JP2011047803A - Method of calculating destruction property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately calculate a destruction property of an object to be destroyed regardless of a structure of the object to be destroyed. <P>SOLUTION: A method of calculating destruction property finds a reference impact pressure waveform for indicating a temporal change in an impact pressure by a discharge cartridge 2 of a discharge impact destruction apparatus 1 using an impact pressure measurement instrument, repeats a destructive test of a specimen and a numerical analysis of the destruction property of the specimen using the reference impact pressure waveform while the quantity of a destruction material 22 of the discharge cartridge 2 is changed, obtains a destructive material quantity-impact pressure characteristic, and calculates the destruction property of the object to be destructed 9 by the numerical analysis based on the reference impact pressure waveform and the destructive material quantity-impact pressure characteristic. Once the reference impact pressure waveform and the destructive material quantity-impact pressure characteristic are found, the destruction property of the object to be destroyed can be easily and accurately calculated without the destructive test regardless of the structure of the object to be destroyed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a destructive property calculation method for calculating the destructive property of an object to be destroyed.

  In recent years, as a method of destroying a destruction object such as a concrete structure or a rock, a destruction container containing a pair of electrodes connected via thin metal wires and a destructive substance such as water as in Patent Document 1 The material to be destroyed is abruptly vaporized by inserting it into the mounting hole formed in the object to be destroyed, and supplying electric energy to the metal thin wire in a short time, and destroying the object to be destroyed by expansion during vaporization. A method has been proposed.

Japanese Patent No. 3773305

  By the way, when destroying a to-be-destructed object by the destructive method as in Patent Document 1, the range to be destroyed in advance and the mode of destruction (that is, the destructive properties including information such as the width and distribution of cracks generated in the to-be-destructed object) ) Can be used to obtain useful information for the construction plan, such as the soundness and strength of the remaining part.

  However, in the actual destruction work, the destruction object is made of various materials and has various structures. Therefore, in order to predict the destruction property of the destruction object, it is the same as the destruction object. It was necessary to destroy a specimen having a structure and observe its fracture properties, and much effort and time were required to predict the fracture properties.

  The present invention has been made in view of the above problems, and an object of the present invention is to easily and accurately calculate the destructive property of the object to be destroyed regardless of the structure of the object to be destroyed.

  The invention according to claim 1 is a destructive property calculation method for calculating the destructive property of an object to be destroyed, and a) a pair of electrodes and a destructive substance connected to each other via a thin metal wire are accommodated in a container. A discharge cartridge is prepared, electric energy is supplied to the pair of electrodes to cause the metal thin wire to melt and vaporize to react with the destructive material, and an impact pressure due to expansion of the destructive material is measured with an impact pressure measuring device. A step of measuring and obtaining a reference impact pressure waveform indicating a temporal change in impact pressure based on the measurement result; and b) the amount of the substance for destruction similar to that of the discharge cartridge in the test body. Storing the changed discharge cartridge, supplying electric energy to a pair of electrodes to destroy the test specimen, and obtaining the destructive properties of the test specimen; c) modeling the structure of the test specimen; A plurality of input waveforms are generated from the impact pressure waveform, and the fracture properties of the specimen when the impact pressures of the plurality of input waveforms are applied are obtained by numerical analysis, and the fracture properties obtained in the step b) are obtained. A step of obtaining an input waveform for obtaining a corresponding destructive property as a calculated impact pressure waveform; d) the step b) and the step c) while changing the amount of the destructive substance used in the step b) To obtain the destruction substance amount-impact pressure characteristic indicating the relationship between the amount of the destruction substance and the calculated impact pressure waveform, and e) modeling the structure of the object to be destroyed, Based on the amount of substance-impact pressure characteristics, an analytical shock pressure waveform is obtained from the amount of the destructive substance used to destroy the object to be destroyed, and numerical analysis is performed using the analytical shock pressure waveform. , Destructive properties of the destruction object And a step of leaving.

  The invention according to claim 2 is the destructive property calculation method according to claim 1, wherein, in the step a), the discharge cartridge is accommodated in an internal space of the impact pressure measuring device, and the impact pressure measuring device is provided. The impact pressure is measured by a pressure sensor arranged in the internal space without being broken.

  Invention of Claim 3 is a destructive property calculation method of Claim 1 or 2, Comprising: In said c) process, changing the maximum pressure, maintaining the shape of the said reference impact pressure waveform approximately. The plurality of input waveforms are generated.

  Invention of Claim 4 is a destructive property calculation method in any one of Claim 1 thru | or 3, Comprising: In modeling of the structure of the said test body and the said to-be-destructed object, the said test body and the to-be-destructed object The stress-strain characteristic of at least one material contained in the object has a strain rate dependency.

  A fifth aspect of the present invention is the destructive property calculation method according to any one of the first to fourth aspects, wherein the destructive substance is self-reactive.

  A sixth aspect of the present invention is the destructive property calculation method according to any one of the first to fifth aspects, wherein the specimen and the object to be destroyed include concrete.

  In the present invention, the destructive property of the destructible object can be easily and accurately calculated regardless of the structure of the destructible object.

