JPS6332221Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drilling rod used, for example, when drilling a hole in a pressurized water-retaining sand layer.

When excavating a tunnel in a pressurized sand layer, the water in the ground must be drained in advance.

The construction method for this purpose is as follows.

(1) Outer bit f and inner bit g at the tip
A hole is drilled into the ground to a predetermined depth by rotating a double-tube drilling machine with a (Fig. 1) This double tube drilling machine has an outer bit f at the tip.
It consists of a hollow casing a having a cylindrical shape, and an inner rod b located therein having an inner bit g at its tip.

This inner rod b is hollow,
This will serve as a water supply channel during excavation.

(2) After drilling, insert inner rod b into casing a
Pull it out from the inside and insert the strainer pipe c for draining water. (Fig. 2) (3) Then, remove the casing a, connect the hose d to the strainer pipe c, and pump the vacuum pump e.
Drain the water from the ground using methods such as (Fig. 3) Water is drained using the method described above, but if the ground is a pressurized sand layer that causes quicksand phenomenon even with a small amount of spring water, it is necessary to remove water from the inner rod b after drilling. After pulling out the strainer pipe c, the sand and water become quicksand and flow into the casing a (Fig. 4), making it difficult to insert the strainer pipe c into the casing a.

The present invention was devised to solve the above problems, and its object is to provide a drilling rod that can prevent quicksand from flowing into the casing and allow smooth insertion of a strainer pipe.

That is, the present invention has a hollow casing that has a flange on the inner circumferential surface of the tip of the drilling hole and a recess that prevents the rotation of the bit with a check valve, and a disc-shaped casing that has a notch on the circumference. The present invention relates to a hole-drilling rod consisting of a holding plate and an elastic plate located in front of the cut portion of the holding plate, which is sandwiched between a bit portion to which a drilling blade is fixed.

Next, the tip bit of this invention (bit with a check valve)
The configuration will be explained based on the drawings. (Fig. 5) The tip bit A of the present invention has a disc-shaped presser plate 1,
It is a pot-lid-shaped member composed of an elastic plate 2 having the same diameter as that of the pot and a bit part 3.

(a) The holding plate 1 is a disc-shaped member having a diameter equal to the inner diameter of a ring bit 4, which will be described later.

Then, several places around the circumference are cut out to form the cut portions 11.

(B) Elastic Plate The elastic plate 2 is a disc-shaped elastic member made of an elastic material such as rubber, and has the same diameter as the inner diameter of the ring bit 4 and a predetermined thickness.

(C) Bit part The bit part 3 is a rectangular parallelepiped member in which a plurality of digging blades 31 are arranged in series on one surface of a steel rod, and its total length is slightly longer than the diameters of the elastic plate 2 and the holding plate 1.
The diameter of the ring bit 4 is also shorter than the diameter of the outer circumference of the ring bit 4.

(d) Structure First, the presser plate 1, the elastic plate 2, and the bit part 3 are stacked one on top of the other in this order.

Next, by screwing a bolt into the bolt hole on the back side of the bit part 3, the holding plate 1 and the elastic plate 2 are bolted together at the center to form an integral structure.

Therefore, the back side of the surface having the digging blade 31 is the elastic plate 2.
I will come into contact with

Further, the upper and lower ends 33 of the bit part 3 are
The entire length of the elastic plate 2 is longer than the diameter of the elastic plate 2, and the elastic plate 2 protrudes outside its circumference.

(E) Casing (Figure 6) Casing B is a hollow cylinder with a normal shape and a ring bit 4 at its tip.
In particular, an annular flange 42 is provided on the inner surface of the ring bit 4, and a recess 41 is formed so that the upper and lower ends 33 of the bit part 3 fit therein.

The depth is such that the tip of the excavating blade 31 and the tip of the ring bit 4 are almost aligned when the bit part 3 is attached.

Next, a method of using the tip bit of the present invention will be explained.

(a) Attaching the tip bit (Fig. 6) Align the upper and lower ends 33 of the bit part 3 with the recess 41, engage the flange 42, and fit the tip bit A into the ring bit 4.

Therefore, the tip bit A is prevented from rotating by the recess 41 and from moving further inward of the casing B by the flange 42.

Therefore, the tip bit A is removably attached only to the side of the excavated object.

At this time, the digging blade 31 of the bit portion 3 faces in the same direction as the digging blade of the ring bit.

(b) Drilling Drilling begins by rotating casing B with tip bit A attached to its tip.

At this time, since the tip bit A is prevented from rotating by the recess 41 as described above, it does not interfere with drilling.

The water for drilling that has passed through the hollow part of the casing B and reached the tip bit A is transferred to the holding plate 1 as shown in Fig. 7.
The elastic plate 2 is pressed from the notch 11 (P) and released into the ground through the gap created by folding it outward.

(c) Completion of excavation When the water supply for excavation is stopped after excavation is completed, spring water pressurized from the ground will flow into casing B with sand, causing pressure ( Multiply by P).

However, since the elastic plate 2 is supported by the presser plate 1 at the rear, it cannot fit inside the ring bit 4.

Therefore, quicksand cannot flow into casing B.

(d) Inserting the strainer pipe (Fig. 8) After completing the drilling, insert the strainer pipe C into the casing B.

Since no quicksand has entered the casing B, its insertion can be performed smoothly.

Strainer pipe C has tip bit A pushed out from ring bit 4.

After pushing the strainer pipe C into the earth by the planned length, remove the casing B.

(E) Start draining water Connect the hose to strainer pipe C and start draining water using the conventional method.

(f) Other embodiments (FIGS. 9 and 10) It is also conceivable to install a valve 5 made of skin or the like inside the ring bit 4 inside the tip bit A.

This valve 5 has a structure in which a central hole 51 is opened in the center and cuts 52 are made radially.

This valve 5 prevents the small amount of quicksand that could not be stopped by the tip bit A from flowing into the casing B any further.

Further, when inserting the strainer pipe C, some sand flowing in can be stopped. (FIG. 11) Since the present invention has been described above, the following effects can be expected.

(b) The tip bit has a check valve structure, so
It is possible to send water from inside the casing, and it is almost impossible for water to flow in from the outside.

Therefore, quicksand does not enter the casing, and the strainer pipe can be inserted smoothly.

(b) Since the tip bit is designed to be discarded into the ground, the drilling machine does not need to be a double pipe type and can be a lightweight one.

[Brief explanation of the drawing]

Figures 1-4: Explanatory diagram of the water drainage method, Figure 5: Explanatory diagram of the configuration of the tip bit, Figures 6-8: Explanatory diagram of how to use it, Figures 9-11: Explanatory diagram of other embodiments. . 1: Holding plate, 2: Elastic plate, 3: Bit part, 4:
Ring bit, 11: Notch part, 31: Drilling blade,
41: recess, 42: flange, A: tip bit,
B: Casing, C: Strainer pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] A hollow casing that has a flange on the inner circumferential surface of the tip of the drilling hole and a recess that prevents the rotation of a bit with a check valve, and a disc that has a notch on the circumference. A bit with a check valve is formed by a shaped holding plate and a bit part to which the excavation blade is fixed, and an elastic plate located in front of the cut part of the holding plate is integrated. A drilling rod, characterized in that a valved bit is fitted into the flange and recess of the casing with its drilling blade positioned on the side of the body to be excavated, and is detachably attached only toward the side of the body to be excavated.