as to eliminate the posse bility of imposing too much load on a single pile or a small number of piles, and to eliminate pile sagging, buckling and to increase the load-bearing capacity of every pile as well.

In this invention, a new construction method and device in pile-constructing work are provided; particularly, a connecting beam is to be built between or among the piles so as to increase the load-bearing capacity of piles, and the strength of pile structure. During that construction work, drill a pile hole in round or square shape with a drilling machine; then, put the earth borer of the present invention into the pile hole to form a semiball-shaped chamber. When the chamber is well drilled, part of its diameter will be overlapped with the equal part of the chamber of an adjacent pile hole; in other words, a tunnel will be formed between two pile holes.Now, fold up the earth borer and pull it out of the pile hole; then, put a folding type of precast reinforcement connecting beam or a steel bar in the semi-ball-shaped chamber, and have another connecting beam or steel bar in the adjacent same chamber arranged in parallel and overlapped manner with the former one.

After that, pour concrete into the both chambers and pile holes, and the construction of the piles and connecting beams is done.

This invention will increase the load-bearing capacity of piles, and the structure strength of single pile, and also prevent some piles from irregularly sagging.

Figure 1 is a sectional view of a verticaltype of earth borer in the present invention being placed into the pile hole.

Figure 2 is a sectional view of the verticaltype of earth borer being gradually unfolded to a horizontal position.

Figure 3 is a front view of a pre-cast connecting beam in the present invention.

Figure 4 is a front view of the said earth borer, showing various parts in detail.

Figure 5 is a sectional view of three piles in the present invention.

Figure 6 is a sectional view of pile holes with the connecting beam holes in the present invention.

Figure 7 is a front view of a number of piles with connecting beams of the present invention being built.

Figures 8 and 9 are the top views of piles with connecting beams being built in different way in the present invention.

Figure 10 shows the dynamic force transmission method of the earth borer in the present invention.

Figures 1 1A and 1 IB are views showing the safety analysis on pile hole of the present invention.

Figure 12 is a sectional view (1 2A) and a top view (1 2B) of two piles in the present invention being built together.

Figure 13 is a sectional view of two piles in the present invention being built together without reinforcement in the connecting beam.

Figure 14 is a sectional view of a horizontaltype of earth borer in the present invention.

Figure 15 is a sectional view of the earth borer in Fig. 14 which moves horizontally in a retractable mode.

Figure 16 is a sectional view of the earth borer, shown in Fig. 1 5 with more parts and operational details.

Figure 17 is an enlarged view of the joint part of the piston rod operation in Fig. 1 5.

Figure 18 is a sectional view of Fig. 1 7.

Figure 19 is a configuration view of the hydraulic cylinders in the present invention.

Figure 20 is a sectional view of horizontal type of earth borer in the present invention.

Figure 21 is a sectional view of Fig. 20, in which the gang-type drills have been driven forwards and horizontally.

Figure 22 is a sectional view of the horizontal type of earth borer shown in Fig. 20 to drill another horizontal connecting beam hole to communicate with the same adjacent hole.

Figure 23 is a sectional view showing two adjacent piles being connected with a concret connecting beam with a method of the present invention.

Figure 24 is a sectional view showing a building seating on a number of piles constructed by the method of the present invention.

Figure 25 is a sectional view showing a concrete connecting beam being reinforced at the bottom portion with two reinforcement steel bars according to the method of the present invention.

Figure 26 is a sectional view showing a connecting beam being reinforced at the top portion with two reinforcement steel bars according to the method of the present inven tion.

Figure 27 shows the joint part of the two steel rods in the present invention.

Figures 28 and 29 are sectional views showing two pairs of separate hydraulic cyiinders to drive the gang-type drills in the present invention.

Figures 30 and 31 are sectional views showing the a double-acting and retractable hydraulic cylinders to drive the gang-type drills in the present invention.

Referring to Fig. 1, there is shown a vertical-type of earth borer in a pile hole 9, which comprises a twin movable boring arm 8, a hollow hammer 2, a steel pipe 1, two gangtype drills 7, two supporting bars 5 of which one end is connected, with pivot 3 to the bottom end of a hollow hammer 2.

The top end of the hollow hammer 2 is attached with a chain 6. The steel pipe 1 is connected with pivot 3, and is controlled from the ground surface. As shown in Fig. 2, when the chain is released, the hollow hammer 2 will go downwards to force the supporting bar 5 to unfold gradually upon the movable boring arms 8 rotating around the pivot 4. Simultaneously, upon the gang-type drills 7 rotating, a semi-ball shaped chamber will gradually beformed from the center of the pile hole.

Upon a semi-ball-shaped chamber being completely formed, part of its diameter will be over-lapped with the similar chamber of the adjacent pile hole, becoming communicated with each other as shown in Fig. 2. Then, pull the chain 6 to lift up the hollow hammer 2 so as to have the movable baring arms 8 folded up in order to take the earth borer out of the pile hole by pulling out the steel pipe 1.

