JP6981606B2 - Pile driving method on bedrock - Google Patents

Description

The present invention relates to a pile driving method for rock, and more particularly to a pile driving method for rock that can stably fix a pile placed in rock by a gun pile method to rock for a long period of time. It is a thing.

Conventionally, piles such as steel sheet piles and steel pipe sheet piles have been placed on the bedrock. In this construction, when the pile is driven with a vibro hammer or the like, the crushed rock crushed by the pile becomes a cushioning material between the tip of the pile and the bedrock, and the striking energy is not sufficiently transmitted to the bedrock. Due to this, there is a problem that the bedrock cannot be easily crushed and the time required for driving the piles becomes long. Therefore, a so-called gunpile method is used in which a water injection pipe connected to a high water pressure pump is provided on the pile to be driven, and the rock crushed by the pile is removed by the jet water jetted from the tip nozzle of the water injection pipe, while the pile is driven into the bedrock. Has been developed (see, for example, Patent Document 1).

When piles are driven by the gun pile method, a certain amount of gap is created between the piles and the bedrock. The larger the gap, the smaller the frictional force between the pile and the bedrock, which is disadvantageous for stably fixing the pile to the bedrock for a long period of time. At present, the piles placed on the bedrock by the gun pile method are used as so-called temporary piles in the short term, so long-term stable fixing strength is not required.

However, if the piles driven into the bedrock by the gun pile method can be used for a long period of time as so-called main piles, it is advantageous because the piles placed can be used as one member constituting various structures. .. For that purpose, it is necessary to devise a method to stably fix the piles driven by the gun pile method to the bedrock for a long period of time.

Japanese Unexamined Patent Publication No. 2004-124505

An object of the present invention is to provide a pile driving method for rock that can stably fix a pile driven to rock by a gun pile method to rock for a long period of time.

In order to achieve the above object, in the pile driving method on the bedrock of the present invention, the crushed rock is placed adjacent to the pile while the tip of the pile is struck against the bedrock by a vibrating pile driving machine to crush the bedrock. In the pile driving method of driving the pile into the bedrock while removing it from the tip area of the pile with the water jetted from the tip nozzle of the water injection pipe, the outer peripheral surface of the tip of the pile is from another part. Also has a thick protruding portion protruding to the outer peripheral side, and the amount of protrusion from the outer peripheral surface is convex to the surface of the outer peripheral surface of at least the tip side of the pile other than the protruding portion. A portion is provided, the pile is tubular, and the protrusion is the tip of the pile, one annular protrusion continuous with the entire circumferential length of the pile, and the rear of the one annular protrusion. It is composed of the other annular protrusion that is connected to the end and is continuous with the total length in the circumferential direction of the pile, and the outer peripheral surface of the other annular protrusion is the outer circumference of the pile rather than the outer peripheral surface of the one annular protrusion. It has a two-stage structure protruding to the side, and the convex portion extends in the longitudinal direction of the pile from the rear end of the other annular protrusion, and the pile is driven into the bedrock to a predetermined depth. Later, cement milk is filled in the gap between the pile and the bedrock, and the cement milk solidifies to fix the pile to the bedrock through the solidified cement milk.
In another method of driving a pile into a bedrock of the present invention, a vibration pile driving machine is used to drive the tip of a pile into the bedrock to crush the bedrock, and the crushed rock is placed adjacent to the pile. In the pile driving method of driving the pile into the bedrock while removing the pile from the tip area of the pile with water sprayed from the tip nozzle of the pile, the outer peripheral surface of the tip of the pile is on the outer peripheral side of other parts. It has a protruding thick-walled protrusion, and a protrusion other than the protruding portion is provided on the surface of the outer peripheral surface of the pile at least on the tip end side so that the amount of protrusion from the outer peripheral surface is equal to or less than the maximum protrusion amount of the protruding portion. The pile is tubular, and the projecting portion is an annular projecting portion continuous with the entire circumferential direction of the pile at the tip end portion of the pile, and the outer peripheral surface of the annular projecting portion in the circumferential direction of the pile. It is composed of a plurality of separated protrusions arranged at intervals, and the convex portion extends from the rear end of each of the plurality of separated protrusions in the longitudinal direction of the pile, respectively. The plurality of separated protrusions of the above are arranged only in the circumferential position where the convex portion exists, and after the pile is driven into the bedrock to a predetermined depth, cement is provided in the gap between the pile and the bedrock. It is characterized in that the pile is fixed to the bedrock through the solidified cement milk by filling the milk and solidifying the cement milk .

