Nondestructive detection method for hidden dangers in ancient city wall based on geological radar and surface wave method

Abstract

The invention belongs to the technical field of ancient city wall hidden danger detection, and discloses an ancient city wall internal hidden danger nondestructive detection method based on a geological radar and a surface wave method, and the method comprises the following steps: carrying out the preparation before detection according to the actual ancient city wall condition; shallow hidden dangers are detected in a geological radar detection mode; adopting a surface wave method to detect middle-deep layer hidden dangers; processing and analyzing the detection data obtained in the two modes; constructing a three-dimensional hidden danger model according to an analysis structure of the detection data; and obtaining a detection result based on the three-dimensional hidden danger model. According to the non-destructive detection method for the hidden dangers in the ancient city wall based on the geological radar and the surface wave method, the geological radar and the high-precision surface wave method are combined, so that the hidden dangers of the shallow layer and the deep layer can be efficiently identified, and the advantages of the geological radar and the surface wave method in detection of different depths and different resolutions are fully exerted; the accuracy, comprehensiveness and scientificity of detection data are ensured, a hidden danger three-dimensional model is constructed, and scientific support is provided for protection and repair of an ancient city wall.

Description

Technical Field

[0001] The invention relates to the technical field of ancient city wall hidden danger detection, and in particular to a method for nondestructive detection of hidden dangers inside ancient city walls based on geological radar and surface wave method. Background Art

[0002] As an important historical and cultural heritage, the protection and preservation of the ancient city wall is of vital importance. However, due to the long history of the ancient city wall, after wars or natural erosion, its internal structure has suffered a certain degree of damage, such as cracks, holes, looseness, material deterioration and other hidden dangers, threatening the long-term stability of cultural relics. Therefore, it is necessary to detect internal hidden dangers of the ancient city wall building to prevent further erosion of the ancient city wall building in advance.

[0003] Traditional hidden danger detection methods, such as physical drilling and destructive testing, are prone to cause secondary damage to the city wall itself, and have limited detection accuracy and depth coverage. Conventional geophysical detection methods are difficult to achieve high-precision shallow detection and comprehensive identification of deep structural hidden dangers at the same time.

[0004] Based on this discovery, geological radar has advantages in shallow high-resolution detection but shallow depth, while the lateral high-resolution surface wave method is good at detecting hidden dangers in medium and deep layers. Therefore, in response to the above problems, the present invention proposes a non-destructive detection method for hidden dangers inside the ancient city wall based on geological radar and surface wave method, which can effectively combine the advantages of different non-destructive detection methods to achieve comprehensive and high-precision detection of hidden dangers in the ancient city wall. Summary of the invention

[0005] The purpose of the present invention is to provide a nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method, which combines the shallow high-resolution detection capability of geological radar and the medium and deep detection capability of surface wave method, effectively covers hidden danger areas at different depths, comprehensively analyzes the data of the two technologies, and constructs an accurate three-dimensional model of hidden danger volume, which is suitable for the rapid detection of hidden dangers inside ancient city walls, provides a scientific basis for the repair and protection of ancient city walls, solves the technical problem that a single nondestructive detection technology cannot simultaneously take into account both shallow high-precision and deep hidden danger identification, and improves the accuracy and reliability of hidden danger identification.

[0006] To achieve the above object, the present invention provides a nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method, comprising the following steps: Step S1, making preparations before detection according to the actual situation of the ancient city wall; Step S2, using geological radar to detect shallow hidden dangers; Step S3, using the surface wave method to detect mid-deep hidden dangers; Step S4, processing and analyzing the detection data obtained in step S2 and step S3; Step S5: construct a three-dimensional hidden danger model according to the analysis structure of the detection data; Step S6: Obtain detection results based on the three-dimensional hidden danger model.

[0007] Preferably, in step S1, the preparatory work before detection specifically includes: Step S11, determining a reasonable detection area and range according to the structural characteristics, material properties and detection requirements of the ancient city wall; Step S12: For shallow hidden dangers, a geological radar detection method with real-time sampling function is used; wherein, the geological radar detection depth is not less than 2.0m; the survey line is arranged on the upper part of the ancient city wall, mainly in the form of grid survey line, the grid spacing is less than the minimum size of the estimated hidden danger body, and the upper, middle and lower survey lines are arranged on the side wall; Step S13: For medium-deep hidden dangers, the surface wave method is used; the survey line is mainly along the direction of the ancient city wall, avoiding the influence of the side walls, and the survey line position is as consistent as possible with the long survey line of the geological radar.

[0008] Preferably, in step S2, a geological radar detection method is used to detect shallow hidden dangers, and the specific process is as follows: Step S21, before detection, conduct a validity test of the geological radar detection method and a parameter validity test; Step S22: according to the actual situation, set the radar antenna frequency, usually frequencies above 300 MHz are used for shallow detection, and frequencies below 100 MHz are used for deep detection; Step S23: organize and execute geological radar detection tasks, generate shallow structure images inside the city wall, and identify shallow cavities and loose body areas.

