JPH11236708A - Self-boring pressure meter test method by wire line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten time required for testing a self-boring pressure meter without lowering work efficiency even if the depth used for a pressure meter test is large and to control the disturbance of the wall of a boring hole to increase degree of accuracy of a test. SOLUTION: A pressure meter is equipped with an excavation device 2 for excavating an investigation objective ground 10 and a driving device 3 for driving the excavation device 2 to form as a self-boring type. The self-boring pressure meter 1 is hung down with a wire line 9, it is inserted inside a boring hole 11 excavated into the investigation objective ground 10 in advance, the bottom of the hole is further excavated after it is lowered down to the bottom of the hole, and a pressure meter test is conducted in a state to finish excavation in the excavated boring hole to obtain data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure meter test system used for measuring deformation characteristics of a ground in a ground survey for designing and constructing a structure. More specifically, the present invention relates to an improvement in a self-boring type pressure meter test method using a self-boring type pressure meter.

[0002]

2. Description of the Related Art A pressure meter test is performed in which a hole wall of a boring is loaded in a radial direction and a strength meter and a deformation characteristic of a ground are examined from a relationship between a pressing force and a displacement of the hole wall at that time. This is one of the in-situ ground survey and testing methods, and is mainly used to determine the deformation (strength) constant of the ground. Generally, after drilling a borehole,
A method called a pre-boring type, in which a new pressure meter test device is attached to the lowermost end of a boring rod and inserted into the boring hole, and the hole wall is loaded concentrically in a radial direction perpendicular to the boring axis, is used. I have.

[0003] In the in-situ test using such a borehole, it is known that the test result largely depends on the quality of the borehole wall, and the quality of the borehole wall greatly changes depending on the drilling conditions. ing. When the boring hole wall is easily collapsed, a pre-boring type pressure meter testing device is not suitable, and a self-boring type pressure meter having a boring bit at the tip of the pressure meter testing device has been developed.

[0004]

However, in the case of a pressure meter test at a large depth, the larger the depth, the more time it takes to ascend and descend the test apparatus (self-boring type pressure meter). Since the ground pressure at the peripheral portion of the wall increases as the depth increases, there is a problem that the wall of the borehole, which affects the reliability of the test result, is likely to be loosened (disturbed) during the elevation of the test apparatus. Therefore, there is a problem that the borehole wall, which is the ground to be investigated, is disturbed and the relationship between the pressing force and the hole wall displacement is shifted.

In the case where core sampling is also performed together with the pressure meter test, switching between the core sampling operation and the pressure meter test, in other words, the switching between the core tube and the pressure meter can be freely performed at an arbitrary depth. It is desirable to be able to do it quickly.

Accordingly, the present invention provides a self-boring method using a high-precision wire line which does not reduce the working efficiency even when the depth of the pressure meter test is increased, reduces the time required for the test, and suppresses disturbance of the borehole wall. It is an object of the present invention to provide a mold pressure meter test method.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a pressure meter is provided with a digging means for digging a ground to be surveyed and a driving means for driving the digging means, so that self-boring is performed. The self-boring type pressure meter is suspended by a wire line, inserted into a boring hole excavated in advance on the ground to be surveyed, lowered to the bottom of the hole, and then further excavated at the bottom of the hole, and the excavated boring The data is obtained by performing a pressure meter test while excavating in the hole.

Accordingly, the self-boring type pressure meter can be quickly moved up and down. Further, the pressure meter test can be performed immediately after the excavation is completed, and the time from the excavation of the test hole to the actual start of the test is shortened. Therefore, since the test hole wall is less likely to be loosened before the test is started, a highly accurate pressure meter test using the hole wall with less disturbance can be performed.

