Method for detecting performance of geocell filled with solid waste recycled aggregate

Abstract

The present application relates to the technical field of geocell detection, and particularly relates to a performance detection method of a geocell filled with solid waste recycled aggregate, which comprises determining a target detection unit and dividing a monitoring sub-region to construct a basic analysis unit; filling simulation aggregate and determining a compact state according to a height change trend; applying a pre-pressing excitation, determining an initial performance state according to a response peak value and a time trend stabilization characteristic of each sub-region, and terminating if unqualified; applying a cyclic compression load, tracking a change trend of a strain difference in each basic analysis unit with a cycle number, determining stress transmission balance according to the change trend, and generating a detection result. The present application solves the technical problem that the existing detection method cannot exclude the interference of filling unevenness and hollow protrusion manufacturing defects before loading, resulting in abnormal detection results and non-unique attribution, and further resulting in the inability to accurately evaluate the synergistic buffering effect of the hollow protrusion array and identify the stress abnormal direction and specific position.

Description

Technical Field

[0001] This invention relates to the field of geocell testing technology, and in particular to a method for testing the performance of geocells filled with recycled solid waste aggregate. Background Technology

[0002] Geocells, as a type of grid-like geosynthetic material, are widely used in engineering fields such as roadbed reinforcement, slope protection, and foundation treatment. Using recycled aggregates from construction solid waste as filling materials for geocells is an effective way to realize the resource utilization of solid waste. However, recycled aggregates have characteristics such as sharp edges, high content of needle-like and flaky particles, and high crushing values, which can easily cause impact damage to the inner wall of the geocell sheet. To address this, existing technologies have proposed a technical solution of setting hollow protrusions on the inner wall of the geocell sheet. The concave deformation of the hollow protrusions absorbs the impact energy of the aggregate, and the synergistic effect between multiple protrusions evenly disperses local stress to the surrounding area, thereby reducing stress concentration on the inner wall of the sheet.

[0003] Existing performance testing methods for geocells mainly include: measuring the elastic modulus of the reinforcement layer by monitoring circumferential strain, identifying surface cracks in the geocell through image processing, and detecting fatigue damage through sidewall deformation. However, these methods are all designed to test the overall structural or material properties of general geocells and cannot assess the local synergistic buffering effect of the hollow protrusion array on the inner wall of the sheet. Furthermore, existing testing methods are mostly static tests or single-point monitoring, which makes it difficult to simultaneously eliminate interference from uneven filling and manufacturing defects of the protrusions before loading. They also cannot identify the specific direction and location of stress transfer anomalies, resulting in test results that cannot provide effective optimization guidance for the design of hollow protrusion layouts.

[0004] Therefore, there is an urgent need to propose a detection method specifically for geocells with hollow protrusions, to verify the synergistic buffering effect of their protrusion arrays, and to provide local anomaly direction indication.

[0005] Chinese Patent Publication No. CN118518466A discloses a method for real-time determination of the elastic modulus of a geocell reinforcement layer, comprising the following steps: placing a monitoring device on one side of the geocell to be monitored; monitoring the circumferential strain of the geocell using the monitoring device; and after the circumferential strain measurement of the geocell is completed, storing and organizing the data acquisition device. This invention can measure the elastic modulus of a geocell layer, and the data acquisition device can be adaptively adjusted according to the monitoring environment. It has a wide range of applications and can protect the device from rain and snow, preventing damage caused by rain and snow erosion, thus providing high protective performance.

[0006] However, the method for real-time determination of the elastic modulus of geocell reinforcement layers has the following problems: This scheme lacks any pre-verification means for the consistency of the initial state of the sample during the filling process; it does not set up array-type multi-region synchronous monitoring, but only reflects macroscopic deformation through overall circumferential strain, and cannot distinguish the strain differences in different regions and their evolution trend with the number of load cycles; it also cannot identify the direction and specific location of the anomaly, so the test results cannot distinguish whether the anomaly is caused by uneven filling, manufacturing defects or the structural design itself, and cannot provide optimization direction for the hollow protrusion arrangement design. Summary of the Invention

[0007] To address this, the present invention provides a performance testing method for geocells filled with recycled solid waste aggregates, which overcomes the problem in the prior art where the interference of uneven filling and manufacturing defects of hollow protrusions cannot be eliminated before loading, resulting in inconsistent attribution of abnormal test results, and consequently, the inability to accurately assess the synergistic buffering effect of the hollow protrusion array and identify the direction and specific location of stress anomalies.

