CN211783355U - Effective grouting length test system for anchor rod - Google Patents
Effective grouting length test system for anchor rod Download PDFInfo
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- CN211783355U CN211783355U CN202020188932.4U CN202020188932U CN211783355U CN 211783355 U CN211783355 U CN 211783355U CN 202020188932 U CN202020188932 U CN 202020188932U CN 211783355 U CN211783355 U CN 211783355U
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- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The utility model belongs to the technical field of geotechnical engineering, especially, relate to an effective grout length test system of stock. The anchor rod effective grouting length testing system comprises an anchor rod effective grouting length testing structure, and further comprises a digital oscilloscope, a post amplifier, a pre-amplifier and an acoustic wave sensor which are arranged outside a rock core, wherein the acoustic wave sensor is arranged at one end of the anchor rod, which is positioned outside a drilled hole, the acoustic wave sensor is connected with the pre-amplifier through a transmission cable, the pre-amplifier is connected with the post amplifier through the transmission cable, and the post amplifier is connected with the digital oscilloscope through the transmission cable. The utility model provides an effective grout length test system of stock can realize the effective grout length's of stock test effectively, conveniently, harmless, quantitatively, need not to carry out destructive test and expensive coring test to the stock, provides effective means for geotechnical engineering's the quality evaluation of strutting.
Description
Technical Field
The utility model belongs to the technical field of geotechnical engineering, especially, relate to an effective grout length test system of stock, be applicable to among the geotechnical engineering such as needs excavation cavern, side slope in fields such as water and electricity, mine, traffic.
Background
The anchor rod is widely applied to civil engineering such as tunnels, mines, slopes and the like, and the motion and deformation of rock and soil bodies are prevented by the anchor rod, so that the stability of the engineering is improved or maintained. The common practice of installing rock bolts is to insert the bolt into a pre-drilled hole and then grout the hole to bond the bolt to the surrounding rock mass, thereby providing reinforcement. However, during this process, the grouting material will flow outwardly due to gravity, forming a non-grouting bonding area at the front end of the bolt. Since the grouting transfers load by creating shear strength between the bolt and the rock, the grouting length is an important component of the stabilization of the bolt system, and the ultimate load of the bolt increases as the grouting length increases and as the grouting length decreases. Therefore, in order to ensure the stability of the construction, the grouting quality of the bolt needs to be evaluated.
The quality of bolt grouting is generally checked by drawing tests or coring tests, but both methods are destructive, time-consuming and expensive, and the quality of the check is difficult to determine completely, and both methods are gradually replaced by non-destructive testing methods in engineering practice. The acoustic wave method is a nondestructive testing method for anchor rod anchoring quality which is generally adopted in the engineering geophysical prospecting field at present. Some theoretical research work has been done on the quality of the anchor rod anchoring by electromagnetic wave method, but it has not been carried out yet. The theoretical basis for detecting the quality of the anchor rod by the sound wave method is the kinematic characteristic of wave propagation in the rod, and the concrete method is that a transient state exciting force is applied to the top end of the anchor rod, a sensor arranged at the top end of the anchor rod receives a reflection signal, and time domain and frequency domain analysis is carried out on the received reflection signal to obtain parameters such as effective anchoring length, mortar saturation, working load, ultimate bearing capacity and the like of the anchor rod, and the anchoring quality of the anchor rod is evaluated according to the parameters. The detection conclusion is greatly influenced by human factors, so the accuracy is low, and the requirements of actual engineering are often difficult to meet, and therefore, the acoustic wave detection method needs to be further developed and perfected.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an effective grout length test system of stock to the not enough of existence among the prior art.
To this end, the above object of the present invention is achieved by the following technical solutions:
the utility model provides an effective grout length test system of stock which characterized in that: the anchor rod effective grouting length testing system comprises an anchor rod effective grouting length testing structure, a digital oscilloscope, a post amplifier, a pre-amplifier and an acoustic wave sensor, wherein the digital oscilloscope, the post amplifier, the pre-amplifier and the acoustic wave sensor are arranged outside a rock core; the effective grouting length testing structure of the anchor rod comprises a core, a drill hole is drilled in the core, the anchor rod is arranged in the drill hole, and grouting bodies are filled between the anchor rod and the drill hole.
When adopting above-mentioned technical scheme, the utility model discloses can also adopt or make up and adopt following technical scheme:
as the utility model discloses a preferred technical scheme: the length of the grout body is 40% or 60%, 80% or 100% of the total length of the anchor rod.
As the utility model discloses a preferred technical scheme: the length of the anchor rod is 2-4 m, and the diameter of the anchor rod is 20-30 mm; the inner diameter of the drill hole in the rock core is 30-40 mm.
The utility model provides an effective grout length test system of stock can realize the effective grout length's of stock test effectively, conveniently, harmless, quantitatively, need not to carry out destructive test and expensive coring test to the stock, provides effective means for geotechnical engineering's the quality evaluation of strutting.