Finally, a pre-cast reinforced concrete connecting beam 1 3 as shown in Fig. 3 will be put into the semi-ball-shaped chamber, extending partially into the semi-ball-shaped chamber of an adjacent pile hole; then, unscrew the steel pipe 1 to have the pre-cast reinforced concrete beam 1 3 separated from the steel pipe 1, which will be pulled out of the pile hole as shown in Fig. 3. (The steel pipe 1 may also be left in the pile hole together with the connecting beam). Upon the pile hole and the semi-ball-shaped chamber being fully poured with concrete, a connecting beam between piles will be built up as shown in Fig. 5. The connecting beam in the present invention may be a reinforced concrete beam, or steel bar beam, or steel plate or a concrete beam.

Fig. 4 shows more details of the gang-type assembly, in which 10 stands for motor, 11 stands for sludge exhausting pipe, 12 stands for gear of the drill. Fig. 7 shows a front view of a number of piles with connecting beams.

Fig. 8 and 9 are showing the top view of piles with connecting beams being built in different way.

Referring to Fig. 6, there is shown a single pile, which is furnished with more than one semi-ball-shaped chambers so as to increase the load-bearing capacity of the pile.

Referring to Fig. 11 A, there are shown the factors which may affect the stability of the pile hole; in that Fig., "F" stands for the resistance force of the bentonite, "W" stands for the weight of soil that may act on the pile hole, "a" stands for the supposed failure line of soil, "Y" stands for the friction force along the failure line: the weight of soil "W" is supported by "Y" and "F" so as to avoid of landslide.

Referring to Fig. 11 B, there are shown the factors which may affect the stability of the semi-ball-shaped chamber; in that Fig., the soil weight "P" is supported by "YS" and "FF" ("YS" stands for the friction force along the failure line, "FF" stands for the resistance force of the bentonite), "b" stands for the supposed failure line after the semi-ballshaped chamber being formed, "a" stands for the failure line before the semi-ball-shaped chamber being formed. The resistance force of the bentonite depends upon its density, and the stability of the inner wall of soil depends upon the viscosity of the water-proof film formed by the bentonite.

Referring to Fig. 1 2A, there is another embodiment showing pile holes a and b to be drilled with reverse rotation drilling method and to be filled with bentonite for keeping the pile hole in shape; then, drill a semi-ballshaped chamber in each pile hole so as to have the chambers of two adjacent pile holes communicated with each other; then, fill the chambers and the tunnel between them with bentonite so as to keep them in shape. In each of the two pile holes, put a reinforcement crib 211 being attached with a steel pipe outside, of which the bottom is pivoted to a supporting bar 15, and the other end of said supporting bar 1 5 is pivoted to the steel beam 13, while one end of the beam 1 3 is connected to the reinforcement crib with a pivot 14.Since the steel beam 1 3 may be controlled to fold or unfold upon the steel pipe 1 being moved up or down, the said two steel beams 1 3 will be placed horizontally in parallel and overlapped manner in the two semi-ball-shaped chambers communicated and overlapped by controlling the steel pipes 1 from the ground after the two reinforcement cribs 211 being completely put into the pile holes respectively; then, pour concrete into the said pile holes, and the construction work is done. Fig. 1 2B is a top view of Fig. 1 2A.

Referring to Fig. 13, there is a still another embodiment showing a concrete connecting beam being furnished between two piles instead of a connecting beam as mentioned above. This way may be used when the semiball-shaped chambers between two pile hole have a considerable depth "L".

Referring to Fig. 14 and 15, there is shown a horizontal-type of earth borer for drilling a hole between two adjacent pile holes so as to construct a connecting beam; said earth borer includes a gang-type drills 7, a machine chamber 102, a pair of upper hydraulic cylinders 103 with their piston rods 110, a pair of lower hydraulic cylinders 104 with their piston rods 111, the supporting rods 105 and 106, the slide groove 107', the fixed iron pieces 137, the protection lids 107 and 108, the case lid 109, the pulleys 112 and 113, and the pivot joints 114, 115, 116, 117, 118, etc. Upon the hydraulic cylinders 103 and 104 being driven, the piston rods 110 and 111 will be driven forwards synchronously to have the supporting rods 105 and 106 push the gang-type drills 7 to move forwards.At the same time, the pulleys 11 2 and 11 3 fixed at the end of the piston rods 110 and 111 will move along the slide groove 107'. The supporting rods 105 and 106 are pivotally fixed to the pivot joints 114, 115, 116 respectively. The hydraulic cylinders 103 and 104 are pivotally attached to the pivot joints 11 7 and 118 respectively.

