CN114357557A - Anti-overturning stable safety evaluation method for penetration explosion damage concrete gravity dam - Google Patents
Anti-overturning stable safety evaluation method for penetration explosion damage concrete gravity dam Download PDFInfo
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Abstract
The invention discloses an anti-overturning stable safety evaluation method for a penetration explosion damage concrete gravity dam, which comprises the following steps: selecting a typical dam section of the concrete gravity dam; the type and the penetration condition of penetration weapons are known; determining the damage form of penetration explosion damage; determining the penetration explosion damage range; determining a damage path of the concrete gravity dam; determining the strength parameter of the residual section and checking the stress; calculating an anti-overturning stable safety coefficient according to an anti-overturning formula; and establishing a penetration explosion damage anti-overturning stable safety evaluation model. The method can evaluate the stability of the penetration explosion damage concrete gravity dam by only using a penetration explosion damage anti-overturning stability evaluation model which passes reliability verification without adopting a field explosion test. Under the condition that the gravity dam is attacked by different penetration weapons, different penetration conditions and different penetration parts, the method can quickly evaluate the anti-overturning stability of the concrete gravity dam damaged by explosion.
Description
Technical Field
The invention belongs to the technical field of gravity dam anti-overturning evaluation, and particularly relates to an anti-overturning stability safety evaluation method for a concrete gravity dam damaged by penetration explosion based on penetration weapons, penetration conditions and penetration parts.
Background
Penetration and striking of a guided weapon on the downstream surface of the concrete gravity dam can cause the upper part of the concrete gravity dam to overturn, cause the dam to be unstably damaged, and cause great threat to the dam safety. Therefore, it is necessary to establish a penetration explosion damage and overturn-resistant stable safety assessment model of the concrete gravity dam based on penetration weapons, penetration conditions and penetration positions, so that the safety performance of the penetration explosion damage concrete gravity dam can be rapidly known, and the rapid assessment mode can provide powerful theoretical basis for decision makers to make relevant plans and avoid greater loss.
Disclosure of Invention
Aiming at the technical problems, the invention aims to provide a method for rapidly evaluating the anti-overturning stability of a concrete gravity dam damaged by penetration explosion, which is used for rapidly evaluating how the safety performance of the dam is after being attacked by a bomb by establishing a penetration explosion damage anti-overturning stable safety evaluation model of the concrete gravity dam based on penetration weapons, penetration conditions and penetration parts, and providing a theoretical basis for a decision maker to make emergency rescue or other measures.
The technical scheme provided by the invention is as follows:
an anti-overturning stable safety evaluation method for penetration explosion damage concrete gravity dam comprises the following steps:
step 1, selecting a typical dam section of a concrete gravity dam;
step 2, knowing the parameters and penetration conditions of penetration weapons;
step 3, firstly, calculating the penetration depth of the projectile body by using a Young empirical formula and combining penetration weapon parameters and penetration conditions; then, judging whether the damage form of the projectile is internal action damage or blasting funnel damage after the projectile explodes in the concrete gravity dam by adopting the blasting funnel theory of Livingston;
step 4, when the shallow surface explosion occurs to form the explosion funnel, calculating the depth and the radius of the explosion pit according to the engineering explosion theory and a corresponding formula; when the internal action damage of penetration explosion occurs, obtaining the damage range of the concrete by adopting a corresponding internal explosion action damage partition calculation method;
step 5, determining a rotation center by utilizing the calculated depth and radius of the explosion pit according to the position of the penetration part, and further obtaining a possible failure section of the concrete gravity dam, namely a failure path of the concrete gravity dam;
step 6, determining the strength parameter of the residual section at the section of the failure path, then performing stress check on the upstream dam facing at the section of the failure path by adopting a material mechanics method, and judging whether the upstream dam facing at the section of the failure path cracks or not and whether a through crack is formed or not;
step 7, solving the anti-overturning stability safety coefficient of the concrete gravity dam by using an anti-overturning calculation formula, and carrying out safety evaluation;
based on the steps, the anti-overturning stable safety performance of the concrete gravity dam can be rapidly calculated by acquiring information of penetration weapons, penetration conditions and penetration positions; collecting data of anti-overturning stable safety performance, and establishing an anti-overturning stable safety assessment database and a model based on penetration weapons, penetration conditions and penetration parts of concrete gravity dams.