Drawings
Fig. 1 is a diagram of the anchor rod effective grouting length testing system provided by the present invention.
Detailed Description
The invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The anchor rod effective grouting length testing system comprises an anchor rod effective grouting length testing structure, and further comprises a digital oscilloscope 101, a post amplifier 102, a pre-amplifier 103 and an acoustic wave sensor 104 which are arranged outside a rock core 201, wherein the acoustic wave sensor 104 is arranged at one end of an anchor rod 203, which is positioned outside a drill hole 202, the acoustic wave sensor 104 is connected with the pre-amplifier 103 through a transmission cable, the pre-amplifier 103 is connected with the post-amplifier 102 through the transmission cable, and the post-amplifier 102 is connected with the digital oscilloscope 101 through the transmission cable.
The effective grouting length test structure of the anchor rod comprises a core 201, a drill hole 202 is drilled in the core 201, an anchor rod 203 is arranged in the drill hole 202, a grouting body 204 is filled between the anchor rod 203 and the drill hole 202, and the length of the grouting body 204 is 40% or 60% or 80% or 100% of the total length of the anchor rod 203.
The length of the anchor rod 203 is 2-4 m, and the diameter is 20-30 mm; the inner diameter of a drill hole 202 in the core 201 is 30-40 mm.
The effective grouting length test system of the anchor rod is tested in the following mode:
(1) excitation signal
Hammering is used as a seismic source to generate energetic sound waves which propagate along the anchor and reflect off the end of the anchor and can be detected by a sound wave sensor, a pre-amplifier and a post-amplifier, wherein the pre-amplifier amplifies the initial signal by converting the microvolt signal of the sound wave sensor to a higher volt signal and a filtered signal, thereby providing a high signal-to-noise ratio. The preamplifier may also match the high impedance of the acoustic wave sensor to the low impedance of the signal cable. The post-amplifier, also known as a power amplifier, can provide voltage gain for the acoustic signals.
(2) Grouting saturation test
The core that utilizes the scene to take back is drilled, and the aperture of drilling is the same with the grout external diameter, is 35mm, and the core diameter is 50mm, and the diameter and the length of anchor rod are 25mm and 3.0 m.
The grouting ratio is 40%, 60%, 80% and 100%, and the grouting length is the effective grouting length. The grouting ratio is the ratio of the length of the grouting body to the overall length of the anchor rod.
High-energy sound waves are generated by adopting a hammering method. Although both the grout and the core may affect the leakage of the acoustic wave propagation, the measured signal has higher amplitude and lower attenuation compared to the non-embedded bolt signal, and thus, the test effect can be guaranteed.
(4) Analysis of results
Recording the sound wave speed under the conditions of 40%, 60%, 80% and 100% grouting ratio, carrying out the same sound wave test in field practice, and comparing the wave speed with the wave speed under the different grouting ratio conditions to obtain the actual corresponding effective grouting length on the field.
The above-mentioned embodiments are only for explaining the preferred embodiments of the present invention, and not for limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made by the present invention fall within the protection scope of the present invention within the spirit and the protection scope of the claims.
Claims (3)
1. The utility model provides an effective grout length test system of stock which characterized in that: the anchor rod effective grouting length testing system comprises an anchor rod effective grouting length testing structure, a digital oscilloscope, a post amplifier, a pre-amplifier and an acoustic wave sensor, wherein the digital oscilloscope, the post amplifier, the pre-amplifier and the acoustic wave sensor are arranged outside a rock core; the effective grouting length testing structure of the anchor rod comprises a core, a drill hole is drilled in the core, the anchor rod is arranged in the drill hole, and grouting bodies are filled between the anchor rod and the drill hole.
2. The anchor rod effective grouting length testing system of claim 1, wherein: the length of the grouting body is 40% or 60% or 80% or 100% of the total length of the anchor rod.
3. The anchor rod effective grouting length testing system of claim 1, wherein: the length of the anchor rod is 2-4 m, and the diameter of the anchor rod is 20-30 mm; the inner diameter of the drill hole in the rock core is 30-40 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020188932.4U CN211783355U (en) | 2020-02-20 | 2020-02-20 | Effective grouting length test system for anchor rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020188932.4U CN211783355U (en) | 2020-02-20 | 2020-02-20 | Effective grouting length test system for anchor rod |
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| CN211783355U true CN211783355U (en) | 2020-10-27 |
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| CN202020188932.4U Active CN211783355U (en) | 2020-02-20 | 2020-02-20 | Effective grouting length test system for anchor rod |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113567551A (en) * | 2021-07-26 | 2021-10-29 | 广西电网有限责任公司玉林供电局 | Grouting compactness testing method based on reflection characteristic |
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2020
- 2020-02-20 CN CN202020188932.4U patent/CN211783355U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113567551A (en) * | 2021-07-26 | 2021-10-29 | 广西电网有限责任公司玉林供电局 | Grouting compactness testing method based on reflection characteristic |
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