It is a figure which shows the structure of a discharge impact destruction apparatus. It is a figure which shows the flow of destruction of the to-be-destructed object by a discharge impact destruction apparatus. It is a figure which shows a discharge impact destruction apparatus and a to-be-destructed object. It is a figure which shows the flow of calculation of the destructive property of a to-be-destructed object. It is a top view of an impact pressure measuring device. It is sectional drawing of an impact pressure measuring device. It is a top view of a test body. It is sectional drawing of a test body. It is a top view of a test body. It is sectional drawing of a test body. It is a figure which shows a measurement impact pressure waveform. It is a figure which shows the time change of the pressure in the case of explosive blasting. It is a figure which shows a reference | standard impact pressure waveform. It is a figure which shows the material constant of the material of a test body. It is a figure which shows the test body after destruction. It is a figure which shows the crack in the upper surface and side surface of a test body. It is a figure which shows the compressive strength of the concrete main body of a test body. It is a figure which shows the tensile strength of the concrete main body of a test body. It is a figure which shows the influence of the strain rate with respect to compressive strength and tensile strength. It is a figure which shows the model of a test body. It is a longitudinal cross-sectional view of the recessed part vicinity in the model of a test body. It is a cross-sectional view of the vicinity of the recess in the model of the test body. It is a figure which shows the calculation destructive property of a test body. It is a figure which shows the test body after destruction. It is a figure which shows the crack in the upper surface and side surface of a test body. It is a figure which decomposes | disassembles and shows the test body after destruction. It is a figure which decomposes | disassembles and shows the test body after destruction. It is a figure which shows the calculation destructive property of a test body. It is a figure which shows the test body after destruction. It is a figure which shows the crack in the upper surface and side surface of a test body. It is a figure which shows the calculation destructive property of a test body. It is a figure which shows the test body after destruction. It is a figure which shows the crack in the upper surface and side surface of a test body. It is a figure which shows the calculation destructive property of a test body. It is a figure which shows the amount of substance for destruction-impact pressure characteristics. It is a vector diagram of the maximum principal strain in the test body. It is a vector diagram of the maximum principal strain in the test body. It is a figure which shows the time change of distortion. It is sectional drawing of an impact pressure measuring device. It is a top view of an impact pressure measuring device.

  FIG. 1 is a diagram showing a configuration of a discharge shock destruction apparatus 1 according to an embodiment of the present invention. The discharge impact destruction apparatus 1 includes a discharge cartridge 2 attached to an object to be destroyed such as a concrete structure or rock, a capacitor 4 connected to the discharge cartridge 2 via a wiring 3, and a capacitor 4 via a wiring 5. A DC power source 6 to be connected is provided, and a discharge switch 31 and a charge switch 51 are provided on the wiring 3 and the wiring 5, respectively. In FIG. 1, a part of the discharge cartridge 2 is drawn in cross section for easy understanding of the drawing.

  The discharge cartridge 2 includes a substantially cylindrical destruction container 21 made of plastic or the like, and a liquid or gel-like destruction substance 22 that can be burned in an oxygen-free or low-oxygen environment filled in the destruction container 21. (That is, a substance having self-reactivity), a pair of electrodes 23 housed in the destruction container 21, and a thin metal wire 24 connected to the distal ends of the pair of electrodes 23 and having a smaller cross-sectional area than the electrodes 23. . The pair of electrodes 23 are connected to each other through the fine metal wires 24 and are connected to the capacitor 4 through the wiring 3.

  The destruction container 21 includes a container main body 211 having an opening at the top, and a lid portion 212 that closes the opening of the container main body 211 and seals the inside of the container main body 211. The pair of electrodes 23 penetrates the lid part 212 of the destruction container 21 and is fixed to the destruction container 21 by the wiring 3 fixed to the lid part 212, and the electrode 23 and the thin metal wire 24 are destroyed in the destruction container 21. Located inside the working material 22.

  FIG. 2 is a diagram showing a flow of destruction of an object to be destroyed by the discharge impact destruction apparatus 1. When the object to be destroyed is destroyed by the discharge impact destruction apparatus 1, first, as shown in FIG. 3, a recess 91 is formed in the object 9 by a drill or the like (step S11). In the present embodiment, the destruction target 9 is a structure including concrete (more specifically, a reinforced concrete structure). The concave portion 91 is a deep hole-shaped loading hole, and the cross section perpendicular to the depth direction of the concave portion 91 is substantially circular. In FIG. 3, the destruction target 9 is drawn in a cross-section for easy understanding of the drawing.

  Subsequently, the discharge cartridge 2 is inserted into the recess 91 of the destruction target 9 (that is, the inside of the destruction target 9), and the depression 91 is filled with a tamping material 92 such as sand (so-called tamping is performed). (Step S12). Next, electric energy is accumulated in the capacitor 4 from the DC power source 6 by turning on the charging switch 51 in a state where the discharge switch 31 of the discharge impact breaking device 1 of the object to be destroyed 9 is turned off.

  Thereafter, the charge switch 51 is turned off and the discharge switch 31 is turned on, whereby the electrical energy accumulated in the capacitor 4 is supplied to the pair of electrodes 23 of the discharge cartridge 2 and the fine metal wires 24 are melted and vaporized. . In the present embodiment, electric energy is supplied to the pair of electrodes 23 under conditions where the voltage is 1 kV to 6 kV, the maximum current value is 1 kA to 50 kA, and the supply time is 1 second or less. The melted and vaporized thin metal wire 24 becomes a metal gas of several thousand degrees, and plasma is generated by further supplying electric energy from the capacitor 4 to the metal gas.

  Then, due to the high temperature and high pressure generated by melting and vaporizing the fine metal wires 24, the destruction substance 22 is reacted in the destruction container 21 of the discharge cartridge 2 to instantaneously evaporate and vaporize the destruction substance 22. The to-be-destructed object 9 is destroyed by the impact force (namely, discharge impact force) generated by the expansion of (step S13). In the discharge shock destruction apparatus 1, the discharge shock force can be changed by changing the amount of the destruction substance 22 in the discharge cartridge 2.

  Next, a destructive property calculation method for calculating the destructive property of the destructible object 9 (in this embodiment, the width and distribution of cracks generated in the destructible item 9 due to the destruction) before the destructive object 9 is destroyed. This will be described with reference to FIG. FIG. 5 is a plan view showing an impact pressure measuring device 81 used for calculation of fracture properties, and FIG. 6 is a cross-sectional view of the impact pressure measuring device 81 cut at a position AA in FIG. is there. FIG. A and FIG. A is a plan view of each of the test bodies 82a and 82b used for calculating the destructive properties, and FIG. B and FIG. B shows the test bodies 82a and 82b in FIG. The position of BB in A, and FIG. It is sectional drawing cut | disconnected in the position of CC in A. FIG. 5 to 8. In B, the discharge cartridge 2 of the discharge impact destruction apparatus 1 is also drawn. Moreover, FIG. 6, FIG. B and FIG. In B, in order to facilitate understanding of the drawing, the configuration behind the cross section is also drawn with a broken line.

