JPH06240669A - Fixing method for steel pipe pile to bedrock - Google Patents

Abstract

PURPOSE:To omit a casing and 4 simplify the work by rotating and pushing a steel pipe pile having bits on the front end thereof into a bedrock while cutting the bedrock therewith, and injecting hardener into a gap between an excavation surface of the bedrock and the surface of a steel pipe. CONSTITUTION:A steel pipe pile 10 is pushed into a bedrock 3 while rotating the steel pipe pile 10 directly before the bedrock 3 in a sedimentary soil layer 2, and in the case the front end of the steel pipe pile 10 is brought into contact with the bedrock 3, it is further pushed thereinto to bore an excavated hole 14 in the bedrock 3. After that, in the case the steel pipe pile 10 can not be penetrated into the bedrock 3 by itself, intermediate excavation for the steel pipe pile 10 is made by means of a down-the-hole hammer, and an inside diameter of the excavated hole 14 is larger than an outside diameter of the steel pipe pile 10 by action of drag-bits 12-A. When, cement milk F is filled in a gap 16 between an internal wall surface of the excavated hole 14 and an outside surface of the steel pipe pile 10. By solidification of the cement milk F, the steel pipe pile 10 is fixed in the bedrock 3 inside the excavated hole 14. According to the constitution, the steel pipe pile 10 can be fixed in the bedrock 3 under a poor subsoil without using casing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for excavating ground to the rock below and fixing a steel pipe pile to the rock.

[0002]

2. Description of the Related Art Conventionally, a construction method as shown in FIGS. 18-22 has been carried out in order to fix a steel pipe pile on rock below the ground. That is, the casing 1 which is one size larger than the steel pipe pile (main pile) to be driven is driven into the ground (for example, the sediment layer) 2 just before the bedrock 3 (FIG. 18). Then, the rock 3 is excavated by the excavator 4 (FIG. 19), and the solidifying agent (for example, mortar) F is injected into the excavation hole 5 formed in the rock (FIG. 20).

After a predetermined amount of the solidifying agent F is injected, the main pile 6 is driven through the inner space of the casing 2 (see FIG. 2).
1). Here, the driving of the main pile 6 is performed until the pile 6 comes into contact with the bottom portion 5B of the excavation hole 5. After the pile driving is completed, it is left for a so-called "curing period".

After the aging period, the casing 1 is pulled out in the direction indicated by the arrow U (FIG. 1). At this point, the main pile (steel pipe pile) 6 has already been fixed to the bedrock 3 by the solidifying agent F.

[0005]

However, since the use of the casing is indispensable in such a conventional technique, a large number of complicated steps as described above have to be performed, and there are various inconveniences associated therewith. . Especially, when the casing is pulled out and the "curing period" preceding it is about 60 of the construction time.
It accounted for -70%, which was the main factor requiring a long time for construction.

The present invention has been proposed in view of such problems of the prior art, and it is possible to fix the steel pipe pile to the rock below the fragile ground without using a casing. The purpose is to provide a construction method.

[0007]

The rock anchoring method for steel pipe piles according to the present invention uses a steel pipe pile in which a bit is attached to the tip end of the steel pipe pile so that the portion radially outward of the steel pipe surface can be excavated. It includes a step of rotating and pushing, and a step of injecting a solidifying agent into a gap between the rock excavation surface and the steel pipe surface.

In the practice of the present invention, when the steel pipe pile alone cannot penetrate into the bedrock, it is preferable that the steel pipe pile be dug and then the steel pipe pile be rotated and pushed.

The term "ground" is used herein to include not only ordinary ground but also fragile ground and the like. The fragile ground means a ground that can drive a steel pipe pile without excavating using a bit etc., but does not have the strength or holding force to ensure the anchorage of the steel pipe pile. For example, it corresponds to a layer of sediment soil.

Further, examples of the solidifying agent include mortar, cement milk and the like.

In carrying out the present invention, a steel pipe is provided in order to prevent soil or the like from falling from the ground into the excavation hole in the rock, or to prevent the injected solidifying agent from being diffused and wasted. It is preferable to provide means for sealing the outer surface of the pile and the inner wall surface of the drill hole, such as a plug.

[0012]

According to the method of fixing rock mass of a steel pipe pile according to the present invention having the above-described structure, the steel pipe pile is first lowered to a position just below the rock mass below the ground. Alternatively, at a site where the rock is exposed on the surface of the earth, steel pipe piles are installed at predetermined positions on the surface of the rock. In this steel pipe pile, a bit is attached to the tip part so that the portion outside the steel pipe surface in the radial direction can also be excavated, so the rock can be excavated (or cut) by pushing in while rotating the steel pipe pile. Can be done.

Here, when it is impossible to excavate the bedrock only by rotating and pushing the steel pipe pile, the down-the-hole hammer is used to carry out the inner excavation of the steel pipe pile. That is, the rock excavation is performed by performing the inner moat by the reverse circulation method while advancing the tip of the steel pipe pile and at the same time pushing the steel pipe pile while rotating.

