CN103926259B - Based on the concrete riper forecast model of ground penetrating radar - Google Patents

Abstract

The invention discloses a kind of concrete riper forecast model based on ground penetrating radar, a kind of in Mass Concrete ground penetrating radar to a kind of prediction new of concrete riper.The method utilizes ground penetrating radar detection to go out the relative dielectric constant of concrete layer, by the correlativity of the water cut in concrete relative dielectric constant and the age of concrete, concrete strength, unit volume, sets up out concrete riper forecast model.The present invention can utilize and predicts in the construction time different concrete layer degree of ripeness and calculate.

Description

Based on the concrete riper forecast model of ground penetrating radar

Technical field

The present invention relates to a kind of concrete riper forecast model based on ground penetrating radar, belong to Hydraulic and Hydro-Power Engineering technical field.

Background technology

Ground penetrating radar is the important detecting devices in Non-Destructive Testing, it receives the electromagnetic wave of being returned by subsurface reflective to underground emitting electromagnetic wave by emitting antenna, when medium medium dielectric constant microwave medium and conductivity there are differences, the electromagnetic wave wave property received can change, can judge whether there are abnormal conditions in detection body according to these variation characteristics, ground penetrating radar precision is general all higher than other detection method, is widely applied in engineering detecting and prospecting.

Concrete riper describes concrete hardenability important indicator in cement, relation is had with hardening temperature and the length of time, current engineering technical personnel establish degree of ripeness forecast model by the instrument such as Ultrasound Instrument, electrical prospecting apparatus, how to predict that concrete riper is the problem of a research by ground penetrating radar.

Above-mentioned research contents comes from the sub-problem " the coupling mechanism in stress field and temperature field " in the state natural sciences fund major mechanical problems of extra-high concrete dam failure damage " under the catastrophe condition ".

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of concrete riper forecast model based on ground penetrating radar, can predict and calculate in the construction time to different concrete layer degree of ripeness.

The present invention is for solving the problems of the technologies described above by the following technical solutions:

A kind of concrete riper forecast model based on ground penetrating radar, utilize the relative dielectric constant of ground penetrating radar detection concrete layer, by the correlativity of the water cut in concrete relative dielectric constant and the age of concrete, concrete strength, unit volume, set up concrete riper forecast model; Be specially:

According to the water cut in the age of concrete, concrete strength and unit volume, show that relative dielectric constant ε expression formula is:

ε＝A+Bw+Cτ+Df _c,n(1)

In formula, w is the water cut in unit volume, determines according to concrete mix; f _c,nfor concrete strength; τ is the age of concrete; A, B, C, D experience factor all for being drawn by linear regression;

Log expressions between concrete strength and the age of concrete is:

f _c,n＝[E+Fln(τ)]f _c,28(2)

In formula, f _{c, 28}for the intensity of concrete after 28 days, determine according to concrete mix; E, F are the experience factor determined according to concrete mix, are drawn by measurement concrete strength test:

Coefficient	C20	C30	C40	C50	C60
						E	0.275	0.233	0.197	0.197	0.197
F	0.162	0.241	0.320	0.317	0.471

Exponential expression between concrete strength and concrete riper is:

f _c,n＝Gexp(-H/Ms)(3)

In formula, G, H are the experience factor determined according to concrete mix, are drawn: Ms is concrete riper by measurement concrete strength test;

Coefficient	C20	C30	C40	C50	C60
						G	25.092	34.6	45.7	59.2	66.4
H	1.52	1.61	1.72	1.87	1.95

Can be derived by expression formula (1) (2) (3), the expression formula based on the concrete riper forecast model of relative dielectric constant:

$Ms=-H/ln\[\frac{\mathrm{\ϵ}-A-Bw-C\exp \left(\frac{f_{c,n}/f_{c,28}-E}{F}\right)}{DG}\].$

Wherein, the described relative dielectric constant utilizing ground penetrating radar detection concrete layer, is specially:

Setting concrete is i layer, and i is natural number; The then relative dielectric constant ε of the i-th layer concrete _ithere are following two kinds of situations:

1) if the thickness of the concrete layer detected is known, then calculate according to two way travel time during ground penetrating radar detection:

${\mathrm{\ϵ}}_i={\left(\frac{{\mathrm{c\Δt}}_i}{2h_i}\right)}^2$

In formula, c is radar wave speed in a vacuum; Δ t _iby radar wave from detection concrete surface to the two way travel time of bottom surface; h _ifor the thickness of detected concrete layer;

2) if the thickness of the concrete layer detected is unknown, then calculate according to reflection coefficient electromagnetic during ground penetrating radar detection:

If a. one-course concrete, then relative dielectric constant ε ₁for

${\mathrm{\ϵ}}_1={\left(\frac{1+R}{1-R}\right)}^2$

In formula, R is reflection coefficient, R=A ₁/ A _m; A ₁for echo amplitude; A _mfor total reflection wave-amplitude, place iron plate in concrete base and obtain;

If b. multi-layer concrete, then relative dielectric constant ε _ifor:

${\mathrm{\ϵ}}_{i+1}={\mathrm{\ϵ}}_i{\[\frac{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}+\frac{A_i}{A_{i-1}}}{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}-\frac{A_i}{A_{i-1}}}\]}^2$

In formula, A _ibe i-th layer of echo amplitude; A _i-1be the i-th-1 layer echo amplitude.