  As shown in FIGS. 5 and 6, the impact pressure measuring device 81 corresponds to a substantially L-shaped first steel material 811 and a lower portion of the first steel material 811 (that is, a horizontal line on the lower side of the L shape) in a front view. The second steel material 812 is disposed on the side surface of the second steel material 812 facing the first steel material 811 in the vertical direction of the second steel material 812 (the vertical direction in FIG. 6). The groove portion 813 is formed over the entire length of the same. The cross section perpendicular to the vertical direction of the groove portion 813 is substantially circular as shown in FIG. 5, and the first steel material 811 and the second steel material 812 are connected by six bolts 815 as shown in FIGS. 5 and 6. Thus, the side opening and the lower opening of the groove 813 are closed by the first steel material 811. As a result, the groove 813 becomes a recess 813 having an opening only in the upper part. The impact pressure measuring device 81 also includes two sheet-like pressure sensors 814 attached to the inner surface and the inner bottom surface of the recess 813. In the present embodiment, a PVDF (polyvinylidene fluoride) film manufactured by Dynasen is used as the pressure sensor 814.

  When calculating the destructive properties of the object 9 to be destroyed, first, the discharge cartridge 2 of the discharge impact destruction apparatus 1 is inserted into the recess 813 of the impact pressure measuring device 81 (that is, in the internal space of the impact pressure measuring device 81). And tamping material 810 such as sand is filled in the concave portion 813 to be tamped. In the present embodiment, the amount of the destruction substance 22 (see FIG. 1) in the destruction container 21 of the discharge cartridge 2 is 10 ml (milliliter).

  Subsequently, as in the case of destruction of the object 9 to be destroyed, electric energy is supplied to the pair of electrodes 23 (see FIG. 1) of the discharge cartridge 2, and the metal thin wires 24 (see FIG. 1) are melted and vaporized and turned into plasma. The destruction material 22 (see FIG. 1) of the discharge cartridge 2 is reacted and instantaneously evaporated by the high temperature and high pressure generated at that time. Then, the impact pressure measuring device 81 is not destroyed by the expansion during the vaporization of the breaking material 22 (that is, the first steel material 811 and the second steel material 812 of the impact pressure measuring device 81 are cracked). The impact pressure is applied to the impact pressure measuring device 81, and the impact pressure is measured by the pressure sensor 814 disposed in the internal space of the impact pressure measuring device 81 (step S21).

  FIG. 9 is a diagram showing the relationship between the elapsed time from the occurrence of the impact pressure and the pressure measured by the pressure sensor 814. A solid line 711 in the figure indicates the time of the pressure acquired by the pressure sensor 814. An impact pressure waveform (hereinafter referred to as “measurement impact pressure waveform 711”) showing a significant change is shown. As shown in FIG. 9, in the measured impact pressure waveform 711, the pressure reaches the maximum value about 50 μ (micro) seconds after the occurrence of the impact pressure, and then the pressure gradually decreases.

  By the way, in the actual destruction of the destruction target 9 by the discharge impact destruction apparatus 1 shown in FIG. 3, after the pressure applied to the inner wall of the recess 91 is maximized due to the vaporization of the destruction substance 22, The pressure escapes from the cracks that occur and decreases rapidly. On the other hand, when explosives are blown up in the recess of the object to be destroyed to destroy the object to be destroyed (that is, when explosive blasting is performed), the pressure applied to the inner wall of the recess is as shown in FIG. It is known as an example that after reaching the maximum value in a few microseconds after the generation of the impact pressure, it rapidly decreases and becomes 0 about 200 μsec after the generation of the impact pressure.

  In the calculation of destructive properties, based on the measured impact pressure waveform 711 (see FIG. 9), which is a measurement result by the pressure sensor 814, and the impact pressure waveform at the time of explosive blasting shown in FIG. A reference impact pressure waveform indicating a temporal change in pressure when an impact pressure is applied to an object that is destroyed by the impact pressure (that is, an object that cracks due to the impact pressure) is obtained (step S22). Specifically, in the measured impact pressure waveform 711 shown in FIG. 9, the waveform after the pressure reaches the maximum value has the same shape as the waveform after reaching the maximum pressure in the impact pressure waveform at the time of explosive blasting shown in FIG. More specifically, the measured impact pressure waveform 711 is corrected so that the pressure rapidly decreases from the maximum value and becomes 0 after 200 μs from the generation of the impact pressure. In FIG. 11, the reference impact pressure waveform 721 which is the corrected impact pressure waveform is indicated by a solid line, and the measured impact pressure waveform 711 is indicated by a broken line.

  When the reference impact pressure waveform 721 is obtained, the breakdown material 22 (see FIG. 1) of the discharge cartridge 2 is used to perform FIG. A thru | or FIG. By actually destroying the test bodies 82a and 82b shown in B, the destructive properties of the test body are acquired. In the present embodiment, two test bodies 82a and 82b are used. The test body 82a is substantially columnar reinforced concrete, and FIG. A and FIG. As shown in B, on the upper surface of the test body 82a (that is, the upper main surface in FIG. 7.B), a recess 821 extending downward about the center line in plan view is formed by an electric core drill or the like. ing. The test body 82a includes a substantially cylindrical concrete body 822, eight main bars 823 extending in the vertical direction and arranged at equal intervals on the circumference centered on the center line inside the concrete body 822, and 8 There are six circumferential strips 824 arranged at equal intervals in the vertical direction so as to intersect with the main strips 823 of the book.