According to the present invention, since the outer peripheral surface of the pile has a protruding portion protruding toward the outer peripheral side from other parts, the frictional resistance between the outer peripheral surface of the pile to be driven and the bedrock is small. Therefore, the pile can be driven smoothly. In addition, since an appropriate gap is secured between the outer peripheral surface of the placed pile and the bedrock, a required amount of cement milk can be filled in this gap.

Then, the cement milk filled in the gap between the pile driven into the bedrock to a predetermined depth and the bedrock solidifies, and the pile is fixed to the bedrock through the solidified cement milk. Since the amount of protrusion of the protrusion provided on the outer peripheral surface on the tip side of the pile is less than the maximum amount of protrusion of the protrusion, the protrusion is protected by the protrusion and is not easily damaged when the pile is placed. .. The presence of this convex portion increases the area of the outer peripheral surface of the pile to be joined to the cement milk. Therefore, it is advantageous to fix the pile to the bedrock more firmly.

It is explanatory drawing which illustrates the process of driving a pile into the bedrock in the vertical cross-sectional view in the pile driving method to the bedrock of this invention. It is explanatory drawing which enlarges and exemplifies the periphery of the tip portion of the pile of FIG. It is explanatory drawing which enlarges and exemplifies the protrusion of the pile in the vertical cross-sectional view. It is explanatory drawing which illustrates the outer peripheral surface on the tip end side of a pile. It is explanatory drawing which illustrates the process of filling cement milk in the gap between the pile which was driven into the bedrock to a predetermined depth, and the bedrock in the vertical cross-sectional view. It is explanatory drawing which illustrates the state in which the cement milk of FIG. 5 is solidified and the pile is fixed to the bedrock through this cement milk in the vertical cross-sectional view. FIG. 6 is a cross-sectional view taken along the line AA of FIG. It is a vertical sectional view of a pile which shows the deformation example of a protrusion. It is a vertical sectional view of a pile which shows another deformation example of a protrusion. It is a front view of the pile which shows the deformation example of a convex part. It is a front view of the pile which shows another deformation example of a convex part. 11 is a cross-sectional view taken along the line BB of FIG. It is explanatory drawing which illustrates the modification which made the protrusion into a two-step structure in the vertical cross-sectional view of the right half of a pile. It is explanatory drawing which illustrates another deformation example of the protrusion in the vertical cross-sectional view of the right half of a pile. It is explanatory drawing which illustrates the pile in the CC cross-sectional view of FIG. The state of fillet welding is illustrated from the front view of the pile, FIG. 16 (A) shows the case where the deformed reinforcing bar is continuously constructed in the longitudinal direction, and FIG. 16 (B) shows the case where the pile is constructed intermittently. It is a front view of the pile which shows another deformation example of a convex part. It is a front view of the pile which shows another deformation example of a convex part. It is explanatory drawing which illustrates the process of filling cement milk with the pile driven into the bedrock to a predetermined depth moved upward in the vertical cross-sectional view.

Hereinafter, the method of driving piles on the bedrock of the present invention will be described based on the embodiment shown in the figure.

The driving site of the pile 2 exemplified in FIGS. 1 and 2 is the ground where the earth and sand layer S is deposited on the bedrock R. In order to drive the pile 2 on this ground by the gun pile method, the vibration oscillated by the vibration pile driving machine 1 such as a vibro hammer is used. As the pile 2, various types such as H-shaped steel and steel sheet pile can be used, but in this embodiment, a steel pipe pile is used.

