CN104198587B - Concrete material is the measuring method of damage development under static load effect - Google Patents

Abstract

The invention discloses concrete material measuring method of damage development under static load effect, advantage is that the method can measure the damage evolution law of concrete material in the case of different loads, measurement result is relatively more accurate, has practical engineering application and theory value widely；And the instrument and equipment used in method is simply, simple to operation.

Description

Concrete material is the measuring method of damage development under static load effect

Technical field

The damage development that the present invention relates to concrete material is measured, and particularly relates to concrete material and damages under static load effect The measuring method that wound develops.

Background technology

At present in engineering, concrete is a kind of application structural material widely, it be widely used civil buildings, Road and bridge, military blindage, nuclear facilities, offshore platform etc..Concrete material under arms during, main by static state The effect of load.Under static load effect, concrete material is internal inevitable that damage is formed and along with damage Wound develops.And the damage evolution law of concrete material is to build concrete material constitutive relation and enter concrete facility The basis of row security monitoring, but there is presently no concrete material measurement side of damage development under static load effect Method.

Summary of the invention

The technical problem to be solved is to provide a kind of concrete material damage development under static load effect Measuring method.

The present invention solves the technical scheme that above-mentioned technical problem used: concrete material damages under static load effect The measuring method developed, including step in detail below:

(1), according to the mix-design of concrete, manufactured size is the concrete standard of 150mm × 150mm × 150mm Test specimen, and the concrete standard test specimen made is carried out standard curing, standard curing condition is: curing temperature 20 ± 2 DEG C, humidity more than 95%, 28 days time；

(2) any one group of opposite planar, in selected concrete standard test specimen, wherein in a plane, fetch bit is in this At least two measuring point on plane diagonal, is designated as measuring point 1,2 ... m, m >=2 and round numbers, then in opposite planar with Measuring point 1,2 ... position corresponding for m takes measuring point, and is designated as measuring point 1 ', 2 ' ... m '；

(3), the transducer in nonmetal ultrasonic detector and main frame are connected firmly, stable, and according to concrete mark The size of quasi-test specimen, set the emitting voltage of nonmetal ultrasonic detector as 1000V, sampling period as 0.4ms, send out The a width of 0.08ms of ejected wave；

(4), the selected one of which opposite planar perpendicular with measuring point place plane as imposed load face, and will wherein One plane and ground or work top flat contact, apply different static loads in opposite planar the most successively P₀、P₁…P_n, n round numbers, wherein P₀=0, P_n≤ σ S, σ are concrete material mix-design intensity, and S is mixed The loading end area of solidifying soil standard specimen；

(5) it is, P when static load suffered by concrete standard test specimen₀Time, on the transducer of nonmetal ultrasonic detector Uniform application couplant, and the transmitting terminal of transducer is fixed on measuring point 1 along the direction perpendicular with measuring point 1 place plane On, the receiving terminal of transducer is fixed on measuring point 1 ' along the direction perpendicular with measuring point 1 ' place plane, measures survey The ultrasound wave longitudinal wave velocity of point 1, for C₀₁, then according to measuring point 2 is measured in identical operation successively ... the ultrasound wave compressional wave of m Velocity of wave, is designated as C₀₂…C_0m；

(6), it is respectively P when static load suffered by concrete standard test specimen₁…P_nTime, divide according to the operation of step (5) Other each measuring point on concrete standard test specimen is carried out ultrasound examination, and record concrete standard under corresponding static load The measuring point 1,2 of test specimen ... the ultrasound wave longitudinal wave velocity at m, is designated as: C₁₁、C₁₂…C_1m..., C_n1、C_n2…C_nm, Obtain corresponding static load P the most respectively₀、P₁…P_nThe meansigma methods of the ultrasound wave longitudinal wave velocity of lower concrete standard test specimen, It is designated as C₀、C₁…C_n, wherein: $C_0=\frac{C_{01}+C_{02}+...+C_{0m}}{m},C_1=\frac{C_{11}+C_{12}+...+C_{1m}}{m},...,$ $C_n=\frac{C_{n1}+C_{n2}+...+C_{\mathrm{nm}}}{m};$

(7), the meansigma methods of the ultrasound wave longitudinal wave velocity of concrete standard test specimen under the different static load effects that will obtain C₀、C₁…C_nSubstitute into the injuring relation formula of concrete material respectivelyIn, wherein: k=0,1,2 ... n, Obtain the impairment value D of concrete standard test specimen corresponding under different static load₀、D₁…D_n, then with different static loads The stress value of the concrete standard test specimen under lotus effectFor abscissa, with corresponding under corresponding stress state The impairment value D of concrete standard test specimen₀、D₁…D_nFor vertical coordinate, carry out the data of B-spline with MATLAB mathematical software Matching, obtainsThe cubic B-spline smooth curve of stress-damage function, just obtains concrete material in static state Damage evolution law under load effect.

In described step (2), measuring point is 3 and divides equally on the diagonal being distributed in plane.

