CN104360046B - Comprehensive geophysical-prospecting combined diagnosis method for hidden danger inside wharf concrete structure - Google Patents

Abstract

The invention discloses a combined geophysical exploration combined diagnosis method for hidden dangers in wharf concrete structures. The invention uses on-site division of the surface of the concrete structure to be tested into cells; uses shock echo instruments for detection; and calibrates the concrete structure to be tested according to the shock echo data The speed of sound wave propagation, use the ground penetrating radar instrument to find out the position of the internal defect; use the ultrasonic CT imaging method to detect the CT image of the internal defect, and further verify the authenticity of the defect image of the ground radar method, after comparing with the design data , and finally determine the type and location of concrete internal defects. Compared with the prior art, the present invention relies on a number of large-scale high-pile wharf projects to form a comprehensive geophysical detection system and new technology for hidden problems in the quality of high-pile wharf concrete structures, providing a pair of "see-through eyes" for quality control ", filling China's technical gap in non-destructive testing and safety assessment of high-pile wharf engineering quality hidden problems.

Description

A comprehensive geophysical prospecting combined diagnosis method for internal hidden dangers of wharf concrete structures

technical field

The invention relates to an implementation method of a water transport project, in particular to a comprehensive geophysical exploration combined diagnosis method for hidden dangers inside a wharf concrete structure.

Background technique

The quality and operation status of water transportation projects are major issues related to the national economy and the people's livelihood. There are possible internal hidden dangers such as cracks, cavities, steel bar corrosion, and broken piles in the concrete structure. How to inspect the project quality in a hidden state has always been a constraint on project quality. Check for bottleneck issues. There are the following disadvantages in the detection of hidden dangers inside the concrete of traditional wharf structures: (1) It is difficult to accurately determine the nature and location of hidden dangers due to the limitations of the instrument itself. For example, the electromagnetic method cannot detect the underground diaphragm wall containing steel bars, and the acoustic wave method It is impossible to detect the steel sheet pile structure with a large depth, and the internal conditions of the underwater concrete structure cannot be accurately detected by the electrical method. (2) In the geophysical method, the detection depth is inversely proportional to the detection accuracy, and a single method cannot distinguish defects of different depths and volumes on the same component; with the rapid growth of China's waterway engineering infrastructure construction, it is urgent to detect the quality of waterway engineering New technologies and methods to conceal problems.

Contents of the invention

The purpose of the present invention is to provide a comprehensive geophysical prospecting joint diagnosis method for hidden dangers inside the wharf concrete structure in order to solve the above problems.

The present invention achieves the above object through the following technical solutions:

The present invention comprises the following steps:

(1) Divide the surface of the concrete structure under test into cells of 400mm×100mm;

(2) Use the shock echo instrument to detect linearly along the X (Y) coordinates in the same direction;

(3) Calibrate the sound wave propagation velocity of the measured concrete structure according to the shock echo data;

(4) According to the wave velocity formula Calculate the relative permittivity ε _r of the measured structure as the medium, and set it as the parameter setting of the ground penetrating radar;

(5) Use the ground penetrating radar instrument to detect along the X (Y) coordinates and in the same direction in a linear manner to find out the position of the internal defect;

(6) Ultrasonic CT imaging method is used to detect the CT images of internal defects, and the authenticity of the defect images of the ground radar method is further verified. After comparing with the design data, the type and location of the internal defects of the concrete are finally determined.

The beneficial effects of the present invention are:

The present invention is a comprehensive geophysical joint diagnosis method for internal hidden dangers of wharf concrete structures. Compared with the prior art, the present invention relies on multiple large-scale high-pile wharf projects to form a comprehensive geophysical detection method for concealed quality problems of high-pile wharf concrete structures. The system method and new technology provided a pair of "perspective eyes" for quality control, filling the technical gap in non-destructive testing and safety assessment of high-piled wharf engineering quality hidden problems in China.

Description of drawings

Fig. 1 is the layout diagram of the web measuring line on the right side of the side span of the present invention;

Fig. 2 and Fig. 3 are the GPR detection section diagrams of survey line 1 and survey line 11 in Table 1;

Fig. 4 and Fig. 5 are the shock-echo spectrograms of the measuring line 7 on the right web of the side span in Table 2;

Fig. 6 and Fig. 7 are the shock-echo spectrograms of the measuring line 9 on the right web of the side span in Table 2;

Fig. 8 and Fig. 9 are the shock-echo spectrograms of the measuring line 11 of the web on the right side of the side span in Table 2;

Figure 10 and Figure 11 are cross-sectional views of the ultrasonic imaging detection of the right web of the side span.

detailed description

The present invention will be further described below in conjunction with accompanying drawing:

The present invention comprises the following steps:

(1) Divide the surface of the concrete structure under test into cells of 400mm×100mm;

(2) Use the shock echo instrument to detect linearly along the X (Y) coordinates in the same direction;

(3) Calibrate the sound wave propagation velocity of the measured concrete structure according to the shock echo data;

(4) According to the wave velocity formula Calculate the relative permittivity ε _r of the measured structure as the medium, and set it as the parameter setting of the ground penetrating radar;

(5) Use the ground penetrating radar instrument to detect along the X (Y) coordinates and in the same direction in a linear manner to find out the position of the internal defect;

(6) Ultrasonic CT imaging method is used to detect the CT images of internal defects, and the authenticity of the defect images of the ground radar method is further verified. After comparing with the design data, the type and location of the internal defects of the concrete are finally determined.