As illustrated in FIGS. 3 and 4, the tip portion of the pile 2 has a protruding portion 2a whose outer peripheral surface protrudes toward the outer peripheral side from other portions by a predetermined protrusion amount t1. Since the protrusion amount t1 is constant, this protrusion amount t1 is the maximum protrusion amount. The protruding portion 2a has a cylindrical shape continuous in the circumferential direction of the pile 2. That is, in the present invention, a pile 2 having a protruding portion 2a having a relatively thick wall at the tip portion as compared with other portions is used. In this embodiment, a pile 2 in which the protrusion 2a is integrally formed in advance is used.

The maximum protrusion amount t1 of the protrusion 2a is preferably, for example, 6 mm or more and 35 mm or less, and more preferably 9 mm or more and 12 mm or less. The longitudinal dimension L of the pile 2 of the protrusion 2a is preferably, for example, 20 mm or more and 300 mm or less.

It is desirable that the protruding portion 2a has higher strength and higher hardness than other portions. The strength of the protrusion 2a is set, for example, to have a tensile strength of 1000 N / mm ² or more.

On the surface of the outer peripheral surface of the pile 2 on the tip end side other than the protruding portion 2a, a convex portion 2b protruding from the surface to the outer peripheral side by a predetermined protrusion amount t2 is provided. The protrusion amount t2 of the protrusion 2b is equal to or less than the maximum protrusion amount t1 of the protrusion 2. It is preferable that the protrusion amount t2 is 1 mm or more and smaller than the maximum protrusion amount t1. If the protrusion amount t2 of the convex portion 2b is less than 1 mm, the effect of improving the adhesion strength between the outer peripheral surface of the pile 2 and the cement milk C becomes too small. When the protrusion amount t2 of the convex portion 2b is made larger than the maximum protrusion amount t1, the convex portion 2b is worn out due to contact with the bedrock R when the pile 2 is driven or the rock powder generated during the driving collides with the rock mass. It becomes easier to do.

The convex portion 2b is generally arranged in a range where the pile 2 is buried in the bedrock R. For example, the range in which the convex portion 2b is provided is a range from the tip of the pile 2 to the rear end of 2 m to 10 m (the rear end position of the range in which the convex portion 2b is provided is set to a position of 2 m to 10 m from the tip of the pile 2). ) Or, the range from the tip of the pile 2 to the rear end to a length of 100% to 500% of the outer diameter of the pile 2 (the rear end position of the range where the convex portion 2b is provided is set from the tip of the pile 2 to the pile 2). Positioned at a length of 100% to 500% of the outer diameter). The protruding portion 2a is not provided with the convex portion 2b.

In this embodiment, the convex portion 2b is an annular convex portion extending in the circumferential direction on the outer peripheral surface of the pile 2, and a plurality of annular convex portions are arranged at intervals in the longitudinal direction of the pile 2. Each annular convex portion is arranged in a direction orthogonal to the longitudinal direction of the pile 2.

A water injection pipe 4 is detachably arranged adjacent to the pile 2. In this embodiment, the water injection pipe 4 extends in the longitudinal direction of the pile 2 along the inner peripheral surface of the pile 2. A single or a plurality of water injection pipes 4 are arranged for one pile 2. A water tank 3 arranged on the ground is connected to the rear end of the water injection pipe 4 directly or via another pipe 3a. The tip of the water injection pipe 4 is a tip nozzle 4a for injecting water W supplied from the water tank 3. The pile 2 is appropriately provided with a steady rest fitting for suppressing the runout of the injection pipe 4 during driving. The tip nozzle 4a is arranged at a position that does not protrude from the tip of the pile 2.

In order to drive the pile 2, the pile 2 is held by a vibrating pile driving machine 1 suspended by a crane or the like. Next, the tip of the pile 2 is driven into the earth and sand layer S while the pile 2 is vibrated by the vibrating pile driving machine 1. When the tip of the pile 2 is located within the range of the earth and sand layer S and has not reached the bedrock R, it is not necessary to inject water W from the tip nozzle 4a.