[0008] To achieve the above objectives, this invention provides a method for testing the performance of geocells used for filling with recycled solid waste aggregate. It includes: Provide a geocell sample to be tested, determine the target detection unit of the sample, and divide the inner wall of the target detection unit into several monitoring sub-regions to construct a basic analysis unit; Simulated aggregate is filled into the target detection unit and its surrounding cells. During the filling process, the height of the filling layer in the target detection unit is continuously monitored. The filling density of the simulated aggregate in the target detection unit is determined based on the height change trend during the filling process. The target detection unit is subjected to a number of pre-pressure excitations to determine the peak response and response time of each monitoring sub-region to the pre-pressure excitation. The initial performance state of the target detection unit is determined based on the trend of the change in the peak response and the trend of the change in the response time of each monitoring sub-region. A cyclic compression load is applied to the target detection unit, and the strain value of each monitoring sub-region is continuously acquired. Based on the position of each monitoring sub-region in the array, the trend of strain difference between the monitoring sub-regions in each basic analysis unit with the number of load cycles is determined on a per-basic analysis unit basis. The stress transmission balance of the inner wall of the target detection unit is determined based on the trend of strain difference. The impact buffering performance test results of the geocell sample are generated based on the stress transfer uniformity.

[0009] Furthermore, the process of determining the target detection unit of the sample and constructing the basic analysis unit includes: Samples were taken from the geocell to be tested; A cell unit located in the central region of the sample is used as the target detection unit; The inner wall of the target detection unit is divided into several monitoring sub-regions arranged in an array along the length and width directions of the inner wall. A single monitoring sub-region in the array is used as the central monitoring sub-region, and several adjacent monitoring sub-regions of the central monitoring sub-region are used to jointly construct a basic analysis unit, wherein the basic analysis units overlap with each other.

[0010] Furthermore, the sample comprises several interconnected complete cell units, each complete cell unit being a grid structure formed by connecting multiple sheets, and the inner wall surface of a single cell unit is provided with several staggered hollow protrusions and several uniformly distributed through holes.

[0011] Furthermore, the process of determining the filling density state of the simulated aggregate within the target detection unit includes: Simulated aggregate is filled into the target detection unit and its surrounding cell units; Vibration is applied to the simulated aggregate during the filling process; During the continuous application of vibration, the height of the filling layer within the target detection unit is continuously monitored; Based on the filling layer height value when the continuous vibration is in a non-decreasing state, it is determined that the simulated aggregate in the target detection unit has reached a dense filling state.

[0012] Furthermore, the process of determining the initial performance state of the target detection unit includes: Several pre-compression excitations are continuously applied to the surface of the simulated aggregate from above the opening of the target detection unit, and the response peak value and response time of each monitoring sub-region under each pre-compression excitation are collected respectively. Based on the response peak value and response time of each monitoring sub-region collected under several consecutive pre-pressure excitations, the change in response peak value and the change in response time of each monitoring sub-region are determined respectively, and a sequence of response peak value change and a sequence of response time change are constructed. When the response peak change sequence and response time change sequence of each monitoring sub-region both show a decrease and approach zero with the increase of the number of pre-excitations, it is determined that the initial performance state of the target detection unit meets the standard. Based on the fact that the response peak value change sequence or response time change sequence of one or more of the monitoring sub-regions shows a trend of increasing with the increase of the number of pre-excitations, it is determined that the response peak value or response time of the current monitoring sub-region has not stabilized, the initial performance state of the target detection unit is not up to standard, and the detection is terminated.

[0013] Furthermore, the process of determining the response peak change sequence and the response time change sequence includes: By comparing the response peak values ​​of each monitoring sub-region under two adjacent pre-pressure excitations, the change in the response peak value of each monitoring sub-region is obtained; By comparing the response times of each monitoring sub-region under two adjacent pre-pressure excitations, the change in the response time of each monitoring sub-region is obtained; The response peak change of each monitoring sub-region determined under several consecutive pre-pressure excitations is arranged in the order of pre-pressure excitation to form a sequence of response peak change of each monitoring sub-region; The response time changes of each monitoring sub-region determined under several consecutive pre-pressure excitations are arranged in the order of pre-pressure excitation to form a sequence of response time changes of each monitoring sub-region.

