JP2016217790A - Evaluation method for striking number of hydraulic hammer and investigation method for front natural ground using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability when investigating soil properties of a front natural ground by use of a hydraulic hammer.SOLUTION: In an evaluation method for striking number of a hydraulic hammer, firstly, a natural ground 32 is determined to be an object to be bored, the natural ground is bored by the hydraulic hammer 24, together with a water supply pressure to the hydraulic hammer measured by a water pressure gage 27 (101), elastic wave propagated in the natural ground 32 by operation of the hydraulic hammer 24 is measured by an acceleration sensor 30 (102), and a regression analysis with respect to the water supply pressure measured by the water pressure gage 27 and the striking number of the hydraulic hammer 24 measured by the acceleration sensor 30 is performed by a processing unit 31 so that a formula (1) is generated to obtain the striking number N corresponding to a given water supply pressure P (103).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating the number of hits of a hydraulic hammer applied when exploring the ground properties of a natural ground spreading in front of a face of a mountain tunnel, and a method for exploring a forward natural ground using the method.

  When excavating a mountain tunnel, grasping the nature of the natural ground spreading ahead of the face with appropriate and high accuracy is very important for efficiently and safely proceeding with the entire excavation work including supporting works and auxiliary works. is important.

  Drilling exploration by non-core drilling using a drill jumbo (percussion drilling machine) or non-core advanced boring machine (rotary percussion drilling machine) is known as a technology for forward exploration of tunnel face. Then, drilling exploration using a hydraulic hammer has been attempted (Patent Documents 1 and 2).

  The hydraulic hammer is applied to the drilling surface by reciprocating the built-in hammer piston with high-pressure water while acting the feed force and rotational torque transmitted from the boring machine via the drilling rod on the drilling surface. Compared to top hammer type drilling machines that are capable of applying striking force and have a striking force on the base end side of the drilling rod, energy loss at the joint between the drilling rods Therefore, the depth of drilling is large and the drilling speed is high.

  For this reason, it is expected that a hydraulic hammer will enable exploration of distant ground farther than before.

JP 2012-193592 A JP 2007-277940 A

  On the other hand, the drilling energy by the hydraulic hammer can be considered to be proportional to the water supply pressure and the number of hits, but the hydraulic hammer is a so-called down-the-hole hammer of the tip hitting type, and the number of hits increases as the drilling depth increases. Since measurement becomes difficult, the water flow rate is used in place of the number of hits when performing forward exploration with a hydraulic hammer (Patent Document 2).

  However, if the hydraulic hammer is not subjected to a reaction force of a certain amount from the drilling surface, the hammering will not start, and in soft ground, the reaction force may not be obtained and the hammering may not be performed. Even when the operation is not performed, water is discharged from the tip of the bit due to the structure.

  Therefore, there is a limit in estimating the number of hits from the water supply flow rate, and the above evaluation method based on the assumption that the water supply flow rate and the number of hits are proportional is not accurate enough to perform a highly reliable forward exploration. The problem was difficult.

  The present invention has been made in consideration of the above-described circumstances, and a hydraulic hammer hitting number evaluation method capable of improving the reliability when exploring the ground properties of a forward ground using a hydraulic hammer and the same It aims at providing the exploration method of the front ground mountain using the.

In order to achieve the above object, according to the method for evaluating the number of hits of a hydraulic hammer according to the present invention, as described in claim 1, the water supply pressure to the hydraulic hammer is adjusted while drilling a predetermined drilling object with the hydraulic hammer. In addition to measuring a plurality of physical quantities that vary in response to the operation of the hydraulic hammer and corresponding to the number of strikes, each physical quantity measuring means,
Using each physical quantity, specify the number of hammer hits for each water supply pressure,
A calculation formula for determining the number of hits N corresponding to an arbitrary water supply pressure P by performing regression analysis of the water supply pressure and the number of hits composed of a plurality of sets,
N = f (P) (1)
Is to create.

  Further, in the hydraulic hammer hitting number evaluation method according to the present invention, the physical quantity is an elastic wave propagating from the hydraulic hammer toward the exposed surface of the drilling object, and the physical quantity measuring means detects the elastic wave. Thus, the acceleration sensor is installed on the exposed surface.