As illustrated in FIGS. 1 and 2, when the tip of the pile 2 reaches the bedrock R, the water W contained in the water tank 3 is supplied to the water injection pipe 4 by a high-pressure pump and injected from the tip nozzle 4a. That is, the pile 2 is vibrated by the vibrating pile driving machine 1, and the pile 2 is driven into the bedrock R while injecting water W from the tip nozzle 4a. That is, it is preferable to start spraying water from the tip nozzle 4a when the tip of the pile 2 to be driven reaches the bedrock R. As a result, the jetted water W does not unnecessarily loosen the sediment layer S, and a gap is substantially not formed between the sediment layer S and the pile 2, so that the cement milk C used in the subsequent process is not formed. It is advantageous to suppress the amount of.

By being hit by the vibrating pile 2, the portion of the bedrock R that collides with the tip of the pile 2 is crushed. The rock Rc generated by crushing the bedrock R exists between the tip of the pile 2 and the bedrock R, but when the tip of the pile 2 moves upward due to the reaction force of the impact and separates from the bedrock R, the tip The water W ejected from the nozzle 4a removes the pile 2 from the tip region. When the pile 2 subsequently hits the bedrock R, there is no rock Rc exerting a buffering action between the tip of the pile 2 and the bedrock R. Therefore, the impact energy of the pile 2 acts on the rock R without being attenuated by the rock Rc, and the rock R can be easily crushed. The crushing of the bedrock R by the impact of the pile 2 and the removal of the rock Rc by the water W ejected from the tip nozzle 4a are repeated, and the pile 2 is driven into the bedrock R. Since the pile 2 has a relatively thick protruding portion 2a at the tip portion, there is an advantage that the pile 2 is less likely to be deformed even if it collides with the bedrock R as compared with other portions.

When the pile 2 is driven to a predetermined depth with respect to the bedrock R, a certain gap g is generated between the driven pile 2 and the bedrock R. This gap g is, for example, about 20 mm to 100 mm. Therefore, as illustrated in FIG. 5, the gap g between the pile 2 and the bedrock R is filled with cement milk C (a mixed material of cement and water). It is advisable to preliminarily add a predetermined amount of the thickener B and the expanding material D to the cement milk C before filling the gap g within a range that does not hinder the fluidity when the cement milk C is filled. Details of the thickener B and the expansion material D will be described later. Since the earth and sand layer S is compacted by the earth pressure, there is substantially no gap between the pile 2 and the earth and sand layer S. Therefore, the earth and sand layer S is in close contact with the pile 2, and the pile 2 is fixed to the earth and sand layer S.

The cement milk C is supplied from the storage tank 5 arranged on the ground to the gap g through the filling pipe 6. Generally, groundwater exists in this gap g, but by filling the cement milk C, the groundwater and the cement milk C are replaced. The number of filling pipes 6 is not limited to one, and may be multiple.

After filling the majority of the gap g with the cement milk C, the cement milk C is solidified by curing for a predetermined time. As illustrated in FIGS. 6 and 7, the cement milk C solidified via the gap g firmly adheres to the surface of the bedrock R carved by the pile 2 and the surface (peripheral surface) of the pile 2. The uniaxial compressive strength of the solidified cement milk C is, for example, 5 N / mm ² or more.

In the present invention, since the convex portion 2b of the pile 2 is provided, the area of the outer peripheral surface of the pile 2 to be joined to the cement milk C is increased as compared with the case where the convex portion 2b is not provided. Therefore, the pile 2 can be more firmly fixed to the bedrock R via the solidified cement milk C. That is, in the present invention, by providing the convex portion 2b, the frictional force (fixing force) between the bedrock R and the peripheral surface of the pile 2 can be significantly increased.

More specifically, when the gap g between the pile 2 and the bedrock R is filled with cement milk C, the boundary surface between the peripheral surface of the pile and the cement milk C and the boundary surface between the cement milk C and the bedrock R are formed. To. At the boundary surface between the cement milk C and the bedrock R, the mutual adhesion strength becomes relatively high due to the influence of the unevenness of the bedrock R. On the other hand, if the peripheral surface of the pile 2 is smooth, the adhesive strength between the piles 2 and the cement milk C is relatively low.