According to a second aspect of the present invention, there is provided a self-boring type pressure meter test method using a wire line.
A cylindrical boring rod movable in the vertical direction is provided in the boring hole, and the self-boring type pressure meter is fixed to the inner wall of the boring rod at the time of self-boring and at the time of the pressure meter test. This boring rod is configured such that a boring hole is excavated in the ground to be surveyed according to the size of its outer diameter, and furthermore, the boring rod is movable in the axial direction along the inner wall of the boring hole. Therefore, the pressure meter fixed to this boring rod can be dug straight along the axial direction of the boring hole, and firmly attached to its inner wall so that highly accurate data can be obtained during the test. Fixed.

According to a third aspect of the present invention, the driving means is a water flow motor using a circulating fluid pressure circulating inside the borehole as a power source for excavation. Therefore, the water flow motor receives pressure from the circulating fluid, rotates its drive shaft, and drives the excavating means to excavate the borehole.

According to a fourth aspect of the present invention, there is provided a self-boring type pressure meter test method using a wire line.
The excavating means includes a rod connected to the driving means and rotating;
And a bit provided at the tip of the rod to rotate and excavate the bottom of the boring hole. Therefore, the rod and the bit rotate under the driving force of the driving means, excavating the bottom of the boring hole, and causing the pressure meter to self-boring.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIG. 1 shows an embodiment of a self-boring type pressure meter 1 used in the wire-line self-boring type pressure meter test method of the present invention. The pressure meter according to the present invention is a self-boring type pressure meter 1 including a digging unit 2 for digging a ground 10 to be surveyed and a driving unit 3 for driving the digging unit 2, and is hung by a wire line 9. It is inserted into the excavated boring hole 11 and the bottom of the hole can be self-bored. The self-boring type pressure meter 1 is provided so that a pressure meter test can be performed inside a drilled hole while excavation is completed.

The excavating means 2 of the self-boring type pressure meter 1 is attached to the tip of the pressure meter 1 and performs rotary boring of the target ground 10 by rotating. A substantially cylindrical bit 21 as shown is used so as to be suitable for excavating in a cylindrical shape. However, the shape of the bit 21 is not particularly limited to such a circular shape. Also, the material of the blade is not particularly limited, for example, such as those having a cutting edge such as diamond or special steel at the tip,
It is preferable to use one that matches the quality of the bedrock of the target ground 10. The rod 22 to which the bit 21 is attached is formed in a hollow shape extending from the vicinity of the driving means 3 to the distal end side in the axial direction of the pressure meter 1 so that the fluid can pass through the inside thereof and most of it. Are provided so as to pass through the inside of the cylindrical tube 23. Therefore, for example, when the water flow motor 31 is used as the driving means 3, the water pressure
The fluid whose rotating shaft is rotated further passes through the inside of the rod 22, and flows out from the tip of the bit 21 at the tip of the rod 22. The fluid flowing out from the tip of the bit 21 in this manner facilitates the work of crushing the rock or the like by the bit 21 and further makes the crushed soil sample or the like muddy. Here, the maximum diameter of the pressure meter 1 is smaller than the outer diameter of the core tube 13 for collecting cores. As a result, the hole drilled by the self-boring of the pressure meter 1 is removed from the core tube 1 as shown in FIG.
3 can be prevented from entering.

A probe 41 constituting the measuring means 4 is provided around the tube 23.
A gap sensor 42 is provided on the inner side of 1 so as to be substantially equally spaced in the axial direction. The outer diameter of the probe 41 may be equal to or larger than the maximum diameter of the bit 21. By setting the outer diameter of the probe 41 to be substantially the same as the bit diameter, it is possible to reduce the influence of disturbance and stress release around the hole wall. Although not shown, the probe portion is provided with a rubber film, a metal plate, or the like.For example, when a metal plate is provided, the displacement of the boring hole wall when a load is applied is determined by the displacement of the metal plate. Then, by reading using the gap sensor 42, the hole wall distortion can be measured.

