JP2571259B2 - Crack monitor permeability test method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a crack monitor permeability test method and an apparatus therefor performed by using a well in rock.

<Conventional technology> The permeability test of rock and the evaluation of existing cracks in rock are the basic data for the design and stability evaluation of structures such as underground tunnels. Was performed independently on separate devices. That is, part of the borehole in the actual bedrock was closed with a packer, water pressure was applied to this part, an in-situ permeability test was performed to measure the amount of leakage, and then a pore-hole television was inserted into the well. Crack evaluation methods such as monitoring microcracks on the hole wall surface under no load and molding the hole wall surface by an impression packer have been adopted.

In addition, there are double packer method and single packer method in how to put the packer, the former digs the boring hole first by the planned length, closes the upper and lower ends of the section to be tested by the packer and pressurizes, For the latter, after boring to the lower end of the test section, apply a packer to the upper end and pressurize, and when performing a test below that, perform boring and then apply a packer to the upper end and pressurize, etc.
The boring operation and the test were alternately repeated.

<Problems to be Solved by the Invention> The water permeability of the rock mass obtained by the above-described water permeability test is evaluated as an average value in a section to which the pressurized water is applied. Was extremely difficult to evaluate. In addition, the distribution of existing cracks on the wellbore wall surface is only performed by molding the wellbore wall surface with an impression packer at no load or photographing the wall surface with a borehole TV, and I want to know the crack behavior when pressurized water flows in In that case, it was only estimated from the microvelocity data in the borehole.

An object of the present invention is to evaluate the water permeability and behavior of a small crack in a rock, conventionally, several types of experiments are required, and there remains a problem in the method of evaluating each crack during water permeation. In view of the circumstances, it is an object of the present invention to eliminate such disadvantages.

<Means for Solving the Problems> According to the crack monitor permeability test method of the present invention, a part of a borehole of in-situ rock is partitioned by a packer, water pressure is applied to the partitioned section, and the pressure is measured in a pressure vessel. A television camera that rotates and moves up and down is arranged in a partition section partitioned by the packer and under a load of water pressure, and photographs a crack on a wall surface of a hole that opens with the inflow of pressurized water. It is possible to monitor crack behavior under well pressure and correct evaluation can be easily obtained.

Further, the crack monitor permeability test apparatus according to the present invention is a packer for partitioning a section for applying water pressure into a borehole of an in-situ rock mass, and for photographing a crack on a hole wall which is opened with the inflow of pressure water. , An azimuth meter for detecting the azimuth of shooting by the television camera, and a rotating / elevating device for the television camera.

<Embodiment> For convenience of explanation, a crack monitor permeability test apparatus according to the present invention will be described with reference to FIG. 1. A compass 2 and a tip fitting 1 are attached to the tip of a glass cylinder 6 having a television camera 5 installed therein. At the rear end of the glass tube 6, a rotation control unit 7 of the TV camera 5 is attached. Base is rotatable. The compass 2 detects the direction of the image taken by the television camera 5. The rear end of the rotation control unit 7 is connected to a core rod 8 having a signal cable 14 therein.
A piping port 10 having a pressure sensor 11 therein is attached, and a signal cable port 13 is connected to an end of the core rod 8. An elevating device 12 disposed between the packer 9 and the signal cable port 13 allows the television camera 5 to be controlled to move up and down with respect to the packer 9 fixed in the wellbore. The looseness of the signal cable 15 when the TV camera 5 moves up and down is adjusted by a spring-type cable expansion / contraction device provided above the signal cable port 13. The piping port 11 is provided with a pressurized water pipe 14 connected to a pressurized water device on the ground so that the pressurized water can be sent to the packer 9 for expansion and the pressurized water can be sent from the front of the packer 9 into the wellbore. .

If the photographing by the television camera 5 is possible in the circumferential direction of the well wall surface, if it is sufficient, the elevating device 12 of FIG. 1 can be omitted as shown in FIG. The equipment is connected by a piping line via signal port 16.

The illustrated example is based on the single packer method and the double packer method is not shown, but may be based on the double packer method. In this case, the television camera 5 is located between the two packers. Be placed.

After lowering the above device to an appropriate position in the well, the packer 9 is expanded by water supply from the pressurized water pipe 14 and pressed against the wall of the well, thereby fixing the device and partitioning a hydraulic load section for the water permeability test. At the same time, water is supplied from the tip of the packer 9 into the well. The situation of the wellbore wall surface under such a hydraulic load is explained by the TV camera 5
By operating the rotation control unit 7, the television camera 5 can take a picture all around the borehole. TV camera 5
When the elevating device 12 is provided, shooting can be performed in a range of a section in which the elevating device can be moved.

<Effect of the Invention> According to the method of the present invention, when a water permeability test is performed in a load section of pressurized water sealed with a packer, at the same time, a picture of a crack on a well wall surface is taken by a television camera one by one. In addition, it is possible to take pictures all around the borehole, and the direction can be known by the compass, so that it is easy to correctly evaluate the permeability and opening change of microcracks, etc. The relationship between distribution and rock permeability can be clarified, and information on the degree of crack growth can be obtained easily.

Since the apparatus according to the present invention is suitable for downsizing, the bore diameter used can be small, so that it can contribute to the reduction of excavation cost and, consequently, the measurement cost. It can be expected to expand the applicable range, such as enabling measurement. By providing the rotation / elevation function of the TV camera, it is possible to take a picture of the entire well and expand the shooting range by a single set in the well, and its direction can be known by the compass.
There is a big thing that contributes to the simplification of measurement.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Tip fitting, 2 ... Compass, 3 ... Lighting, 4 ... Reflector, 5 ... TV camera, 6 ... Glass cylinder, 7 ... Rotation control unit, 8 ... Core rod, 9 ... ... Packer, 10 ... Piping port, 11 ... Pressure sensor, 12 ... Elevating device, 13 ... Signal cable port, 14 ... Pressurized water piping, 15 ... Signal cable

 ────────────────────────────────────────────────── ─── Continuation of the front page Examiner Shinji Fujiwara (56) References JP-A-59-185218 (JP, A) JP-A-53-19101 (JP, A) Jpn.

Claims (2)

(57) [Claims] 1. A part of a borehole of an in-situ rock mass is partitioned by a packer, a hydraulic pressure is applied to the partitioned section, and a television camera which rotates and moves up and down in a pressure-resistant container is partitioned by the packer. A crack monitor permeation test method characterized in that the crack is photographed on a wall surface of a hole that is opened with the inflow of pressurized water by being arranged in a partition section having a crack. 2. A packer for partitioning a section in which water pressure is applied into a borehole of an in-situ rock, a television camera for photographing a crack on a hole wall opened with the inflow of pressurized water, and the television camera. 1. A crack monitor permeability test apparatus comprising: a compass for detecting a direction of photographing by a camera; and a rotary elevating device for the television camera.