JPH01284740A - Various evaluating methods for anchor test - Google Patents

Abstract

PURPOSE:To perform various evaluation quantitatively by measuring acoustic emission (AE) while carrying out loading and unloading in a single or plural cycles. CONSTITUTION:An AE meter device consists of an AE sensor 12, amplifier (AMP), filter (LPF, HPF), counter, oscilloscope, data recorder, CPU, printer, and a power unit. When an anchor is tested, the tension material of the anchor is loaded and when strain energy is released from an anchor body, a tendon, the ground, etc., and propagated as a sound, the acoustic emission which is inputted through an anchor head part and a rod is detected by a sensor and the output which is larger than a specific level, i.e., threshold value is counted as a pulse. Necessary various evaluation is performed based upon those materials.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention provides basic information on the design and construction of ground anchors such as temporary anchors and permanent anchors built in the ground to connect structures and the ground. Various anchor tests such as tests, aptitude tests, confirmation tests, special tests, etc. are required to be conducted, but when evaluating these anchor tests, acoustic emission measurements are also used. The aim is to provide a more accurate quantitative evaluation method. This evaluation method applies to all anchor construction methods, such as anchorages for mountain restraints, landslide prevention piles, lattice frames, underground structures, steel towers, underground structures, offshore structures, suspension structures such as fishing bridges, and structures on sloped sites. It is ideal for use as anchorage anchors when making things, as reaction force anchors during loading tests and unusual caisson installations, and for large-scale excavation work.

"Prior Art" In Japan, since the "Earth Anchor Design and Construction Standards" were established in September 1976, pull-out tests, tension tests, aptitude tests, etc. have been conducted in accordance with the standards to determine the specifications of anchors. Evaluation methods, such as how to organize and judge test results, are often based on these standards. Furthermore, it is carried out according to standards that are almost the same in other countries. The conventional anchor test will be described below.

The pull-out test is performed at a pre-calculated ultimate pull-out force of 0.2
Loading and unloading are repeated in five stages at double intervals, and loading is carried out until the anchor is pulled out or reaches 90% of the yield stress of the tensile material.The ultimate pullout force is determined by −The displacement curve has been completely extended (
The tension force at the point where the amount of displacement increases rapidly under the same load is the ultimate pulling force. In addition, if the ultimate pulling force cannot be determined from the test results, the maximum load at that time shall be the designed ultimate pulling force.

In the tensile test, the planned maximum load is 1.2 to 1.3 times that of the design anchor, and loading and unloading are repeated in five stages at intervals of 0.2 times that force. The loading speed during loading and unloading is kept as constant as possible, and the same load is maintained for a sufficient period of time at each virgin load. For example, it may take 5 minutes for sandy ground and 10 minutes for clay ground.

In the confirmation test, the anchor is loaded once with a tension force of 0.1 to 0°2 times that of the design anchor. At maximum load, maintain the same load for a sufficient period of time.

Judgment of pass/fail through the confirmation test is made by comparing it with the load-displacement relationship of the anchor certified in the tensile test, and the elongation properties must not essentially deviate from the tensile test results.

In other words, quality control is generally performed using projections based on the relationship between displacement (elastic displacement, compositional displacement) and load, and the design section includes specific information necessary to calculate the pull-out resistance. No formulas or constants are shown. This indicates that a method for quantitatively evaluating these has not yet been established.

``Problems to be solved by the invention'' An earth anchor is defined as ``an integrated anchor is made at the tip of a tensile member that is embedded in the ground by injecting cement paste or cement mortar, and it connects the tensile member with the anchor head. The force applied to the tensile member of the anchor, which is mechanically connected to the structure through the anchor, is transmitted into the ground from the anchor itself.'' Therefore, designing an anchor means arranging the anchors appropriately against the external force applied to the structure, selecting the force applied to each anchor (design anchor force), and ensuring sufficient safety against the design anchor force. Therefore, it is necessary to design an integrated anchor that has both the same height and the displacement as small as possible.

The anchor-integrated design must satisfy all of the following conditions:

■ The design anchor force of the anchor must have a predetermined safety factor with respect to the ultimate pullout force.

■ The design anchor force of the anchor must have a predetermined safety factor relative to the tensile strength of the tensile material.

■ The degree of adhesion stress between the anchor tensile material and the injection material or the bearing stress for the injection material must be below the respective allowable stress levels.

■ The displacement of the anchor head when a tensile force up to the design anchor force is applied to the anchor is close to within the elastic range.