The present invention is based on the comprehensive geophysical prospecting joint diagnosis technology of the ground penetrating radar method, the impact echo method and the ultrasonic CT method, and is used for internal hidden dangers (cracks, holes, steel bar corrosion, etc.) , broken piles, cold seams, etc.) detection and evaluation.

The ground penetrating radar method is based on the dielectric difference between the detection target and the surrounding medium, and utilizes the principle that the electromagnetic wave propagation path in the medium, the electromagnetic field strength and the waveform change with the electromagnetic properties and geometric shapes of the passing medium, through A detection method that studies the round-trip travel time, amplitude, frequency and phase characteristics of the reflected wave relative to the direct wave to determine the concealed object in the detected medium.

The impact-echo method uses a short-term mechanical impact (lightly tapping the concrete surface with a small steel ball or a small hammer) to generate a low-frequency stress wave. The longitudinal wave propagates into the structure and is reflected back by defects and the bottom surface of the component. These reflections The waves are picked up by sensors mounted near the point of impact and sent to a portable instrument with built-in high-speed data acquisition and signal processing.

The ultrasonic CT imaging mainly includes ray tomography based on ray theory and wave tomography based on wave theory. Ray theory regards the propagation path of ultrasonic rays as a straight line under the condition of ignoring scattering, and realizes the reconstruction of the cross-section through path tracing, travel time calculation and iterative reconstruction; wave theory considers the scattering effect of sound waves, and studies the The influence of inhomogeneity on the sound field, by establishing the relationship between the medium parameters and the received data,

The ground-penetrating radar method uses high-frequency electromagnetic pulse waves for continuous scanning, and has a high sampling rate. , for the one-dimensional area within the survey line, the defect type can be qualitatively judged, and the distribution and depth information of the defect can be quantitatively judged.

The shock-echo method requires only one test surface and does not require a couplant. The sound wave is lower in frequency than the ultrasonic wave (IE frequency range is usually 2-20kHz), which makes the shock-echo method avoid the high signal attenuation and Too much clutter interference, after calibration, each measuring point can directly get defect position and depth information.

Further, the concrete tomographic ultrasonic imager has the function of real-time imaging of the internal structure of the object, and can be tested only by using pulse echo on one side of the object.

The above three different methods can not only independently judge the internal defects of concrete, but also confirm each other. The calibrated shock echo data can provide accurate wave velocity values for the ultrasonic imaging method, and the ground-penetrating radar method can accurately find the location of internal defects, and the defect image of the ultrasonic imaging method further verifies the ground-penetrating radar method. The authenticity of the defect image is compared with the design data to finally determine the type of concrete internal defect.

As shown in Figure 1: the concrete strength of the right web of the side span is C55, the average slab thickness is 80cm, and the age of the wall is about 30 days when tested.

As shown in Table 1, Figure 2 and Figure 3, the analysis of ground penetrating radar results:

Table 1 Analysis table of ground penetrating radar results on the right side web of the side span

As shown in Table 2 and Figure 4 to Figure 9, the analysis of shock echo results:

Table 2 Analysis table of impact echo results of the right web of the side span

As shown in Table 3, Figure 10 and Figure 11 is the analysis of ultrasound imaging results:

Comprehensive geophysical prospecting combined with diagnostic testing infers that there are void anomalies in (x6~x7,y7), (x6~x7,y11), (x6~x7,y15), (x6~x7,y17), and the range of the survey line is about 6cm, which is in line with Compared with the design drawings and verified on site, the detected void anomaly is actually a vertical prestressed buried pipe with a diameter of 60mm.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. a comprehensive geophysical prospecting joint diagnosis method of internal hidden danger of wharf concrete structure, is characterized in that, comprises the following steps: (1) Divide the surface of the concrete structure under test into cells of 400mm×100mm; (2) Use the shock echo instrument to detect linearly along the X (Y) coordinates in the same direction; (3) Calibrate the sound wave propagation velocity of the measured concrete structure according to the shock echo data; (4) According to the wave velocity formula Calculate the relative permittivity ε _r of the measured structure as the medium, and set it as the parameter setting of the ground penetrating radar; (5) Use the ground penetrating radar instrument to detect along the X (Y) coordinates and in the same direction in a linear manner to find out the position of the internal defect; (6) Ultrasonic CT imaging method is used to detect the CT images of internal defects, and the authenticity of the defect images of the ground penetrating radar method is further verified. After comparing with the design data, the type and location of the internal defects of the concrete are finally determined.