A core wave velocity and resistivity test device and method

Abstract

The present invention provides a core wave velocity and resistivity test device and method, including a fixed frame, a core clamp and a test device, wherein the fixed frame is provided with a slide rail, and the core clamp includes two core clamps, which are slidably arranged on the fixed frame through the slide rail, and the two core clamps are arranged oppositely, and the spacing is adjustable; the core clamp is in a horizontally arranged cylindrical shape, and a plurality of springs are arranged on the circumference of the cylinder wall, and a fixing piece is arranged on the spring to elastically abut against the core sample to be tested; the core clamp cylinder bottom is provided with a receiving portion, and the receiving portion is used to be provided with a test device to perform wave velocity test or resistivity test. The present invention can comprehensively measure the resistivity and wave velocity of rock, and can be applicable to cores of different diameters and lengths, as well as broken samples.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering and relates to a core wave velocity and resistivity testing device and method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] When constructing a tunnel, under high ground stress conditions, the engineering mechanical properties of the cavern surrounding rock will become different from those of the surrounding rock under low stress conditions as the burial depth increases. Due to the limitations of geological survey methods and techniques, the engineering geological problems of the tunnel section cannot be accurately discovered and identified. The disadvantage of TBM is that it has poor adaptability to the geological environment. When encountering emergencies or special geological environments, it often gets stuck, which may even cause damage to the machine. TBM jams are often caused by insufficient understanding of the surrounding rock conditions and lack of important parameters that lead to jams.

[0004] Changes in geoelectric properties and wave velocity are important characteristics that characterize changes in rock mass structure. These two types of testing methods are often used in field tests and laboratories. For TBM jam prediction research, sampling is often carried out on site, and wave velocity tests are used to study the damage of the rock mass on site. At the same time, resistivity tests are carried out on the rock properties to study changes in rock water content and predict TBM jams. During the test process, it is often necessary to test the broken rock under certain water content conditions, as well as to test samples of different diameters and lengths, which cannot be achieved by existing instruments and devices. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a core wave velocity and resistivity test device and method, which can comprehensively measure the resistivity and wave velocity of rocks and can be applied to cores of different diameters and lengths, as well as broken samples.

[0006] According to some embodiments, the present invention adopts the following technical solutions:

[0007] A core wave velocity and resistivity test device, comprising a fixing frame, a core holder and a test device, wherein:

[0008] The fixing frame is provided with a slide rail, and the core clamps include two core clamps, which are slidably arranged on the fixing frame through the slide rail, and the two core clamps are arranged opposite to each other, and the distance between them is adjustable;

[0009] The core holder is in the shape of a horizontally arranged cylinder, and a plurality of springs are arranged on the circumference of the cylinder wall, and a fixing piece is arranged on the spring to elastically abut against the core sample to be measured;

[0010] The bottom of the core holder cylinder is provided with a receiving portion, and the receiving portion is used to be provided with a testing device for performing a wave velocity test or a resistivity test.

[0011] As an optional implementation, a plurality of slide rails are arranged on the fixing frame, the slide rails are arranged in parallel, a bracket is arranged at the lower end of the core clamp, and a slide groove matching the slide rails is arranged at the bottom of the bracket.

[0012] As an optional implementation, a plurality of slide grooves are arranged on the fixing frame, and the slide grooves are arranged in parallel. A bracket is arranged at the lower end of the core clamp, and a sliding block adapted to the slide groove is arranged at the bottom of the bracket.

[0013] As an optional embodiment, a baffle is further included, and the baffle is connected to the fixing frame by threads to fix / limit the distance between the core clamps.

[0014] As an optional implementation, the fixing member is an elastic fixing block, such as a rubber block.

[0015] As an optional implementation, one end of the fixing member is fixedly connected to the spring, has a certain degree of freedom, and can move radially to adapt to core samples to be tested of different diameters.

[0016] As an optional embodiment, the testing device is an electrode and / or a transducer.

[0017] As an optional embodiment, the core holder and the fixing frame are non-polarizable metal.

[0018] As an optional embodiment, it further comprises an outer shell container, wherein the outer shell container is hollow and has an annular cross section.

[0019] As a further feature, connecting parts are provided on both sides of the shell container to connect with the core holder.