After the rock has been excavated to a predetermined depth, a solidifying agent is injected into the gap between the excavated surface of the rock and the surface of the steel pipe. Then, when the solidifying agent is hardened, the steel pipe pile is fixed to the rock.

As described above, according to the present invention, the steel pipe pile in which a bit is attached to the tip end portion of the steel pipe so as to be able to excavate a portion radially outward of the steel pipe surface without using a casing functions as a casing and an excavating tool. . Therefore, the casing can be omitted.

Further, as a result of the omission of the casing, the work corresponding to the casing withdrawing step in the prior art becomes unnecessary. Therefore, there is no need to wait for the curing period, and the rock fixing work is completed when the solidifying agent is injected. As a result, the working time is significantly increased (60-70%)
Shortened.

[0017]

EXAMPLES Examples of the present invention will be described below with reference to FIGS.

FIGS. 1 to 3 show the outline of the method for fixing rock mass of steel pipe piles according to the present invention. First, as shown in FIG. 1, a steel pipe pile 1
Push 0 into the sediment layer (ground) 2 while rotating it to just before the bedrock 3. Here, a drag bit 12-A is attached to the tip end of the steel pipe pile 10 so that the outer portion of the steel pipe pile 10 in the radial direction can be excavated. Although not shown, the above process is not necessary when the rock is exposed on the surface of the earth.

When the tip of the steel pipe pile 10 comes into contact with the bedrock 3, the steel pipe pile 10 is further pushed while being rotated by a member (not shown in FIGS. 1-3) provided on the ground. Here, since the drag bit 12-A is provided at the tip of the steel pipe pile 10, the excavation hole 14 is drilled in the bedrock 3 (FIG. 2). As shown in FIGS. 14-17, the drag bit 12-A is configured to be able to excavate or cut the inside of the steel pipe pile 10 in the radial direction.

If the steel pipe pile 10 is only rotated and pushed in, the rock bed 3
When it is impossible to excavate or cut the steel pipe, the down digging hole hammer (not shown) is used to carry out the inner excavation of the steel pipe pile 3. This middle excavation is performed in such a manner that the rock is excavated prior to the tip of the steel pipe pile 10.

Due to the action of the drag bit 12-A, the inner diameter of the excavation hole 14 becomes larger than the outer diameter of the steel pipe pile 10. In other words, a gap as shown by reference numeral 16 in FIG. 2 is formed between the inner wall surface of the excavation hole 14 and the outer surface of the steel pipe pile 10. Here, in order to prevent the sedimentary soil from entering the gap 16 from the sedimentary soil layer 2 and to prevent the cement milk from being diffused and wasted in the sedimentary soil layer at the time of injecting cement milk described later, a seal is provided. Plug 18
Is provided on the outer surface of the steel pipe pile 10. In addition, the mounting position of the plug 18 is to ensure that the steel pipe pile 10 is stable.
The range from the tip of 0 to how long should be fixed in the bedrock 3, in other words, how much the excavation depth of the bedrock 3 should be determined.

Thereafter, as shown in FIG. 3, the gap 16 is filled with a solidifying agent, for example, cement milk F. Conventionally, it is necessary to wait for the curing period of the cement milk F for pulling out the casing, but since the casing is not used in the present invention, the work for fixing the steel pipe pile 10 to the bedrock 3 is completed at the stage shown in FIG. To do. After that, when the cement milk F is solidified, the steel pipe pile 10 is fixed in the bedrock 3 in the excavation hole 14.

FIG. 4-13 shows the steps shown in FIGS. 1-3 in more detail. Hereinafter, with reference to FIG. 4-13, the rock fixing method of the steel pipe pile outlined in FIG. 1-3 will be described in more detail.

First, a mini backhoe 20 is excavated on the ground surface S of the sediment layer 3 (FIG. 4). Next, a mount and a power casing jack (both of which are comprehensively represented by reference numeral 22; FIG. 5) are installed in the mini backhoe 20. At the same time, a steel pipe pile indicated by reference numeral 10 in FIGS. 1 to 3 (with a drag bit 12A attached to its tip) is prepared (FIG. 6).

Next, the pile driver 24 is installed as shown in FIG. 7, and the steel pipe pile 10 is driven (or built) through the frame 22 as shown in FIG. As shown in Fig. 1, the steel pipe pile 10 is built in such a way that the pile tip is underground (see Fig. 1).
-3, indicated by reference numeral 3).

When the tip of the pile reaches the rock mass, the steel pipe pile 10 is rotated and pushed in by the pile driving machine 24 in order to excavate the rock mass by the drag bit 12-A (FIG. 9). That tube,
Excavation as shown in FIG. 2 is performed.

When the bedrock 3 (FIGS. 2 and 3) has been excavated to a predetermined depth, the pile driver 24 is removed (FIG. 10) and the reference numeral 22 is given.
Remove the gantry and the power casing jack, which are comprehensively shown in Fig. 11 (Fig. 11). Then, the solidifying agent (for example, cement milk) shown in FIG. 3 is injected.

