Monitoring method suitable for earthen ruin test wall response under static and dynamic action

Abstract

The invention discloses a monitoring method suitable for earthen site test wall response under static and dynamic effects, and relates to the technical field of civil cultural relic protection research, and the method comprises the steps: 1, making an earthen site full-scale model; 2, embedding a sensor in the earthen ruin full-scale model; 3, after the wall body of the earthen ruins full-size model is maintained, spraying a white ground color at one end of the wall body, and painting black spots with the diameter of 10-20 mm on the white ground color; 4, arranging an XTDA three-dimensional optical deformation measurement system; 5, static and dynamic loads are applied to the earthen ruin full-scale model; and 6, recording data in the test process, and verifying and backing up the data. According to the method, monitoring and analysis of data such as displacement, stress strain and acceleration of an earthen ruin body under the static and dynamic action can be met, progressive and instantaneous damage characteristics of the earthen ruin and a reinforcing body of the earthen ruin can be quantitatively described, and a scientific basis is provided for stability evaluation of the earthen ruin, formulation of protection measures and disaster early warning.

Description

Technical Field

[0001] The present invention relates to the technical field of civil heritage conservation research, and particularly to a monitoring method applicable to the response of a test wall of an earthen heritage site under static and dynamic actions. Background Art

[0002] Earthen architecture is one of the most important types of architecture in the history of human development. More than one-third of the cultural heritages are earthen architectural sites, and earthen architectural sites are preserved on all continents of the world. China is one of the countries with the richest types and the widest distribution of earthen heritage sites in the world. The earthen heritage architecture carries a lot of information about China's historical development and social progress, and is a very important artistic display in China's material cultural heritage. For a long time, affected by natural factors and human activities, the preservation of earthen architectural sites has been greatly threatened. Except for a few earthen heritage sites preserved indoors, most of the outdoor sites are inevitably eroded by natural external forces, resulting in various diseases such as extensive development of cracks, erosion, deformation, gullies, surface weathering, and even collapse in the earthen heritage site itself. Especially under the action of huge temperature differences, freeze-thaw cycles, sand-carrying winds, and long-term water-salt migration, the diseases of the already structurally fragile earthen heritage sites further develop, and finally tend to be damaged, collapsed, and disappear, and the precious historical and cultural information carried by them also vanishes.

[0003] In response to diseases such as cracks, erosion, deformation, and surface weathering of earthen heritage sites, researchers have effectively curbed the further development of a large number of earthen heritage site diseases by adopting measures such as bolt anchoring, propping and reinforcement, and crack grouting. Surface anti-weathering and saline-alkali disease prevention and control measures have greatly slowed down the threat of progressive deterioration of the surface layer of the heritage site to the earthen heritage site, and a complete set of technologies, series of reinforcement materials, and technical equipment have been formed. However, due to the relatively fragile interface of the earthen heritage site building, how to collect and obtain data such as internal stress and strain, acceleration, etc. of rammed earth or masonry earthen heritage sites under static and dynamic actions, and quantitatively characterize the progressive and instantaneous damage characteristics of earthen heritage site buildings has become an important link in the stability assessment and reinforcement technology of earthen heritage site buildings. Therefore, researching the technology and method of a test response test device for earthen heritage sites under static and dynamic actions is of great significance for promoting the scientific and systematic development of earthen heritage site protection. Summary of the Invention

[0004] The purpose of the present invention is to provide a monitoring method applicable to the response of a test wall of an earthen heritage site under static and dynamic actions, so as to solve the problems existing in the above-mentioned prior art, and can meet the monitoring and analysis of data such as displacement, stress and strain, acceleration, etc. of the earthen heritage site itself under static and dynamic actions, and can quantitatively describe the progressive and instantaneous damage characteristics of the earthen heritage site and its reinforced body, and provide a scientific basis for the stability assessment of the earthen heritage site, the formulation of protection measures, and disaster warning.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides a monitoring method applicable to the response of a test wall of an earthen heritage site under static and dynamic actions, comprising the following steps:

[0007] Step 1: Fabricate a full-scale model of the earthen heritage site;

[0008] Step 2: Embed a strain gauge sensor assembly, a pressure cell sensor, and an acceleration sensor in the full-scale model of the earthen heritage site;

[0009] Step 3: After the wall of the full-scale model of the earthen heritage site is cured, spray a white background color on one end of the wall, and paint black spots with a diameter ranging from 10 mm to 20 mm on the white background;

[0010] Step 4: Arrange an XTDA three-dimensional optical deformation measurement system capable of monitoring the deformation of the full-scale model of the earthen heritage site;

[0011] Step 5: Apply static and dynamic loads to the full-scale model of the earthen heritage site and record the environmental parameters;

[0012] Step 6: Record the monitoring data of the strain gauge sensor assembly, the acceleration sensor, the pressure cell sensor, and the XTDA three-dimensional optical deformation measurement system during the test, and verify and back up the data.

[0013] Preferably, the strain gauge sensor assembly includes an X-direction strain gauge, a Y-direction strain gauge, and a Z-direction strain gauge. The manufacturing method of the Z-direction strain gauge is to longitudinally cut a cylindrical rubber rod in half, and then paste the strain gauge at the two longitudinal cut surfaces of the rubber rod.

[0014] Preferably, the manufacturing method of the Z-direction strain gauge is to cut the rubber rod longitudinally into two halves with a wallpaper knife, then evenly apply glue on the two longitudinal cut surfaces of the rubber rod, place the strain gauge in the middle of the two half rubber rods in the length direction, then close the two half rubber rods, press for 10 s and then clamp with a clip. After the clip is maintained for 2 h, remove the clip and check if there are any gaps at the bonding site. If there are gaps, fill and seal them with glue. If there are no gaps, the Z-direction strain gauge is manufactured.

[0015] Preferably, the diameter of the rubber rod is 9 mm and the length is 50 mm.

[0016] Preferably, in Step 2, the embedding method of the strain gauge sensor assembly is to position the sensor in the full-scale model of the earthen heritage site according to the position designed in the test. Dig a hole with a depth of 65 mm × 65 mm × 65 mm in the rammed layer within the area range, place the X-direction strain gauge and the Y-direction strain gauge in the correct directions, drill a groove with a depth of 50 mm and a diameter of 9 mm downward in the hole in the Z direction, and then insert the rubber rod.

[0017] Preferably, in step two, the method for embedding the acceleration sensor is to dig a hole with a depth of 5 mm and a size of 15 mm×15 mm in the soil layer within the area range, and embed the acceleration sensor in the dug hole.

[0018] Preferably, in step two, the method for embedding the pressure cell sensor is to lay 2 mm standard sand for leveling within the area range and embed the pressure cell sensor.

[0019] Preferably, the strain gauge sensor assembly, the acceleration sensor, and the pressure cell sensor are all communicatively connected to the data acquisition system.

[0020] Preferably, in step three, after the wall of the full-scale model of the earthen site is cured, spray a white base color on one end of the wall with white matte paint, and after the paint dries, draw black spots with a diameter of 10 mm to 20 mm on the white base color with a black marker pen.

[0021] Preferably, the XTDA three-dimensional optical deformation measurement system includes a tripod, a fill light fixedly arranged on the tripod, an industrial camera fixedly arranged on the tripod, and a workstation communicatively connected to the fill light and the industrial camera.

[0022] The present invention has achieved the following technical effects compared with the prior art:

[0023] The monitoring method applicable to the response of the earthen site test wall under static and dynamic actions provided by the present invention

[0024] (1) The monitoring method applicable to the response of the earthen site test wall under static and dynamic actions provided by the present invention is based on the full-scale wall test model of traditional ramming and masonry processes, establishes a monitoring device for the internal stress and strain, displacement, and acceleration of the earthen site, and a monitoring analysis system for three-dimensional full-field strain measurement. It accurately measures various mechanical parameters inside the soil body and more truly reflects the internal force mechanism and failure mode of the earthen site.