Here, considering the degree of frictional force on the peripheral surface of the pile 2, if the peripheral surface of the pile 2 is smooth, for example, when a pulling force is applied to the pile 2, the adhesive strength between the peripheral surface of the pile 2 and the cement milk C is about. When it reaches, slip occurs at the boundary between the peripheral surface of the pile and the cement milk C prior to the boundary surface between the cement milk C and the bedrock R. Therefore, a frictional force lower than the peripheral frictional force developed by the adhesion between the cement milk C and the bedrock R can be obtained.

However, in the present invention, since the convex portion 2b is provided on the outer peripheral surface of the pile 2, the adhesion strength between the outer peripheral surface of the pile 2 and the cement milk C is improved to the same level as the adhesion strength between the cement milk C and the bedrock R. It is possible to do. That is, the peripheral frictional force developed by the adhesion between the cement milk C and the bedrock R can be made equal to the peripheral frictional force developed by the adhesion between the peripheral surface of the pile 2 and the cement milk C. , Cement milk C is efficiently used to improve the frictional force between the bedrock R and the peripheral surface of the pile 2.

Moreover, since the protrusion amount t2 of the protrusion 2b is equal to or less than the maximum protrusion amount t1 of the protrusion 2a, the protrusion 2b is protected by the protrusion 2a when the pile 2 is driven, and is contacted with or crushed by the bedrock R. The specifications are such that it is easy to prevent problems such as damage and wear due to contact with rock powder. Therefore, the convex portion 2b can be maintained in a sound state even after the pile 2 is driven.

In addition, since the pile 2 has the protruding portion 2a of the above-mentioned specifications at the tip portion, the gap g between the pile 2 and the bedrock R becomes an appropriate size. Since this gap g is not too small, friction from the ground (earth and sand layer S and bedrock R) acting on the peripheral surface of the pile 2 being driven is reduced, and the pile 2 can be smoothly driven. On the other hand, in order not to make the gap g excessive, the maximum protrusion amount t1 of the protrusion 2a is set to 35 mm or less, more preferably 12 mm or less. As a result, it is possible to avoid a decrease in the frictional bearing capacity from the ground (earth and sand layer S and bedrock R) acting on the peripheral surface of the pile 2 after placing.

As described above, according to the present invention, the pile 2 can be stably fixed to the bedrock R for a long period of time. In particular, since the pull-out resistance of the pile 2 can be expected to be significantly improved, sufficient seismic resistance can be ensured even if the pile 2 is used as one member constituting the structure. Therefore, the pile 2 driven by the gun pile method can be used not only as a temporary pile but also as a main pile.

When the pile 2 in which the protrusion 2a is integrally formed in advance is used, the long-term stable durability of the protrusion 2a (pile 2) can be ensured as compared with the pile 2 to which the protrusion 2a is retrofitted. It will be advantageous. Therefore, in order to use it as a permanent pile, it is preferable to use a pile 2 in which the protruding portion 2a is integrally formed in advance.

As the thickener B to be blended in advance with the cement milk C, various concrete thickeners such as bentonite, cellulose ether, and calcium carbonate can be used. As the expansion material D, for example, various concrete expansion materials such as lime, gypsum, and a calcined compound containing bauxite as a main component can be used.

By blending the thickener B, it becomes difficult to separate the cement and water in the cement milk C component. When the cement and water are separated, the fixing force of the pile 2 to the bedrock R decreases. Therefore, by blending the thickener B, the fixing force of the pile 2 can be stably maintained for a long period of time. It will be advantageous. However, if the blending ratio of the thickener B becomes excessive, the fluidity of the cement milk C when filling the gap g deteriorates, and it becomes difficult to fill the gap g densely. On the other hand, if the blending ratio of the thickener B is too small, the expected separation resistance (action and effect of suppressing the separation between cement and water) cannot be exhibited. Therefore, the blending amount of the thickener B is preferably 3% by weight or more and 12% by weight or less with respect to the cement contained in the cement milk C, and more preferably 5% by weight or more and 8% by weight or less.