  Also, in the method for evaluating the number of hits of a hydraulic hammer according to the present invention, the physical quantity is a fluctuation component of the water supply pressure to the hydraulic hammer, and the physical quantity measuring means is a hydrometer of a high-pressure pump connected to the hydraulic hammer. It is.

  Further, in the hydraulic hammer hitting number evaluation method according to the present invention, the physical quantity is a fluctuation component of a circumferential strain in a high-pressure hose extending from the hydraulic hammer to a high-pressure pump, and the physical quantity measuring means is a fluctuation component of the circumferential strain. The strain gauge is attached to the high-pressure hose so as to be detected.

  In the hydraulic hammer hitting number evaluation method according to the present invention, the regression analysis is performed using the degree of wear of the hydraulic hammer as a parameter.

Further, according to the method for exploring the front ground according to the present invention, a hydraulic hammer is attached to the tip of a drilling rod attached to a boring machine, and the hydraulic hammer is placed in front of an exposed surface such as a face. In the exploration method of the front ground where the ground property of the front ground is explored by drilling a spreading ground,
Measure the water supply pressure to the water pressure hammer to make the water supply pressure P,
By applying the water supply pressure to the formula (1) created by the hydraulic hammer impact number evaluation method according to any one of claims 1 to 5, the impact number N corresponding to the water supply pressure P is obtained,
The magnitude of the drilling energy by the hydraulic hammer is defined as an energy index value M, and the energy index value is expressed by the following formula using the water supply pressure P and the hit number N:
M = P · N / V (2)
V: calculated from the drilling speed,
The ground property of the front ground is estimated using the energy index value M.

  Moreover, the exploration method of the front ground according to the present invention is the hydraulic hammer hitting number evaluation method according to claim 2, wherein the hydraulic hammer hitting number evaluation method according to any one of claims 1 to 5, The exposed surface of the object to be drilled is an exposed surface such as the face, and the elastic wave is an elastic wave generated when drilling a natural ground spreading immediately after the exposed surface such as the face.

  As described above, when evaluating the drilling energy by a hydraulic hammer, the method of estimating the number of hits from the water supply flow rate is insufficient in accuracy.

  When excavating a natural ground having a fragile part, the present applicant frequently observes a phenomenon in which the water supply pressure decreases at the crack location. In such a situation, the number of hits decreases due to the characteristics of the hydraulic hammer described above. Therefore, when research and development were conducted focusing on whether the number of hits could not be estimated from the water supply pressure, the present invention was made.

  That is, in the hydraulic hammer hitting number evaluation method according to the present invention, first, a plurality of water supply pressures to the hydraulic hammer are measured with different sizes while a predetermined drilling target is drilled with the hydraulic hammer.

  On the other hand, simultaneously with a plurality of measurements of the water supply pressure, physical quantities that vary in response to the operation of the hydraulic hammer and corresponding to the number of hits are measured by the physical quantity measuring means.

  Here, when high-pressure water is supplied to the hydraulic hammer, if the drilling target is of good quality, the hydraulic hammer receives a predetermined reaction force from the drilling target, so that the high-pressure water is supplied to the vibration mechanism of the hydraulic hammer. The vibration mechanism is caused to flow, but when the drilling object is crackable, for example, if the reaction force from the drilling object is insufficient, the high-pressure water does not flow to the vibration mechanism of the hydraulic hammer as it is. Water is discharged.

  For this reason, the water supply pressure is high when the water hammer is hit, and the water supply pressure is low when the water hammer is not being hit.

That is, since it can be considered that there is a predetermined correlation between the water supply pressure and the number of hits, the number of hits of the hydraulic hammer is specified for each water supply pressure using each measured physical quantity, An equation for calculating the number of blows N corresponding to an arbitrary water feed pressure P by performing regression analysis of the water feed pressure and the number of blows consisting of
N = f (P) (1)
Create

  In this way, when performing forward exploration in tunnel excavation work, the number N of hits of the hydraulic hammer is appropriately estimated from the above equation (1) only by measuring the water supply pressure P when drilling with the hydraulic hammer. Thus, it becomes possible to search the front ground with much higher reliability than in the past, which used the water flow rate instead of the number of hits.