The protection lids 107 and 108 as shown in Fig. 1 5 will be extended and retracted back and forth by following the motion of the gangtype drills 7.

Referring to Fig. 16, there is shown the horizontal-type of earth borer with more parts, in which the electric motor 1 32 upon being energized will drive the hydraulic pump 133, and a hydraulic power will go thru the control valve 134, the hydraulic pipes 1 35 and 136, and the hydraulic cylinders 103 and 104 to have the piston rods 110 and 111 moved synchronously forwards at a speed of 0.5 cm/sec. to 5 cm/sec.; 102 stands for the machine chamber of the borer; 102' stands for the outer case of the borer; 128 stands for the bentonite pipe with extension joint; 129 stands for the sludge pipe with extension joint; 1 25 stands for a hydraulic motor to drive the gang-type drills 7 drilling; 1 26 stands for a gang gears to drive each of the drills 7.

Referring to Fig. 17, there is shown an enlarged view of the joint part of the piston rod operation, which includes the pulley 112, 113 and the slide groove 107'.

Fig. 1 8 shows a sectional view of Fig. 1 7.

Fig. 1 9 shows the configuration of the hydraulic cylinders, in which the upper hydraulic cylinders 103 are mounted in the upper portion at the both sides of the outer case 102', while the lower hydraulic cylinders 104 are mounted in the lower portion at the both sides of the outer case 102'.

Referring to Fig. 20 and 21, there is shown the earth borer 144 being furnished at its bottom with four drilling disks 144' so as to drill a square-shaped pile hole with a cast-inplace construction method; then, a hollow steel cylinder is driven into the pile hole, and at the bottom of the hollow steel cylinder, the earth borer 144 is put in, and is driven with an electric motor 140. Upon the sludge being exhausted to the ground surface, the hollow steel cylinder 1 39 will descend slowly.As soon as the borer at the bottom of the hollow steel cylinder reaches a pre-determined depth, turn on the power of the hydraulic cylinder of the earth borer so as to have the piston rods 110 and 111 of the pair hydraulic cylinders moved forwards slowly at a speed ranging from 0.5 cm/sec. to 5 cm/sec., and at the same time, turn on the power of the gangtype drills to let them rotate at a speed ranging from 40 rpm to 60 rpm. As a result of the pushing force of the piston rods 110 and 111, the supporting rods 105 and 106 will have the gang-type drills moved forwards horizontally. Simultaneously, the water pipe (or bentonite pipe) will spray water so as to have the soil in the hole become sludge, which will be exhausted to the ground surface via the sludge pipe.During the gang-type drills moving forwards, the protection lids 107 and 108 will also be drawn outwards to prevent from a landslide from the top of the horizontal hole. Upon the gang-type drills moving a pre-determined distance (approximate 1.2 to 1.5 times of the diameter of the pile), the drills are to be recovered; simultaneously, the concrete will be poured via the bentonite pipe, and the hollow steel pipe 1 39 will also be pulled out slowly.

Referring to Fig. 22, there is shown the gang-type drills of the earth borer drilling another horizontal hole so as to have the hole communicate with the former one (The time of that communication between the two horizontal holes may be indicated by the material exhausted to the ground with the sludge pipe, or by the stroke meter of the hydraulic cylinder); apparently, this may be done by following the same operation procedures as mentioned above. By using the same method, more than one of said connecting beam may be constructed between two or among more than two pile holes in the central portion of a pile hole or other appropriate portion thereof.

Referring to Fig. 33, there are shown two adjacent piles 145 and 151 being connected with a concrete connecting beam 148; in Fig.

23, "D" stands for the diameter of a round pile or one side of a square pile.

Referring to Fig. 24, there is shown a building being rested on a number of piles constructed by means of the method of the present invention, in which 1 55 stands for a building, 1 53 stands for the piles, and 1 54 stands for the concrete connecting beams; these beams have no reinforcement steel bars because of their considerable height and thickness having provided with sufficient shearing strength, resistance to compressive strength, and tension-proof.

As occasion demands, the concrete con necting beams may be reinforced with the reinforcement steel bars 1 60 and 1 62 at the bottom portion as shown in Fig. 25, in which two reinforcement cribs 1 50 and 1 52 may be inserted into the pile holes upon the horizontal holes having been furnished; further, at one side but opposite the horizontal hole, two steel rods 1 56 and 1 57 are attached outside the reinforcement cribs respectively, and the bottom end of each of said steel rods 1 56 and 1 57 is furnished with a pivot joint 163 or 166 respectively.One end of the supporting rods 159 and 161 is pivotally connected with pivot joints 1 64 and 1 65 to the central portion of the reinforcement steel bar 1 60 and 1 62 respectively, while the other end of the supporting rods 159 and 161 is pivotally connected with pivot joints 1 63 and 1 66 to the lower end of the steel rod 1 56 and 1 57 respectively.One end of the reinforcement steel bar 1 60 and 1 62 is pivotally connected to a suitable point on the reinforcement crib 1 50 and 1 52 respectively with pivot joints 1 67 and 168. 1 58 stands for a joint between the sections of the steel rod 1 56 or 1 57. By means of the aforesaid pivot joints, supporting rods, and the steel rods, the reinforcement steel bars upon being inserted into the pile hole may be controlled on the ground surface to place either in vertical or horizontal position.