[0014] Furthermore, the process of determining the trend of strain differences between monitoring sub-regions within each of the aforementioned basic analysis units as a function of the number of load cycles includes: Within each load cycle, the strain peak value of the central monitoring sub-region and the strain peak values ​​of several adjacent monitoring sub-regions are obtained respectively. The difference between the strain peak value of the central monitoring sub-region and the strain peak value of the adjacent monitoring sub-regions in each direction is calculated to determine the strain difference value in different directions under load cycle. The strain difference values ​​in the same direction under multiple consecutive load cycles are arranged in the order of load cycles to form a sequence of strain difference values ​​in the current direction.

[0015] Furthermore, the process of determining the trend of strain differences between monitoring sub-regions within each of the aforementioned basic analysis units as a function of the number of load cycles also includes: Based on the variation trend of the strain difference value sequence in each direction with the number of load cycles, the variation trend of strain difference in each direction is determined. When the strain difference value sequence in any direction gradually approaches the strain difference value sequence in other directions as the number of load cycles increases, the strain difference change trend is determined to be consistent. When the strain difference value sequence in any direction shows an increasing trend with the number of load cycles, the strain difference change trend is determined to be a continuous increase. When the strain difference value sequence in any direction shows a decreasing trend with the increase of the number of load cycles, the strain difference change trend is determined to be a continuous decrease.

[0016] Furthermore, the process of determining the stress transmission uniformity of the inner wall of the target detection unit includes: When the strain difference value sequence in different directions within any basic analysis unit tends to be consistent with the increase of the number of load cycles, the stress transfer balance of the local area corresponding to the basic analysis unit is determined to be qualified. Based on the fact that the strain difference value sequence in any direction within any basic analysis unit shows an increasing trend with the increase of the number of load cycles, while the strain difference value sequence in other directions tends to be consistent, it is determined that there is stress transmission hindrance in the local area corresponding to the basic analysis unit in that direction. When the strain difference value sequence in any direction within any basic analysis unit shows a decreasing trend with the increase of the number of load cycles, it is determined that there is excessive stress transmission in the local area corresponding to the basic analysis unit in that direction.

[0017] Furthermore, the process of generating the impact buffering performance test results of the geocell sample based on the stress transfer uniformity includes: Based on the stress transmission balance determination results of each of the basic analysis units, the synergistic buffering effect of the local area corresponding to each of the basic analysis units is determined, and the synergistic buffering effect distribution result of the inner wall of the target detection unit is generated. Based on the distribution results of the synergistic buffering effect, the test results of the shock buffering performance of the geocell are generated, wherein the test results include overall test results and local test results.

[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: By continuously monitoring the change trend of the filling layer height during the filling process, and using the fact that the height value no longer decreases under continuous vibration as the criterion for determining dense filling, this invention solves the problem of inconsistent filling states affecting the comparability of subsequent test results. Furthermore, by introducing pre-compression excitation before applying cyclic compression loads, and utilizing the stabilizing characteristics of the response peak and response time of each monitored sub-region under continuous excitation as the criterion for determining the initial performance state, this invention eliminates the interference of uneven filling and manufacturing defects such as hollow protrusions on the test results. This solves the technical problem of inconsistent attribution of anomalies due to the lack of a pre-verification step in traditional methods. By tracking the evolution trend of strain differences in different directions within a basic analysis unit consisting of a central monitoring sub-region and its four adjacent monitoring sub-regions (above, below, left, and right) under cyclic compression loads, the system identifies the uniform transmission of stress in all directions when the strain differences in the four directions tend to be consistent, the presence of stress transmission stagnation in a certain direction when the strain difference in a certain direction continuously increases, and the presence of excessive stress transmission in a certain direction when the strain difference in a certain direction continuously decreases. This achieves a leap from determining the overall stress transmission balance to identifying the direction of local stress anomalies, providing directional guidance for optimizing the spacing of hollow protrusions and improving the positive feedback value of the detection results for structural design.