By blending the expansion material D with the cement milk C, the cement milk C expands and the pressure on the periphery increases, and as a result, the adhesiveness between the pile 2 and the cement milk C is improved. The blending amount of the expanding material D that can be expected to have a corresponding effect is about 10% by weight (for example, 5% by weight or more and 15% by weight or less) with respect to the cement contained in the cement milk C.

Since a sufficient frictional force can be secured between the placed pile 2 and the earth and sand layer S, it is not necessary to dare to fill the gap between the two with cement milk C. That is, in order to sufficiently secure the fixing strength of the pile 2 while suppressing the amount of cement milk C used, the cement milk C should be substantially filled and solidified only in the gap g between the pile 2 and the bedrock R. good.

Therefore, when filling the gap g with the cement milk C, it is preferable to know the depth position (range) of the bedrock R in advance. Then, by appropriately adjusting the supply amount and supply position of the cement milk C and supplying the cement milk C to the gap g, the cement milk C is filled only in the depth position (range) where the bedrock R exists. good.

The cement milk C can be filled from the upper side of the gap g or from the lower side of the gap g. When the cement milk C is filled from the lower side of the gap g, the groundwater existing in the gap g is removed from the gap g and the cement milk C can be easily filled tightly. Therefore, for example, the cement milk C is supplied from the storage tank 5 in a state where the filling pipe 6 is extended to the vicinity of the lower end of the gap g.

When the pile 2 is a steel pipe pile, filling pipes 6 are extended in the longitudinal direction of the pile 2 on the inner peripheral side of the pipe and the outer peripheral side of the pipe, respectively. It is advisable to fill the gap g with the inner peripheral surface of the pile 2 with cement milk C, respectively. This makes it easy to fill the entire range of the gap g sufficiently and quickly with the cement milk C. In the case of other types of piles 2 that are not steel pipe piles, it is more preferable to fill the cement milk C in a plurality of systems using a plurality of filling pipes 6, but it is more preferable to use one filling pipe 6. Cement milk C can also be filled.

In this embodiment, the protrusion 2a is integrally formed with the pile 2, but as illustrated in FIG. 8, a ring having a thickness t1 is joined to the tip of the pile 2 by welding or the like to join the protrusion 2a. Can also be provided. Further, as illustrated in FIG. 9, the protruding portion 2 may have a shape protruding not only on the outer peripheral side of the pile 2 but also on the inner peripheral side.

In this embodiment, the annular convex portion to be the convex portion 2b is arranged in a direction orthogonal to the longitudinal direction of the pile 2, but as illustrated in FIG. 10, the annular convex portion is arranged in the longitudinal direction of the pile 2. On the other hand, it can be arranged in an inclined direction.

The convex portion 2b exemplified in FIGS. 11 and 12 is formed by a deformed reinforcing bar extending in the longitudinal direction of the pile 2. It is preferable that the plurality of deformed reinforcing bars forming the convex portions 2b are arranged at equal intervals in the circumferential direction of the pile 2. It should be noted that this equidistant interval does not mean only a perfect equidistant interval, but also includes allowing a slight deviation (for example, about ± 3 ° in the circumferential direction about the axis of the pile 2). It means approximately equal intervals. The number of deformed reinforcing bars to be arranged depends on the size of the outer diameter of the pile 2, but it should be 4 or more, and the pile 2 and the cement milk C should be sufficiently attached according to the adhesion strength between the bedrock R and the cement milk C. It is desirable to use a number that can secure a sufficient adhesion strength.

In FIGS. 11 and 12, a protruding portion 2a having a maximum protruding amount t1 larger than the protruding amount t2 of the deformed reinforcing bar (convex portion 2b) is continuously formed over the entire length in the circumferential direction of the pile 2. The protrusion 2a may also have a two-stage structure as illustrated in FIG. _{In FIG. 13, an annular protrusion 2a 1} continuous in the circumferential direction with a protrusion amount t3 smaller than the protrusion amount t2 of the deformed reinforcing bar (convex portion 2b) and the protrusion 2a ₁ continuously on the outer peripheral surface of the pile 2. _{An annular protrusion 2a 2} having a protrusion amount t4 larger than the protrusion amount t2 is provided. The protrusion 2a ₁ is formed by the protrusion 2a 1 and the protrusion 2a _2. Therefore, the maximum protrusion amount t1 (= t4) of the protrusion 2a is set to be larger than the protrusion amount t2 of the protrusion 2b.