Therefore, the design of the anchor integral can be broadly divided into the design of the anchor integral and the design of the anchor tension member for the required ultimate pullout force. Among these, items ■ and ■ related to the design of anchor tensile materials are mainly determined by conditions other than the ground, such as breakage of the tensile material or the adhesion strength between the tensile material and the injection material, and This can be said to be a problem that can be fully resolved through selection and quality control of injection agents. However, the items ■ and ■ regarding the design of the anchor unit against the ultimate pull-out force are mainly determined by the force required for failure when failure occurs due to ground conditions, and are determined by the strength of the attachment between the anchor unit and the ground, and the It is greatly influenced by the strength of the shear resistance, the construction method, etc., and there are many variations, and design calculations are considered to be only a guideline, and it has not been possible to quantitatively evaluate this. In other words, the design of an integrated anchor for ultimate pulling force is: (a) Complex changes in the ground are difficult to predict, and a calculation method has not yet been established.

Ex) The pulling force varies greatly depending on the construction method and skill of the construction technology.

Problems such as these remain, and the current situation is that a complete design can only be completed after the ultimate bearing capacity has been confirmed through a pull-out test.

The purpose of testing the earth anchor is to test whether the installed anchor has satisfactory performance through tests that meet the respective design conditions, and then to send it out as a finished product. In other words, first, it is determined whether the anchor construction has satisfied the performance predicted at the time of design, and if it is insufficient, countermeasures such as reinforcement are taken in advance.
The purpose is to safely anchor the target structure to the ground. Therefore, it is desirable to develop an appropriate quality control method using a non-destructive testing method for anchor testing. Through our experience in pulling out numerous anchors, we have experienced that the majority of poor-quality anchors are largely affected by ground conditions, such as lifting of the anchor and cracks in the surrounding ground. There was a desire to develop a method that could accurately measure the frictional strength between the unit and the ground, as well as the frictional strength unique to the ground. However, with conventional anchor testing methods, in addition to the complexity of on-site work, it is difficult to elucidate the failure mechanism (frictional resistance failure between the anchor unit and the ground, or shear failure of the ground) for poor-quality anchor units. It was difficult.

The present inventors have researched and developed a new anchor test evaluation method that overcomes the above-mentioned technical problems and satisfies the requirements.The inventors have focused on the following: In recent years, attempts have been made to apply a technology called AE to various fields as a non-destructive test for structural members and the like. AE is a phenomenon in which an object deforms under external force, and in the process leading to destruction, strain energy is released and propagates as sound. Since this is detected at a stage before the main destruction of structural members, etc., attempts have been made to apply it to various fields as a non-destructive test for the purpose of detecting defects and diagnosing the degree of soundness. Therefore, field AE
This paper uses a measuring device to measure AE during a pull-out test of an anchor unit, and proposes a quantitative evaluation method for quality control (test method) of the anchor unit and specifications for anchor strength design. That is, firstly, the various evaluation methods of the anchor test according to the present invention embody a non-destructive inspection method for anchor quality control. This is intended to enable a clear understanding of the causes.

Second, by using various evaluation methods for anchor tests according to the present invention, a quantitative evaluation method for design values related to the ground and injection materials necessary for anchor strength design is established.

"Means for solving the problems" The present invention is configured as follows as means for solving the problems.

The first invention to be patented measures acoustic emission (hereinafter referred to as AE) in an anchor test of a ground anchor, and
The load-displacement amount is measured, and the AE emission characteristics and the load-displacement amount are measured.
This is a variety of evaluation methods for anchor tests characterized by evaluating basic tests, aptitude tests, confirmation tests, special tests, etc. by looking at the correlation with displacement characteristics.

Here, the ground anchor is a general term for temporary anchors and permanent anchors.

Therefore, not only conventional earth anchors but also rock anchors are included in the scope of the present invention.

Anchor exams are basic exams, aptitude exams,
This includes all confirmation tests and special tests. Therefore, for anchor testing, the "Earth Anchor Design and Construction Standards" must be used.
It also includes pull-out tests, tensile tests, confirmation tests, and special tests.

The basic test refers to a test conducted to understand the ultimate pullout force of the anchor against the ground and its behavior, and to determine the predetermined number of anchors to be used in the design of the anchor.

The suitability test refers to a test in which a load is repeatedly applied to the anchor actually used to confirm whether the design and construction of the anchor are appropriate based on the load-displacement characteristics.

A confirmation test is a test conducted to confirm that the anchor actually used is safe against the design anchor force.

