CN101738457B - Nondestructive testing method for testing reinforcing effect of earthen site - Google Patents

Abstract

The invention relates to a nondestructive testing method for testing the reinforcing effect of an earthen site, which adopts a thermal infrared imager and a mobile illumination lamp which is used for artificially warming the surface of the earthen site. The method comprises the following steps of: analyzing the changing process of the temperature along with the time to calculate thermal inertia; inversely calculating the elastic modulus of the earth according to a relationship between the pre-tested thermal inertia of the earth and the elastic modulus of the earth; and comparing the elastic modulus of the reinforced earth with that of the un-reinforced earth to evaluate the reinforcing effect. The method can implement quality assessment and effect judgment after a protective measure so as to perform a nondestructive test and quantitative analysis on the earthen site. The method has an important directive function on the application, the popularization and the normative construction technology of the conventional anti-weathering reinforcing materials.

Description

A kind of lossless detection method of testing reinforcing effect of earthen site

Technical field

The present invention relates to technical field of nondestructive testing, concretely, relate to a kind of lossless detection method that is used to detect reinforcing effect of earthen site.

Background technology

Xinjiang, Gansu, Ningxia and the Shaanxi in NORTHWEST CHINA area are domestic; Under the remnants many ancient times earth construction site; Like the half way up the mountain village in the suburbs, Xi'an, Shaanxi and the human living ruins, the earth gulf of Qinan County, Gansu, the Jiao He ancient city of Xinjiang Turfan Prefecture, the ancient city, cynomorium songaricum city in Anxi, Gansu county; Native ruins such as Western Xia Imperial Mausoleum soil.These earth construction site history are remote, and very high archaeology and historical value are arranged, and fully show the civilization of Chinese nation's mature culture.The type in soil ruins generally is divided into silty clay or the silty sand rammer is built, or directly utilizes the immature soil to dig and make, or utilizes adobe masonry, or builds mud with plank sheathing and build.In a single day when dry, there is higher relatively intensity in native ruins, meet water, native ruins are strong disintegration.This has just determined that native ruins are one type that cannot say for sure most in the historical relic of ruins to deposit.Why the Northwest preserves in open-air native ruins, because of northwest drought unique weather conditions short of rain.But, over the past thousands of years, serious wind erosion and concentrated heavy showers erosion damage, the large quantities of weathering of native ruins, large tracts of land are caved in, and are just suffering destructive destruction.Study the disease and the origin cause of formation in native ruins, rescuing the native ruins of protection targetedly is very urgent, very difficult tasks.China begins to carry out the science protection development test of soil property ruins from the end of the eighties in last century in a few place.Under China historical relic's protection worker unremitting effort, to the beginning of this century, the protection work of native ruins has obtained considerable progress.Wherein, the protection reinforcement technique in native ruins has been done a large amount of indoor and site test research, the research of surface, native ruins efflorescence prevention reinforcement material has been obtained important achievement in recent years.

Literature search through to prior art is found; Chinese patent discloses " a kind of native ruins strengthening agent and reinforcement process " (publication number: CN693588A;); This technology provide is the inorganic material of host with high mode potassium silicate (being called for short PS), is used for the reinforcing on surface, native ruins, and this method has good anti-heavy showers and washes away the effect of destroying with anti-dust storm wind erosion.But method for evaluating quality, the effect judgement that implement after the safeguard measure in native ruins do not form a kind of quantitative analysis method as yet.Like this, influence the formation of standardization construction technology to a great extent, limited the application and the popularization of existing efflorescence prevention reinforcement material.On the other hand, because the maximum characteristics of native ruins protection reinforcing engineering are to maintain the original state, and very long evolutionary process is gone through in native ruins, and proterties is extremely fragile, and this just requires to adopt as far as possible in the construction overall process not damaged detection technique.

Summary of the invention

Judge for effect after strengthening native ruins enforcement safeguard measure, the objective of the invention is to characteristic, a kind of lossless detection method of testing reinforcing effect of earthen site is provided, be used to estimate the effect after native ruins reinforce to native ruins reinforcement protection.

