JP3513698B2 - Drilling head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavation head attached to the tip of an excavation shaft of an excavation device used in a construction method of a column-row underground continuous wall.

[0002]

2. Description of the Related Art In construction of earth retaining walls for civil engineering and construction, SMW (soil mixing wall) method is generally used in which soil and cement-based suspension are mixed and stirred at the current position to continuously form a columnar underground wall. It has become a target.

This construction method has an advantage that a continuous wall can be excavated and constructed efficiently in a short time in the extending direction of the underground wall by using a large-scale triaxial pile driving machine. Therefore, the construction period can be shortened and the cost can be reduced. Therefore, instead of the RC underground continuous wall construction method, which has a relatively high construction cost, it has been required to be applied at all construction sites. For this reason, there has been a demand for construction on a ground including hard rock and a continuous wall extending to a large depth exceeding 40 m in the ground.

A conventional drilling head used in this method is shown in FIGS. 7 and 8. The excavating head 100a of FIG. 7 is for soft ground to which this method has been applied, and has a spiral earth removing blade 2 formed on the peripheral surface of the tip end of the excavating shaft 1, and the earth removing blade 2 A plurality of claw-shaped drill bits 3 are attached to the lower end. By pushing the excavation shaft 1 into the ground while rotating the excavation shaft 1, the excavation bit 3 excavates so as to strip the ground. The excavated soil is conveyed upward by the soil discharge blade 2.

The excavation head 100b shown in FIG. 8 corresponds to hard ground such as rock and rock that cannot be excavated by the one for soft ground to which this method has been conventionally applied. Therefore, a tunnel bowling machine for excavating rock ( A roller bit used for TBM) is attached to the tip of the excavation shaft. This excavation head 100b has a roller bit shaft support member 4 at the tip of the excavation shaft 1, a rotary shaft 7 in a direction intersecting with the excavation shaft 1, and a plurality of crushing bit rows 5a on the outer periphery thereof, A roller bit 6 for excavating hard ground is provided so as to be rotatable around an axis 7. By pushing the excavation shaft 1 into the ground while rotating it, the roller bit 6 revolves around the axis of the excavation shaft 1 while rotating around the rotation shaft 7 due to the friction with the ground, and at this time, the roller bit 6 is rotated around the outer periphery of the roller bit 6. The crushing bit 5 provided comes into contact with the bedrock and crushes it to dig.

The above-described excavation head can be used depending on the soil condition, but in excavation of soft-hard composite soil, exchanging the excavation head is time-consuming and has a problem of significantly lowering the construction efficiency. . To solve this problem, there has been proposed an excavating bit provided by combining the excavating bit 3 of the excavating head 100a shown in FIG. 7 and the roller bit 6 of the excavating head 100b shown in FIG.

Japanese Unexamined Patent Publication (Kokai) No. 7-166788 is known as an excavating head for efficiently excavating the ground where different soils coexist without exchanging the head.
This conventional example is shown in FIG. The excavation head 100c forms an earth removal blade (spiral blade) 2 around the excavation shaft 1 and an excavation bit (excavation claw) 3 at the lower end thereof to form a part of the earth removal blade (spiral blade) 2. A pair of cone bearings 4a is formed on each of the cone bearings 4a, and each cone bearing 4a rotatably supports a roller bit (cone) 6 around an axis X2 inclined with respect to the rotation axis X1 of the excavation shaft 1. The lower end position of the excavation bit (excavation claw) 3 is set higher than the lower end position of the roller bit (cone) 6 and lower than the upper end position.

According to the excavation head 100c, it is possible to obtain an effect that good excavation can be performed on the ground having both soft soil and hard rocks and boulders without exchanging the excavation head. However, in order to improve the excavation efficiency, it is desirable that the excavation bit (excavation claw) 3 is located at the tip of the soft ground to excavate the soil, but when the soil reaches the hard soil, the roller bit (cone) 6 is removed. Excavation bit (claw for excavation) to make contact with bedrock
The lower end position of 3 is set higher than the lower end position of the roller bit (cone) 6. For this reason, when excavating the soft ground, the roller bit (cone) 6 is provided at the lower end of the excavation bit (excavation claw) 3 to rotate,
There was a problem that both sides of excavation became a resistance and lowered excavation efficiency. In addition, excavated soil such as soft clay adheres to the excavation bit (excavation claw) 3 and the roller bit (cone) 6, which has been an obstacle to reducing the excavation force.