  The object to be drilled is not necessarily an actual natural ground, but may be a test specimen that is simulated so as to reproduce the state of the natural ground that would be encountered in tunnel excavation.

  As long as the water pressure for creating the equation (1) is measured in the same manner as the water pressure P when performing the forward exploration, the method and procedure thereof are arbitrary. For example, a water pressure gauge built in the high-pressure pump is used. It is possible to obtain an average value of peak values measured over a certain period of time.

  The physical quantity measured by the physical quantity measuring means varies in response to the operation of the hydraulic hammer and corresponds to the number of hits, and can be regarded as the number of hits as it is, and conversion and association are required. There are cases, but it is possible to determine or derive by experimentation which one of them and what kind of conversion or association is necessary in the latter case. What is necessary is just to specify the number of hits.

  As long as the physical quantity is as described above, an arbitrary quantity can be adopted, but a mechanical physical quantity such as a load, a stress or a corresponding displacement or strain is a typical example. It can be broadly divided into physical quantities in solid mechanics such as propagating elastic waves and vibrations of drive mechanisms connected to hydraulic hammers, and hydrodynamic physical quantities such as pressure fluctuations in high-pressure water. What is necessary is just to select a physical quantity measurement means suitably from a well-known technique for each.

In particular,
(a) The physical quantity is an elastic wave propagating from the hydraulic hammer toward the exposed surface of the drilling object, and the physical quantity measuring means is an acceleration sensor installed on the exposed surface so that the elastic wave is detected To
(b) The physical quantity is a fluctuation component of the water supply pressure to the hydraulic hammer, and the physical quantity measuring means is a hydrometer of a high-pressure pump connected to the hydraulic hammer.
(c) The physical quantity is a fluctuation component of circumferential strain in a high-pressure hose extending from the hydraulic hammer to the high-pressure pump, and the physical quantity measuring means is attached to the high-pressure hose so that the fluctuation component of circumferential strain is detected. A configuration such as a strain gauge can be employed.

  The number of hydraulic hammer hits using the measured physical quantity can be identified, for example, by performing a laboratory test and grasping the corresponding relationship. For example, in the configuration (a), The vibration frequency of the elastic wave can be regarded as the number of hits of the hydraulic hammer as it is, and in the configuration of (b), 1/2 of the fluctuation frequency in the measured water supply pressure can be set as the number of hits of the hydraulic hammer. In the configuration of (c), it is possible to regard the fluctuation frequency in the measured circumferential strain as it is as the number of hits by the hydraulic hammer.

  When performing regression analysis of water pressure and the number of hits consisting of multiple sets, it is desirable to take into account differences in the type and specifications of the hydraulic hammer, especially if the wear level of the hydraulic hammer is used as a parameter. In addition, it is possible to appropriately reflect the difference in the degree of wear due to the drilling time, in other words, the degree of wear according to the drilling results, and to further improve the accuracy of exploration of the front ground. .

In order to explore the front ground using the above-described method for evaluating the number of hammer hits, a hydraulic hammer is attached to the tip of a drilling rod attached to a boring machine, and the exposed surface such as a face is used with the hydraulic hammer. The ground pressure spreading forward is drilled, but when drilling the natural ground with a hydraulic hammer, the water supply pressure P to the hydraulic hammer is measured and the water supply pressure is applied to the above-described equation (1). Thus, the hitting number N corresponding to the water supply pressure P is obtained, and then the water supply pressure P and the hitting number N are calculated by the following equation:
M = P · N / V (2)
V: By applying to the drilling speed, an energy index value M, which is the magnitude of the drilling energy by the hydraulic hammer, is calculated, and then the ground property of the front ground is estimated using the energy index value M. Good.

  The procedure for creating the formula (1) can be selected as appropriate from the above-described configuration, but the exposed surface of the drilling object is an exposed surface such as a face and the elastic wave spreads immediately after the exposed surface such as the face. If the structure is created as an elastic wave generated when drilling a natural ground, the number of hits N is estimated using a regression analysis result based on data obtained from the natural ground where tunnel excavation is performed. Therefore, it is possible to search the forward ground with sufficient accuracy and high reliability.