Solving the problems of the technologies described above the technical scheme of being taked is: utilize the infrared thermal imagery detection technique; Gather native ruins surface temperature field data; And make full use of this information and the relevant thermal process and the inner link of soil body mechanical property, reach the purpose of the mechanics parameter of inside soil body being made quantitative evaluation.

The objective of the invention is to realize like this:

A kind of lossless detection method of testing reinforcing effect of earthen site the steps include:

(a) the native ruins soil body of enforcement reinforcing is measured soil body coefficient of heat conductivity λ and specific heat c indoor carrying out with thermal pulse method;

(b) said sample is measured soil body void ratio ρ; Measure sample severe (γ) with " core cutter method ", measure soil body water cut (ω), measure soil body soil particle proportion (G) with " pycnometer method " with " oven drying method "; Calculate soil body void ratio by formula then $\mathrm{\ρ}=\frac{G(1+\mathrm{\ω})}{\mathrm{\γ}};$

(c) according to formula $p=\sqrt{\mathrm{\ρ\; C\λ}}$ Calculate soil body thermal inertia; (d) elastic modulus (E) of the test soil body; Sample is placed in the unconfined compression test appearance, under the situation that does not add any lateral pressure, applies pressure at right angle, till test specimen is destroyed, the normal stress σ and the elasticity normal strain ε of record sample in process of the test _e, ratio between two can obtain the sample elasticity modulus $(E=\frac{\mathrm{\σ}}{{\mathrm{\ϵ}}_e})$

(e) result according to (c), (d) just can cross the relation (rule-of-thumb relation fits curve) of setting up soil body thermal inertia and elastic modulus;

(f) reinforce the thermal infrared test that the field by using thermal infrared imager carries out native ruins surface temperature in native ruins;

(g), calculate native ruins thermal inertia according to test result;

(h) according to the soil body thermal inertia of e foundation and the relation (fitting curve) of elastic modulus, the elastic modulus of the inverse soil body;

(j) elastic modulus of the contrast soil mass consolidation and the unguyed soil body is estimated consolidation effect.

The technical standard of above-mentioned thermal infrared imager is:

1) minimum temperature difference of surveying is 0.1-0.5 ℃;

2) visible range is the degree of 0.1-0.5cm moment;

3) recording mode: be digital recording;

4) illuminating lamp is 60 watts-190 watts a portable lighting lamp, is used for the artificial native ruins surface temperature that increases;

5) with illuminating lamp the irradiation of 10 fens clock times is carried out on surface, native ruins and made its intensification, real-time Transmission, the real time record of full Dynamic IR vision signal are carried out in the cooling of turning off the light then simultaneously.

The present invention utilizes infrared radiation that the principle that object or material surface detect is carried out, and infrared ray is a kind of invisible light adjacent with visible light, has the general performance of visible light.After converting the power signal of object radiation to electric signal through infrared eye, handle, reach on the display screen, obtain and the corresponding thermography of body surface heat distribution through electronic system.The structure of interior of articles, the hot rerum natura of material, the thermal diffusion of inside and the heat interchange of surface and external environment are depended in the temperature field of body surface.Therefore,, and make full use of inner link between this information and the relevant thermal process transitivity, just can make the scientific quantitative evaluation the physical and mechanical parameter of interior of articles as long as gather body surface temperature field data.

Learnt by thermodynamic (al) result of study: (any temperature always has the character that keeps its original temperature state in a period of time after not receiving extraneous heating system to its thermal inertia that depends on of material surface variation of temperature.) size.Concerning a certain material, thermal inertia is the intrinsic attribute of this material.When object absorption or release heat, the amplitude that object temperature changes and the thermal inertia of object are inversely proportional to, that is, the object that thermal inertia is big, its variation of temperature amplitude is little, and on the contrary, if the thermal inertia of object is little, then its variation of temperature amplitude is big.Therefore, thermal inertia is the internal factor that causes that the material skin temperature changes, and it is a constant physical quantity in thermodynamics.With regard to the soil body, thermal inertia may be defined as:

$p=\sqrt{\mathrm{\ρc\λ}}$

Wherein P is a thermal inertia, and λ is a coefficient of heat conductivity, and ρ is a void ratio, and c is a specific heat.