[0025] (2) The monitoring method applicable to the response of the earthen site test wall under static and dynamic actions provided by the present invention is not only applicable to the static and dynamic response test of earthen site buildings, but also provides a new method and idea for related research and projects in the field of geotechnical engineering.

[0026] (3) The multi-variable parameter measurement and high precision of the monitoring method applicable to the response of the earthen site test wall under static and dynamic actions provided by the present invention are helpful for studying the mechanical properties of the object to be measured. The simple operation and high integration reduce the maintenance cost and operation difficulty, improve work efficiency, and can be widely applied to the static and dynamic response test in the fields of earthen site protection and other related geotechnical engineering. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 It is a structural schematic diagram of the monitoring device provided by the present invention for the response of the earthen site test wall under static and dynamic actions;

[0029] In the figure: 1 - XTDA three-dimensional optical deformation measurement system; 2 - data acquisition system; 3 - full-scale model of the earthen site; 4 - layout section of strain gauge sensor components; 5 - layout section of acceleration sensors; 6 - layout section of pressure cell sensors; 7 - signal line; 8 - tripod; 9 - industrial camera; 10 - supplementary light; 11 - industrial camera; 12 - workstation. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] Since the earthen site structure is a discontinuous structure, the layer interface is very weak compared to the rammed soil layer or masonry soil layer and is easily damaged by external forces. A single mechanical parameter and a small-scale earthen site building model cannot consider the influence of the layer interface and size effect and cannot truly reflect the real stress mechanism and failure mode of the earthen site. Therefore, how to monitor and obtain multiple data of the earthen site body under static and dynamic actions based on the full-scale simulation test of the earthen site, quantitatively describe the progressive and instantaneous failure characteristics of the earthen site and its reinforcement, and study the mutual feedback mechanism and dynamic response law between the earthen site body and the reinforcement has become a key issue in evaluating the overall stability of the earthen site. The purpose of the present invention is to provide a monitoring method for the response of the earthen site test wall under static and dynamic actions to solve the problems existing in the prior art, which can meet the monitoring and analysis of data such as displacement, stress and strain, and acceleration of the earthen site body under static and dynamic actions, and can quantitatively describe the progressive and instantaneous failure characteristics of the earthen site and its reinforcement, providing a scientific basis for the stability evaluation, formulation of protection measures and disaster warning of the earthen site.

[0032] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific implementation manners.

[0033] The object of the present invention is to provide a monitoring method applicable to the response of a soil heritage test wall under static and dynamic actions, which is applied to a monitoring device applicable to the response of a soil heritage test wall under static and dynamic actions. The device mainly consists of three major parts, as Figure 1 shown, including a full-scale model 3 of a soil heritage with various sensors arranged therein, a data acquisition system 2, and an XTDA three-dimensional optical deformation measurement system 1. Strain gauges, pressure cells, and acceleration sensors buried in the full-scale model 3 of the soil heritage, i.e., the soil heritage wall, are interconnected through signal lines 7, and then the data is transmitted to the data acquisition system 2 and finally to the PC terminal; the XTDA three-dimensional optical deformation measurement system 1 uses a high-speed camera to collect images of the measured object at various deformation stages in real time, realizes stereo matching by using accurately identified fiducial points or digital speckles, reconstructs the three-dimensional spatial coordinates and displacements of the surface points of the object, calculates the deformation amount of the object, and supplements and verifies the data measured by the strain gauges.