[0020] The outer shell container is made of acrylic material.

[0021] The working method based on the above device comprises the following steps:

[0022] Two core holders are arranged opposite to each other on the fixed frame, and the distance between them is adjusted and fixed;

[0023] Placement of test equipment;

[0024] The core sample to be tested is placed between the core holders so that the fixing part abuts against the core sample to be tested to position it;

[0025] If the core sample to be tested is a broken rock mass, a shell container of suitable diameter is selected, the broken rock mass is placed in the shell container, and the shell container is fixed between the core holders;

[0026] Perform a resistivity test or a sonic test.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] For cores and broken samples with different diameters and lengths, the present invention can use the experimental device to simultaneously measure two parameters, namely, the resistivity and wave velocity of the rock.

[0029] The ultrasonic pulse signal emitted by the core holder of the present invention is emitted from the transducer on one side and received in the core holder on the other side. The wave velocity of the core between the two transducers at the position can be determined based on acoustic parameters such as acoustic time and amplitude.

[0030] The present invention solves the problem of coupling between the sample and the core holder by applying conductive grease on the core holder, thereby improving the accuracy and reliability of the test and allowing direct measurement without changing the device.

[0031] The present invention can obtain wave velocity results through wave velocity testing, and obtain resistivity results through resistivity testing, thereby realizing the testing of core acoustic waves and resistivity, and utilizing the data consistency of the two parameters to improve the accuracy and reliability of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1 is a schematic diagram of the fixing frame;

[0034] Figure 2 is a schematic diagram of a core holder;

[0035] Figure 3 It is a three-dimensional schematic diagram of the outer shell container;

[0036] Figure 4 This is a schematic diagram after installation.

[0037] Among them: 1. fixing frame, 2. slideway, 3. fixing baffle screw hole, 4. baffle, 5. fixing core holder screw hole, 6. core holder, 7. fixing contact, 8. core holder bracket, 9. slideway, 10. small hole, 11. spring, 12. shell container, 13. foam cylinder, 14. acrylic cylinder. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0041] Example 1

[0042] A core wave velocity and resistivity test device, such as Figure 1 , Figure 2 and Figure 3 As shown, it includes: a fixing frame 1 for installing two slideways 2, a baffle 4 fixed on the fixing frame, a core holder 6 that can move freely on the slideway, a core holder bracket 8 and a slide chute 9, a shell container 12 for breaking rock mass testing, and conductive grease.

[0043] The fixing frame 1 and the core holder 6 are made of non-polarized metal, the outer layers of the bracket 8, the slide groove 9 and the outer shell container 12 are made of acrylic material, and the inner layer of the outer shell container 12 is a cylindrical tube 13 made of foam material.

[0044] A small hole 10 is provided at the center of the core holder 6 , in which an electrode or a planar transducer can be installed.

[0045] When performing wave velocity or resistivity measurement, a certain amount of conductive grease is applied to the core holder 6 .

[0046] The baffle plate 4 is fixed on 1 through two single-board fixing screw holes 3.

[0047] The screw hole 5 of the core holder can fix the position of the core holder 6 by penetrating into different lengths. For samples of different lengths, the screw can be adjusted.

[0048] The fixed contact 7 is fixed to the core holder 6 by a spring 11 and can move freely in the radial direction. The spring 11 has the same elastic modulus and can be used to fix samples of different diameters and align the centers of the samples.

[0049] The slide groove 9 can be installed on the slideway 2 of the fixed frame and can move freely on the slideway.

[0050] The outer shell container 12 is composed of a foam cylinder 13 and an acrylic cylinder 14, wherein the foam cylinder 13 is slightly longer than the acrylic cylinder 14. If the shell container 12 is installed on a core holder when testing a broken rock mass, the shell container 12 can be made into different diameters and different lengths.

[0051] The foam cylinder 13 effectively blocks the sound waves from being conducted along the outer shell container.

[0052] The acrylic cylinder 14 has a certain strength and can prevent the foam cylinder 13 from being damaged.

[0053] Conductive grease is a coupling agent, which is applied to the core holder 6 to solve the coupling problem between the sample and the core holder, and can be used for both wave velocity test coupling and resistivity test coupling.

