JP2827020B2 - Pit excavation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pit excavation method for digging a pit in hard ground for pile driving foundation work or the like.

[Conventional technology]

In the conventional pit excavation method, while rotating a cylindrical casing and building it in the ground, the earth and sand in the casing is discharged using a grab bucket or the like to excavate a pit surrounded by the casing, and the tip of the casing is excavated. Reaches the hard ground,
A drilling hammer having an impact hammer driven up and down at the lower end is inserted into the casing, and a vertical hole surrounded by the casing is continuously excavated even on hard ground by rotary press-fitting of the casing and rotary impact of the impact hammer.

[Problems to be solved by the invention]

However, in the above-mentioned construction method, since the casing and the excavating hammer are rotated independently of each other when excavating the supporting ground, complicated adjustment and maintenance management work are required for each rotation, and the equipment used is large and expensive. There was a drawback that would be.

In addition, when the vertical hole is excavated in the hard ground, if the casing is rotated, the ground on the outer periphery of the casing collapses, and if the groundwater leaks, a boiling state occurs.

Therefore, an object of the present invention is to eliminate the conventional disadvantages and to provide a vertical excavation method in which even when a deep vertical hole is excavated in hard ground, the ground around the vertical hole does not collapse or a boiling state does not occur.

[Means for solving the problem]

In order to achieve the above object, the shaft excavation method of the present invention is to excavate a shaft surrounded by a casing by discharging earth and sand in the casing while rotating the cylindrical casing to build the ground. When the casing tip reaches the hard ground, an auxiliary casing is connected to the upper part of the casing, and a digging hammer having a hitting hammer driven at an up and down direction at the lower end is inserted into the auxiliary casing and the casing, and a casing rotary installation device is provided. By rotating the auxiliary casing and the casing by, and driving the impact hammer while rotating the excavation hammer by the rotation transmission from the auxiliary casing, excavate a pit continuous with the pit in the hard ground, After excavating a vertical hole to a certain extent in the hard ground, the rotation of the auxiliary casing and the casing is stopped, and the auxiliary casing is removed from the casing. Disconnect the casing, drives the striking hammer while rotating only the drilling hammer through the auxiliary casing by a casing rotating denominated inclusive device is characterized by further drilling Tateana.

(Operation)

Therefore, after the rotation of the casing is stopped, the pit is excavated only with the excavation hammer, so there is no friction between the casing and the ground around the pit, and the soil around the pit is collapsed and the boiling water is leaked due to groundwater leakage. Pit can be excavated without occurrence.

In addition, as compared with the conventional method, the casing and the excavating hammer can be driven only by rotating the casing rotating installation device, so that the adjustment of the rotation of the casing and the excavating hammer and the maintenance work are simplified, and the size of the device used is reduced. In addition, the cost can be reduced.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a cylindrical casing 1 is
The grab bucket 5 suspended from a crane or the like via a wire rope 4 is inserted into the casing 1 as shown in FIG. The earth and sand in the casing 1 is discharged, and the vertical hole 6 surrounded by the casing 1 is inserted into the hard ground 7.
Dig up to.

When the tip of the casing 1 reaches the hard ground 7, the grab bucket 5 is pulled out of the casing 1 and, as shown in FIG.
Are connected by bolts, and a hammer 9 is inserted into the auxiliary casing 8 and the casing 1 from above the auxiliary casing 8.

As shown in FIG. 4, on the inner periphery of the auxiliary casing 8, a locking ridge 8a for rotating the impact hammer 9 is provided, and the impact hammer 9 is provided at the lower end of the cylindrical rod 9a with air. Has a hammer 9b that is driven vertically by a rod
A locking ridge 9c that engages with the locking ridge 8a of the auxiliary casing 8 is formed on the outer periphery of 9a in the axial direction.

Subsequently, as shown in FIG.
While rotating, the rotary press of the casing 1 and the rotation of the hammer 9 are performed.
The hard ground 7 is excavated by driving the hammer 9b. The excavated earth and sand is discharged from between the rod 9a, the casing 1, and the auxiliary casing 8 by the pressure of the air driving the hammer 9b, and the vertical hole 6 surrounded by the casing 1 is continuously formed in the hard ground 7. .