[0034] The monitoring method provided by the present invention applicable to the response of a soil heritage test wall under static and dynamic actions, in this embodiment, includes the following steps:

[0035] Step 1: Fabricate the full-scale model 3 of the soil heritage;

[0036] Step 2: Embed a strain gauge sensor assembly, a pressure cell sensor, and an acceleration sensor in the full-scale model 3 of the soil heritage;

[0037] Step 3: After the wall of the full-scale model 3 of the soil heritage is cured, spray a white background color on one end of the wall, and paint black spots with a diameter of 10 mm to 20 mm on the white background color;

[0038] Step 4: Arrange the XTDA three-dimensional optical deformation measurement system 1 capable of monitoring the deformation of the full-scale model 3 of the soil heritage;

[0039] Step 5: Apply static and dynamic loads to the full-scale model 3 of the soil heritage, and use the data acquisition system 2 and the XTDA three-dimensional optical deformation measurement system 1 to record the changes. During the data acquisition process, environmental parameters related to the response of the test wall, such as temperature, humidity, water content, etc., are also recorded;

[0040] Step 6: Record the monitoring data of the strain gauge sensor assembly, the acceleration sensor, the pressure cell sensor, and the XTDA three-dimensional optical deformation measurement system 1 during the test process, check the collected data to ensure the integrity and accuracy of the data, and then back up the data to prevent data loss and facilitate subsequent data analysis and processing.

[0041] In one embodiment, the strain gauge sensor assembly includes an X-direction strain gauge, a Y-direction strain gauge, and a Z-direction strain gauge. The manufacturing method of the Z-direction strain gauge is to longitudinally cut a cylindrical rubber rod in half, and then paste the strain gauge at the two longitudinal cut surfaces of the rubber rod.

[0042] Further, the manufacturing method of the Z-direction strain gauge is as follows: use a utility knife to cut the rubber rod longitudinally into two halves, then evenly apply glue on the two longitudinal cut surfaces of the rubber rod. The glue is preferably Swiss soft glue ergo6700 (other glues are likely to harden the rubber rod and affect the test sensitivity). Place the strain gauge in the middle of the two halves of the rubber rod along the length direction, then align the two halves of the rubber rod, press for about 10 s and then clamp with a clip to make them fully contact and bond. After the clip is maintained for about 2 h, remove the clip and check if there are any gaps at the bonding site. If there are no gaps, the Z-direction strain gauge is completed. If there are gaps, fill and seal them with glue to complete the manufacturing of the Z-direction strain gauge.

[0043] Further, the diameter of the rubber rod is 9 mm and the length is 50 mm.

[0044] Further, in step two, strain gauges, accelerometers, and pressure cell sensors are laid layer by layer according to different design schemes of the full-scale model 3 of the earthen site. Specifically, the strain gauge sensor assembly is buried along the buried section 4 of the strain gauge sensor assembly. The burying method is to position the sensor in the full-scale model 3 of the earthen site according to the positions designed in the test. Dig a hole with a depth of 65 mm × 65 mm × 65 mm in the rammed layer within the area range. Place the X-direction strain gauge and the Y-direction strain gauge in the correct directions. For the Z direction, drill a groove with a depth of 50 mm and a diameter of 9 mm downward in the hole, and then insert the rubber rod.

[0045] Further, in step two, the accelerometer is buried along the buried section 5 of the accelerometer. The burying method is to dig a hole with a depth of 5 mm and a size of 15 mm × 15 mm in the soil layer within the area range, and bury the accelerometer in the dug hole.

[0046] Further, in step two, the pressure cell sensor is buried along the buried section 6 of the pressure cell sensor. The burying method is to level the area within the range with 2 mm standard sand, bury the pressure cell sensor, compact the soil around the sensor to fix it, compact the signal line 7 with loose soil to prevent the sensor from moving due to the signal line 7, and sort out the signal line 7 according to the position numbers. After one layer is completed, check the sensor numbers and positions again. After confirming that there are no errors, continue with the next step of wall making.

[0047] In one embodiment, the strain gauge sensor assembly, the acceleration sensor, and the pressure cell sensor are all communicatively connected to the data acquisition system 2. After step four and before step five, signal line 7 needs to be connected. Connect the signal lines 7 of each sensor to the data acquisition system 2, and connect the data acquisition system 2 to the PC terminal so that the sensor data can be transmitted to the data acquisition system 2 and then to the PC terminal.