As further prioritization scheme of the present invention, the expression formula between described concrete strength and concrete riper also comprises logarithm, hyperbolic form.

As further prioritization scheme of the present invention, described concrete strength and the expression formula between the age of concrete also comprise index, hyperbolic form.

The present invention adopts above technical scheme compared with prior art, has following technique effect:

1) by the concrete specific inductive capacity detected, concrete riper can be calculated by Capability Maturity Model formula;

2) concrete strength that can be drawn very easily under differing maturity by the degree of ripeness calculated is reached the required age time value.

Accompanying drawing explanation

Fig. 1 is ground penetrating radar detection schematic diagram.

Fig. 2 is process flow diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

By ground penetrating radar detection concrete as shown in Figure 1, with reference in figure 1 shown in (a), as electromagnetic wave R ₀when inciding the interphase of ground floor medium with certain angle, can produce reflection wave and refraction wave at this decomposition face electromagnetic wave, echo amplitude is A ₀, R ₁reflection wave is for second layer dielectric interface, and refraction wave is exactly its incident wave, and incide second layer interphase and produce reflection and refraction equally, echo amplitude is A ₁, reflection and refraction can be produced in each bed interface.

In the concrete relative dielectric constant process of ground penetrating radar detection, common two kinds of detection methods: is by calculating concrete relative dielectric constant return interval; Two is in the medium that two kinds of specific inductive capacity are different, produce reflection according to electromagnetic wave, and the certain relation existed between reflection coefficient and relative dielectric constant, utilizes reflection coefficient to determine relative dielectric constant under the thickness unknown situation of concrete layer.

Setting concrete is i layer, and i is natural number; The then relative dielectric constant ε of the i-th layer concrete _ithere are following two kinds of situations:

1) if the thickness of the concrete layer detected is known, then calculate according to two way travel time during ground penetrating radar detection:

${\mathrm{\ϵ}}_i={\left(\frac{{\mathrm{c\Δt}}_i}{2h_i}\right)}^2$

In formula, c is radar wave speed in a vacuum; Δ t _iby radar wave from detection concrete surface to the two way travel time of bottom surface, as shown in (b) in Fig. 1; h _ifor the thickness of detected concrete layer;

2) if the thickness of the concrete layer detected is unknown, then calculate according to reflection coefficient electromagnetic during ground penetrating radar detection:

If a. one-course concrete, then relative dielectric constant ε ₁for

${\mathrm{\ϵ}}_1={\left(\frac{1+R}{1-R}\right)}^2$

In formula, R is reflection coefficient, R=A ₁/ A _m; A ₁for echo amplitude; A _mfor total reflection wave-amplitude, place iron plate in concrete base and obtain.

If b. multi-layer concrete, then relative dielectric constant ε _ifor:

${\mathrm{\ϵ}}_{i+1}={\mathrm{\ϵ}}_i{\[\frac{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}+\frac{A_i}{A_{i-1}}}{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}-\frac{A_i}{A_{i-1}}}\]}^2$

In formula, A _ibe i-th layer of echo amplitude; A _i-1be the i-th-1 layer echo amplitude.

A kind of concrete riper forecast model based on ground penetrating radar, as shown in Figure 2, utilize the relative dielectric constant of ground penetrating radar detection concrete layer, by the correlativity of the water cut in concrete relative dielectric constant and the age of concrete, concrete strength, unit volume, set up concrete riper forecast model; Be specially:

According to the water cut in the age of concrete, concrete strength and unit volume, show that relative dielectric constant ε expression formula is:

ε＝A+Bw+Cτ+Df _c,n(1)

In formula, w is the water cut in unit volume, determines according to concrete mix; f _c,nfor concrete strength; τ is the age of concrete; A, B, C, D experience factor all for being drawn by linear regression, gets A=4.7565, B=0.0016, C=0.0262, D=-0.0057

Log expressions between concrete strength and the age of concrete is:

f _c,n＝[E+Fln(τ)]f _c,28(2)

In formula, f _{c, 28}for the intensity of concrete after 28 days, determine according to concrete mix; E, F are the experience factor determined according to concrete mix, are drawn by measurement concrete strength test:

Coefficient	C20	C30	C40	C50	C60
						E	0.275	0.233	0.197	0.197	0.197
F	0.162	0.241	0.320	0.317	0.471

Exponential expression between concrete strength and concrete riper is:

f _c,n＝Gexp(-H/Ms)(3)

In formula, G, H are the experience factor determined according to concrete mix, by measurement concrete strength test:

Coefficient	C20	C30	C40	C50	C60
						G	25.092	34.6	45.7	59.2	66.4
H	1.52	1.61	1.72	1.87	1.95

Can be derived by expression formula (1) (2) (3), the expression formula based on the concrete riper forecast model of relative dielectric constant:

$Ms=-H/ln\[\frac{\mathrm{\ϵ}-A-Bw-C\exp \left(\frac{f_{c,n}/f_{c,28}-E}{F}\right)}{DG}\].$

By the concrete riper forecast model based on relative dielectric constant, thus draw the concrete characteristic quantity such as the age of concrete and intensity:

$\mathrm{\τ}=\exp \left(\frac{f_{c,n}/f_{c,28}-E}{F}\right);$

f _c,n＝Gexp(-H/Ms)。

The above; be only the embodiment in the present invention; but protection scope of the present invention is not limited thereto; any people being familiar with this technology is in the technical scope disclosed by the present invention; the conversion or replacement expected can be understood; all should be encompassed in and of the present inventionly comprise within scope, therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.

Claims (5)

1. the concrete riper forecast model based on ground penetrating radar, it is characterized in that, utilize the relative dielectric constant of ground penetrating radar detection concrete layer, by the correlativity of the water cut in concrete relative dielectric constant and the age of concrete, concrete strength, unit volume, set up concrete riper forecast model; Be specially:

According to the water cut in the age of concrete, concrete strength and unit volume, show that relative dielectric constant ε expression formula is:

ε＝A+Bw+Cτ+Df _c,n(1)

In formula, w is the water cut in unit volume, determines according to concrete mix; f _c,nfor concrete strength; τ is the age of concrete; A, B, C, D are the experience factor drawn by linear regression;

Log expressions between concrete strength and the age of concrete is:

f _c,n＝[E+Fln(τ)]f _c,28(2)

In formula, f _{c, 28}for the intensity of concrete after 28 days, determine according to concrete mix; E, F are the experience factor determined according to concrete mix, are drawn by measurement concrete strength test;

Exponential expression between concrete strength and concrete riper is:

f _c,n＝Gexp(-H/Ms)(3)

In formula, G, H are the scale-up factor determined according to concrete mix, are drawn by measurement concrete strength test; Ms is concrete riper;

Can be derived by expression formula (1) (2) (3), the expression formula based on the concrete riper forecast model of relative dielectric constant:

$Ms=-H/\ln \[\frac{\mathrm{\ϵ}-A-Bw-C\exp \left(\frac{f_{c,n}/f_{c,28}-E}{F}\right)}{DG}\].$

2. a kind of concrete riper forecast model based on ground penetrating radar according to claim 1, it is characterized in that, the described relative dielectric constant utilizing ground penetrating radar detection concrete layer, is specially:

Setting concrete is i layer, and i is natural number; The then relative dielectric constant ε of the i-th layer concrete _ithere are following two kinds of situations:

1) if the thickness of the concrete layer detected is known, then calculate according to two way travel time during ground penetrating radar detection:

${\mathrm{\ϵ}}_i={\left(\frac{{\mathrm{c\Δt}}_i}{2h_i}\right)}^2$

In formula, c is radar wave speed in a vacuum; Δ t _iby radar wave from detection concrete surface to the two way travel time of bottom surface; h _ifor the thickness of detected concrete layer;

2) if the thickness of the concrete layer detected is unknown, then calculate according to reflection coefficient electromagnetic during ground penetrating radar detection:

If a. one-course concrete, then relative dielectric constant ε ₁for

${\mathrm{\ϵ}}_1={\left(\frac{1+R}{1-R}\right)}^2$

In formula, R is reflection coefficient, R=A ₁/ A _m; A ₁for echo amplitude; A _mfor total reflection wave-amplitude;

If b. multi-layer concrete, then relative dielectric constant ε _ifor:

${\mathrm{\ϵ}}_{i+1}={\mathrm{\ϵ}}_i{\[\frac{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}+\frac{A_i}{A_{i-1}}}{\frac{4\sqrt{{\mathrm{\ϵ}}_i{\mathrm{\ϵ}}_{i-1}}}{{\mathrm{\ϵ}}_i-{\mathrm{\ϵ}}_{i-1}}-\frac{A_i}{A_{i-1}}}\]}^2$

In formula, A _ibe i-th layer of echo amplitude; A _i-1be the i-th-1 layer echo amplitude.

3. a kind of concrete riper forecast model based on ground penetrating radar according to claim 2, is characterized in that, described total reflection wave-amplitude A _mobtain by placing iron plate in concrete base.

4. a kind of concrete riper forecast model based on ground penetrating radar according to claim 1, it is characterized in that, the expression formula between described concrete strength and concrete riper also comprises logarithm, hyperbolic form.

5. a kind of concrete riper forecast model based on ground penetrating radar according to claim 1, it is characterized in that, described concrete strength and the expression formula between the age of concrete also comprise index, hyperbolic form.