Further, in the step 2, parameters of the penetration weapon comprise the quality of the bullet, the cross section area of the bullet, the type of the bullet, the length of the bullet, the diameter of the bullet, the loading amount of the bullet and the curvature radius of the surface of the bullet; the penetration conditions include penetration speed and hit angle.
Further, in the step 3, the penetration depth H of the projectile bodyqThe calculation formula of (a) is as follows:
in the formula: m is the projectile mass, kg; v. of0The target landing speed of the projectile body is m/s; a is the cross-sectional area of the elastomer, m2(ii) a S is an indicator of penetration;
n adopts different calculation methods according to different warheads:
in the formula: l isnIs the warhead length, m; d is the diameter of the projectile, m; CRH is the ratio of the radius of curvature of the head surface of the earth-boring bullet to the radius of the cross-section of the earth-boring bullet.
Furthermore, in the step 3, the penetration depth H of the projectile bodyqIn the calculation formula (2), the calculation formula of the penetrability index S is as follows:
S＝2.7(fcQ)-0.3 (4)
in the formula: f. ofcUnconfined compressive strength, MPa; q is the rock quality index.
Further, in the step 3, the method for judging whether the damage form of the projectile body is internal action damage or blasting funnel damage after the projectile body is exploded inside the concrete gravity dam comprises the following steps:
under the condition that the missile explosive equivalent and the deformation energy coefficient of concrete are known, the explosive burial depth of the concrete surface in a state of forming a damage critical funnel can be obtained by adopting a blasting funnel theory proposed by Livingston, and the following formula is shown:
WC＝EbQ1/3 (5)
in the formula: q is the explosive amount, kg; ebThe deformation energy coefficient of the rock; wCIs the critical buried depth, m.
When the penetration depth H of the projectile bodyqLess than the critical depth of burial W of the explosiveCConcrete gravity damPenetration explosion occurs inside to form a blasting funnel; when the penetration depth H of the projectile bodyqGreater than the critical buried depth W of the explosiveCIn time, the internal action of penetration explosion is damaged, and the surface of the concrete gravity dam cannot form an explosion funnel.
Further, in step 4, when the superficial explosion occurs to form a blasting funnel, the projectile body is penetrated to the maximum depth in the target and then is exploded, the center of the detonation is at the center of the loading, and according to the engineering blasting theory, the depth of the crater is determined by the following formula:
H＝Hq-L·cos α (6)
in the formula: hqThe penetration depth of the warhead in the medium is m; l is the height of the charge center; α is the hit angle.
After the depth of the crater is calculated, the crater radius is determined by using the relationship among the explosive quantity, the crater depth and the crater radius, and the formula is as follows:
Q＝f(H/r)qsign board·H3 (7)
In the formula: q is the explosive amount, kg; q. q.sSign boardExplosive consumption per volume of medium to form a standard throwing funnel, kg/m3(ii) a H is penetration crater depth, m; f (H/r) is an exponential function of blasting effect.
Further, f (H/r) is calculated as:
substituting the formula (8) into the formula (7) to obtain:
wherein: r is the radius of the crater, m; eta is TNT and is converted into conversion coefficient according to antimony, and the conversion coefficient is 1.1.
Further, in the step 4, when the penetration explosion internal action is damaged, a concrete damage range is obtained by adopting a corresponding internal explosion action damage partition calculation method; radius of crush zone R1Radius of fracture zone R2The following theoretical formula can be used for determining:
in the formula: r1Is the crush ring radius; rho0D is the explosive density and the explosive detonation velocity; n is the pressure increase coefficient when the explosive explosion product expands and collides with the wall of the gun hole, and is generally 10; k is the radial decoupling coefficient of charge, K is db/dc，db，dcThe radius of the blast hole and the radius of the explosive package are respectively; gamma is the expansion adiabatic index of detonation products, and is generally taken as 3; leIs the axial coefficient of charge; α is the load propagation attenuation index (shock wave zone); rhocdUniaxial dynamic compressive strength; r isbThe radius of the blast hole is; sigmaRThe radial stress on the interface of the crushing ring and the crack ring; sigmatdUniaxial dynamic tensile strength; β is the load propagation attenuation exponent (stress wave region).
Wherein B is calculated using the formula:
B＝[(1+b)2+(1+b2)-2μd(1-μd)(1-b)2]0.5 (12)
in the formula, b is a lateral stress coefficient; mu.sdIs the dynamic Poisson's ratio of rock, mudμ is the static poisson ratio of the rock at 0.8 μ.