The flowchart which showed the implementation procedure of the hit | damage number evaluation method of the hydraulic hammer which concerns on this embodiment, and the exploration method of a front ground using the same. It is the figure which showed the hydraulic hammer impact number evaluation system 21 for implementing the hydraulic hammer impact number evaluation method which concerns on this embodiment, (a) is a drilling machine used for it, (b) is a block diagram. The graph which showed a mode that the water supply pressure measured with the water pressure gauge 27 was plotted on the horizontal axis, the number of hits of the hydraulic hammer 24 measured by the acceleration sensor 30 was plotted on the vertical axis, and the regression analysis was performed. The graph which showed the procedure which calculates | requires the hit | damage number N with respect to arbitrary water supply pressures using the calculation formula (1) obtained by the regression analysis.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for evaluating the number of hammer hits and a method for exploring a front ground using the hammer according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing a procedure for evaluating the number of impacts of a hydraulic hammer according to the present embodiment and a method for exploring a front ground using the same, and FIG. 2 is a method for evaluating the number of impacts of a hydraulic hammer according to the present embodiment. It is a hydraulic hammer hit number evaluation system for carrying out.

As shown in FIG. 2 (a), the hydraulic hammer impact number evaluation system 21 includes a boring machine 22, a drilling rod 23 connected to the boring machine, and a hydraulic hammer 24 attached to the tip thereof. As shown in FIG. 2B, a hydraulic hammer 24, a high-pressure pump 26 connected to the hydraulic hammer, and a hydrometer 27 built in the high-pressure pump, The acceleration sensor 30 as a physical quantity measuring means attached to the face 29 that is the exposed surface of the natural ground 32 in the tunnel 28, and the arithmetic processing unit 31 that processes the measurement data output from the water pressure gauge 27 and the acceleration sensor 30. The arithmetic processing unit is configured to specify the number of vibrations measured by the acceleration sensor 30 as the number of hits of the hydraulic hammer 24, and the number of hits and the water pressure gauge And a pressure feed, which is measured by regression analysis at 7, calculation formula for determining the hit number N corresponding to any feed water pressure P,
N = f (P) (1)
Is supposed to create.

  In order to evaluate the number of hits of the hydraulic hammer using the method for evaluating the number of hits of the hydraulic hammer according to the present embodiment, first, as shown in FIG. While drilling at 24, a plurality of water supply pressures to the hydraulic hammer are measured with different sizes using the water pressure gauge 27 (step 101).

  On the other hand, along with a plurality of measurements of the water supply pressure by the water pressure gauge 27, elastic waves propagating in the natural ground 32 by the operation of the hydraulic hammer 24 are respectively measured by the acceleration sensor 30 (step 102).

  Here, the above-described elastic wave is a physical quantity that varies in response to the operation of the hydraulic hammer 24 and corresponding to the number of hits. In this embodiment, the vibration frequency is directly used as the number of hits of the hydraulic hammer 24. It is possible to specify.

  The measurement of the water supply pressure by the water pressure gauge 27 and the measurement of the elastic wave by the acceleration sensor 30 are performed at a drilling depth such that the elastic wave can be measured with a sufficient S / N ratio, for example, a natural ground 32 immediately after the face 29. It is better to do it.

Next, a calculation to obtain the number N of impacts corresponding to an arbitrary water supply pressure P by performing regression analysis on the water supply pressure and the number of impacts measured by the water pressure gauge 27 and the acceleration sensor 30 with the arithmetic processing unit 31. formula,
N = f (P) (1)
Is created (step 103).

FIG. 3 is a plot of measured values with the water supply pressure and the number of hits being plotted on the horizontal axis and the vertical axis, respectively, for example, a linear function indicated by a straight line 41 in FIG.
N = aP + b (1 ′)
a, b; constants can be used as calculation formulas.

  Thus, if the calculation formula which calculates | requires the hit | damage number N of the hydraulic hammer 24 with respect to arbitrary water supply pressure P is created, this will be applied to the exploration method of a front ground, but in this embodiment, preparation of a calculation formula is carried out. In order to tunnel the excavated natural ground as it is, the exploration method of the forward natural ground is continuously performed on the same natural ground 32.

  That is, while drilling the natural ground 32 with the hydraulic hammer 24, the water pressure P to the hydraulic hammer is measured with the hydraulic pressure gauge 27 (step 104).