Further, for example, a water flow motor 31 is provided as a driving means 3 inside the main body side of the self-boring type pressure meter 1. The water flow motor 31 uses the circulating fluid pressure circulating inside the borehole 11 as a power source for excavation, and thereby drives the bit 21 to rotate. Although not shown, the pressure pump 32, the valve 33, the volumetric meter 34, the pressure gauge 35 constituting the driving means 3 and the gap sensor amplifier 43 constituting the measuring means 4 are provided in the vicinity of the water flow motor 31. And so on.
The pressurizing pump 32 is provided so as to pressurize the rubber film of the probe 41 in the pressure meter 1 so that the hole wall can be loaded. By adjusting the loading pressure, the displacement of the hole wall can be adjusted. The valve 33 is provided integrally with the pressurizing pump 32 to prevent the backflow of the pressurized fluid, and the volume meter 34 and the pressure gauge 35 detect the internal water volume and pressure. The gap sensor amplifier 43
Amplifies the signal detected by the gap sensor 42 and transmits the amplified signal to the data measurement processing unit 7.

Further, a battery 5 is provided inside the self-boring type pressure meter 1 and at a position near the pressurizing pump 32 and the like to supply electric power to devices such as the pressurizing pump 32. Further, a control board 61 and a transmission board 62 separately provided in the pressure meter 1 send out the measurement data obtained by the measuring means 4 to the ground and control the movement of the excavating means 2 and the driving means 3. . A connector 63 is provided on the transmission board 62.
Is connected to the data measurement processing section 7 on the ground by a communication cable 71 or the like.

The ground data measurement processing section 7 is provided so as to analyze data transmitted from the self-boring type pressure meter 1 to perform measurement and analysis. Data measurement and analysis are performed by the data measurement control microcomputer 72, and the result is printed out by the printer 73. The data measurement control microcomputer 72 is connected to the pressure meter 1 via the communication cable 71. The communication cable 71 is provided such that a cable connector 74 connected to the connector 63 of the transmission board 62 is attached to the end of the communication cable 71, and the communication cable 71 is arbitrarily wound up by a cable winding device 75. The pressure meter 1 in the boring hole 11 and the data measurement processing unit 7 can be connected at any time by attaching and detaching the pressure meter.

A fixing means 8 for fixing the pressure meter 1 in the boring rod 12 of the boring hole 11 is provided on the pressure meter 1 as shown in FIG. This fixing means 8
Is constituted by a plurality of contacts that open and close so as to press the inner wall of the boring rod 12 in the present embodiment, but is not limited thereto.
Any material can be used as long as it can be fixed in the boring rod 12.

Further, a wire line 9 for suspending the pressure meter 1 and moving up and down in the borehole 11 is provided.
Although not particularly shown, it is wound on, for example, a wire winding device installed on the surface of the ground, and the height of the pressure meter 1 is adjusted by being wound or fed by the wire winding device. ing. At the end of the wire line 9, although not particularly shown, a detachable connecting means such as a hook for connecting to the fixing means 8 of the pressure meter 1 is provided.

A test procedure by the test system of the present invention using the self-boring pressure meter 1 having the above-described configuration will be described below with reference to FIGS.

First, as shown in FIG. 2, in order to conduct a pressure meter test on a boring hole 11 previously excavated in the target ground 10, a boring rod 1 is used.
Boring is started using the circulating fluid circulating in the borehole 11 by the core tube 13 and the core tube 13. The boring rod 12 has a hollow cylindrical shape, has a sufficient axial length from the ground surface to the bottom of the boring hole, and is movable in the vertical direction. The core tube 13 can be fixed inside the boring rod 12, and is fixed integrally with the boring rod 12 when performing coring boring. The fixing means 14 for fixing the core tube 13 to the inner wall of the boring rod 12 is provided above the core tube 13 similarly to the pressure meter 1. The core tube 13 also has a hollow shape with an open bottom surface. Integrated boring rod 12 and core tube 1
3 excavates the hole bottom and stops excavation when the core is collected in the core tube 13 as shown in FIG. Here, the core tube 13 fixed in the boring rod 12 is released from being fixed, pulled by the wire line 9 and pulled up from the bottom of the boring hole (FIG. 4), and the core collected by the core tube 13 is removed from the ground surface. It is taken out by. Further, the boring rod 12 is also slightly lifted from the bottom of the hole (FIG. 5), and is stopped halfway in the boring hole 11.