[0019] Furthermore, this invention divides the inner wall of the target detection unit into rectangular array monitoring sub-regions that match the density of the hollow protrusions. It constructs overlapping basic analysis units using the central monitoring sub-region along with its four adjacent monitoring sub-regions (above, below, left, and right). This allows each basic analysis unit to independently reflect the stress transmission characteristics of a local area. Simultaneously, the overlapping array coverage achieves a holistic characterization of the stress distribution across the entire inner wall, overcoming the limitations of single measuring points in distinguishing stress transmission directions and overall testing in locating local defects. Moreover, by monitoring the change in the height of the filling layer during the filling process, and using a continuous decrease in the change approaching zero as the criterion for determining dense filling, it avoids deviations in detection results caused by inconsistent filling states. This solves the technical problem of traditional detection methods being unable to distinguish defect sources due to the lack of a pre-verification step.

[0020] Furthermore, this invention applies multiple pre-compression excitations to the target detection unit after it has been filled and compacted before applying cyclic compression load, and collects the response peak value and response time of each monitoring sub-region. The change in response peak value and response time between two adjacent excitations decreases and approaches zero with the increase of excitation times as the criterion for determining whether the initial performance state meets the standard. Before loading and testing, this invention simultaneously verifies the consistency between the uniformity of filling and compaction of the simulated aggregate in each region and the initial contact state of the hollow protrusions. This avoids interference with subsequent test results due to uneven filling or defects in protrusion manufacturing, and overcomes the shortcomings of traditional methods that cannot simultaneously evaluate the uniformity of filling and the contact state of protrusions before loading, resulting in non-unique attributions for abnormalities.

[0021] Furthermore, this invention uses the difference between the strain peak values ​​of the central monitoring sub-region and the adjacent monitoring sub-regions in the four directions (upper, lower, left, and right) within the basic analysis unit as the strain difference value in each direction during the cyclic compression load application process. The strain difference values ​​in the same direction under multiple consecutive load cycles are arranged in cyclic order to form a strain difference value sequence. A uniform stress transmission is determined by the consistency of the four-directional strain difference value sequence with increasing load cycles; a continuously increasing strain difference value sequence in a certain direction indicates stress transmission stagnation in that direction; and a continuously decreasing strain difference value sequence in a certain direction indicates excessive stress transmission in that direction. This invention simultaneously evaluates the stress transmission balance in different directions of each local area during the cyclic load application process and generates detection results that include overall pass / fail judgment and indications of the location and defect type of unqualified local areas. This overcomes the shortcomings of traditional methods that can only determine overall pass / fail status and cannot identify the direction and specific location of stress anomalies, providing directional guidance for the local optimization of hollow protrusion arrangement and through-hole distribution. Attached Figure Description

[0022] Figure 1 This is a flowchart of a performance testing method for geocells used for filling solid waste recycled aggregates according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a geocell sample to be tested for filling solid waste recycled aggregate according to an embodiment of the present invention; Figure 3 This is a sensor distribution diagram of geocells used for filling solid waste recycled aggregate according to an embodiment of the present invention. Figure 4 A flowchart for determining the initial performance state of the target detection unit in an embodiment of the present invention; Figure 5 This is a flowchart illustrating the process of determining the stress transmission uniformity of the inner wall of the target detection unit according to an embodiment of the present invention; In the figure, 1-Geocell to be tested, 2-Sheet, 3-Cell unit, 4-Hollow protrusion, 5-Strain gauge, 6-Through hole. Detailed Implementation

[0023] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0024] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0025] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0026] Please see Figure 1 The diagram shows a flowchart of a performance testing method for geocells used for filling solid waste recycled aggregates according to an embodiment of the present invention. The performance testing method of this embodiment includes: Step S1: Provide a geocell sample to be tested, determine the target detection unit of the sample, and divide the inner wall of the target detection unit into several monitoring sub-regions to construct a basic analysis unit; Step S2: Fill the target detection unit and its surrounding cells with simulated aggregate. During the filling process, continuously monitor the height of the filling layer in the target detection unit. Determine the compaction state of the simulated aggregate in the target detection unit based on the height change trend during the filling process. Step S3: Apply a number of pre-pressure excitations to the target detection unit to determine the peak response and response time of each monitoring sub-region to the pre-pressure excitation. Determine the initial performance state of the target detection unit based on the trend of the change in the peak response and the trend of the change in the response time of each monitoring sub-region. Terminate the detection when the initial performance state is unqualified. Step S4: Under the condition that the initial performance state meets the standard, apply a cyclic compression load to the target detection unit, continuously acquire the strain value of each monitoring sub-region, and determine the strain difference trend of the monitoring sub-regions in each basic analysis unit with the number of load cycles based on the position of each monitoring sub-region in the array, taking each basic analysis unit as a unit. Determine the stress transmission balance of the inner wall of the target detection unit according to the strain difference trend. Step S5: Generate the impact buffering performance test results of the geocell sample based on the stress transfer uniformity.