Because physical parameters such as the coefficient of heat conductivity of the soil body and its density, elastic modulus, Poisson ratio have certain relation; Therefore; As long as set up the relation between the physical and mechanical parameters such as soil body thermal inertia and elastic modulus, Poisson ratio; Obtain the infrared thermal imagery of the material reinforced front and back of PS, native ruins at the scene, just can realize utilizing infrared detection to carry out the purpose of the material reinforced effect of quantitative evaluation PS.

Description of drawings

Fig. 1 is the process flow diagram of technical scheme of the present invention.

Fig. 2 be among the embodiment thermal inertia and elastic modulus fit curve

Embodiment

Below in conjunction with accompanying drawing the present invention is described further again:

Embodiment

The about 10m of native ruins area that is reinforced ², wall thickness 0.8-1.0m the steps include:

1, take disturbed soil (being generally the avalanche thing) at scene, native ruins, process 10 samples of different densities in the laboratory with compacting process, height is 5cm, and diameter is 2.5cm;

2, carry out soil body coefficient of heat conductivity λ and specific heat c mensuration in indoor employing thermal pulse method; The device of thermal pulse method is made up of a well heater and three samples and the warm galvanic couple of surveying that are placed on the well heater both sides.After well heater passes to electric current, can draw the coefficient of heat conductivity and the specific heat of sample according to the temperature variation of tested sample.Coefficient of heat conductivity and should follow these steps to carry out than heat test:

(a) weighing sample mass is measured specimen size, calculates the density of sample;

(b) the sample arrangement is finished.When the variation of initial temperature in 10min of sample less than 0.05 ℃, and sample upper and lower surfaces temperature difference can begin to measure during less than 0.1 ℃;

(c) connect heater power source, and start stopwatch simultaneously, measure the heating circuit electric current;

(d) heat time heating time, (τ ') was controlled at 4-6min, when 1-2 ℃ of sample upper surface temperature rising, and record upper surface thermoelectrical potential and corresponding time.Then measure thermoelectrical potential and corresponding time on the thermal source face, therebetween at a distance from surpassing 1min;

(e) coefficient of heat conductivity, specific heat of combustion, void ratio, thermal inertia, the elastic modulus that obtain of test is as shown in table 1:

Test result among table 1. embodiment

Specimen coding	Coefficient of heat conductivity (W -1.m.K -1)	Specific heat KJ.m -3.K -1	Void ratio	Thermal inertia J/m 2.K.S 1/2	Elastic modulus MPa
						1?2?3?4?5?6?7?8?9?10	0.300.350.520.610.760.850.931.061.160.48	1497159018901968230526382186251628491701	1.201.131.160.740.860.940.620.820.611.01	1.091.061.080.860.930.920.780.900.781.00	19.018.016.035.228.026.039.035.242.022.4

3, said sample is measured soil body void ratio ρ; Measure sample severe (γ) with " core cutter method ", measure soil body water cut (ω), measure soil body soil particle proportion (G) with " pycnometer method " with " oven drying method "; Calculate soil body void ratio by formula then $\mathrm{\ρ}=\frac{G(1+\mathrm{\ω})}{\mathrm{\γ}}$ Test result is seen table 1.

4, according to formula $p=\sqrt{\mathrm{\ρ\; C\λ}}$ Calculate the thermal inertia of the soil body; Result of calculation is as shown in table 1.

5, the elastic modulus (E) of the test soil body; Sample is placed on unconfined compression test appearance (the portable no lateral confinement clay intensity test appearance of 16-T178; Wuhan Kant's instrument and equipment company limited produces) in; Under the situation that does not add any lateral pressure, apply pressure at right angle; Till test specimen is destroyed, the normal stress of record sample in process of the test.With elasticity normal strain ε _e, ratio between two can obtain the sample elasticity modulus $(E=\frac{\mathrm{\σ}}{{\mathrm{\ϵ}}_e})$ , test result is as shown in table 1.