As means for avoiding these inconveniences, drilling liquid injection nozzles 30a, 30b are provided at the tip of the drilling shaft 1,
Injection nozzle 30 at the tip of the excavation shaft that sends the cleaning liquid from the ground
Although a structure is adopted in which the a and 30b are sprayed toward the excavating claw (excavating bit) 3 and the roller bit (cone) 6 to excavate while cleaning, there is a drawback that the above-ground equipment becomes large accordingly. ing.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to achieve high excavation efficiency in soft ground and to cope with hard rock when it reaches hard rock. It is an object of the present invention to provide a drilling head in which a drilling bit is efficiently driven with a low torque, and further, excavated soil does not adhere to the drilling bit to reduce the drilling force.

Further, by using this drilling head, in the drilling method for soft-hard composite ground, not only single-axis drilling but also triaxial large-scale pile driving can be performed simultaneously with three-axis drilling. By eliminating the exchanging process of the excavation head when arriving at the bedrock, the aim is to shorten the construction period and reduce the cost by eliminating the need for the pre-drilling process that was previously performed with a single shaft to secure the driving torque for the excavation shaft.

[0012]

In order to solve the above-mentioned problems, the invention according to claim 1 has an excavation shaft that is simultaneously excavated in the ground in a single-axis or parallel state, and a plurality of excavation bits are attached to the tip. In the state, it is attached to each tip portion of the excavation shaft to excavate soft ground and convey excavated debris, and an earth scraper having a rotating shaft in a direction intersecting with the excavation shaft and a plurality of crushing bit rows on the outer periphery. An earth-discharging blade having a roller bit that excavates rock in a rotatable state around the rotation axis, and a spiral blade that is continuous with the top of the earth-discharging scraper and that conveys excavated debris from the earth-discharging scraper upward. And a tip of the excavating shaft so that a roller scraper for guiding the excavated debris in the gap of the crushing bit row to the soil discharging blade is located between the plurality of roller bits. Attached to, together with the drill bit to drill ground prior to the roller bits, roller bits when it reaches the bedrock ahead, characterized in that drilling a rock.

The invention of claim 2 is the invention of claim 1, wherein the excavation bit is attached to the tip of the soil discharge scraper through a rock pressure sensing member, and the rock pressure sensing member is excavated. It is characterized in that it detects that the rock pressure acting on the bit exceeds a predetermined value, and that the excavation bit is retracted above the lower end of the roller bit by the detection.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the rock pressure sensing member is attached to the tip of the soil discharge scraper, and the excavation is provided inside the case. And a spring for pressing the bit with a predetermined torque.

A fourth aspect of the present invention is the invention according to any one of the first to third aspects, wherein the roller bit is formed in a conical shape having an apex facing the center of the excavation axis, and the crushing bit string is crushed. It is characterized in that it has an exclusion wall provided so as to be passed between the bits to prevent debris from being caught in the gap between the crushing bits.

According to the present invention, in excavation of soft ground, a plurality of excavation bits attached to the tip of the soil discharging scraper efficiently excavate, and the excavated soil is guided to the roller scraper and the soil discharging scraper to form a spiral shape. It is conveyed upward by the soil removal blade.

When a hard ground such as a gravel or a rock is reached, the rock pressure sensing member senses that the rock pressure acting on the excavation bit exceeds a predetermined value, and the excavation bit is moved to a position lower than the lower end of the roller bit. The roller bit can be evacuated upwards, and the hard rock can hit the hard rock first, so that the hard rock can be efficiently excavated so as to be crushed.

Further, since the excavated soil attached to the roller bit which reduces the excavating force is scraped off by the roller scraper and guided to the discharged soil scraper, the excavated soil attached between the crushing bits is prevented by the exclusion wall. High excavation power can be maintained.