Further, in the step 6, the stress strength of the damaged path section is reduced due to the damage of part of the concrete, and corresponding stress strength reduction is required; when the damage variable is defined in terms of the fracture area, it is considered that the main mechanism of material degradation is the reduction of the effective bearing area due to micro-defects, so the strength of the concrete after damage is σ ═ 1-D0)σ0，D0As a damage variable, σ0The concrete stress intensity is not damaged;
according to a material mechanics method, performing stress check on the upstream dam face of the section of the failure path obtained in the step 5, obtaining whether the maximum tensile stress applied to the dam face exceeds the tensile strength of concrete, and further judging whether a through crack is formed: when the maximum tensile stress borne by the upstream dam face of the broken path section is smaller than the tensile strength of the concrete, the upstream dam face of the broken path section cannot crack; when the maximum tensile stress on the upstream dam face of the broken path section exceeds the tensile strength of concrete, the upstream dam face cracks, and finally a through crack is formed.
Further, in step 7, the anti-overturning stability safety coefficient of the concrete gravity dam is obtained by using an anti-overturning calculation formula, and the anti-overturning calculation formula of the concrete gravity dam is as follows:
in the formula: gamma ray0Is a structural importance coefficient; psi is the design condition coefficient; gamma raydIs the structural coefficient of anti-overturning stability; sigma M0Calculating the sum of the face toppling moments on the basis; sigma MsCalculating the sum of the anti-overturning moments on the surface on the basis; wherein, γ0Psi and gammadInquiring the manual of hydraulic engineering design to obtain.
After the damage path is obtained, calculating the moment of the dead weight of the upper concrete gravity dam to the rotation center, then calculating the dead weight of the upper concrete gravity dam, the concrete cohesion, the uplift pressure and the moment of the horizontal water pressure to the rotation center, then calculating the sum of the anti-overturning moments and the sum of the overturning moments, finding out relevant parameters, and substituting the parameters into the formula (24), namely knowing the stability of the concrete gravity dam damaged by the penetration explosion;
introduction of the safety factor K of anti-overturningsTo evaluate the anti-overturning stability of gravity dams:
safety factor K against overturningsThe calculation formula of (a) is as follows:
the anti-overturning stable safety evaluation method for the explosion damaged concrete gravity dam has the beneficial effects that:
(1) the method can quickly evaluate the stability of the concrete gravity dam damaged by penetration explosion, save a large amount of time and facilitate decision compared with the inspection of each damaged part of the dam, can more quickly evacuate downstream residents when the dam break is possible, and can more quickly take emergency measures when the dam is possibly repaired.
(2) Under the condition that the concrete gravity dam is subjected to any penetration weapon, any penetration condition and any penetration part striking, the penetration explosion damage and overturn-resistant stable safety evaluation model of the concrete gravity dam established by the method disclosed by the invention is still applicable, and the universality is also a great benefit.
Drawings
FIG. 1 is a flow chart of the method of the present invention.
Fig. 2 is a schematic diagram showing the concrete gravity dam being damaged by penetration and explosion to form a blasting funnel (in the figure, letters indicate the length of each side, r is the radius of a blasting bomb pit, H is the depth of the blasting bomb pit, G is gravity, U is uplift pressure, P is horizontal water pressure, and c' A is cohesion between concrete).
FIG. 3 is a schematic diagram of the concrete gravity dam with penetration explosion to form internal action damage (the letter indicates the length of each side, b)0G is gravity, U is uplift pressure, P is horizontal water pressure, c' a is cohesion between the concretes) to damage the radius of the damaged area.
Detailed Description
The invention will be further explained with reference to the drawings. The content of the invention is not limited to this at all.
Examples
As shown in fig. 1-3, the anti-overturning stable safety evaluation method for the concrete gravity dam damaged by penetration explosion specifically comprises the following steps:
1. selecting a typical dam section of the concrete gravity dam;
2. the model of the penetration weapon is known, parameters such as the mass of a projectile body, the cross-sectional area of the projectile body and the loading amount of the weapon are known, and penetration conditions such as impact speed and the like are clarified;
3. firstly, a Young empirical formula which is widely applied at present and has high reliability is utilized, the penetration depth of a projectile body is calculated by combining the type of a penetration weapon and penetration conditions, and the Young empirical formula is as follows:
in the formula: m is the projectile mass, kg; v. of0The target landing speed of the projectile body is m/s; a is the cross-sectional area of the elastomer, m2。
A conical warhead: n is 0.56+0.25Ln/d (3)
In the formula: l isnIs the length of the bullet (m), d is the diameter of the bullet (m), CRH is the ratio of the radius of curvature of the head surface of the earth-boring bullet to the radius of the cross section of the earth-boring bullet, and S is the penetration index.