Compared with prior art, it is an advantage of the invention that the method can measure the damage of concrete material in the case of different loads Hindering Evolution, measurement result is relatively more accurate, has practical engineering application and theory value widely；And in method The instrument and equipment used is simple, simple to operation.

Accompanying drawing explanation

Fig. 1 is the loading surface on concrete standard test specimen and the schematic diagram of test surfaces in the present invention；

Fig. 2 is the damage evolution law of the concrete material obtained measured by the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail.

As it can be seen, concrete material measuring method of damage development under static load effect, including step in detail below:

(1), according to the mix-design of concrete, manufactured size is the concrete standard of 150mm × 150mm × 150mm Test specimen, and the concrete standard test specimen made is carried out standard curing, standard curing condition is: curing temperature 20 ± 2 DEG C, humidity more than 95%, 28 days time；

(2), in selected concrete standard test specimen before and after one group of opposite planar, on the front facet, take and be evenly distributed on this Three measuring points on plane diagonal, are designated as measuring point 1,2,3, more corresponding with measuring point 1,2,3 on back plane Position takes measuring point, and is designated as measuring point 1 ', 2 ', 3 '；

(3), the transducer in nonmetal ultrasonic detector and main frame are connected firmly, stable, and according to concrete mark The size of quasi-test specimen, set the emitting voltage of nonmetal ultrasonic detector as 1000V, sampling period as 0.4ms, send out The a width of 0.08ms of ejected wave；

(4), selected upper next group opposite planar perpendicular with measuring point place plane is as imposed load face, and puts down lower Face and work top flat contact, upper plane applies the most successively different static load 0kN, 100kN, 200kN, 300kN, 400kN, 500kN, 600kN, mix-design intensity σ of concrete material is 30MPa, concrete standard The loading end area S of test specimen is 0.0225m²；

(5), when suffered by concrete standard test specimen, static load is 0kN, at the transducer of nonmetal ultrasonic detector Upper uniform application couplant, and the transmitting terminal of transducer is fixed on measuring point along the direction perpendicular with measuring point 1 place plane On 1, the receiving terminal of transducer is fixed on measuring point 1 ' along the direction perpendicular with measuring point 1 ' place plane, measures survey The ultrasound wave longitudinal wave velocity 4.624km/s of point 1, then according to the ultrasonic compressional of measuring point 2,3 is measured in identical operation successively Wave-wave speed is respectively 4.639km/s, 4.652km/s；

(6), when static load suffered by concrete standard test specimen be respectively 100kN, 200kN, 300kN, 400kN, 500kN, During 600kN, respectively each measuring point on concrete standard test specimen is carried out ultrasound examination according to the operation of step (5), And record the ultrasound wave longitudinal wave velocity at the measuring point 1,2,3 of concrete standard test specimen under corresponding static load, it is respectively as follows: 4.416km/s, 4.447km/s, 4.433km/s, 4.122km/s, 4.198km/s, 4.164km/s, 3.746km/s, 3.761km/s、3.785km/s,3.248km/s、3.268km/s、3.275km/s,2.657km/s、2.690km/s、 2.635km/s, 1.935km/s, 1.949km/s, 1.925km/s, obtain concrete under corresponding static load the most respectively The meansigma methods of the ultrasound wave longitudinal wave velocity of standard specimen, be respectively as follows: 4.638km/s, 4.432km/s, 4.161km/s, 3.746km/s、3.264km/s、2.661km/s、1.936km/s；

(7), the meansigma methods of the ultrasound wave longitudinal wave velocity of concrete standard test specimen under the different static load effects that will obtain 4.638km/s、4.432km/s、4.161km/s、3.746km/s、3.264km/s、2.661km/s、1.936km/s Substitute into the injuring relation formula of concrete material respectivelyIn, wherein: k=0,1,2 ... 7, obtain different quiet The impairment value 0 of concrete standard test specimen corresponding under state load, 0.0869,0.1951,0.3414,0.5047,0.6708, 0.8258, then with the stress value 0MPa of concrete standard test specimen under different static load effects, 4.444MPa, 8.888MPa, 13.333MPa, 17.778MPa, 22.222MPa, 26.667MPa are abscissa, with corresponding stress state The impairment value of lower corresponding concrete standard test specimen is vertical coordinate, carries out the data of B-spline with MATLAB mathematical software Matching, obtainsThe cubic B-spline smooth curve of stress-damage function, just obtains concrete material in static state Damage evolution law under load effect.

The following is the derivation of the injuring relation formula to concrete material, this derivation is with " theory of stress wave ", " damage force Learn " based on material:

Ultrasound wave is propagated in concrete medium by three kinds of forms, compressional wave, shear wave and surface wave, and the propagation of compressional wave is fast Degree is the fastest, therefore this method mainly studies the propagation law of compressional wave in concrete material.Assuming that concrete material is uniform Medium, then its dynamic elastic modulus E_dWith the longitudinal wave velocity C propagated wherein₁Relation can represent with following formula:

$C_1=\sqrt{\frac{E_d(1-\mathrm{\ν})}{\mathrm{\ρ}(1-2\mathrm{\ν})(1+\mathrm{\ν})}}---\left(1\right),$

Wherein: E_dFor the dynamic modulus of elasticity of concrete material, C₁For the longitudinal wave velocity propagated in concrete, ρ is concrete The density of material, ν is the Poisson's ratio of concrete material.