As described above, since the excavation head is automatically switched to the excavation head suitable for either soft ground or hard rock, the excavation shaft is not subjected to an excessive torque load. For this reason,
Not only single-axis drilling but also triaxial simultaneous excavation can be performed by a triaxial pile driving machine with excavation axes mounted in parallel.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a drilling head of the present invention,
2 is a sectional view showing a side surface of the drilling head of the present invention, and FIG. 3 is a bottom view of FIG. The same components as those described in the related art will be described with the same reference numerals.

The drilling head 10 of the present invention shown in FIGS.
0 is an excavation shaft 1 that is attached to a large pile driving machine such as a three-axis machine and is simultaneously excavated in the ground in a parallel state, and a plurality of excavation bits 3 that are attached to the tip of the excavation shaft 1 An excavation scraper 8 attached to the tip end portion for excavating soft ground and conveying excavation debris, a rotary shaft 7 in a direction intersecting with the excavation shaft 1, and a plurality of crushing bit rows 5a on the outer periphery, A roller bit 6 for excavating rock in a rotatable state around a rotary shaft 7, and an earth removal blade consisting of a spiral blade that is continuous with the upper part of the earth removal scraper 8 and conveys the excavated earth and stones from the earth removal scraper 8 upward. Two
In the excavating head 100 including a roller scraper 9 for guiding the excavated debris in the gap of the crushing bit string 5a to the soil discharging blade 2, the roller scraper 9 is attached to the tip of the excavating shaft 1 so as to be located between the plurality of roller bits 6. ing.

With the above structure, in the ordinary soft ground, the excavation bit 3 excavates the ground before the roller bit 6, and when it reaches the rock, the roller bit 6 precedes the rock to excavate the rock. Is characterized by.

As shown in FIG. 1, an excavation bit 3 suitable for excavating soft ground is attached to the tip of an earth-discharging scraper 8,
The upper end of the soil discharging scraper 8 is connected to the soil discharging blade 2 extending upward in a spiral shape. The lower end of the excavating bit 3 shown by the phantom line L is attached so as to be below the tip of the crushing bit string 5a provided around the roller bit 6.

Therefore, when excavating the soft ground, as shown in FIG.
As shown in (a), as the excavation shaft 1 rotates, the excavation bit 3 moves in the circumferential direction F to excavate the ground G. Figure 5
(B) shows the operation of the excavation bit 3 excavating the ground G,
The tip of the excavation bit 3 excavates the ground G in a horizontal direction as shown by an arrow F.

A roller bit 6 suitable for excavating a hard rock or a boulder shown in FIG. 1 is rotatably attached to a rotating shaft 7 of a roller bit shaft supporting member 4 fixedly attached to the tip of the excavating shaft 1. There is. 2 shows a cross-sectional view showing the side surface of FIG.
The mounting state of the roller bit 6 and the roller scraper 9 will be described below with reference to FIG.

The roller bit 6 has a plurality of crushing bit rows 5a on the outer circumference, and a ball bearing 7a and a roller bearing 7b are provided on the rotary shaft portion at the tip of the roller bit shaft support member 4.
It is rotatably attached via a rotating member such as. The rotary shaft portion has a rotary shaft 7 which is directed downward toward the center of rotation of the excavating shaft 1 in a direction intersecting with the excavating shaft 1, and a conical roller bit 6 having a vertex directed toward the center of the excavating shaft 1 is formed. Each of the plurality of crushing bit strings 5a provided on the outer periphery is attached so that the lower end L contacts the ground. The roller bit 6 on the left side has four crushing bit rows 5a so that the range up to the center of the digging shaft 1 can be digged, and the roller bit 6'on the right side has three crushing bit rows 5a.

Further, a roller scraper 9 for guiding the excavated debris in the gaps between the plurality of crushing bit rows 5a to the soil discharging blade 2.
Is attached to the tip of the excavation shaft 1 so as to be located between the left and right roller bits 6, 6 ′. Roller scraper 9
Has a comb tooth-shaped tip, and the teeth of the comb are located between the crushing bit rows 5a of the roller bit 6 to scrape off the excavated debris attached to the roller bits 6. Therefore, it is possible to prevent the excavation force of the roller bit 6 from being reduced by the adhered debris.