S＝2.7(fcQ)-0.3 (4)
In the formula: f. ofcUnconfined compressive strength (MPa); q is the rock quality index.
Under the condition that the missile explosive equivalent and the deformation energy coefficient of concrete are known, the explosive burial depth of the concrete surface in a state of forming a damage critical funnel can be obtained by adopting a blasting funnel theory proposed by Livingston, and the following formula is shown:
WC＝EbQ1/3 (5)
in the formula: q is the explosive amount, kg; ebThe deformation energy coefficient of the rock; wCIs the critical buried depth, m.
When the penetration depth H of the projectile bodyqLess than the critical depth of burial W of the explosiveCWhen the concrete gravity dam is used, penetration explosion occurs inside the concrete gravity dam to form a blasting funnel, and the blasting funnel is shown in figure 2; when in usePenetration depth H of projectileqGreater than the critical buried depth W of the explosiveCWhen the internal action of penetration explosion is damaged, the surface of the concrete gravity dam cannot form an explosion funnel, and the explosion funnel is shown in figure 3.
4. When superficial explosion occurs to form a blasting funnel, the projectile body is penetrated to the maximum depth in the target and then is exploded, the center of the detonation is at the center of the charge, and according to the engineering blasting theory, the depth of a crater is determined by the following formula:
H＝Hq-L·cosα (6)
in the formula: hqThe penetration depth of the warhead in the medium is m; l is the height of the charge center; α is the hit angle.
After the depth of the crater is calculated, the crater radius is determined by using the relation among the loading amount, the crater depth and the crater radius, and the formula is as follows:
Q＝f(H/r)qsign board·H3 (7)
In the formula: q is the explosive amount, kg; q. q.sSign boardExplosive consumption per volume of medium to form a standard throwing funnel, kg/m3(ii) a H is penetration crater depth, m; f (H/r) is an exponential function of blasting effect.
Regarding the calculation method of f (H/r), the calculation formula proposed by Soviet Union Boyle Kuffov is adopted, and the formula is as follows:
substituting the formula (8) into the formula (7) to obtain:
wherein: r is the radius of the crater, m; eta is TNT and is converted into conversion coefficient according to antimony, and the conversion coefficient is 1.1.
When the internal action damage of penetration explosion occurs, the concrete damage range is obtained by adopting a corresponding internal explosion action damage partition calculation method. Radius of crush zone R1Radius of fracture zoneR2The following theoretical formula can be used for determining:
in the formula: r1Is the crush ring radius; rho0D is the explosive density and the explosive detonation velocity; n is the pressure increase coefficient when the explosive explosion product expands and collides with the wall of the gun hole, and is generally 10; k is the radial decoupling coefficient of charge, K is db/dc，db，dcThe radius of the blast hole and the radius of the explosive package are respectively; gamma is the expansion adiabatic index of detonation products, and is generally taken as 3; leIs the axial coefficient of charge; α is the load propagation attenuation index (shock wave zone); sigmacdUniaxial dynamic compressive strength; r isbThe radius of the blast hole is; sigmaRThe radial stress on the interface of the crushing ring and the crack ring; sigmatdUniaxial dynamic tensile strength; β is the load propagation attenuation exponent (stress wave region).
Wherein B is calculated using the formula:
B＝[(1+b)2+(1+b2)-2μd(1-μd)(1-b)2]0.5 (12)
in the formula, b is a lateral stress coefficient; mu.sdIs the dynamic Poisson's ratio of rock, mudμ is the static poisson ratio of the rock at 0.8 μ.
5. After the downstream surface of the concrete gravity dam is subjected to penetration striking, the upper part of the concrete gravity dam can overturn, according to the penetration position, the rotating center can be determined by combining the depth of the explosion crater and the crater radius calculated in the previous step, due to cohesive force among the concrete, the overturning resistance stability of the concrete gravity dam is greatly influenced, and therefore the possible failure section of the concrete gravity dam can be judged, namely the failure path of the concrete gravity dam is obtained.