[0027] Specifically, this invention addresses the impact of inconsistent filling states on the comparability of subsequent test results by continuously monitoring the change trend of the filling layer height during the filling process and using the stabilization characteristics of the response peak and response time of each monitored sub-region under continuous vibration as the criterion for determining dense filling. Furthermore, by introducing pre-compression excitation before applying cyclic compression load, and utilizing the stabilization characteristics of the response peak and response time of each monitored sub-region under continuous excitation as the criterion for determining the initial performance state, this invention eliminates the interference of uneven filling and manufacturing defects such as hollow protrusions on the test results. This solves the technical problem of inconsistent attribution of anomalies due to the lack of a pre-verification step in traditional methods. Finally, by tracking cyclic compression... The study analyzes the evolution trend of strain differences in different directions within a basic analysis unit consisting of a central monitoring sub-region and its four adjacent monitoring sub-regions (above, below, left, and right) under reduced load, with the number of load cycles. The study uses the uniformity of strain differences in the four directions to indicate uniform stress transmission, the continuous increase of strain differences in a certain direction to indicate stress transmission stagnation in that direction, and the continuous decrease of strain differences in a certain direction to indicate excessive stress transmission in that direction. This achieves a leap from determining the overall stress transmission balance to identifying the direction of localized stress anomalies, providing directional guidance for optimizing the spacing of hollow protrusions and enhancing the positive feedback value of the detection results for structural design.

[0028] Please see Figure 2 and Figure 3 As shown, Figure 2 This is a schematic diagram of the geocell sample to be tested for use as a filler for recycled solid waste aggregate in an embodiment of the present invention. Figure 3 This is a sensor distribution diagram for geocells used for filling solid waste recycled aggregate according to an embodiment of the present invention. In this embodiment, the process of determining the target detection unit of the sample and constructing the basic analysis unit includes: A sample is taken from the geocell 6 to be tested. The sample contains several interconnected complete geocell units 3. Each geocell unit 3 is formed by connecting multiple sheets 2 to form a grid structure. The inner wall surface of a single complete geocell unit 3 is provided with several staggered hollow protrusions 4 and several uniformly distributed through holes 6. A cell unit located in the central region of the sample is used as the target detection unit; Along the length and width directions of the inner wall of the target detection unit, the inner wall of the target detection unit is divided into several monitoring sub-regions arranged in a rectangular array with a spacing that matches the arrangement spacing of the hollow protrusions 4 on the inner wall of the target detection unit. Using one monitoring sub-region in the rectangular array as the central monitoring sub-region, together with the four adjacent monitoring sub-regions located above, below, to the left and to the right of the central monitoring sub-region, a basic analysis unit is constructed.

[0029] In this embodiment, based on the requirement that at least one complete ring of cell units is needed around the central cell to provide enclosure constraints, the sample contains no less than 3×3 cell units. The cell units outside the central area serve as boundary constraint units to provide boundary constraints to the target detection unit after subsequent filling with simulated aggregate, so as to simulate the mutual constraint effect between adjacent cell units of geocells under actual service conditions.

[0030] In this embodiment, each monitoring sub-region includes at least one hollow protrusion 4 disposed on the inner wall of the sheet, and a strain gauge 5 is attached to the inner wall surface of each monitoring sub-region to ensure that the strain gauge 5 can detect the sheet strain response at the location of the hollow protrusion 4 in that region; the number of monitoring sub-regions is determined according to the arrangement density of the hollow protrusions 4 on the inner wall of the target detection unit, and the spacing between adjacent monitoring sub-regions matches the arrangement spacing of the hollow protrusions 4 on the inner wall of the target detection unit, wherein... The matching relationship is as follows: during the division process, the arrangement spacing of a single hollow protrusion 4 is used as the basic unit, the division spacing is an integer multiple of the basic unit, and the value of the division spacing is such that each monitoring sub-region contains at least one complete hollow protrusion 4; when the arrangement spacing of the hollow protrusion 4 is inconsistent in each direction, the arrangement spacing in each direction is used as the basic unit in the corresponding direction to determine the division spacing in that direction.