FIG. 6A shows a main part of the roller bit 6, and a plurality of crushing bits 5, 5 around the crushing bit string 5a.
An exclusion wall 12 is provided so as to be passed between the crushing bits 5 to prevent the excavated debris from being caught between the crushing bits 5. Figure 6
(B) shows an operation in which the roller bit 6 excavates the ground G, and the rotation of the roller bit causes the tip of the crushing bit 5 to descend to the ground G one after another and crush the rock in the vertical direction indicated by the arrow F. Excavate.

FIG. 3 is a bottom view of the excavation head 100 of the present invention. In this embodiment, two earth-moving scrapers 8 each having an excavation bit 3 at the tip thereof are attached at 180 ° intervals, and Two roller bits 6 having a rotating shaft 7 are provided between the soil discharging scrapers 8. The rotation of the excavation shaft 1 rotates the excavation bit 3 and the roller bit 6 along the circumference indicated by the imaginary line S to excavate the ground.

FIG. 4 is a view showing a part of the excavation head 100 with the roller bit 6 removed to explain the rock pressure sensing member 10 attached to the tip of the soil discharge scraper 8 of the present invention. The excavation bit 3 is attached to the tip of the soil discharge scraper 8 via the rock pressure sensing member 10, and the rock pressure sensing member 10 senses that the rock pressure acting on the excavation bit 3 has exceeded a predetermined value. With this sensing, drill bit 3
Is retracted above the lower end of the roller bit 6.

The rock pressure sensing member 10 is a soil discharge scraper 8
Case 10a attached to the tip of the
The spring 10b is provided inside a and presses the excavation bit 3 with a predetermined torque. FIG. 4B is an enlarged view of a main part of the rock pressure sensing member 10. A coil that presses the excavation bit 3 with a predetermined torque inside a case 10a attached to the tip of the soil discharge scraper 8 by connecting means such as welding. -Shaped spring 10b is provided, and the excavation bit 3 is attached by the bit fixing bolt 10c. This drill bit is
When a hard ground such as rock is reached, the rock pressure acting on the excavation bit 3 exceeds a predetermined value, whereby the spring 10b contracts and the excavation bit 3 retracts in the direction of arrow F1. Therefore, the roller bit 6 which is normally located above the excavation bit 3 and suitable for rock excavation comes into contact with hard ground such as rock.

FIG. 4C shows a rock pressure sensing member 10 'according to another embodiment. The rock pressure sensing member 10 ′ is a bit fixing bolt 10 that is horizontally provided at the tip of the soil discharge scraper 8.
The case 10a ', which is equipped with c'and is rotatably attached to the bit fixing bolt 10c', is attached with a predetermined torque by the spring 10b 'so that the excavating bit 3 at the tip maintains the direction of the extension line L1 of the soil scraper 8. It is energized. When the rock pressure sensing member 10 'reaches a hard ground such as rock, the rock pressure acting on the excavation bit 3 becomes a predetermined value or more, so that the spring 10b' is rotated and contracted upward, so that the excavation bit 3 is arrowed. Retreat in the F2 direction. For this reason, usually the drill bit 3
Roller bit 6 suitable for rock excavation located above the rock
Comes into contact with hard ground such as rock.

[0033]

The present invention has the following effects. In excavation of soft ground, a plurality of excavation bits attached to the tip of the soil discharge scraper efficiently advance, and the excavated soil is guided to the roller scraper and the soil discharge scraper and conveyed upward by the spiral soil discharge blade. .

When reaching a hard ground such as a large rock or a rock, the rock pressure sensing member senses that the rock pressure acting on the excavation bit exceeds a predetermined value, and the excavation bit is moved to the lower end of the roller bit. The hard rock can be efficiently excavated so that the roller bit hits the hard rock first and the hard rock is crushed.