[0009] Preferably, in step S3, the surface wave method is used to detect the hidden dangers in the middle and deep layers, and the specific process is as follows: Step S31, before detection, conducting a validity test of the surface wave method and a parameter validity test; Step S32: According to the actual situation, select appropriate offset distance, track spacing, recording length, sampling interval, and organize on-site surface wave detection; Step S33: Stay away from all kinds of vibration interference sources during the operation, and record the acquisition parameters and the coordinates of the start and end points of the detector in detail for each acquisition profile; Step S34: invert the shear wave velocity distribution to identify hidden dangers deep in the wall.

[0010] Preferably, in step S4, the detection data obtained in steps S2 and S3 are processed and analyzed, and the specific process is as follows: Step S41: Determine the shallow anomaly under the seawall of the ancient city wall using geological radar data. When interpreting the results, use multiple survey lines to jointly interpret: First, delineate survey line anomalies; Then, the scope of the hidden danger body is delineated by the abnormality of the survey line; Step S42, determine the opening of the side wall of the ancient city wall by using the geological radar data, and determine the opening of the air-raid shelter by combining with the multi-frequency antenna; Step S43, comprehensively determine the internal cavities of the ancient city wall by using the surface wave method data and the geological radar data: First, determine the anomaly of the surface wave method survey line; Then, the spatial distribution of potential hazards in air-raid shelters is determined based on the surface wave line anomalies and the side wall openings. For line anomalies without side wall openings, they are determined to be loose bodies or internal cavities after comprehensive analysis.

[0011] Preferably, in step S5, a three-dimensional hidden danger model is constructed according to the analysis results of the detection data, as follows: Step S51, comparing and analyzing the results obtained by the two detection methods to determine the location, depth and nature of the hidden danger, and constructing a three-dimensional hidden danger model; Step S52: Overlay the geological radar interpretation results and the surface wave method interpretation results, analyze the spatial relationship between the shallow hidden danger body and the deep hidden danger body, and determine the risk level of the hidden danger body.

[0012] Preferably, in step S52, the risk level of the hidden danger body includes: the overlap of the shallow loose body and the deep hidden danger body indicates that the hidden danger body is still developing; and the dense soil body above the deep hidden danger body indicates that the hidden danger body is temporarily stable.

[0013] Preferably, in step S6, based on the three-dimensional hidden danger model, the detection result is obtained, which is specifically as follows: Step S61: construct a three-dimensional model of hidden dangers inside the ancient city wall according to the detection results, and generate a hidden danger distribution map; Step S62: Provide a detection report based on the hidden danger distribution map, detailing the location, form and severity of the hidden dangers, and put forward relevant repair suggestions.

[0014] Therefore, the present invention adopts the above-mentioned non-destructive detection method of hidden dangers inside the ancient city wall based on geological radar and surface wave method, and the beneficial effects are as follows: (1) High-resolution shallow detection: Geological radar can detect shallow hidden dangers in the wall, such as loose bodies and voids, with centimeter-level accuracy; (2) Identification of deep hidden dangers: The horizontal high-resolution surface wave method can effectively identify deep structural problems of the wall and solve the problem of insufficient detection depth of geological radar; (3) Data mutual verification: By comparing and integrating the data obtained from the two detection methods, the accuracy and completeness of the hidden danger identification results are ensured; (4) Construction of a three-dimensional hidden danger model: The results of the two detection methods are combined to form a three-dimensional model of the hidden danger body of the ancient city wall, providing an accurate decision-making basis for scientific repair.

[0015] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a detection flow chart of the nondestructive detection method of hidden dangers inside the ancient city wall based on geological radar and surface wave method of the present invention; Figure 2 It is a schematic diagram of the result of the combined interpretation of geological radar and surface wave method of the present invention; Figure 3 It is a three-dimensional model diagram of hidden dangers of the ancient city wall constructed by combining the data of the two detection methods. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0018] like Figure 1 As shown, the nondestructive detection method for hidden dangers inside the ancient city wall based on geological radar and surface wave method of the present invention comprises the following steps: Step S1: Perform pre-detection preparations based on the actual situation of the ancient city wall.

[0019] Step S11: Determine a reasonable detection area and range according to the structural characteristics, material properties and detection requirements of the ancient city wall.

[0020] Step S12: For shallow hidden dangers, geological radar (GPR) with real-time sampling function is preferred; the detection depth is selected to be no less than 2.0m. The survey lines are arranged on the upper part of the ancient city wall, mainly grid survey lines, and the grid spacing should be less than the minimum size of the estimated hidden danger body. The upper, middle and lower survey lines are arranged on the side wall.