6. The stress intensity of the broken path section is reduced due to the damage of part of concrete, and corresponding stress intensity reduction is needed. When the damage variable is defined according to the crack area, the main mechanism of material degradation is considered to be the reduction of the effective bearing area caused by micro-defects, so the stress strength of the damaged concrete is as follows:
σ＝(1-D0)σ0 (13)
wherein, sigma is the concrete stress intensity after damage, MPa; d0As a damage variable, σ0The concrete stress strength without damage is MPa.
Because the dam body is internally provided with the anti-seepage drainage facilities such as the drainage pipe, the drainage gallery and the like, the uplift pressure in the dam body is very small and can be ignored, so when the stress check is carried out on the upstream dam face of the cross section of the failure path by adopting a material mechanics method, the uplift pressure is not considered, and the formula is as follows:
wherein, the sum of vertical component forces of all loads above the calculated section is Sigma W; sigma M is the sum of the moments of all loads acting on the calculation section and the section vertical water flow direction forming mandrel; x is the length of the calculated cross section; sigmayu、σydHorizontal cross-sectional upstream and downstream edge stresses, respectively.
Calculating the positive stress sigma on the horizontal section of the dam body by using the formula (14) and the formula (15)yAnd τ, σxAnd σ1、σ2Can be obtained according to the balance condition of the edge micro-body, and is simplified as follows:
τu＝(pu-σyu)n1 (16)
τd＝(σyd-pd)m1 (17)
σxu＝pu-τun1 (18)
σxd＝pd+τdm1 (19)
σ1u＝(1+n1 2)σyu-pun1 2 (20)
σ1d＝(1+m1 2)σyd-pdm1 2 (21)
σ2u＝pu (22)
σ2d＝pd (23)
in the formula, τu、τdRespectively the upper and lower edge shear stress; n is1、m1The slope rates of the upstream dam and the downstream dam are respectively; sigmaxu、σxdHorizontal normal stresses at the upstream and downstream edges, respectively; sigma1u、σ1dThe maximum main stress of the edges of the dam faces at the upper and lower reaches respectively; sigma2u、σ2dThe minimum principal stress of the edges of the dam faces at the upper and lower reaches respectively; p is a radical ofu、pdThe water pressure strength (when the silt pressure exists, the pressure is counted in) at the dam surface of the upstream dam and the downstream dam respectively.
The maximum tensile stress borne by the upstream dam face of the section of the failure path can be obtained by using the formula, when the tensile stress is smaller than the tensile strength of concrete, the upstream dam face of the section of the failure path cannot crack, and the cohesive force among the concrete needs to be considered when the anti-overturning calculation is carried out on the upper gravity dam of the section of the failure path; when the tensile stress is greater than the tensile strength of the concrete, the upstream dam face of the section of the failure path is cracked, and finally a through crack is formed.
7. The anti-overturning stable safety coefficient of the concrete gravity dam is solved by utilizing an anti-overturning calculation formula, and the anti-overturning calculation formula of the concrete gravity dam is as follows:
in the formula: gamma ray0Is a structural importance coefficient; psi is the design condition coefficient; gamma raydIs the structural coefficient of anti-overturning stability; sigma M0Calculating the sum of the face toppling moments on the basis; sigma MsThe sum of the anti-overturning moments on the surface is calculated on the basis. Wherein, γ0Psi and gammadInquiring the manual of hydraulic engineering design to obtain.
After the damage path is known, the moment of the dead weight of the upper concrete gravity dam to the rotation center is calculated, then the moments of the horizontal water pressure, the sediment pressure, the cohesive force between the concrete and the like to the rotation center are calculated, then the sum of the anti-overturning moments and the sum of the overturning moments are calculated, relevant parameters are found out, and the parameters are substituted into the formula (24), so that the condition that the invasion explosion damages the stability of the concrete gravity dam can be known. Without introducing the antidumping safety factor KsTo evaluate the anti-overturning stability of gravity dams:
8. based on the ideas and the steps, under the condition of any penetration weapon, penetration condition and penetration part, the anti-overturning stable safety performance of the concrete gravity dam can be rapidly calculated by changing parameters, namely a database is established, so that the safety of the concrete gravity dam can be known by looking up a table as long as the type, the condition and the action part of the penetration weapon are known, and the model is an anti-overturning stable safety evaluation model for the concrete gravity dam based on penetration weapon, penetration condition and penetration part explosion damage.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any modification, equivalent replacement, and improvement made by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention.