6, the result according to (4), (5) sets up the relational expression of elastic modulus and soil body thermal inertia (seeing accompanying drawing 2), and the elastic modulus (P) that plan draws is E=102-78P with the relation of soil body thermal inertia (P),

7, adopt thermal infrared imager (Sata Electric Power Infrared Technology Co., Ltd., Guangzhou produce SAT-S160 type thermal infrared imager) and the thermal infrared that the illuminating lamp that is used to increase native ruins surface temperature carries out native ruins surface temperature to test at the scene;

The technical standard of thermal infrared imager is:

1) minimum temperature difference of surveying: the temperature difference that native ruins are produced before and after reinforcing is very little, therefore as the detection of minimum temperature difference, need accomplish 0.1 ℃ degree;

2) moment the visible range: in order to make a drawing, need reaction subtlety one by one.Differentiate the situation of peeling off of establishing surface layer, need the degree of 0.1cm at least.

3) recording mode: digital recording.

4) illuminating lamp is 100 watts a portable lighting lamp, is used for the artificial native ruins surface temperature that increases.

5) with illuminating lamp the irradiation of 10 fens clock times is carried out on surface, native ruins and made its intensification, real-time Transmission, the real time record of full Dynamic IR vision signal are carried out in the cooling of turning off the light then simultaneously.

8, according to test result, given certain time period soil body surface temperature, the ruins thermal inertia must be unearthed; Chosen three soil mass consolidations in an embodiment and three unguyed soil bodys have been done the thermal inertia test, its value is respectively the unguyed soil body (0.95,0.90,0.97) soil mass consolidation and is (0.78,0.82,0.70).

9, according to the soil body thermal inertia of 6 foundation and the relation of elastic modulus, the elastic modulus of the inverse soil body; Unguyed elastic modulus of soil body (27.9MPa, 31.8MPa, 26.3MPa) soil mass consolidation elastic modulus (41.1MPa, 38.0MPa, 47.3MPa)

10, the elastic modulus of the contrast soil mass consolidation and the unguyed soil body can find out that the elastic modulus of soil body after the reinforcing has improved 50%-70%, and consolidation effect very significantly.

Claims (2)

1. one kind is detected reinforcing effect of earthen site not damaged method, is undertaken by following step:

(a) the native ruins soil body that enforcement is reinforced to needs is measured soil body coefficient of heat conductivity λ and specific heat c indoor carrying out with thermal pulse method;

(b) said sample is measured soil body void ratio ρ; Measure sample severe γ with " core cutter method ", measure soil body water cut ω, measure soil body soil particle proportion G with " pycnometer method " with " oven drying method "; Calculate soil body void ratio by formula then:

(c) calculate soil body thermal inertia according to formula

;

(d) elastic modulus E of the test soil body; Sample is placed in the unconfined compression test appearance, under the situation that does not add any lateral pressure, applies pressure at right angle, till test specimen is destroyed, the normal stress σ and the elasticity normal strain ε of record sample in process of the test _e, ratio between two can obtain the sample elasticity modulus

(e) result according to (c), (d) just can cross the relation of setting up soil body thermal inertia and elastic modulus;

(f) reinforce the thermal infrared test that the field by using thermal infrared imager carries out native ruins surface temperature in native ruins;

(g), calculate native ruins thermal inertia according to test result;

(h) according to the soil body thermal inertia of (e) foundation and the relation of elastic modulus, the elastic modulus of the inverse soil body;

(j) elastic modulus of the contrast soil mass consolidation and the unguyed soil body is estimated consolidation effect.

2. according to the said a kind of detection reinforcing effect of earthen site not damaged method of claim 1, it is characterized in that the technical standard of described thermal infrared imager is:

1) minimum temperature difference of surveying is 0.1-0.5 ℃;

2) visible range is the degree of 0.1-0.5cm moment;

3) recording mode: be digital recording;

4) illuminating lamp is 60 watts-190 watts a portable lighting lamp, is used for the artificial native ruins surface temperature that increases;

5) with illuminating lamp the irradiation of 10 fens clock times is carried out on surface, native ruins and made its intensification, real-time Transmission, the real time record of full Dynamic IR vision signal are carried out in the cooling of turning off the light then simultaneously.

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