  Here, the water supply pressure P is measured by the same method as when the calculation formula (1) was created. Also, as for the hydraulic hammer 24, if the type, specification or years of use are different, the number of hits may be different even with the same water supply pressure. Is desirable.

  Next, the hitting number N of the hydraulic hammer 24 corresponding to the water pressure is obtained by applying the measured water pressure P to the equation (1) (step 105).

  FIG. 4 shows a procedure for obtaining the hit number N of the hydraulic hammer 24 against the water pressure by applying the water pressure P to the equation (1 ′) shown by the straight line 41 in FIG. In the example of the figure, when the measured value of the water supply pressure is 1400 MPa, the number of hits of the hydraulic hammer 24 is 45 Hz.

Next, the magnitude of the drilling energy by the hydraulic hammer is defined as an energy index value M, and the energy index value is expressed by
M = P · N / V (2)
V: Drilling speed
(Step 106), and the ground property of the front ground is estimated using the energy index value M (step 107).

  As described above, according to the hydraulic hammer hitting number evaluation method and the forward ground exploration method using the hydraulic hammer according to the present embodiment, when the forward exploration is performed in the excavation work of the tunnel 28, the cutting by the hydraulic hammer 24 is performed. By simply measuring the water supply pressure P at the time of drilling, it is possible to appropriately estimate the number of hits N of the hydraulic hammer from the above-described equation (1), and thus, conventionally, the water supply flow rate is used instead of the number of hits. However, it will be possible to conduct exploration of the front ground with extremely high reliability.

  Further, according to the forward ground exploration method according to the present embodiment, since the calculation formula (1) is created using the same ground 32 as the forward exploration target as a drilling target, actual tunnel excavation is performed. The number N of hits is estimated using the regression analysis result based on the data obtained in the natural ground, and thus it is possible to search the forward natural ground with higher accuracy.

  In the present embodiment, a calculation formula for determining the number of blows N corresponding to an arbitrary water supply pressure P is created using the natural ground where the tunnel 28 is constructed, that is, the natural ground 32 where the forward exploration is performed, as a drilling target. However, the calculation formula need not be the same as the ground where the forward exploration is performed, and it is not necessary that the ground is a ground. You may make it produce the above-mentioned calculation formula by making a test body into a drilling target object.

  In the present embodiment, the physical quantity of the present invention is an elastic wave propagating from the hydraulic hammer 24 toward the face 29 that is the exposed surface of the natural ground 32, and the physical quantity measuring means is also configured to detect the elastic wave. Although the acceleration sensor 30 is installed on the face 29, the physical quantity and the physical quantity measuring means for measuring the physical quantity are not limited to the combination described above.

  For example, the physical quantity of the present invention can be a fluctuation component of the water supply pressure to the hydraulic hammer 24, and the physical quantity measuring means can be the water pressure gauge 27 of the high-pressure pump 26 connected to the hydraulic hammer 24.

  In the case of the above modification, the fluctuation frequency of the water supply pressure and the number of hits of the hydraulic hammer 24 do not always match, so the hit timing of the hydraulic hammer 24 is confirmed by the acceleration sensor 30 as necessary. However, it is necessary to examine how the fluctuation of the water supply pressure is related to the timing of hitting the hydraulic hammer 24 and to determine the number of hits of the hydraulic hammer 24 after that.

  For example, if the water supply pressure fluctuates at a frequency twice that of the hammering timing of the hydraulic hammer 24, 1/2 of the fluctuation frequency of the water pressure may be specified as the number of hits of the hydraulic hammer 24.

  As another modification, the physical quantity of the present invention is used as a fluctuation component of circumferential strain in a high-pressure hose (not shown) extending from the hydraulic hammer 24 to the high-pressure pump 26, and the physical quantity measuring means is also used as the circumferential strain. It can be a strain gauge attached to the high pressure hose so that the fluctuating component is detected.

  Even in the case of the above-described modification, the variation frequency of the circumferential strain in the high-pressure hose does not always match the number of hits of the hydraulic hammer 24. Therefore, as in the above-described modification, the acceleration sensor 30 may be used as necessary. While checking the hammering timing of the hydraulic hammer 24, investigate how the fluctuation of the circumferential strain in the high pressure hose is related to the hammering timing of the hydraulic hammer 24, and then specify the number of hammering of the hydraulic hammer 24 The procedure to do is necessary.