As illustrated in FIGS. 14 and 15, the projecting portion 2a ₂ may be provided on the outer peripheral surface of the projecting portion 2a ₁ and may be arranged only at the position where the deformed reinforcing bar (convex portion 2b) is present. In this structure, _{the protrusions 2a 2} are arranged on _{the outer peripheral surface of the annular protrusion 2a 1} at intervals in the circumferential direction. _{The protrusions 2a 2} illustrated in FIG. 13 can also be arranged at intervals in the circumferential direction in the same manner.

The deformed reinforcing bar that becomes the convex portion 2b is attached to the outer peripheral surface of the pile 2 by fillet welding, for example. The fillet welded portion U can be seamlessly continuous in the longitudinal direction of the deformed reinforcing bar as illustrated in FIG. 16 (A), but is in a state of being spaced in the longitudinal direction as illustrated in FIG. 16 (B). It can also be. When the fillet welded portion U is formed as shown in FIG. 16B, the cement milk C that has entered the portion not fillet welded between the fillet welded portions U (the built-up portions) adjacent to each other in the longitudinal direction. And the fillet welded portion U are engaged with each other. Therefore, a higher adhesion strength can be expected due to the slip-preventing effect between the fillet welded portion U and the cement milk C.

Further, since the fillet welded portion U is formed in the vicinity of the contact portion between the outer peripheral surface of the pile 2 and the outer peripheral surface of the deformed reinforcing bar, it is located at a position where it is difficult to contact the bedrock R when the pile 2 is placed. Will exist. Therefore, the fillet welded portion U has minimal wear even after the pile 2 is driven, which is advantageous for maintaining a sound state.

In addition to the merit that the deformed reinforcing bar is easily available, since the surface is uneven, it is more advantageous to increase the bonding area with the cement milk C. When the convex portion 2b extends in the longitudinal direction of the pile 2, it is possible to avoid an increase in frictional resistance between the sediment layer S and the bedrock R and the pile 2 when the pile 2 is driven. Further, since the cement milk C smoothly flows downward along the convex portion 2b, it becomes easy to fill the gap g densely and steadily.

As illustrated in FIG. 17, the convex portion 2b may be a spiral convex portion extending spirally in the circumferential direction on the outer peripheral surface of the pile 2. When the convex portion 2b has this shape, the cement milk C filled from above can be smoothly flowed downward along the spiral convex portion.

As illustrated in FIG. 18, a convex portion 2b extending in the longitudinal direction of the pile 2 and a convex portion 2b extending in the circumferential direction may be combined. Alternatively, at least one of these convex portions 2b may be combined with the convex portion 2b extending so as to be inclined with respect to the longitudinal direction of the pile 2. Alternatively, the net-like body can be formed into a convex portion 2b by winding it around the outer peripheral surface of the tip portion of the pile 2.

The filling procedure of cement milk C can also be as in the embodiment illustrated in FIG. In this embodiment, after the pile 2 is driven into the bedrock R to a predetermined depth, the pile 2 is moved upward and maintained at a position above the bedrock R. A cylindrical gap g1 is formed in the bedrock R by driving the pile 2 to a predetermined depth.

In this state, a predetermined amount of cement milk C is filled in the tubular gap g1. Then, the pile 2 is driven again to a predetermined depth. The cement milk C is pushed by the pile 2 and enters the gap g between the pile 2 and the bedrock R. After that, the cement milk C is solidified by curing for a predetermined time to bring it into the state illustrated in FIGS. 6 and 7.

In this embodiment, since the cement milk C is filled in the state where the pile 2 does not exist in the bedrock R, the filling can be performed quickly and the working time can be shortened. Further, since the pile 2 is pushed into the filled cement milk C, it is advantageous for the cement milk C to be densely filled in the gap g between the pile 2 and the bedrock R.