  In the present embodiment, the diameter of the upper and lower surfaces of the test body 82a is 600 mm, and the height is 600 mm. The cross section perpendicular to the vertical direction of the recess 821 is substantially circular, and the depth from the upper surface of the recess 821 is 350 mm. As the main reinforcement 823, an SD (deformed bar) 345 having a length of 500 mm and D22 is used, and as the rebar 824, SD295 of D10 is used. The interval in the vertical direction between the adjacent strips 824 is 100 mm.

  The test body 82b is a substantially columnar reinforced concrete similar to the test body 82a. A and FIG. As shown in B, on the upper surface of the test body 82b, a recess 821 extending downward about the center line in plan view is formed by an electric core drill or the like. The test body 82b includes a substantially cylindrical concrete main body 822, eight main bars 823 extending in the vertical direction and arranged at equal intervals on two concentric circles centered on the center line inside the concrete main body 822, and the inner side. 7 circumferential bars 824 arranged at equal intervals in the vertical direction so as to intersect the eight main muscles 823, and equal intervals in the vertical direction so as to intersect with the eight outer main muscles 823. Seven circumferential strips 824 arranged in a circle.

  In the present embodiment, the diameter of the upper and lower surfaces of the test body 82b is 600 mm, and the height is 800 mm. Moreover, the cross section perpendicular | vertical to the up-down direction of the recessed part 821 is substantially circular, and the depth from the upper surface of the recessed part 821 is 500 mm. The main muscle 823 is 700 mm long and D22 SD345 is used, and the strap 824 is D10 SD295. The vertical distance between the adjacent strips 824 in the vertical direction is 100 mm, and the vertical position of the inner seven strips 824 and the vertical position of the seven outer strips 824 are made equal. The FIG. 12 shows the material constants of the concrete body 822, the main reinforcement 823, and the band reinforcement 824 of the test bodies 82a and 82b.

  In acquiring the destructive property by the destructive substance 22, first, a new discharge cartridge 2 in which the amount of the destructive substance 22 is changed to 5 ml from the discharge cartridge 2 used in step S21 is shown in FIG. A and FIG. It is inserted into the recess 821 of the test body 82a shown in B (that is, accommodated in the test body 82a), and the tamping material 826 such as sand is filled in the recess 821. Subsequently, as in the case of destruction of the object 9 to be destroyed, electric energy is supplied to the pair of electrodes 23 (see FIG. 1) of the discharge cartridge 2, and the metal thin wires 24 (see FIG. 1) are melted and vaporized and turned into plasma. The destruction material 22 (see FIG. 1) of the discharge cartridge 2 is reacted and instantaneously evaporated by the high temperature and high pressure generated at that time. Then, the test body 82a is destroyed by the impact pressure due to the expansion during the vaporization of the destructive substance 22, and the destructive properties (that is, the crack width and distribution) of the test body 82a are acquired (step S23).

  FIG. A shows the external appearance of the test body 82a in which a crack after fracture occurred, and FIG. B is a diagram showing the width and distribution of cracks 825 generated on the upper surface and side surfaces of the specimen 82a after fracture. FIG. In B, for convenience of illustration, the side surface of the test body 82a is drawn in an expanded manner, and the center portion in the left-right direction of the side surface corresponds to the lower portion of the upper surface in the drawing. FIG. In B, the crack 825 having a width of less than 1.0 mm is shown by a thin line, and the main reinforcing bar 823 and the band reinforcing bar 824 are drawn together by a broken line (FIGS. 20.B, 23.B, and 25.B). The same applies to). Cracks 825 having a maximum width of several millimeters are formed on the side surface of the test body 82a, and these cracks 825 extend approximately along the main bars 823 and the band bars 824. Many of the cracks 825 generated on the side surface of the test body 82a reach the top and bottom surfaces of the test body 82a. In addition, a crack 825 is also generated on the upper surface of the test body 82a.

  Next, based on the material constants shown in FIG. 12, static stress-strain characteristics of each material (concrete body 822, main reinforcement 823, and strip reinforcement 824) of the test body 82a are defined, and further, the strain rate of each material Dynamic modeling of the structure of the specimen 82a is performed in consideration of the dependency. In other words, in modeling the structure of the test body 82a, the stress-strain characteristics of each material of the test body 82a have a strain rate dependency.

In the static modeling, the compression side uses a simplified hysteresis model including a stress decrease region, and the tension side follows the 1/4 model in the softening region. FIG. 14 and FIG. 15 are diagrams showing the compressive strength and tensile strength of the concrete body 822 of the test body 82a, respectively. The ● mark (ε ′ = ^{0 s −1} ) in the drawing indicates the static compressive strength and tensile strength. Show. At this time, the fracture energy Gf shown in Equation 1 is 78.8 N / m, and the crack width w when the tensile stress shown in Equation 2 is 0 is 0.2 mm. The values shown in FIG. 12 are used for the compressive strength fc and the tensile strength ft in Equations 1 and 2, and the maximum dimension dmax of the coarse aggregate is 20 mm. Further, the crack width w is converted by distortion by dividing it by the characteristic length Lch (in this embodiment, the representative length is 100 mm).

On the other hand, in the dynamic modeling, the influence of the strain rate ε ′ is expressed as in Equations 3 and 4 when the strain rate ε ′ is 30 s ⁻¹ or less, and the strain rate ε ′ is greater than 30 s ^−1. The large range is expressed as Equation 5 and Equation 6. In Equations 3 to 6, fcd and ftd represent dynamic compressive strength and tensile strength, respectively, and fcs and fts represent static compressive strength and tensile strength, respectively. The coefficients α, β, γ, and δ are values shown in Equations 7 to 10.

The influence of the strain rate ε ′ shown in Equations 3 to 6 is expressed as shown in FIG. 16, and the dynamic compressive strength and tensile strength considering the effect of the strain rate ε ′ are shown in FIG. 14 and FIG. It is indicated by a mark other than the mark (ε ′ = 0.01 to 100 s ⁻¹ ). The horizontal axis in FIG. 16 indicates the strain rate, and the vertical axis indicates the ratio of the dynamic compressive strength and tensile strength to the static compressive strength and tensile strength.