[0048] In one embodiment, step three is to draw speckles on the wall section: After the wall of the full-scale model 3 of the earthen ruins is cured, spray a white base color on one end of the wall with white matte paint. After the paint dries, use a black marker to draw irregular black spots with a diameter of about 10 mm to 20 mm on the white base color, and ensure a certain density for the recognition of the XTDA three-dimensional optical deformation measurement system 1.

[0049] In one embodiment, the XTDA three-dimensional optical deformation measurement system 1 includes a tripod 8, a fill light 10 fixedly arranged on the tripod 8, industrial cameras 9 and 11 fixedly arranged on the tripod 8, and a workstation 12 communicatively connected to the fill light 10 and the industrial camera 9. In step four, the on-site layout of the XTDA three-dimensional optical deformation measurement system 1 needs to ensure the safety and stability of the measurement lens, ensure that the measurement lens remains stationary during the process of collecting speckle images; determine through the camera lens combination that the field of view for collection and shooting can cover the entire area to be measured; keep a safe measurement distance for the measurement head; on the premise of meeting the field of view, keep a safe distance between the measurement head and the object to be measured. The system comes with a built-in photographic lighting system, which is not affected by the on-site ambient light and does not require additional light sources.

[0050] The monitoring method provided by the present invention for the response of the earthen ruins test wall under static and dynamic actions has the following effects:

[0051] (1) Simultaneously obtain multiple mechanical parameters inside the earthen ruins

[0052] By making a full-scale model of the earthen ruins and simultaneously arranging various types of sensors such as strain gauges, pressure cells, and accelerometers according to different earthen ruins model design schemes, fully considering their geometric dimensions, material properties, and structural details, it can more truly reflect the internal force mechanism and failure mode of the earthen ruins.

[0053] (2) Improve the measurement of the internal deformation of the soil mass by the strain gauge sensor assembly

[0054] Select a rubber rod that can accurately respond to the deformation of the soil mass as the deformation transfer medium, paste and wrap a strain gauge with high sensitivity in the rubber rod and arrange it inside the earthen ruins test wall, so that the deformation of the soil mass is transferred to the strain gauge, driving the strain gauge to expand and contract, and measuring the real and stable deformation inside the soil mass.

[0055] (3) Supplementary verification of sensor data for the XTDA three-dimensional optical deformation measurement system

[0056] The XTDA three-dimensional optical deformation measurement system measures and calculates the deformation of an object, and converts the calculation into stress and strain values of the test model, supplementing the tensile stress data that cannot be measured by the pressure cell sensor.

[0057] (4) Fully meet the data monitoring and acquisition of the earthen site interface

[0058] The device provided by the present invention not only meets the acquisition of sensor data in a small area, but also can acquire data of the entire wall section, indicating that the test response device fully meets the data monitoring and acquisition of the earthen site interface under static and dynamic actions.

[0059] (5) Measure the internal stress of the soil mass more realistically and accurately

[0060] At the same time, strain gauges and soil pressure cell sensors are arranged, and the true stress inside the test wall is measured by the mutual assistance of the two.

[0061] The monitoring method provided by the present invention for the response of the earthen site test wall under static and dynamic actions is based on a full-scale wall test model of traditional ramming and masonry processes, establishing a monitoring device for the three-dimensional full-field strain measurement system of internal stress, strain, displacement and acceleration of the earthen site, and a monitoring and analysis system for multi-variable parameters, accurately measuring various mechanical parameters inside the soil mass, and more realistically reflecting the stress mechanism and failure mode inside the earthen site;

[0062] The device and method provided by the present invention are not only applicable to the static and dynamic response test of earthen site buildings, but also provide a new method and idea for related research and engineering in the field of geotechnical engineering.