Further, the excavated soil attached to the roller bit for reducing the excavating force is scraped off by the roller scraper and guided to the discharged soil scraper, and the excavated soil attached between the crushing bits is prevented by the exclusion wall. High excavation power can be maintained.

As described above, since the excavation head is automatically switched to the excavation head suitable for either soft ground or hard rock, the excavation shaft is not subjected to an excessive torque load. For this reason,
Not only single-axis drilling but also triaxial simultaneous excavation can be performed by a triaxial pile driving machine with excavation axes mounted in parallel. By eliminating the exchanging process of the excavating head when arriving at hard rock and eliminating the pre-existing process that was previously performed with a single axis to secure the excavating shaft drive torque, it is possible to reduce the construction period and cost.

[Brief description of drawings]

FIG. 1 is a front view of a drilling head of the present invention.

FIG. 2 is a cross-sectional view showing a side surface of the drilling head of the present invention.

FIG. 3 is a bottom view of FIG.

FIG. 4A is a front view showing a part of the excavation head of the present invention, FIG. 4B is an enlarged view of an essential part showing the rock pressure sensing member of FIG.
(C) is an enlarged view of a main part showing a rock pressure sensing member of another form.

5A is an explanatory view showing the operation of the excavation bit of the present invention, and FIG. 5B is an explanatory view of the operation of the excavation bit in FIG. 5A excavating the ground.

FIG. 6A is an explanatory diagram showing the operation of the roller bit of the present invention, and FIG. 6B is an explanatory diagram of the operation of the crushing bit of FIG.

FIG. 7 is a front view of a prior art drilling head.

FIG. 8 is a perspective view of another prior art drilling head.

FIG. 9 is a front view of another prior art drilling head.

[Explanation of symbols]

1 excavation axis 2 Excavation blade (spiral blade) 3 Drill bits (drilling claws) 4 Roller bit shaft support member 5 crushing bits 6 Roller Bit (Cone) 7 rotation axis 8 earth removal scraper 9 Roller scraper 10 Rock pressure sensing member 10a, 10a 'case 10b, 10b 'spring 10c, 10c 'Bit fixing bolt 30a, 30b Drilling fluid injection nozzle 100,100a, 100b, 100c Drilling head X1, X2 rotation axis G ground,

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-166788 (JP, A) Actual development Sho 59-111888 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) E21B 10/44 E21B 10/08-10/24 E21B 12/06

Claims (4)

(57) [Claims] 1. An excavation shaft that is simultaneously excavated into the ground in a single-axis or parallel state, and a plurality of excavation bits are attached to the tip of the excavation shaft, which are attached to respective tip portions of the excavation axis to excavate soft ground. A roller for excavating rock in a rotatable state around the rotation axis, which has a soil discharge scraper for transporting the excavation debris, a rotation axis in a direction intersecting the excavation axis, and a plurality of crushing bit rows on the outer periphery. In the excavation head including a bit and an excavation blade that is continuous to the upper part of the excavation scraper and is configured by a spiral blade that conveys the excavated debris from the excavation scraper upward, A roller scraper that guides to the soil blade is attached to the tip of the excavation shaft so as to be located between the plurality of roller bits, and the excavation bit precedes the roller bit. The excavation head is characterized in that the roller bit precedes and excavates the rock when it reaches the rock, while traveling to excavate the ground. 2. The excavating bit is attached to the tip of the soil discharge scraper via a rock pressure sensing member, and the rock pressure sensing member is configured to detect that the rock pressure acting on the excavating bit is equal to or greater than a predetermined value. The excavation head according to claim 1, wherein the excavation bit is detected and the excavation bit is retracted above the lower end of the roller bit by the detection. 3. The rock pressure sensing member includes a case attached to the tip of the soil discharge scraper, and a spring provided inside the case for pressing the excavation bit with a predetermined torque. The excavating head according to claim 1 or 2. 4. The roller bit is formed in a conical shape having an apex directed toward the center of the excavation axis, and the crushing bit string is provided so as to be passed between the crushing bits so that debris is sandwiched between the crushing bits. The excavation head according to claim 1, further comprising an exclusion wall that prevents