  In modeling the test body 82a, a ¼ model shown in FIG. 17 is used in consideration of the shape of the test body 82a and the symmetry of the applied load (that is, the impact pressure by the discharge cartridge 2). The condition of the cut-out surface 827 passing through the center line is plane symmetric. Further, the boundary condition of the bottom surface of the test body 82a is the surface contact with the rigid surface. The main bar 823 and the band bar 824 (see FIGS. 7.A and 7.B) are modeled as truss elements, and the concrete body 822, the main bar 823, and the band bar 824 are completely attached. The concrete body 822 uses a reduction integration element of 8-node solid, and the element division of the recess 821 is 16 divisions in the circumferential direction (four divisions in the 1/4 model). FIG. A and FIG. B shows a longitudinal sectional view and a transverse sectional view of a portion (indicated by a circle in FIG. 17) in the vicinity of the bottom of the concave portion 821 which is a pressure acting portion in the model of the test body 82a. The arrow indicates the pressure acting on the recess 821.

  When the modeling of the test body 82a is completed, the fracture characteristic of the test body 82a when the impact pressure of the input waveform is applied is obtained by numerical analysis using the reference impact pressure waveform obtained in step S22 as an input waveform. . In the present embodiment, FEM (finite element method) is used as a numerical analysis method, and the time when it can be considered that a sufficient time has passed after the destruction of the test body 82a (that is, the time when the distortion can be considered to have converged to a constant value). For example, the distribution of the maximum principal strain (tensile strain) of the test body 82a at 3000 μsec after the generation of the impact pressure is obtained as the destructive property of the test body 82a.

  Subsequently, the fracture properties obtained by numerical analysis (hereinafter referred to as “calculated fracture properties”) and FIG. When the actual destructive property of the test body 82a shown in B (that is, the destructive property acquired in step S23) is compared, and the calculated destructive property corresponds to the actual destructive property and can be regarded as equivalent, the input waveform is Acquired as a calculated impact pressure waveform. On the other hand, when the calculated destructive property does not correspond to the actual destructive property, the next input waveform is generated based on the reference impact pressure waveform. The next input waveform is obtained by changing the maximum pressure of the reference impact pressure waveform while maintaining the shape of the reference impact pressure waveform (in this embodiment, by multiplying the entire reference impact pressure waveform by a predetermined value). Generated.

  Then, the calculated destructive property of the test body 82a when the impact pressure of the next input waveform is applied is obtained, and the calculated destructive property and the actual destructive property are compared. In the method for calculating the destructive property of the to-be-destructed object 9, a new input waveform is generated based on the reference impact pressure waveform until the calculated destructive property corresponding to the actual destructive property of the specimen 82a is obtained. The calculated destructive property is compared with the actual destructive property, and an input waveform in which the calculated destructive property corresponding to the actual destructive property is obtained is acquired as a calculated impact pressure waveform. In other words, a plurality of input waveforms are generated from the reference impact pressure waveform, and the destructive properties of the test body 82a when the impact pressures of the plural input waveforms are applied are obtained by numerical analysis and correspond to the actual destructive properties. An input waveform that provides destructive properties is acquired as a calculated impact pressure waveform (step S24).

  FIG. 19 is a diagram showing the calculated destructive properties of the test body 82a when the impact pressure of the calculated impact pressure waveform is applied. FIG. 19 shows perspective views of the 1/4 model of the test body 82a as viewed from the side opposite to the center line and from the center line side (the same applies to FIGS. 22, 24, and 26). In the calculated destructive property shown in FIG. 19, horizontal distortion (that is, distortion corresponding to the crack) occurs at the approximate position of the discharge cartridge 2 on the side surface of the test body 82 a, and the vertical direction extending along the main muscle 823. Distortion has occurred. Further, a polygonal distortion along the band 824 is generated on the upper surface of the test body 82a. These distortions are shown in FIG. It closely matches the distribution of cracks 825 in the actual fracture properties of the specimen 82a shown in FIG. Further, from the calculated destructive properties shown in FIG. 19, it can be seen that a crack is generated along the main muscle 823 inside the specimen 82a.

  When the calculated impact pressure waveform is acquired for the first specimen 82a, a new discharge cartridge 2 in which the amount of the destructive substance 22 is 10 ml (that is, a new cartridge similar to the discharge cartridge 2 used in step S21) is obtained. The discharge cartridge 2) is inserted into the recess 821 (see FIGS. 7.A and 7.B) of the second test body 82a. In other words, the amount of the destructive substance 22 is changed from when the first specimen 82a is destroyed (steps S25 and S26). Subsequently, returning to step S23, the tamping material 826 is filled in the recess 821, and electric energy is supplied to the discharge cartridge 2 to evaporate the destructive substance 22 as in the case of the destruction of the first specimen 82a. Vaporize. Then, due to the impact pressure at the time of vaporization of the destructive material 22, the test body 82 a is formed as shown in FIG. Destroyed as shown in FIG. As shown to B, the destructive property of the test body 82a is acquired (step S23). Cracks 825 having a maximum width of 20 mm to 30 mm are formed on the side surface of the test body 82a, and these cracks 825 extend along the main bars 823 and the band bars 824. As in the case where the amount of the destructive material 22 is 5 ml, many cracks 825 generated on the side surface of the test body 82a reach the top surface and the bottom surface of the test body 82a, and the top surface of the test body 82a also cracks. 825 has occurred.

  The second specimen 82a is destroyed until the part outside the main reinforcement 823 and the band reinforcement 824 of the concrete body 822 is separated from the inside part, and the part outside the main reinforcement 823 and the band reinforcement 824 is FIG. As shown to A, it is in the state which can be easily removed as several concrete lump. FIG. B shows the test body 82a after the part outside the main reinforcement 823 and the band reinforcement 824 of the concrete main body 822 is removed. FIG. In the specimen 82a after destruction shown in B, neither the main muscle 823 nor the strap 824 is broken.