[0021] Step S13: For mid-deep hidden dangers, the high-precision surface wave method that can improve the horizontal high resolution is preferred. The survey line is mainly along the direction of the ancient city wall, avoiding the influence of the side walls, and the survey line position is as consistent as possible with the long survey line of the geological radar.

[0022] Step S2: Use geological radar (GPR) to detect shallow hidden dangers. The specific process is as follows: Step S21: before detection, conduct effectiveness test of geological radar detection method and parameter effectiveness test.

[0023] Step S22: Select an appropriate radar antenna frequency. Frequencies above 300 MHz are usually used for shallow layer high-resolution detection, and frequencies below 100 MHz are used for deep layer detection.

[0024] Step S23: organize and execute the detection task, generate the shallow structure image inside the city wall, and identify the shallow voids and loose body areas.

[0025] Step S3: Use the lateral high-precision surface wave method to detect mid-deep hidden dangers. The specific process is as follows: Step S31: Conduct a validity test of the surface wave method and a parameter validity test before detection.

[0026] Step S32: According to the actual situation, select appropriate offset distance, track spacing, recording length, sampling interval, etc., and organize on-site detection.

[0027] Step S33: Stay away from all kinds of vibration interference sources during the operation, and record the acquisition parameters, detector start and end point coordinates, etc. in detail for each acquisition profile.

[0028] Step S34, invert shear wave velocity distribution. Deep detection is mainly used to identify hidden dangers deep in the wall, such as deep soil cavities, loose bodies, etc.

[0029] Among them, the joint interpretation results of geological radar and lateral high-resolution surface wave method are shown as follows: Figure 2 shown.

[0030] Step S4: Process and analyze the detection data obtained in step S2 and step S3.

[0031] Step S41, determine the shallow anomaly under the seawall of the ancient city wall by geological radar data, and interpret the results by joint interpretation of multiple survey lines; first, delineate the survey line anomaly; then, delineate the scope of the hidden danger body by the survey line anomaly.

[0032] Step S42, determine the opening of the side wall of the ancient city wall by using the geological radar data, and determine the opening of the air-raid shelter by combining with the multi-frequency antenna; Step S43, comprehensively determine the internal cavities of the ancient city wall by using the surface wave method data and the geological radar data; first, determine the surface wave method survey line anomalies; then, determine the spatial distribution of the burial depth, direction, etc. of the air-raid shelter-type hidden danger body based on the surface wave method survey line anomalies and the side wall openings; for the survey line anomalies without side wall openings, determine them as loose bodies or internal cavities after comprehensive analysis.

[0033] Step S5: construct a three-dimensional hidden danger model based on the analysis results of the detection data.

[0034] Step S51, comparing and analyzing the results obtained by the two detection methods to determine the location, depth and nature of the hidden danger, and constructing a three-dimensional hidden danger model; Step S52, superimpose the geological radar interpretation results and the surface wave method interpretation results, analyze the spatial relationship between the shallow hidden danger body and the deep hidden danger body, and determine the risk level of the hidden danger body. If the shallow loose body and the deep hidden danger body (cavity, loose body, etc.) overlap, it indicates that the hidden danger body is still developing; and if the upper soil of the deep hidden danger body is dense, it indicates that the hidden danger body is temporarily stable.

[0035] Step S6: Obtain detection results based on the three-dimensional hidden danger model.

[0036] Step S61: construct a three-dimensional model of hidden dangers inside the ancient city wall according to the detection results, and generate a hidden danger distribution map; Step S62: Provide a detection report based on the hidden danger distribution map, detailing the location, form and severity of the hidden dangers, and put forward relevant repair suggestions.

[0037] Example Taking an ancient city wall as an example, nondestructive detection is performed using the nondestructive detection method for hidden dangers inside the ancient city wall based on geological radar and surface wave method proposed in the present invention.

[0038] First, the shallow layer of the city wall was detected using geological radar, and multiple loose bodies and side wall openings were identified.

[0039] At the same time, a high-precision surface wave method was used to detect medium and deep structures, and many air-raid shelters, loose bodies, etc. were discovered.

[0040] Finally, through data fusion, a three-dimensional hidden danger model of the ancient city wall was constructed, and detailed repair suggestions were put forward based on the model.