Next, the pressure meter 1 is inserted from the surface of the ground so as to pass through the boring rod 12, and is lowered to the bottom of the boring hole while being suspended by the wire line 9. When the lower end of the pressure meter 1 reaches the bottom of the hole, the lowering is stopped, and the pressure meter 1 is fixed inside the boring rod 12 by the fixing means 8 at that position (FIG. 6). The wire line 9 that has suspended the self-boring type pressure meter 1 is once removed here and raised to the ground surface. Thereafter, the pressure meter 1 starts self-boring by rotating the bit 21 at the lower end thereof with a water flow generated by a circulating fluid (for example, muddy water) circulating in the boring hole 11. The pressure meter 1 digs down the hole bottom while being integrated with the boring rod 12 (FIG. 7), and a point where the lower end of the boring rod 12 was the hole bottom up to this point (that is, the pressure meter 1 started self-boring). The excavation is stopped when it reaches the point (Fig. 8). Here, after the communication cable 71 is lowered from the ground surface side and connected to the connector 63 on the upper end side of the pressure meter 1, the pressure meter test is started while the pressure meter 1 is fixed to the inner wall of the boring rod 12 (FIG. 9). ).

Therefore, this pressure meter test is performed in a state where the excavation has been completed in the hole where the pressure meter 1 has self-bored the boring hole 11. This pressure meter test is not particularly different from the conventional one, and the hole wall is loaded in the radial direction via a cylindrical rubber film etc., and the strength and strength of the ground are determined from the relationship between the applied pressure and the hole wall displacement at that time. Deformation characteristics are being investigated.

When the pressure meter test is completed, the pressure meter 1 is removed from the communication cable 71 and replaced with the wire line 9 again. (FIG. 10). The core tube 13 is provided in the boring rod 12 from which the pressure meter 1 is pulled out.
Are inserted again and fixed (FIG. 11). At this time, the core tube 13 is placed on the upper edge of the hole excavated by the pressure meter 1 and its tip is
It is set to be the same height as the tip of No. 2. As shown in FIG. 12, the boring rod 12 and the core tube 13 dig (reaming) to a point at the bottom of the hole excavated by the pressure meter 1 while being integrally fixed. At this time, the inside of the boring hole 11 is in the same state as that shown in FIG. The test procedure can be repeated again to dig deeper. Therefore, it is possible to conduct a ground survey at a deeper depth.

According to the self-boring type pressure meter test system using the wire line 9 for performing the test as described above, the pressure meter 1 performs the self-boring of the boring hole 11 in the hole where the excavation has been completed almost as it is. Since the meter test is performed, the time from when the test hole is drilled to when the test actually starts is short. Therefore, it is needless to say that the test time can be shortened, and the wall of the test hole becomes less loose before the test is started. It can be performed.

Moreover, since the pressure meter 1 is hung by the wire line 9, even when the core sampling operation and the pressure meter test are performed alternately, replacement of the equipment can be easily performed. Therefore, the test system of the present invention has a great effect particularly in a pressure meter test at a large depth.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the communication cable 71 and the wire line 9 are separate, but the communication cable 71 and the wire line 9 are integrated, for example, by passing the communication cable 71 through the wire line 9. Needless to say, this eliminates the need to replace them during the test process.

[0029]

As is apparent from the above description, in the self-boring type pressure meter test method using the wire line according to the first aspect of the present invention, the excavating means for excavating the ground to be surveyed by the pressure meter and the driving of the excavating means are described. Self-boring type pressure meter is suspended by a wire line, inserted into a boring hole excavated in advance on the ground to be surveyed, lowered to the bottom of the hole, and then the hole is removed. Since the bottom is further excavated and the data is obtained by performing the pressure meter test while excavating in the excavated borehole, perform the pressure meter test immediately after excavation is completed And the time from the excavation of the test hole to the actual start of the test can be shortened. In addition, since the test hole wall is less likely to be loosened before the test is started, a highly accurate pressure meter test using a sample with less disturbance can be performed. In addition, since the wire line is used, the self-boring type pressure meter and the core tube can be freely replaced at an arbitrary depth. In addition, since a self-boring type pressure meter is used, the size of the test apparatus can be reduced as a whole, and workability can be improved.