When the pit 6 excavated in the hard ground 7 reaches a certain depth, as shown in FIG.
And the casing 1 are separated, the auxiliary casing 8 is slightly lifted up, the rotation of the casing 1 is stopped, and as shown in FIG. 8, the auxiliary casing 8 is rotated and the hammer 9 is rotated while rotating only the hammer 9. 9b is driven to excavate the hard ground 7, and the pit 6 is excavated further.

As a result, the rotary pushing of the casing 1 is stopped, so that friction between the casing 1 and the ground around the pit 6 is eliminated, and the pit 6 is deepened without collapse of the ground around the pit 6 or occurrence of a boiling state of groundwater. Can excavate.

When the excavation of the pit 6 is completed, the hammer 9 is pulled out, the auxiliary casing 8 is connected to the upper part of the casing 1, and
While pulling out and collecting the casing 1, concrete is poured into the vertical hole 6 or a replacement method is performed.

〔The invention's effect〕

As described above, the pit excavation method of the present invention rotates a cylindrical casing to excavate a pit surrounded by a casing in the ground, and when the casing tip reaches the hard ground, an auxiliary casing is provided at the upper part of the casing. The excavation hammer is inserted into the auxiliary casing and the casing, and the auxiliary casing and the casing are rotated by the casing rotary erection device, and the excavation hammer is rotated by the rotation transmission from the auxiliary casing to rotate the excavation hammer in the hard ground. After drilling a vertical hole to a certain extent in the hard ground, the rotation of the auxiliary casing and the casing is stopped, the auxiliary casing is separated from the casing, and a drilling hammer is provided through the auxiliary casing by the casing rotating installation device. While rotating only the shaft, the pit is excavated further, so the casing rotation After stopping, the eliminates friction between the ground around the casing and Tateana can deeply excavated Tateana without the occurrence of boiling of collapse and groundwater of the ground surrounding Tateana. In addition, since the casing and the excavating hammer are rotated only by the casing rotating installation device, adjustment of the rotation of the casing and the excavating hammer and maintenance work are simplified,
In addition, the size and cost of the device used can be reduced.

[Brief description of the drawings]

Fig. 1 shows an embodiment of the present invention. Fig. 1 is a sectional view showing a process of erection of a casing, Fig. 2 is a sectional view of a process of excavating a vertical hole in ordinary ground, and Fig. 3 is a hard ground. FIG. 4 is a cross-sectional view showing a state in which an auxiliary casing is connected to a casing obtained by excavating a pit that has reached up to, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.
The figure is a cross-sectional view of a process of excavating a vertical hole in hard ground while rotating the casing and the hammer by the auxiliary casing, FIG. 6 is a cross-sectional view showing a rotationally engaged state of the auxiliary casing and the hammer, and FIG. FIG. 8 is a cross-sectional view of a state where the auxiliary casing and the casing are separated, and FIG. 8 is a cross-sectional view of a step of excavating a vertical hole in the hard ground by rotating only the impact hammer. 1 ... casing, 2 ... casing rotating installation device,
3 ... normal ground, 5 ... grab bucket, 6 ... pit,
7: Hard ground, 8: Auxiliary casing, 9: Impact hammer

Claims (1)

(57) [Claims] 1. While rotating a cylindrical casing to build it in the ground, discharging earth and sand in the casing and excavating a vertical hole surrounded by the casing, and when the casing tip reaches the hard ground, An auxiliary casing is connected to the upper part of the casing, and a digging hammer having a hitting hammer driven vertically is inserted into the auxiliary casing and the casing, and the auxiliary casing and the casing are rotated by a casing rotating installation device. Along with driving the impact hammer while rotating the excavation hammer by rotation transmission from the auxiliary casing, excavating a pit continuous with the pit on the hard ground, and excavating a pit to some extent on the hard ground The rotation of the auxiliary casing and the casing is stopped, and the auxiliary casing is separated from the casing. Tateana drilling method, characterized in that the grayed rotation denominated inclusive device drives the striking hammer while rotating only the drilling hammer through the auxiliary casing, further drilling Tateana.