[0041] Therefore, the present invention adopts the above-mentioned non-destructive detection method for hidden dangers inside the ancient city wall based on geological radar and surface wave method, combines the shallow high-resolution detection capability of geological radar and the medium and deep detection capability of surface wave method, effectively covers hidden danger areas of different depths, comprehensively analyzes the data of the two technologies, and constructs an accurate three-dimensional model of hidden danger volume, which is suitable for the rapid detection of hidden dangers inside the ancient city wall, provides a scientific basis for the repair and protection of the ancient city wall, solves the technical problem that a single non-destructive detection technology cannot simultaneously take into account the identification of shallow high-precision and deep hidden dangers, and improves the accuracy and reliability of hidden danger identification.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A non-destructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method, characterized in that: The following steps are involved: Step S1, making preparations before detection according to the actual situation of the ancient city wall; Step S2, using geological radar to detect shallow hidden dangers; Step S3, using the surface wave method to detect mid-deep hidden dangers; Step S4, processing and analyzing the detection data obtained in step S2 and step S3; Step S5: construct a three-dimensional hidden danger model according to the analysis structure of the detection data; Step S6: Obtain detection results based on the three-dimensional hidden danger model.

2. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 1 is characterized in that: In step S1, the preparation work before detection specifically includes: Step S11, determining a reasonable detection area and range according to the structural characteristics, material properties and detection requirements of the ancient city wall; Step S12: For shallow hidden dangers, a geological radar detection method with real-time sampling function is used; wherein, the geological radar detection depth is not less than 2.0m; the survey line is arranged on the upper part of the ancient city wall, mainly in the form of grid survey line, the grid spacing is less than the minimum size of the estimated hidden danger body, and the upper, middle and lower survey lines are arranged on the side wall; Step S13: For medium-deep hidden dangers, the surface wave method is used; the survey line is mainly along the direction of the ancient city wall, avoiding the influence of the side walls, and the survey line position is as consistent as possible with the long survey line of the geological radar.

3. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 2 is characterized in that: In step S2, the shallow hidden dangers are detected by geological radar detection, and the specific process is as follows: Step S21, before detection, conduct a validity test of the geological radar detection method and a parameter validity test; Step S22: according to the actual situation, set the radar antenna frequency, usually frequencies above 300 MHz are used for shallow detection, and frequencies below 100 MHz are used for deep detection; Step S23: organize and execute geological radar detection tasks, generate shallow structure images inside the city wall, and identify shallow cavities and loose body areas.

4. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 2 is characterized in that: In step S3, the surface wave method is used to detect the hidden dangers in the middle and deep layers. The specific process is as follows: Step S31, before detection, conducting a validity test of the surface wave method and a parameter validity test; Step S32: According to the actual situation, select appropriate offset distance, track spacing, recording length, sampling interval, and organize on-site surface wave detection; Step S33: Stay away from all kinds of vibration interference sources during the operation, and record the acquisition parameters and the coordinates of the start and end points of the detector in detail for each acquisition profile; Step S34: invert the shear wave velocity distribution to identify hidden dangers deep in the wall.

5. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 1 is characterized in that: In step S4, the detection data obtained in steps S2 and S3 are processed and analyzed. The specific process is as follows: Step S41: Determine the shallow anomaly under the seawall of the ancient city wall using geological radar data. When interpreting the results, use multiple survey lines to jointly interpret: First, delineate survey line anomalies; Then, the scope of the hidden danger body is delineated by the abnormality of the survey line; Step S42, determine the opening of the side wall of the ancient city wall by using the geological radar data, and determine the opening of the air-raid shelter by combining with the multi-frequency antenna; Step S43, comprehensively determine the internal cavities of the ancient city wall by using the surface wave method data and the geological radar data: First, determine the anomaly of the surface wave method survey line; Then, the spatial distribution of potential hazards in air-raid shelters is determined based on the surface wave line anomalies and the side wall openings. For line anomalies without side wall openings, they are determined to be loose bodies or internal cavities after comprehensive analysis.

6. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 1 is characterized in that: In step S5, a three-dimensional hidden danger model is constructed according to the analysis results of the detection data, as follows: Step S51, comparing and analyzing the results obtained by the two detection methods to determine the location, depth and nature of the hidden danger, and constructing a three-dimensional hidden danger model; Step S52: Overlay the geological radar interpretation results and the surface wave method interpretation results, analyze the spatial relationship between the shallow hidden danger body and the deep hidden danger body, and determine the risk level of the hidden danger body.

7. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 6 is characterized in that: In step S52, the risk level of the hidden danger body includes: the overlap of the shallow loose body and the deep hidden danger body indicates that the hidden danger body is still developing; the dense soil above the deep hidden danger body indicates that the hidden danger body is temporarily stable.

8. The nondestructive detection method for hidden dangers inside ancient city walls based on geological radar and surface wave method according to claim 1 is characterized in that: In step S6, based on the three-dimensional hidden danger model, the detection results are obtained, as follows: Step S61: construct a three-dimensional model of hidden dangers inside the ancient city wall according to the detection results, and generate a hidden danger distribution map; Step S62: Provide a detection report based on the hidden danger distribution map, detailing the location, form and severity of the hidden dangers, and put forward relevant repair suggestions.

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