Claims (10)
1. An anti-overturning stable safety evaluation method for penetration explosion damage concrete gravity dam is characterized by comprising the following steps:
step 1, selecting a typical dam section of a concrete gravity dam;
step 2, knowing the parameters and penetration conditions of penetration weapons;
step 3, firstly, calculating the penetration depth of the projectile body by using a Young empirical formula and combining penetration weapon parameters and penetration conditions; then, judging whether the damage form of the projectile is internal action damage or blasting funnel damage after the projectile explodes in the concrete gravity dam by adopting the blasting funnel theory of Livingston;
step 4, when the shallow surface explosion occurs to form the explosion funnel, calculating the depth and the radius of the explosion pit according to the engineering explosion theory and a corresponding formula; when the internal action damage of penetration explosion occurs, obtaining the damage range of the concrete by adopting a corresponding internal explosion action damage partition calculation method;
step 5, determining a rotation center by utilizing the calculated depth and radius of the explosion pit according to the position of the penetration part, and further obtaining a possible failure section of the concrete gravity dam, namely a failure path of the concrete gravity dam;
step 6, determining the strength parameter of the residual section at the section of the failure path, then performing stress check on the upstream dam facing at the section of the failure path by adopting a material mechanics method, and judging whether the upstream dam facing at the section of the failure path cracks or not and whether a through crack is formed or not;
step 7, solving the anti-overturning stability safety coefficient of the concrete gravity dam by using an anti-overturning calculation formula, and carrying out safety evaluation;
based on the steps, the anti-overturning stable safety performance of the concrete gravity dam can be rapidly calculated by acquiring information of penetration weapons, penetration conditions and penetration positions; collecting data of anti-overturning stable safety performance, and establishing an anti-overturning stable safety assessment database and a model based on penetration weapons, penetration conditions and penetration parts of concrete gravity dams.
2. The method of claim 1, wherein: in the step 2, parameters of the penetration weapon comprise the quality of the bullet, the cross section area of the bullet, the type of the bullet, the length of the bullet, the diameter of the bullet, the loading amount of the bullet and the curvature radius of the surface of the bullet; the penetration conditions include penetration speed and hit angle.
3. The method of claim 1, wherein: in the step 3, the penetration depth H of the projectile bodyqThe calculation formula of (a) is as follows:
in the formula: m is the projectile mass, kg; v. of0The target landing speed of the projectile body is m/s; a is the cross-sectional area of the elastomer, m2(ii) a S is an indicator of penetration ability;
n adopts different calculation methods according to different warheads:
an oval warhead:
a conical warhead:
in the formula: l isnIs the warhead length, m; d is the diameter of the projectile, m; CRH is the ratio of the radius of curvature of the head surface of the earth-boring bullet to the radius of the cross-section of the earth-boring bullet.
4. The method of claim 3, wherein: in the step 3, the penetration depth H of the projectile bodyqIn the calculation formula (2), the calculation formula of the penetrability index S is as follows:
S＝2.7(fcQ)-0.3 (4)
in the formula: f. ofcUnconfined compressive strength, MPa; q is the rock quality index.
5. The method of claim 1, wherein: in the step 3, the method for judging whether the damage form of the projectile body is internal action damage or blasting funnel damage after the projectile body is exploded in the concrete gravity dam comprises the following steps:
under the condition that the missile explosive equivalent and the deformation energy coefficient of concrete are known, the explosive burial depth of the concrete surface in a state of forming a damage critical funnel can be obtained by adopting a blasting funnel theory proposed by Livingston, and the following formula is shown:
WC＝EbQ1/3 (5)
in the formula: q is the explosive amount, kg; ebThe deformation energy coefficient of the rock; wCIs the critical buried depth, m;
when the penetration depth H of the projectile bodyqLess than the critical depth of burial W of the explosiveCIn the process, penetration explosion occurs inside the concrete gravity dam to form a blasting funnel; when the penetration depth H of the projectile bodyqGreater than the critical buried depth W of the explosiveCIn time, the internal action of penetration explosion is damaged, and the surface of the concrete gravity dam cannot form an explosion funnel.