Special tests refer to tests conducted for anchors used for special purposes or under special conditions, as necessary, to understand the behavior of the anchor and confirm its safety.

The second invention for which a patent is sought is to measure the load-retroactive displacement amount in the anchor test of the ground anchor, measure AE, and calculate the count value of AE in the correlation with the load-retroactive displacement amount. This is an anchor test evaluation method characterized by quantitatively evaluating the yield pull-out force of the anchor against the ground (rupture starting point) using the initial surge point.

The third invention to be patented is to measure the load-retroactive displacement amount in the ground anchor anchor test, measure AE, and calculate the counted value of AE in correlation with the load-retroactive displacement amount characteristic. This is an anchor test evaluation method characterized by quantitatively evaluating the yield point of the anchor's ultimate pull-out force against the ground by looking at the point of rapid increase in the value and the subsequent continuous high activity state.

The fourth invention to be patented is to measure the load-displacement amount on the anchor head and the ground or rock surface in the anchor test of the ground anchor, and measure their AE, and calculate the load-displacement characteristics. This evaluation method for anchor tests is characterized in that the soundness of the ground or rock mass to be constructed is evaluated by looking at the activity of AE emission in the correlation between

The fifth invention for which a patent is sought is to measure the load-elastic displacement amount and AE in the ground anchor anchor test, and to detect an initial rapid increase in the count value of AE in the correlation with the load-elastic displacement amount. This is an anchor test evaluation method characterized by quantitatively evaluating the yield load (fracture starting point) of the tendons using points.

The sixth invention for which a patent is sought is to measure the load-elastic displacement amount and AE in the ground anchor anchor test, and to determine the point at which the AE count increases sharply in the correlation with the load-elastic displacement amount. This anchor test evaluation method is characterized in that the yield point of the ultimate load of the tendons is quantitatively evaluated by looking at the subsequent continuous high activity conditions.

The seventh invention for which a patent is being sought is that, in ground anchor aptitude tests, loading and unloading of a predetermined planned maximum test load is repeated on the actually used anchor, and the load is -
It is characterized by measuring the amount of displacement, measuring AE, and looking at the correlation between the AE emission characteristics and the load-displacement characteristics to quantitatively evaluate safety against the design load. This is an evaluation method of anchor test.

The eighth invention for which a patent is being sought is to measure the load-displacement amount while repeatedly loading and unloading a predetermined planned maximum test load on the actually used anchor during a ground anchor confirmation test, and to measure the AE during that time. Measure AE
The present invention is characterized in that the correlation between the release characteristics and the load-displacement characteristics is compared with the results of the suitability test according to claim 7 to quantitatively evaluate safety against the design load. This is an evaluation method of anchor test.

The ninth invention to be patented is that in a permanent anchor deterioration diagnostic test, the load-displacement amount is measured while repeating loading and unloading of the planned maximum test load on the permanent anchor actually in use. Measure the AE and compare the correlation between the AE emission characteristics and the load-displacement characteristics with the results of the suitability test of claim 7 to diagnose the deterioration of the permanent anchor and quantify the safety against the design load. This is an anchor test evaluation method that is characterized by a

The 10th invention for which a patent is sought is, in a special test of a ground anchor, when the anchor is used for a special purpose or under special conditions, the ground anchor is tested in a state in which it will be used, or in a state close to it, prior to design. In, A
This is an anchor test evaluation method characterized by measuring E and load-displacement, and evaluating the special test by looking at the correlation between the AE emission characteristics and the load-displacement characteristics. .

"Embodiments" The present invention will be described in detail below based on illustrated embodiments.

The present invention measures AE as well as load-displacement in an anchor test of a ground anchor,
This is a variety of evaluation methods for anchor tests, characterized in that basic tests, aptitude tests, confirmation tests, special tests, etc. are evaluated based on the correlation between the AE emission characteristics and the load-displacement characteristics.

Example 1 Figure 1 is a schematic diagram during an anchor test. Steel is placed on a concrete loading platform to obtain zero reaction force, and noise is absorbed between the steel, seat plate, and center hole jack to eliminate acoustic noise. It is preferable to insert the material, and use a dial gauge on the anchor head and the ground surface to measure changes in the anchor body and the ground, or a differential transformer type displacement meter to continuously observe the amount of displacement. . The force applying device uses a manual pump, electric pump, and pressure accumulator.

In addition, the anchor test in this invention is a basic test (pulling test), an aptitude test (pulling test), a confirmation test, and a special test.