Referring to Fig. 26, there are shown two reinforcement steel bars may be placed at the top portion of the concrete connecting beam by means of the same aforesaid method as shown in Fig. 25. In Fig. 26, there are the same number of pivot joints 171, 179, 175, 178, 1 73 and 177, and of supporting rods 1 74 and 180, and of reinforcement steel bars 172 and 176, and of steel rods 169 and 170 as those shown in Fig. 25.

Referring to Fig. 27, there is shown the joint part of two steel rods in the present invention.

The gang-type drills may also be driven directly by means of an upper pair of hydraulic cylinders and a lower pair of hydraulic cylinders as shown in Fig. 28. Fig. 29 shows the gang-type drills being driven forwards horizontally. In that embodiment, the rear ends of the hydraulic cylinders are attached with pivot joints 11 7 and 11 8 to the suitable points in the machine chamber 102 respectively.

Referring to Fig. 30, there is shown another embodiment of the driving means of the gang-type drills; in that embodiment, the hydraulic cylinder is a double-acting hydraulic cylinder, which is retractable as shown in Fig.

31.

Apparently, the aforesaid different embodiments can perform the same function of moving the gang-type drills forwards, but can save the manufacturing cost and maintenance problems.

Claims (11)

1. An apparatus and construction method for increasing bearing capacity of piles with connecting beams comprising: an earth borer which includes a steelbar, a hollow hammer with chain, pivots, a twin movable boring arm having two gang-type drills, and two supporting bars; the construction method which comprises the following steps: (1) to drill a pile hole with a well-known method and putting said earth borer in the pile hole at a given depth, (2) to apply a drive force to said earth borer with a device on the ground surface, (3) during rotating, to apply a force to have said twin boring arm gradually unfolded so as to drill a semiball-shaped chamber around a pile hole, and preferably the diameter of said chamber able to overlap with the chamber of an adjacent pile hole, (4) and then, to pull the chains so as to lift up the hollow hammer and to fold up the twin boring arm for pulling it out of the pile hole and simultaneously to fill the chambers with bentonite, (5) to put into the pile hole a reinforcement crib being attached outside with a steel pipe, of which the bottom is pivoted to a supporting bar, and the other end of said supporting bar being pivoted to the steel beam, while one end of said beam being connected to said reinforcement crib with a pivot, and then said steel beam being placed horizontally in parallel and over-lapped manner with the other beam of adjacent crib by operating the steel pipe outside the cribs, (6) to pour concrete into the pile holes the chambers and the tunnel between said two chambers to complete the construction work.

2. According to Claim 1, wherein the connecting beams between two adjacent piles may be installed in parallel at the same horizon, and they may be fixed in position upon being poured and enclosed with concrete.

3. According to Claim 1, wherein the connecting beam between two adjacent piles may be made with concrete only and without reinforcement steel bars on condition that the height and thickness of said connecting beam are considerably big.

4. According to Claim 1, the pile in the present invention may be furnished with one or more than one connecting beam or the like.

5. According to Claim 1, the piles in the present invention may be arranged in unit of four piles or connected one another entirely.

6. According to Claim 1, the pile hole in the present invention may be furnished with one or more than one said semi-ball-shaped chamber.

7. According to Claim 1, the gang-type drills may be a horizontally moving type being driving two pairs of hydraulic cylinders (one upper pair and one bottom pair) and supporting rods.

8. According to Claim 7, wherein a num ber of protection lids may be furnished around said gang-type drills, and are retractable together with the gang-type drills, and a case lid is also furnished around the gang-type drills for preventing from landslide in the hole of connecting beam (or horizontal hole).

9. According to Claim 7, the hole of connecting beam (or horizontal hole) made with said gang-type drills is a rectangular hollow space or a cubic hollow space.

10. According to Claim 1, the pile hole may be in round or square shape.

11. According to Claim 3, wherein the reinforcement steel bar may be placed at the bottom portion or in the top portion of the concrete connecting beam, and able to be controlled on ground surface.

1 2. According to Claim 1, wherein the gang-type drills may be driven with two pairs of cylinders directly or with a double-acting hydraulic cylinder which is retractable.

1 3. According to Claim 1, the various components and parts of the construction method of the present invention are those shown in the drawings attached, and any and later those are similar in operational functions should also be deemed as the scope and spirit of the present invention.