Thus can get the initial velocity of wave E in concrete material₀, Wherein: C₀For the initial longitudinal wave velocity propagated in concrete, ρ₀For the initial density of concrete material, ν₀For coagulation The initial Poisson's ratio of soil material, and concrete material is during by static load, this research supposes the close of concrete material Spend constant, and effects of Poisson's ratio is little on the impact of concrete damage, then concrete is during by static load Damage development will appear as the evolution of concrete dynamic modulus of elasticity, if concrete is by during static load, makes coagulation with local methods Become impairment value be D, then it follows that $C=\sqrt{\frac{E_0(1-D)(1-{\mathrm{\ν}}_0)}{{\mathrm{\ρ}}_0(1-{2\mathrm{\ν}}_0)(1+{\mathrm{\ν}}_0)}}---\left(3\right)$

(2) formula is substituted into (3) formula, it is possible to draw the relational expression of the impairment value D of concrete:

$D=1-{\left(\frac{C}{C_0}\right)}^2---\left(4\right)$

Wherein: C₀For the initial longitudinal wave velocity propagated in concrete, C is concrete in the case of different static loads, mixed The ultrasound wave longitudinal wave velocity propagated in solidifying soil material.

Claims (2)

1. concrete material measuring method of damage development under static load effect, it is characterised in that include in detail below Step:

(1), according to the mix-design of concrete, manufactured size is the concrete standard of 150mm × 150mm × 150mm Test specimen, and the concrete standard test specimen made is carried out standard curing, standard curing condition is: curing temperature 20 ± 2 DEG C, humidity more than 95%, 28 days time；

(2) any one group of opposite planar, in selected concrete standard test specimen, wherein in a plane, fetch bit is in this At least two measuring point on plane diagonal, is designated as measuring point 1,2 ... m, m >=2 and round numbers, then in another plane With measuring point 1,2 ... position corresponding for m takes measuring point, and is designated as measuring point 1 ', 2 ' ... m '；

(3), the transducer in nonmetal ultrasonic detector and main frame are connected firmly, stable, and according to concrete mark The size of quasi-test specimen, set the emitting voltage of nonmetal ultrasonic detector as 1000V, sampling period as 0.4ms, send out The a width of 0.08ms of ejected wave；

(4), the selected one of which opposite planar perpendicular with measuring point place plane as imposed load face, and will wherein One plane and ground or work top flat contact, apply different static loads in another plane the most successively P₀、P₁…P_n, n round numbers, wherein P₀=0, P_n≤ σ S, σ are concrete material mix-design intensity, and S is mixed The loading end area of solidifying soil standard specimen；

(5) it is, P when static load suffered by concrete standard test specimen₀Time, on the transducer of nonmetal ultrasonic detector Uniform application couplant, and the transmitting terminal of transducer is fixed on measuring point 1 along the direction perpendicular with measuring point 1 place plane On, the receiving terminal of transducer is fixed on measuring point 1 ' along the direction perpendicular with measuring point 1 ' place plane, measures survey The ultrasound wave longitudinal wave velocity of point 1, for C₀₁, then according to measuring point 2 is measured in identical operation successively ... the ultrasound wave compressional wave of m Velocity of wave, is designated as C₀₂…C_0m；

(6), it is respectively P when static load suffered by concrete standard test specimen₁…P_nTime, divide according to the operation of step (5) Other each measuring point on concrete standard test specimen is carried out ultrasound examination, and record concrete standard under corresponding static load The measuring point 1,2 of test specimen ... the ultrasound wave longitudinal wave velocity at m, is designated as: C₁₁、C₁₂…C₁M ..., C_n1、C_n2…C_nM, Obtain corresponding static load P the most respectively₀、P₁…P_nThe meansigma methods of the ultrasound wave longitudinal wave velocity of lower concrete standard test specimen, It is designated as C₀、C₁…C_n, wherein:

(7), the meansigma methods of the ultrasound wave longitudinal wave velocity of concrete standard test specimen under the different static load effects that will obtain C₀、C₁…C_nSubstitute into the injuring relation formula of concrete material respectivelyIn, wherein: k=0,1,2 ... n, Obtain the impairment value D of concrete standard test specimen corresponding under different static load₀、D₁…D_n, then with different static loads The stress value of the concrete standard test specimen under lotus effectFor abscissa, with corresponding under corresponding stress state The impairment value D of concrete standard test specimen₀、D₁…D_nFor vertical coordinate, carry out the data of B-spline with MATLAB mathematical software Matching, obtainsThe cubic B-spline smooth curve of stress-damage function, just obtains concrete material in static state Damage evolution law under load effect.

2. concrete material measuring method of damage development under static load effect as claimed in claim 1, it is special Levy and be that in described step (2), measuring point is 3 and divides equally on the diagonal being distributed in plane.