At the time of injecting the solidifying agent, as shown in FIG. 12, the mortar pump 26 is used to inject the solidifying agent F using the tremie pipe 27. Here, as shown in FIG. 3, the plug 1
8 prevents the solidifying agent F from diffusing into the sediment layer 2. When the injection of the solidifying agent is completed, the mortar pump 26 is removed and the work is completed.

The excavation work of the bedrock 3 and the injection work of the solidifying agent will be further described with reference to FIGS.

FIG. 14 shows steps corresponding to FIG. Here, for simplification, the excavation hole 14 is shown as a vertical hole, and the reference numeral 10I indicates the internal space of the steel pipe pile 10. When injecting the cement milk F, as shown in FIG. 15, the cement milk is supplied through the steel pipe pile inner space 10I. The arrow Ft in FIG.
Shows the streamline of cement milk. As is clear from FIG. 15, the cement milk F fills the gap 16 between the outer surface of the steel pipe pile 10 and the inner wall surface of the excavation hole 14, and the cement milk F is solidified so that they are integrally joined. Of.

14 and 15, only the steel pipe portion of the steel pipe pile 10 is excavated in the bedrock 3, and the portion corresponding to the internal space 10I is not excavated. However, the rock mass corresponding to the internal space 10I may be excavated. 16 and 17 show such an example.

In FIG. 16, the bedrock corresponding to the internal space 10I is excavated by the excavator 30 in the steel pipe pile 10. After that, the cement milk F is injected as shown in FIG.

[0033]

The effects of the present invention are listed below.

(1) It is possible to omit the conventional casing which was indispensable for anchoring the steel pipe pile rock mass.

(2) As a result of omitting the casing, the work corresponding to the casing withdrawing process in the prior art is unnecessary, the number of processes is reduced, and the work is simplified.

(3) There is no need to wait for the curing period to elapse, and the working time is greatly shortened.

(4) The work cost can be kept low.

[Brief description of drawings]

FIG. 1 is a diagram showing one process in one embodiment of the present invention.

FIG. 2 is a diagram showing a process different from that in FIG.

FIG. 3 is a diagram showing a process different from that in FIGS.

FIG. 4 is a diagram showing the excavation process of the mini backhoe in the embodiment of FIGS. 1-3.

FIG. 5 is a diagram showing a process of installing a gantry and the like in the embodiment of FIGS.

FIG. 6 is an overall view of a steel pipe pile in the embodiment of FIGS.

FIG. 7 is a diagram showing a pile driver installation step in the embodiment of FIGS. 1-3.

FIG. 8 is a diagram showing a driving (building) process of the steel pipe pile in the embodiment of FIGS.

FIG. 9 is a diagram showing a rock excavation process of a steel pipe pile in the embodiment of FIGS.

FIG. 10 is a diagram showing a pile driver removal process in the embodiment of FIGS. 1-3.

FIG. 11 is a diagram showing a removal process of the gantry and the like in the embodiment of FIGS.

FIG. 12 is a diagram showing a solidifying agent injecting step in the embodiment of FIGS.

FIG. 13 is a diagram showing a work completed state in the embodiment of FIGS.

FIG. 14 is a diagram showing one aspect of rock excavation.

FIG. 15 is a view showing a state of injecting a solidifying agent after the excavation mode shown in FIG. 14;

FIG. 16 is a diagram showing an aspect different from that of FIG. 14 of rock excavation.

FIG. 17 is a diagram showing a state of injecting a solidifying agent after the excavation mode shown in FIG. 16;

FIG. 18 is a view showing a casing driving step in the prior art.

FIG. 19 is a diagram showing a rock excavation process in the related art.

FIG. 20 is a view showing a solidifying agent injecting step in the prior art.

FIG. 21 is a view showing a main pile driving step in the prior art.

FIG. 22 is a view showing a casing pulling-out step in the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Casing 2 ... Ground (for example, sediment layer) 3 ... Rock 4 ... Excavator 5, 14 ... Excavation hole perforated in rock F ... Caking agent 6, 10 ... Steel pipe pile (main pile) 5B ... Bottom of excavation hole 12A ... Drag bit 16 ... Gap between inner wall surface of excavation hole and outer surface of steel pipe pile 18 ... Plug for sealing 20 ... Mini backhoe 22 ... Stand and power casing jack 24 ... Pile driver 26 ... Truck mixer vehicle 10I ... Steel pipe pile internal space Ft ... Streamline of injected coagulant

Claims (2)

[Claims] 1. A step of rotating and pushing while rock bed is cut by a steel pipe pile in which a bit is attached to a tip end portion of the steel pipe surface so as to be able to excavate a portion radially outside of the steel pipe surface, and an excavated surface of the rock bed and a steel pipe surface. A method of fixing rock mass of a steel pipe pile, characterized by including the step of injecting a solidifying agent into the gap between and. 2. The method of fixing rock mass of a steel pipe pile according to claim 1, wherein when the rock mass cannot be penetrated only by the steel pipe pile, the inner excavation of the steel pipe pile is performed, and then the steel pipe pile is rotated and pushed.