  Next, a plurality of input waveforms are generated from the reference impact pressure waveform obtained in step S22, and the destructive properties of the test body 82a when the impact pressures of the plurality of input waveforms are applied are described above. An input waveform that is obtained by numerical analysis using the above model and obtains a destructive property corresponding to the actual destructive property is obtained as a calculated impact pressure waveform (step S24). 22 is a diagram showing the calculated fracture properties of the test specimen 82a when the impact pressure of the calculated impact pressure waveform is applied, and the strain distribution in the arithmetic fracture properties shown in FIG. It closely matches the distribution of cracks 825 in the actual fracture properties of the specimen 82a shown in FIG. It can also be seen from the calculated fracture properties shown in FIG. 22 that a crack is formed along the main bar 823 inside the specimen 82a.

  Subsequently, a new discharge cartridge 2 in which the amount of the destructive substance 22 is 10 ml is shown in FIG. A and FIG. It is inserted into the recess 821 of the test body 82b shown in B (steps S25 and S26). Then, the process returns to step S23, and the tamping material 826 is filled in the concave portion 821, and electric energy is supplied to the discharge cartridge 2 to evaporate the destruction substance 22 in the same manner as the destruction of the test body 82a. Due to the impact pressure at the time of vaporization of the destructive material 22, the test body 82 b is changed to FIG. As shown in FIG. As shown to B, the destructive property of the test body 82b is acquired (step S23).

  Cracks 825 having a maximum width of several millimeters are formed on the side surface of the test body 82b, and these cracks 825 extend approximately along the main bars 823 and the band bars 824. Unlike the case of the test body 82a, few cracks 825 generated on the side surface of the test body 82b reach the upper surface and the bottom surface of the test body 82b, and no crack 825 occurs on the upper surface of the test body 82b. . Such a difference in the destructive properties between the test body 82a and the test body 82b is considered to be caused by the vertical length of the test body and the vertical position of the discharge cartridge 2.

  Next, the structure of the test body 82b is modeled by the same method as the test body 82a. Then, a plurality of input waveforms are generated from the reference impact pressure waveform obtained in step S22, and the destructive property of the test body 82b when the impact pressures of the plurality of input waveforms are applied is the model of the test body 82b. An input waveform that is obtained by numerical analysis and obtains a destructive property corresponding to the actual destructive property is acquired as a calculated impact pressure waveform (step S24). 24 is a diagram showing the calculated fracture property of the test specimen 82b when the impact pressure of the calculated impact pressure waveform is applied. The strain distribution in the arithmetic fracture property shown in FIG. It matches well with the distribution of cracks 825 in the actual destructive properties of the specimen 82b shown in FIG. In addition, it can be seen from the calculated fracture property shown in FIG. 24 that a crack is formed along the main bar 823 inside the specimen 82b.

  When the calculated impact pressure waveform is acquired, a new discharge cartridge 2 in which the amount of the destructive material 22 is 15 ml is placed in the recess 821 (see FIGS. 8.A and 8.B) of the second specimen 82b. Inserted (steps S25 and S26). Subsequently, the process returns to step S23, and the tamping material 826 is filled in the recess 821, and electric energy is supplied to the discharge cartridge 2 to evaporate the destructive substance 22 in the same manner as when the first specimen 82b is destroyed. Vaporize. Then, due to the impact pressure at the time of vaporization of the destructive material 22, the test body 82 b is formed as shown in FIG. As shown in FIG. As shown to B, the destructive property of the test body 82b is acquired (step S23). Cracks 825 having a maximum width of several millimeters are formed on the side surface of the test body 82b, and these cracks 825 extend approximately along the main bars 823 and the band bars 824. As with the case where the amount of the destructive material 22 is 10 ml, there are few cracks 825 generated on the side surface of the test body 82b, and there are few cracks on the upper surface of the test body 82b. 825 has not occurred.

  Next, a plurality of input waveforms are generated from the reference impact pressure waveform obtained in step S22, and the destructive property of the test body 82b when the impact pressures of the plurality of input waveforms are applied is the above-described test body 82b. An input waveform that is obtained by numerical analysis using the above model and obtains a destructive property corresponding to the actual destructive property is obtained as a calculated impact pressure waveform (step S24). 26 is a diagram showing the calculated fracture property of the test specimen 82b when the impact pressure of the calculated impact pressure waveform is applied, and the strain distribution in the arithmetic fracture property shown in FIG. It matches well with the distribution of cracks 825 in the actual destructive properties of the specimen 82b shown in FIG. In addition, it can be seen from the calculated destructive properties shown in FIG. 26 that a crack is formed along the main bar 823 inside the specimen 82a.

As described above, steps S23 and S24 are repeated for all the prepared specimens while changing the amount of the destruction substance 22 of the discharge cartridge 2 (step S25), and the destruction substance used for breaking the specimen. The destructive substance amount-impact pressure characteristic indicating the relationship between the amount of 22 and the calculated impact pressure waveform acquired in step S24 is acquired (step S27). FIG. 27 is a diagram illustrating the relationship between the amount of the destructive substance 22 and the maximum pressure of the calculated impact pressure waveform corresponding to the destructive substance amount-impact pressure characteristic. As shown in FIG. 27, the maximum pressure when the amount of the destructive substance 22 is 5 ml, 10 ml and 15 ml is 1.5 kN / mm ² , 1.8 kN / mm ² and 2.0 kN / mm ² , respectively. is there.

  Here, the distortion in the cross section perpendicular to the vertical direction of the test bodies 82a and 82b will be described. FIG. A and FIG. B is a vector diagram of the maximum principal strain in a cross section obtained by cutting the test bodies 82a and 82b perpendicularly in the vertical direction at the position where the discharge cartridge 2 is disposed, and the destruction of the test bodies 82a and 82b by the numerical analysis described above. It is calculated at the time of acquisition of properties.