In the pullout test, loading and unloading are repeated in five stages at intervals of 0.2 times the ultimate pullout force calculated in advance, until the anchor is pulled out or the yield stress of the tensile material is reached. Load until it reaches 90%.

In the tensile test, the planned maximum load is 1.2 to 1.3 times the load of the set anchor, and 5
Loading and unloading are repeated in stages, the loading speed during loading and unloading is kept as constant as possible, and the same load is maintained for a sufficient period of time for each virgin load.

In the confirmation test, a tension force of 1.0 to 1.2 times the design anchor was loaded once. At maximum load, hold the same load for a sufficient period of time.

FIG. 2 is a block diagram of the AE measuring device.

The AE sensor uses an acceleration sensor with a resonance frequency of 30 kHz. The input signal is passed through an amplifier (30~80d
After being amplified by a low-pass filter (L, P, F,), the low frequency range (30 Hz to 20
0H2), and bypass filters (H, P, F,
) is separated into a high frequency range (300Hz to 10kHz), each is compared with an arbitrary set voltage value (threshold value), and if the signal is larger than the threshold value, the count circuit
It is counted. This count value is output to the printer at arbitrary time intervals.The main unit is powered by a battery. An oscilloscope and data recorder are used to observe the AE signals emitted during testing and to analyze the signals after the experiment.

To install the sensor during testing, either attach the magnetic AE sensor directly to the tension material, or attach a wave rod to the tension material and fix the sensor there. If the tensile material is a light beam, the jacking or tightening should be done directly to the metal fittings. For the purpose of detecting ground failure, iron rods (50 cm to 2
m) and fix the sensor on its head. In the case of group anchors, methods such as fixing sensors to the heads of adjacent anchors are used.

Acoustic emissions (A
E) is detected by a sensor, and the output above a predetermined level, that is, above the threshold value, is counted as a pulse. The number of pulses obtained every 10 seconds is accumulated over the elapsed test time. The yield pullout force or the ultimate pullout force is evaluated at the point where the cumulative amount of pulses increases rapidly. In addition, the evaluation diagram (ΣAE-P/
P,) is created, and if there is a sharp increase point in the cumulative amount of AE in the design anchor test, the quality of the anchor is poor, and if there is no rapid increase point, the soundness of the anchor is of good quality, etc. is evaluated.

Example 2゜ Figure 3 is a schematic diagram of anchor A installed in the ground.

Deformed reinforcing bolts are used as tension members. Figure 3 (
A) shows the load-displacement curve. FIG. 4 shows the load-displacement curve of the final loading stage and the number of pulses of AE every 10 seconds and the cumulative amount of pulse number. At the inflection point of the load-displacement curve and the part where the displacement increases rapidly, the number of AE pulses per 10 seconds and the cumulative amount show a rapid increase, indicating that AE has a good correlation with the deformation behavior of the load-displacement curve. show. If we focus on the cumulative amount, we can uniquely determine the point of rapid increase, and this point coincides with the displacement point on the load-displacement curve. FIG. 5 shows the elapsed test time and load during the pull-out test, the number of pulses every 10 seconds, and the cumulative amount of the number of pulses. There is a sharp increase point in the pulse cumulative amount, and this point corresponds to an inflection point of the load-displacement curve. The inflection point of the load-displacement curve or the rapid increase in displacement can be considered as the yield point or failure point of the anchor, indicating that highly accurate evaluation by AE is possible. In addition, when cracks are observed on the ground surface during the initial stage of loading, the fact that the increase in the number of pulses every 10 seconds is closely related, and AE can be used to evaluate the onset of ground failure with higher precision. be able to.

Figures 6(a) and 6(b) show the results of a pullout test for anchor B installed on the same type of ground. Similarly, the rapid increase point of the AE pulse can be uniquely determined. The reason why there is only one sharp increase point depends on the loading speed.

FIGS. 7 and 8 show the relationship between the cumulative amount of AE and the load at each loading stage for each anchor. Similarly, a sharp increase point can be uniquely determined.