[0054] Example 2

[0055] Embodiment 2 of the present invention provides a working method of a core wave velocity and resistivity test device as in Embodiment 1, comprising the following steps:

[0056] 1. Apply a certain amount of conductive grease on the rock holder 6.

[0057] 2. Fix the core holder 6 on the core holder bracket 8 through the bayonet connection.

[0058] 3. Install one of the core holder brackets 8 on the slideway 2 through the slide groove 9, and then install the other core holder device on the slideway 2 facing each other.

[0059] 4. Install the baffle 4 on the fixing frame 1.

[0060] 5. Place the core in one of the fixed rock holders so that all four fixed contacts 7 press on the sample.

[0061] 6. Adjust the position of another core holder 6 to clamp the core.

[0062] 7. Adjust the screw hole 5 of the core holder to the appropriate position to fix the sample.

[0063] 8. When the sample is a broken rock mass, select a suitable shell container 12 and install it on the fixed frame 1, such as Figure 4 shown.

[0064] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A core wave velocity and resistivity test device, characterized in that: It includes a fixing frame, a core holder and a testing device, wherein: The fixing frame is provided with a slide rail, and the core clamps include two core clamps, which are slidably arranged on the fixing frame through the slide rail, and the two core clamps are arranged opposite to each other, and the distance between them is adjustable; The core holder is in the shape of a horizontally arranged cylinder, and a plurality of springs are arranged on the circumference of the cylinder wall, and a fixed contact is arranged on the spring to elastically abut against the core sample to be measured; A receiving portion is provided at the center of the bottom of the core holder cylinder, and the receiving portion is used to be provided with a testing device, and the testing device is an electrode or a transducer for performing a resistivity test or a wave velocity test; During the test, apply a certain amount of conductive grease on the core holder; It also includes a shell container, which is hollow and has a ring-shaped cross section and is made into different diameters and different lengths. The shell container with a suitable diameter is selected according to the core sample; The outer shell container is composed of an inner foam cylinder and an outer acrylic cylinder, and the foam cylinder is slightly longer than the acrylic cylinder; connecting parts are arranged on both sides of the outer shell container to connect with the core holder; when the core sample to be tested is a broken rock mass, the broken rock mass is arranged in the outer shell container and installed on the core holder; The fixing frame is provided with a plurality of slide rails, the slide rails are arranged in parallel, a bracket is provided at the lower end of the core clamp, and a slide groove adapted to the slide rails is provided at the bottom of the bracket; The fixing frame is provided with a plurality of slide grooves, the slide grooves are arranged in parallel, a bracket is provided at the lower end of the core clamp, and a slider adapted to the slide groove is provided at the bottom of the bracket; It also includes a baffle, which is connected to the fixing frame by threads and is used to fix / limit the spacing between the core clamps; The fixed contact is an elastic fixed block; One end of the fixed contact is fixedly connected to the spring, has a certain degree of freedom, and can move radially to adapt to core samples to be tested with different diameters; The fixed contact is fixed on the core holder by a spring and is free to move in the radial direction. The spring has the same elastic modulus and is used to fix core samples of different diameters and align the centers of the core samples. Place the core sample in one of the fixed core holders so that the four fixed contacts press the sample, and adjust the position of the other core holder to clamp the core sample; The core holder and the fixing frame are made of non-polarizable metal; The ultrasonic pulse signal emitted by the core holder is transmitted from the transducer on one side, and the signal is received in the core holder on the other side, and the wave velocity of the core between the two transducers at the position is determined according to the acoustic time and amplitude acoustic parameters; The foam cylinder blocks the ultrasonic pulse signal from being conducted along the outer shell container.

2. A working method based on the device according to claim 1, characterized in that: The following steps are involved: Two core holders are arranged opposite to each other on the fixed frame, and the distance between them is adjusted and fixed; Placement of test equipment; The core sample to be tested is placed between the core holders so that the fixed contact point abuts against the core sample to be tested to position it; If the core sample to be tested is a broken rock mass, a shell container of suitable diameter is selected, the broken rock mass is placed in the shell container, and the shell container is fixed between the core holders; Perform a resistivity test or a sonic test.

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