According to a second aspect of the present invention, there is provided a method for testing a self-boring type pressure meter using a wire line, wherein a cylindrical boring rod movable in a vertical direction is provided in a boring hole. Because it is fixed to the inner wall of this boring rod during self-boring and during the pressure meter test, it can be dug straight along the axial direction of the boring hole, and highly accurate data can be obtained during the test. it can.

Further, in the self-boring type pressure meter test method using a wire line according to the third aspect of the present invention, the driving means is a water flow motor using a circulating fluid pressure circulating in the borehole as a drilling power source. The excavating means can be driven by receiving pressure from the fluid and rotating its drive shaft.

In the self-boring type pressure meter test method using a wire line according to the present invention, the excavating means includes a rod which is connected to the driving means and rotates, and a boring hole which is provided at the tip of the rod and rotates and rotates. And a bit for digging the bottom. Thus, the rod and the bit are rotated using the driving force of the driving means, and the pressure meter can be self-bored by excavating the bottom of the boring hole.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a ground to be investigated showing a state in which a self-boring type pressure meter constituting the present invention is located in a boring hole.

FIG. 2 is a longitudinal sectional view showing a test procedure according to the present invention, and shows a state where coring boring is started.

FIG. 3 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which coring boring has been completed.

FIG. 4 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which a core tube is recovered from a boring hole.

FIG. 5 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which a boring rod is pulled up halfway.

FIG. 6 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which a self-boring type pressure meter is inserted into a boring hole and fixed.

FIG. 7 is a longitudinal sectional view showing a test procedure of the present invention, and shows how a self-boring type pressure meter excavates inside a boring hole.

FIG. 8 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which excavation by a self-boring type pressure meter has been completed.

FIG. 9 is a longitudinal sectional view showing a test procedure of the present invention, showing a state in which a borehole wall is loaded and a pressure meter test is being performed.

FIG. 10 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which a self-boring type pressure meter is collected from a boring hole.

FIG. 11 is a longitudinal sectional view showing a test procedure of the present invention, and shows a state in which a core tube is set again in a boring hole.

FIG. 12 is a vertical cross-sectional view showing a test procedure of the present invention, showing a state where reaming is performed using a core tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Self-boring type pressure meter 2 Excavation means 3 Driving means 9 Wire line 10 Surveyed ground 11 Boring hole 12 Boring rod 21 Bit 22 Rod 31 Water flow motor

Claims (4)

[Claims] 1. A self-boring pressure meter having a pressure meter provided with a digging means for digging a ground to be examined and a driving means for driving the digging means, wherein the self-boring pressure meter is suspended by a wire line. Insert the drilling hole in the target ground in advance into the drilled hole and lower it to the bottom of the hole, then make the hole bottom further excavate, and perform the pressure meter test with the excavation completed in the excavated borehole A self-boring pressure meter test method using a wire line, characterized by obtaining data. 2. A boring rod having a cylindrical shape movable in a vertical direction is provided in the boring hole, and the self-boring type pressure meter is fixed to an inner wall of the boring rod during self-boring and during a pressure meter test. The self-boring type pressure meter test method using a wire line according to claim 1, wherein: 3. A self-boring wire-type self-boring motor according to claim 1, wherein said driving means is a water flow motor using a circulating fluid pressure circulating inside said boring hole as an excavation power source. Pressure meter test method. 4. The excavating means comprises a rod connected to the driving means and rotating, and a bit provided at the tip of the rod and rotating and excavating a bottom of a boring hole. A self-boring type pressure meter test method using the wire line according to claim 1.