[0063] The multi-variable parameter measurement and high precision of the device provided by the present invention contribute to the study of the mechanical properties of the object to be measured. The simple operation and high integration reduce the maintenance cost and operation difficulty, improve the work efficiency, and can be widely applied to the static and dynamic response test of earthen site protection and other related fields of geotechnical engineering.

[0064] In the present invention, specific examples are used to elaborate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A monitoring method for the response of earthen ruins test walls under static and dynamic effects, characterized in that: The following steps are involved: Step 1: Make a full-scale model of the earthen site; Step 2: embedding a strain gauge sensor assembly, a pressure box sensor and an acceleration sensor in the full-scale model of the earthen ruins; Step 3: After the wall of the full-scale model of the earthen ruins is cured, a white base color is sprayed on one end of the wall, and black spots with a diameter of 10 mm to 20 mm are painted on the white base color; Step 4: Arrange an XTDA three-dimensional optical deformation measurement system capable of monitoring the deformation of the full-scale model of the earthen site; Step 5: applying static and dynamic loads to the full-scale model of the earthen ruins, and recording environmental parameters; Step 6: Record the monitoring data of the strain gauge sensor assembly, the acceleration sensor, the pressure box sensor, and the XTDA three-dimensional optical deformation measurement system during the test, and verify and back up the data.

2. A monitoring method for the response of an earthen site test wall under static and dynamic action according to claim 1, characterized in that: The strain gauge sensor assembly includes an X-axis strain gauge, a Y-axis strain gauge and a Z-axis strain gauge. The Z-axis strain gauge is manufactured by cutting a cylindrical rubber rod longitudinally from the middle and then pasting the strain gauge to two longitudinal sections of the rubber rod.

3. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 2 is characterized by: The manufacturing method of the Z-axis strain gauge is as follows: use a wallpaper knife to cut the rubber rod into two halves along the longitudinal direction, then evenly apply glue on the two longitudinal sections of the rubber rod, place the strain gauge between the two halves of the rubber rod in the length direction, then align the two halves of the rubber rod, press for 10 seconds, clamp them with a clamp, maintain the clamp for 2 hours, then remove the clamp, check whether there is a gap at the bonding position, if there is a gap, fill and seal it with glue, if there is no gap, the Z-axis strain gauge is completed.

4. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 3 is characterized by: The rubber rod has a diameter of 9 mm and a length of 50 mm.

5. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 4 is characterized by: In step 2, the embedding method of the strain gauge sensor assembly is to locate the position of the sensor in the full-scale model of the earthen site according to the position designed by the experiment, dig a 65mm×65mm×65mm hole in the rammed layer within the area, place the X-axis strain gauge and the Y-axis strain gauge in the direction, drill a 50mm deep and 9mm diameter groove downward in the hole in the Z direction, and then insert the rubber rod.

6. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 5 is characterized by: In step 2, the method for embedding the acceleration sensor is to dig a 15mm×15mm hole with a depth of 5mm in the soil layer within the area, and bury the acceleration sensor in the dug hole.

7. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 6 is characterized by: In step 2, the method for embedding the pressure box sensor is to spread 2 mm standard sand within the area for leveling and embed the pressure box sensor.

8. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 7 is characterized by: The strain gauge sensor assembly, the acceleration sensor, and the pressure box sensor are all communicatively connected to a data acquisition system.

9. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 1 is characterized by: In step three, after the wall maintenance of the full-scale model of the earthen ruins is completed, a white matte paint is used to spray a white base color on one end of the wall. After the paint is dry, black spots with a diameter of 10 mm to 20 mm are painted on the white base color with a black marker.

10. The monitoring method for the response of earthen ruins test wall under static and dynamic action according to claim 1, characterized in that: The XTDA three-dimensional optical deformation measurement system includes a tripod, a fill light fixed on the tripod, an industrial camera fixed on the tripod, and a workstation communicatively connected to the fill light and the industrial camera.

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