Embodiment 3 FIG. 9 shows a schematic diagram of anchors C and D installed in bedrock. Deformed reinforcing bolts are used as tension members. 9th
Figure (a) shows the load-displacement curve during the test. Figure 10,
FIG. 11 shows the test elapsed time and load for anchors C and D during the confirmation test, the number of pulses every 10 seconds, and the cumulative amount of the number of pulses. At the same load level, the number of pulses per 10 seconds and the cumulative amount of pulses are larger for anchor C than for anchor D. Figure 12 shows the anchor head and displacement on the ground surface at each loading stage. Compared to anchor D, where the maximum displacement is observed on the anchor head and the displacement tends to increase symmetrically, the maximum displacement of anchor C is observed on the ground surface, and the amount of displacement is large. This unique rock deformation behavior is thought to be due to latent cracks observed near the borehole wall of Anchor C during drilling, and is closely related to the increase in the number of AE pulses. . This shows that it is possible to evaluate the soundness of the ground and rock where the anchor is constructed using AE. Figure 13 shows the cumulative amount of AE and the load (P) during the test, as well as the design load (Pa
), there is no sharp increase in the cumulative amount of AE for both anchors C and D below the design anchor, and the anchors as a whole are judged to be good.

Embodiment 4 FIG. 14 shows a schematic diagram of anchors E and F with long tension portions installed on bedrock. The tensile material used is PC steel stranded wire. Figures 15 and 16 show load-displacement curves for anchors E and F during a pullout test. Figure 17, 1st
Figure 8 shows the elapsed test time, the load, the number of pulses every 10 seconds, and the cumulative amount of the number of pulses. The AE signal is observed from the beginning of loading. The activity level is particularly high after the second loading step. This corresponds to an increase in the amount of deformation in the load-displacement curve. FIGS. 19 and 20 show the relationship between the load of each loading step and the cumulative amount of AE. In the second loading step, there is a sharp increase point in the cumulative amount. This fact is considered to indicate that the anchor body is undergoing destruction, and it is considered desirable to evaluate the anchor strength from this point.

Embodiment 5 FIG. 21 shows a schematic diagram of an anchor G installed in a bedrock. The tensile material is deformed reinforcing bolts.

Figure 22 shows the load-displacement curve during the test.

Generally, two patterns of anchor breaking mechanisms are known as shown in the figure.

In case (a), the load-displacement curve is relatively gentle, and the time elapsed from local failure to total failure is somewhat long. General nuki is a rising phenomenon.

In (b), the load-displacement curve is relatively steep, and the time elapsed from local failure to complete failure is a rather short one, which is a failure phenomenon.

In this test, the failure mode (b) was observed, indicating failure at the attachment surface between the mortar and the rock. Figure 21 shows the load, the number of AE pulses per 10 seconds, and the cumulative amount. AE pulses are measured from low load levels, and a rapid increase in the number of pulses is observed at the point where the displacement increases rapidly. Figure 22 shows the cumulative amount of AE and P
/ PO shows the relationship. The sharp increase point of AE exists before the design anchor force, and this anchor is determined to be of poor quality.

"Effects of the Invention" The present invention measures acoustic emissions as well as load-displacement in an anchor test of a ground anchor, and from the correlation between the AE emission characteristics and the load-displacement characteristics, This allows various evaluations such as basic tests, aptitude tests, confirmation tests, special tests, etc., which are called anchor tests, to be made quantitative.

Therefore, unlike predictions or calculations, various actual evaluations can be quantitatively measured, eliminating errors caused by calculations, dramatically improving accuracy, and making it possible to identify yield points.

In particular, if the AE method is used in conjunction with the design of anchors that have a strong empirical element and the judgment of various tests, and if we focus on the point where the cumulative amount of AE increases rapidly, it is possible to uniquely pull out the yield (rupture starting point) regardless of the type of anchor. You can determine the power. In addition, if you create an evaluation diagram based on the AE data obtained from the pull-out test, you can more easily conduct the confirmation test to find good-quality anchors (there is no sharp increase in AE below the design load), poor-quality anchors (no sharp increase in AE below the design load), The presence of a sharp increase point in AE can be determined as follows. Furthermore, the soundness of the ground or rock can be simultaneously evaluated based on this evaluation diagram.