In each of the above-described embodiments, the case where the pile 2 is placed on the ground where the sediment layer S is deposited on the bedrock R has been described as an example, but the ground has only the bedrock R without the sediment layer S. Pile 2 can also be driven. In this case as well, the procedure in which the pile 2 is driven into the bedrock R to a predetermined depth and then the gap g or the gap g1 is filled with cement milk C and solidified is the same as in each of the above-described embodiments.

1 Vibration pile driving machine 2 Pile 2a, 2a ₁ , 2a ₂ Protruding part 2b Convex part 3 Water tank 3a Piping 4 Water injection pipe 4a Tip nozzle 5 Storage tank 6 Filling pipe B Thickening material C Cement milk D Expansion material S Sediment Layer R Bedrock U Fillet weld W Water

Claims (5)

While the tip of the pile is struck against the bedrock by a vibrating pile driving machine to crush the bedrock, the crushed rock is ejected from the tip nozzle of the water injection pipe arranged adjacent to the pile from the tip area of the pile. In the pile driving method for driving the pile into the bedrock while eliminating the pile, the outer peripheral surface of the tip of the pile has a thick protruding portion protruding toward the outer peripheral side from other parts, and the protruding portion. A convex portion having a protrusion amount from the outer peripheral surface equal to or less than the maximum protrusion amount of the protrusion is provided on the surface of the outer peripheral surface at least on the tip end side of the pile other than the above, and the pile is tubular and the protrusion is formed. , One annular protrusion that is continuous with the circumferential length of the pile at the tip of the pile and the other annular that is connected to the rear end of the one annular protrusion and is continuous with the circumferential length of the pile. It has a two-stage structure in which the outer peripheral surface of the other annular protrusion protrudes toward the outer peripheral side of the pile from the outer peripheral surface of the one annular protrusion, and the convex portion is the other. The pile extends in the longitudinal direction of the pile from the rear end of the annular protrusion of the pile, and after the pile is driven into the bedrock to a predetermined depth, cement milk is filled in the gap between the pile and the bedrock. A method for placing piles in a bedrock, characterized in that the piles are fixed to the bedrock through the solidified cement milk by solidifying the cement milk. While the tip of the pile is struck against the bedrock by a vibrating pile driving machine to crush the bedrock, the crushed rock is ejected from the tip nozzle of the water injection pipe arranged adjacent to the pile from the tip area of the pile. In the pile driving method for driving the pile into the bedrock while eliminating the pile, the outer peripheral surface of the tip of the pile has a thick protruding portion protruding toward the outer peripheral side from other parts, and the protruding portion. A convex portion having a protrusion amount from the outer peripheral surface equal to or less than the maximum protrusion amount of the protrusion is provided on the surface of the outer peripheral surface at least on the tip end side of the pile other than the above, and the pile is tubular and the protrusion is formed. An annular protrusion that is continuous with the entire circumferential length of the pile at the tip of the pile, and a plurality of separated protrusions that are arranged at intervals in the circumferential direction of the pile on the outer peripheral surface of the annular protrusion. The convex portion extends from the rear end of each of the plurality of separated protrusions in the longitudinal direction of the pile, and each of the plurality of separated protrusions has the convex portion. It is arranged only in the existing circumferential position, and after driving the pile into the bedrock to a predetermined depth, cement milk is filled in the gap between the pile and the bedrock, and the cement milk solidifies. A method for placing piles on a bedrock, which comprises fixing the piles to the bedrock via solidified cement milk. After the pile is driven into the bedrock to a predetermined depth, the pile is moved to a position higher than the bedrock, and the pile is driven into the bedrock to form cement milk. The pile driving into the bedrock according to claim 1 or 2 , wherein the unsupplied driving marks are filled with the cement milk in a predetermined amount, and then the piles are again driven to the predetermined depth by the vibration pile driving machine. Construction method. The pile driving method according to any one of claims 1 to 3 , wherein the maximum protrusion amount of the protrusion is 6 mm or more and 35 mm or less, and the protrusion amount of the protrusion is 1 mm or more. The pile driving method for rock according to any one of claims 1 to 4 , wherein the convex portion is a deformed reinforcing bar.

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