  FIG. As shown in A, in the vicinity of the center of the test body 82a (that is, in the vicinity of the recess 821), a large strain is generated in a direction perpendicular to the radial direction (hereinafter referred to as “tangential direction”). The direction of distortion changes in the radial direction at a position 824 (hereinafter referred to as “rearrangement position”). Further, in the region between the position away from the bar arrangement position and the outer edge, the tangential distortion is again dominant. FIG. As shown in B, a large distortion occurs in the tangential direction in the vicinity of the center of the test body 82b (that is, in the vicinity of the concave portion 821), and the tangential direction in the region between the inner bar arrangement position and the outer bar arrangement position. The distortion is outstanding. FIG. A and FIG. As shown in B, in the test bodies 82a and 82b, the direction of distortion is changed by the main muscle 823 and the band muscle 824, and a crack is formed along the main muscle 823 and the band muscle 824 or outward from the main muscle 823 and the band muscle 824. Arise.

  29 is the same as FIG. A and FIG. It is a figure which shows the time change of the distortion of the concrete main body 822 and the strip reinforcement 824 in the crossing position of the main reinforcement 823 shown with a circle in B, and a bar arrangement position. As shown in FIG. 29, in the test body 82a, the strain generated in the strip 824 is settled at about 0.3% after about 500 μsec from the occurrence of the strain, and is outside of the strip 824 of the concrete body 822. The strain produced at the site settles at about 6% after about 1500 μsec. Further, in the test body 82b, the strains generated in the inner and outer band streaks 824 are settled at about 0.4% and about 0.2% about 500 μsec after the occurrence of the strain, respectively. The strain generated in the region between the inner band 824 and the outer band 824 is settled at about 1.0% after about 500 μsec, and the region outside the outer band 824 of the concrete body 822. The strain produced in is settled at about 6% after about 2000 μsec.

As described above, the distortion at the portion between the strip 824 and the outer edge of the concrete body 822 is larger than that at the other portion. This is because the pressure wave traveling from the center of the test body toward the outer edge is the outer edge. This is considered to be due to the fact that the strain is reflected by the reflection (ie, the free end) and overlapped with the subsequent pressure wave in the relevant portion and grown. Further, in FIG. 29, the slope of the curve indicating the temporal change in strain represents the strain rate ε ′, and ε ′ is several tens s ⁻¹ at the portion between the strip 824 and the outer edge of the concrete body 822. Take a relatively large value. From this, it can be said that in order to improve the accuracy of the numerical analysis, it is preferable to consider the strain rate dependency in the modeling of the test bodies 82a and 82b.

  When the acquisition of the destructive substance amount-impact pressure characteristics is completed, the structure of the destruction target 9 is modeled by a method according to the modeling of the test bodies 82a and 82b described above. Subsequently, based on the amount of destructive material-impact pressure characteristics acquired in step S27, an analysis impact pressure waveform is obtained from the amount of destructive material 22 used to destroy the object 9 to be destructed. In the present embodiment, from the graph shown in FIG. 27, the maximum pressure corresponding to the amount of the destructive substance 22 used to destroy the object 9 is obtained, and the maximum of the reference impact pressure waveform 721 (see FIG. 11) is obtained. The analysis impact pressure waveform is obtained by multiplying the reference impact pressure waveform 721 by the ratio of the maximum pressure to the value. Then, by performing a numerical analysis by FEM using the analysis impact pressure waveform, the destruction of the destruction target 9 when the impact pressure having the analysis impact pressure waveform is applied to the inner wall of the recess 91 of the destruction target 9 The properties are calculated in the same manner as in the case of obtaining the destructive properties of the test bodies 82a and 82b (step S28).

  The destruction property of the destruction target 9 is calculated by changing the amount of the destruction material 22 and the depth and position of the recess 91 in which the discharge cartridge 2 is inserted before the actual destruction of the destruction target 9. The amount of the destructive substance 22 and the depth and position of the recess are determined so that the desired destructive properties are obtained. As a result, optimization of the destruction work of the destruction target 9 (that is, improvement of safety, reduction of work cost, etc.) is realized.

  In the destructive property calculation method according to the present embodiment, from the viewpoint of increasing the destructive property calculation accuracy, the specimens 82a and 82b and the object 9 to be destructed have the same type of structure (that is, a single same property). Preferably, the calculation method is applied only to the destructive object 9 which is a reinforced concrete structure similar to the test bodies 82a and 82b. However, the present invention can be applied to an object to be destroyed (for example, a structure or a rock formed only with concrete) having a structure different from that of the test bodies 82a and 82b. In this case, after modeling the structure of the object to be destroyed, the analytical impact obtained based on the reference impact pressure waveform obtained in the above-described steps S22 and S27 and the destructive substance amount-impact pressure characteristics. By performing a numerical analysis using the pressure waveform, the destructive properties of the object to be destroyed are obtained.

  As described above, in the fracture property calculation method according to the present embodiment, the reference impact pressure waveform is obtained using the impact pressure measuring device 81, the fracture test of the test bodies 82a and 82b, and the test body 82a and 82b. The calculated impact pressure waveform is acquired based on the numerical analysis of the destructive property to acquire the destructive substance amount-impact pressure characteristic, and the destruction object 9 is determined based on the reference impact pressure waveform and the destructive substance amount-impact pressure characteristic. Destructive properties are calculated. As a result, once the reference impact pressure waveform and the amount of destructive material-impact pressure characteristics are obtained, the destructive property of the destructible object can be calculated easily and accurately without performing a destructive test regardless of the structure of the destructible object. can do.