The present invention measures acoustic emissions in anchor tests of ground anchors and evaluates their AE.
Since various evaluations can now be made quantitatively based on release characteristics, it has become possible to implement a non-destructive testing method for anchor quality control.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram during the anchor test, and Figure 2 is a schematic diagram of the anchor test.
This is a block diagram of the AE measuring device, Figure 3 is a schematic diagram of anchor A installed in the ground, Figure 3 (A) is the load-displacement curve of Figure 3, and Figure 4 is a diagram of the anchor A installed in the ground. , Figure 4 shows the load-displacement curve at the final loading stage,
Figure 5 shows the number of AE pulses every 10 seconds and the cumulative amount of the number of pulses. , Figures 6(a) and 6(b) show the results of the pullout test for anchor B installed on the same type of ground, and Figures 7 and 8 show the cumulative amount of AE and load at each loading stage for each anchor. Figure 9 is a schematic diagram of anchor C9D installed in bedrock. Figure 9 (a) is the load-displacement curve during the test.
The figure shows the test elapsed time and load of anchor C1D during the confirmation test, the number of pulses every 10 seconds, and the cumulative amount of the number of pulses. Figure 12 shows the displacement of the anchor head and ground surface at each loading stage. Figure 13 shows the relationship between the cumulative amount of AE and the test load (P) normalized by the design load (Po). , F are schematic diagrams, and Figures 15 and 16 show the load-displacement curves during pull-out tests for anchors E and F. Figures 17 and 18 show the elapsed test time and load, and the curves for each 10 seconds. Figures 19 and 20 show the relationship between the load of each loading step and the cumulative amount of AE, and Figure 21 shows the relationship between the load of each loading step and the cumulative amount of AE. A schematic diagram is shown, and Fig. 22 shows a load-displacement curve during the test.

Claims (10)

[Claims] (1) In anchor tests of ground anchors, acoustic emissions (hereinafter referred to as AE) are measured, as well as load-displacement, and the correlation between the AE emission characteristics and load-displacement characteristics is determined. Various evaluation methods for anchor tests characterized by evaluating basic tests, aptitude tests, confirmation tests, special tests, etc. (2) In the ground anchor anchor test, the load-retroactive displacement is measured, and AE is also measured, and the anchor yields to the ground at the initial rapid increase point of the AE count in the correlation with the load-retroactive displacement. An anchor test evaluation method characterized by quantitatively evaluating the pull-out force (fracture starting point). (3) In the anchor test of the ground anchor, the load-retroactive displacement amount was measured, and AE was also measured, and the correlation with the load-retroactive displacement characteristic was found to indicate the point at which the AE count increased and the subsequent continuous An anchor test evaluation method characterized by quantitatively evaluating the yield point of the anchor's ultimate pullout force against the ground by looking at high activity conditions. (4) In anchor testing of ground anchors, the load-displacement amount on the anchor head and the ground or rock surface is measured, and their AEs are measured, and the activity of AE release is determined in correlation with the load-displacement characteristics. An anchor test evaluation method characterized by evaluating the soundness of the ground or rock mass on which the anchor is constructed. (5) In the ground anchor anchor test, the load-elastic displacement amount is measured, and AE is also measured, and the initial rapid increase point of the AE count value is determined by the correlation between the load and the elastic displacement amount. An anchor test evaluation method characterized by quantitatively evaluating points). (6) In the anchor test of the ground anchor, the load-elastic displacement amount is measured, and AE is also measured, and the correlation with the load-elastic displacement amount shows a rapid increase in the count value of AE and subsequent continuous high activity. An anchor test evaluation method characterized by quantitatively evaluating the yield point of the tendon's ultimate load based on the situation. (7) In the suitability test of ground anchors, while repeatedly loading and unloading a predetermined planned maximum test load on the actually used anchor, the load-displacement amount is measured, and the AE
An anchor test evaluation method characterized in that safety against a design load is quantitatively evaluated by measuring the AE emission characteristics and the correlation between the load-displacement characteristics. (8) In ground anchor confirmation tests, we repeatedly load and unload a predetermined planned maximum test load on the actual anchor, measure the load-displacement amount, and measure the AE during that time, and measure the AE emission characteristics and load. -Evaluation of an anchor test characterized in that safety against a design load is quantitatively evaluated by comparing the correlation with displacement characteristics with the results of the suitability test according to claim 7. Law. (9) In a permanent anchor deterioration diagnostic test, the planned maximum test load is repeatedly applied and unloaded to the permanent anchor actually used, and the load-displacement amount is measured.
Measure the AE and compare the correlation between the AE emission characteristics and the load-displacement characteristics with the results of the suitability test of claim 7,
An anchor test evaluation method characterized by diagnosing permanent anchor deterioration and quantitatively evaluating safety against design loads. (10) In special tests of ground anchors, when the anchor is used for a special purpose or under special conditions, the amount of load-displacement is measured in the state in which it will be used or in a state close to it, prior to design. In addition, the anchor test is characterized by measuring AE and looking at the correlation between the AE emission characteristics and the load-displacement characteristics to quantitatively evaluate safety against the design load. Evaluation method.