6. The method of claim 1, wherein: in the step 4, when the superficial explosion occurs to form a blasting funnel, the projectile body is penetrated to the maximum depth in the target and then explodes, the center of the detonation is at the center of the loading, and according to the engineering blasting theory, the depth of a crater is determined by the following formula:
H＝Hq-L·cosα (6)
in the formula: hqThe penetration depth of the warhead in the medium is m; l is the height of the charge center; alpha is the hit angle;
after the depth of the crater is calculated, the crater radius is determined by using the relationship among the explosive quantity, the crater depth and the crater radius, and the formula is as follows:
Q＝f(H/r)qsign board·H3 (7)
In the formula: q is the explosive amount, kg; q. q.sSign boardExplosive consumption per volume of medium to form a standard throwing funnel, kg/m3(ii) a H is penetration craterDepth, m; f (H/r) is an exponential function of blasting effect.
7. The method of claim 6, wherein: the formula for f (H/r) is:
substituting the formula (8) into the formula (7) to obtain:
wherein: r is the radius of the crater, m; eta is TNT and is converted into conversion coefficient according to antimony, and the conversion coefficient is 1.1.
8. The method of claim 1, wherein: in the step 4, when the penetration explosion internal action is damaged, a concrete damage range is obtained by adopting a corresponding internal explosion action damage partition calculation method; radius of crush zone R1Radius of fracture zone R2The following theoretical formula can be used for determining:
in the formula: r1Is the crush ring radius; rho0D is the explosive density and the explosive detonation velocity; n is the pressure increase coefficient when the explosive explosion product expands and collides with the wall of the gun hole, and is generally 10; k is the radial decoupling coefficient of charge, K is db/dc，db，dcThe radius of the blast hole and the radius of the explosive package are respectively; gamma is the expansion adiabatic index of detonation products, and is generally taken as 3; leTo be provided withThe axial coefficient of the drug; α is the load propagation attenuation index (shock wave zone); sigmacdUniaxial dynamic compressive strength; r isbThe radius of the blast hole is; sigmaRThe radial stress on the interface of the crushing ring and the crack ring; sigmatdUniaxial dynamic tensile strength; β is the load propagation attenuation index (stress wave zone);
wherein B is calculated using the formula:
B＝[(1+b)2+(1+b2)-2μd(1-μd)(1-b)2]0.5 (12)
in the formula, b is a lateral stress coefficient; mu.sdIs the dynamic Poisson's ratio of rock, mudμ is the static poisson ratio of the rock at 0.8 μ.
9. The method of claim 1, wherein: in the step 6, the stress intensity of the broken path section is reduced because part of the concrete is damaged, and corresponding stress intensity reduction is required; when the damage variable is defined in terms of the fracture area, it is considered that the main mechanism of material degradation is the reduction of the effective bearing area due to micro-defects, so the strength of the concrete after damage is σ ═ 1-D0)σ0，D0As a damage variable, σ0The concrete stress intensity is not damaged;
according to a material mechanics method, performing stress check on the upstream dam face of the section of the failure path obtained in the step 5, obtaining whether the maximum tensile stress applied to the dam face exceeds the tensile strength of concrete, and further judging whether a through crack is formed: when the maximum tensile stress borne by the upstream dam face of the broken path section is smaller than the tensile strength of the concrete, the upstream dam face of the broken path section cannot crack; when the maximum tensile stress on the upstream dam face of the broken path section exceeds the tensile strength of concrete, the upstream dam face cracks, and finally a through crack is formed.
10. The method of claim 1, wherein: in the step 7, the anti-overturning stable safety coefficient of the concrete gravity dam is obtained by using an anti-overturning calculation formula, and the anti-overturning calculation formula of the concrete gravity dam is as follows:
in the formula: gamma ray0Is a structural importance coefficient; psi is the design condition coefficient; gamma raydIs the structural coefficient of anti-overturning stability; sigma M0Calculating the sum of the face toppling moments on the basis; sigma MsCalculating the sum of the anti-overturning moments on the surface on the basis;
after the damage path is obtained, calculating the moment of the dead weight of the upper concrete gravity dam to the rotation center, then calculating the dead weight of the upper concrete gravity dam, the concrete cohesion, the uplift pressure and the moment of the horizontal water pressure to the rotation center, then calculating the sum of the anti-overturning moments and the sum of the overturning moments, finding out relevant parameters, and substituting the parameters into the formula (24), namely knowing the stability of the concrete gravity dam damaged by the penetration explosion;
introduction of the safety factor K of anti-overturningsTo evaluate the anti-overturning stability of gravity dams:
safety factor K against overturningsThe calculation formula of (a) is as follows:
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