  Further, in step S21, the discharge cartridge 2 is accommodated in the recess 821 (that is, the internal space) of the impact pressure measuring device 81, and the impact is measured by the pressure sensor 814 disposed in the recess 821 without breaking the impact pressure measuring device 81. By measuring the pressure, the measured impact pressure waveform 711 shown in FIG. 9 can be obtained with high accuracy. Accordingly, in step S22, the reference impact pressure waveform 721 shown in FIG. 11 can be obtained with high accuracy based on the measured impact pressure waveform 711. As a result, in step S28, the destructive property of the object to be destroyed can be calculated with higher accuracy.

  In step S24, a plurality of input waveforms can be easily generated by changing the maximum pressure while approximately maintaining the shape of the reference impact pressure waveform. In step S24, the modeling of the structures of the test bodies 82a and 82b is performed in a state where the stress-strain characteristics of the materials included in the test bodies 82a and 82b have strain rate dependence. The modeling of the structure of the object 9 is performed in a state in which the stress-strain characteristics of the material included in the destruction object 9 have strain rate dependence, similarly to the modeling of the test bodies 82a and 82b. Thereby, it is possible to improve the accuracy of numerical analysis when acquiring the destructive properties of the test bodies 82a and 82b and the object 9 to be destroyed, and to calculate the destructive properties of the test bodies 82a and 82b and the object 9 to be destructed with higher accuracy. can do.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  In step S21, the impact pressure may be measured by an impact pressure measuring device having a structure different from that of the impact pressure measuring device 81 shown in FIGS. For example, an impact pressure measuring device 81a shown in FIGS. 30 and 31 includes a thick iron pipe 816, an iron plate 817 that closes the upper and lower openings of the iron pipe 816, an acrylic plate 818 that is attached to the inner surface of the iron pipe 816, and A pressure sensor 814 attached to the inner surface of the plate 818 which is a smooth surface is provided, and a silica sand 819 is filled around the discharge cartridge 2 located in the inner space of the iron tube 816. In the impact pressure measuring device 81a, the height of the iron pipe 816 is 180 mm, the outer diameter is 76.3 mm, and the wall thickness is 7.0 mm. The impact pressure is measured by the pressure sensor 814 in the iron pipe 816.

  In the above embodiment, two types of test bodies 82a and 82b are used in step S23. However, one type or three or more types of test bodies may be used in step S23. In addition, the shape of the test body is preferably a cylinder from the viewpoint of facilitating numerical analysis, but may be various shapes other than the cylinder (for example, a prism). In an actual destructive work, since a concrete structure is often used as a destructible object, the test body used in step S23 preferably includes concrete, but may be formed of a material other than concrete. .

  In step S24, DEM (discrete element method), RBSM (rigid spring model), or the like may be used as a numerical analysis method instead of FEM. In the modeling of the test bodies 82a and 82b and the object 9 to be destroyed, the stress-strain characteristics of at least one material included in the test bodies 82a and 82b and the object 9 to be destroyed have a strain rate dependence. The accuracy of obtaining destructive properties is improved.

  In the above embodiment, the recess 91 is a hole formed in the object 9 to be destroyed, but a groove formed in the object 9 may be used as the recess 91. Moreover, the above-described discharge impact destruction apparatus 1 can be used for, for example, finishing destruction work in tunnels, concrete structure demolition work, underwater destruction work, and other destruction / demolition work in which blasting work is restricted.

9 Destroyer 2 Discharge cartridge 21 Destruction container 22 Destructive substance 23 Electrode 24 Metal wire 81, 81a Impact pressure measuring device 82a, 82b Specimen 721 Reference impact pressure waveform 813 Recess 814 Pressure sensor

Claims (6)

A destructive property calculation method for calculating the destructive property of a destruction object,
a) By preparing a discharge cartridge containing a pair of electrodes connected to each other via a fine metal wire and a destructive substance in a container and supplying electric energy to the pair of electrodes to melt and vaporize the fine metal wire Reacting the destructive substance, measuring an impact pressure due to expansion of the destructive substance with an impact pressure measuring device, and obtaining a reference impact pressure waveform indicating a temporal change in the impact pressure based on the measurement result;
b) Inside the test body, a discharge cartridge similar to the discharge cartridge or having a changed amount of the destructive substance is accommodated, and electric energy is supplied to a pair of electrodes to destroy the test body, Acquiring the destructive properties of the specimen,
c) Modeling the structure of the specimen, generating a plurality of input waveforms from the reference impact pressure waveform, and determining the fracture properties of the specimen when the impact pressures of the plurality of input waveforms are applied by numerical analysis B) obtaining an input waveform that provides a destructive property corresponding to the destructive property obtained in step b as a calculated impact pressure waveform;
d) Relationship between the amount of the destructive material and the calculated impact pressure waveform by repeating the steps b) and c) while changing the amount of the destructive material used in the step b) Obtaining a destructive substance amount-impact pressure characteristic,
e) Modeling the structure of the object to be destructed, and determining an analytical shock pressure waveform from the amount of the destructive substance used for destructing the destructible based on the destructive substance amount-impact pressure characteristic, Calculating the destructive properties of the object to be destroyed by performing numerical analysis using the shock pressure waveform for analysis; and
A destructive property calculation method comprising: The fracture property calculating method according to claim 1,
In step a), the discharge cartridge is accommodated in the internal space of the impact pressure measuring device, and the impact pressure is measured by a pressure sensor disposed in the internal space without breaking the impact pressure measuring device. The destructive property calculation method characterized by this. The fracture property calculation method according to claim 1 or 2,
In the step c), the plurality of input waveforms are generated by changing the maximum pressure while substantially maintaining the shape of the reference impact pressure waveform. A destructive property calculation method according to any one of claims 1 to 3,
In modeling the structure of the specimen and the object to be destroyed, the stress-strain characteristic of at least one material contained in the specimen and the object to be destroyed has a strain rate dependency. Calculation method. A destructive property calculation method according to any one of claims 1 to 4,
A destructive property calculation method, wherein the destructive substance is self-reactive. A destructive property calculation method according to any one of claims 1 to 5,
The method for calculating destructive properties, wherein the specimen and the object to be destroyed include concrete.

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