  For example, if the circumferential strain of the high-pressure hose varies at the same frequency as the impact timing of the hydraulic hammer 24, the variation frequency of the circumferential strain in the high-pressure hose may be directly specified as the number of impacts of the hydraulic hammer 24. .

  In this embodiment, it is desirable to use a hydraulic hammer for forward exploration that has the same type, specifications, or years of use as the hydraulic hammer that created the calculation formula (1). When creating (1), if the type, specification or age of the hydraulic hammer is created as a parameter, it is sufficient to select the calculation formula corresponding to the hydraulic hammer used at the time of forward exploration. No restrictions on hydraulic hammers used for forward exploration.

  In particular, if the regression analysis for calculating the calculation formula (1) is performed with the wear level of the hydraulic hammer as a parameter, the usage time of each hydraulic hammer, in other words, the difference in the wear level depending on the drilling results. Can be appropriately reflected in the estimation of the number of hits, and the exploration accuracy of the front ground can be further improved.

22 Boring machine 23 Drilling rod 24 Hydraulic hammer 27 Water pressure gauge (physical quantity measuring means)
29 Face (exposed surface of drilling object)
30 Acceleration sensor (physical quantity measuring means)
32 Natural ground (drilling object)

Claims (7)

While measuring a plurality of water supply pressures to the hydraulic hammer while drilling a predetermined drilling object with a hydraulic hammer, a physical quantity that varies in response to the operation of the hydraulic hammer and corresponding to the number of hits Measure each with measuring means,
Using each physical quantity, specify the number of hammer hits for each water supply pressure,
A calculation formula for determining the number of hits N corresponding to an arbitrary water supply pressure P by performing regression analysis of the water supply pressure and the number of hits composed of a plurality of sets,
N = f (P) (1)
A method for evaluating the number of strokes of a hydraulic hammer, characterized in that: The physical quantity is an elastic wave propagating from the hydraulic hammer toward the exposed surface of the drilling object, and the physical quantity measuring means is an acceleration sensor installed on the exposed surface so that the elastic wave is detected. Item 2. The method for evaluating the number of hammer hits according to Item 1. The method for evaluating the number of hits of a hydraulic hammer according to claim 1, wherein the physical quantity is a fluctuation component of the water supply pressure to the hydraulic hammer, and the physical quantity measuring means is a hydraulic meter of a high-pressure pump connected to the hydraulic hammer. The physical quantity is a fluctuation component of circumferential strain in a high-pressure hose extending from the hydraulic hammer to the high-pressure pump, and the physical quantity measuring means is a strain gauge attached to the high-pressure hose so that the fluctuation component of the circumferential strain is detected. The method for evaluating the number of hammer hits according to claim 1. The method for evaluating the number of hits of a hydraulic hammer according to any one of claims 1 to 4, wherein the regression analysis is performed using the degree of wear of the hydraulic hammer as a parameter. A foreground for exploring the ground properties of the front ground by attaching a hydraulic hammer to the tip of the bore rod mounted on the boring machine and drilling a ground that extends forward of the exposed surface such as a face with the hydraulic hammer. In the mountain exploration method,
Measure the water supply pressure to the water pressure hammer to make the water supply pressure P,
By applying the water supply pressure to the formula (1) created by the hydraulic hammer impact number evaluation method according to any one of claims 1 to 5, the impact number N corresponding to the water supply pressure P is obtained,
The magnitude of the drilling energy by the hydraulic hammer is defined as an energy index value M, and the energy index value is expressed by the following formula using the water supply pressure P and the hit number N:
M = P · N / V (2)
V: calculated from the drilling speed,
A method for exploring a forward ground, wherein the ground property of the forward ground is estimated using the energy index value M. The method for evaluating the number of hits of a hydraulic hammer according to any one of claims 1 to 5 is the method for evaluating the number of hits of a hydraulic hammer according to claim 2, wherein an exposed surface of the drilling object is exposed to the face or the like. 7. A method for exploring a forward natural ground according to claim 6, wherein the elastic wave is an elastic wave that is generated when drilling a natural ground that spreads immediately after an exposed surface such as a face.

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