[0031] In this embodiment, the strain gauge 5 is a resistance strain gauge, which is attached to the inner wall surface of the sheet corresponding to the monitoring sub-region by adhesive. Each strain gauge is connected to the strain acquisition instrument by wires to collect the strain signal of each monitoring sub-region in real time.

[0032] In this embodiment, the basic analysis units overlap with each other, that is, each monitoring sub-region in the rectangular array simultaneously serves as the central monitoring sub-region or adjacent monitoring sub-region of multiple different basic analysis units.

[0033] In this embodiment, the process of determining the filling density state of the simulated aggregate within the target detection unit based on the height change trend of the height value during the filling process includes: Simulated aggregate is filled into the target detection unit and its surrounding cell units; Vibration is applied to the simulated aggregate during the filling process; During the continuous application of vibration, the height of the filling layer within the target detection unit is continuously monitored; Based on the height change trend of the filling layer height during the filling process, the filling density state of the simulated aggregate is determined.

[0034] In this embodiment, the simulated aggregate is configured according to the gradation curve of the target solid waste recycled aggregate. Its needle-like and flaky particle content and angular characteristics are consistent with the target solid waste recycled aggregate. The particle size distribution of the simulated aggregate matches the opening size and arrangement spacing of the hollow protrusions 4 on the inner wall of the target detection unit.

[0035] Specifically, the particle size range of the particles that account for the main mass proportion in the simulated aggregate corresponds to the opening size of the hollow protrusion 4, so that the aggregate particles can be partially embedded in the gap between adjacent hollow protrusions 4 and form contact with the inner wall of the sheet. At the same time, the particles will not be suspended above the protrusions because their particle size is larger than the arrangement spacing of the hollow protrusions 4. This ensures that the simulated aggregate can effectively contact the hollow protrusions 4 during the filling process and avoids being suspended above the protrusions due to the excessively large aggregate particle size.

[0036] In this embodiment, the vibration is applied by a vibration table, the vibration frequency is determined according to the particle size of the simulated aggregate, and the vibration duration is based on the stability of the filling layer height value, without pre-limiting a fixed vibration time.

[0037] In this embodiment, the height value of the filling layer is monitored by a displacement sensor.

[0038] Specifically, the displacement sensor is positioned above the target detection unit, and its measuring beam is perpendicular to the surface of the simulated aggregate filling layer inside the target detection unit. This is used to collect the vertical distance between the filling layer surface and the sensor in real time, in order to determine the filling layer height value.

[0039] In this embodiment, based on the fact that the height of the filling layer is in a non-decreasing state under vibration, it is determined that the filling of the simulated aggregate in the target detection unit has reached a dense filling state.

[0040] Specifically, during the filling process, the filling layer height value within the acquisition cycle is continuously recorded, and the change in the filling layer height value between adjacent acquisition cycles is calculated. When the change continuously decreases along the acquisition cycle and approaches zero, it is determined that the simulated aggregate filling has reached a dense filling state, and then vibration and filling are stopped. The acquisition cycle is 1 second to 5 seconds.

[0041] Specifically, this invention divides the inner wall of the target detection unit into rectangular array monitoring sub-regions that match the density of the four rows of hollow protrusions. It then constructs overlapping basic analysis units using the central monitoring sub-region along with its four adjacent monitoring sub-regions (above, below, left, and right). This allows each basic analysis unit to independently reflect the stress transmission characteristics of a local area. Simultaneously, the overlapping array coverage achieves a holistic characterization of the stress distribution across the entire inner wall, overcoming the limitations of single measuring points in distinguishing stress transmission directions and overall testing in locating local defects. Furthermore, by monitoring the change in the height of the filling layer during the filling process, and using a continuous decrease in the change approaching zero as the criterion for determining dense filling, it avoids deviations in detection results caused by inconsistent filling states. This solves the technical problem of traditional detection methods being unable to distinguish the source of defects due to the lack of a pre-verification step.

[0042] Please see Figure 4 As shown, this is a flowchart illustrating the process of determining the initial performance state of the target detection unit according to an embodiment of the present invention. In this embodiment, the process of determining the initial performance state of the target detection unit includes: Under the condition that the filling density meets the standard, multiple pre-compression excitations are continuously applied to the surface of the simulated aggregate from above the opening of the target detection unit; The strain gauges 5 in each monitoring sub-region are used to collect the peak response and response time of each monitoring sub-region under each pre-compression excitation. The initial performance state of the target detection unit is determined based on the change trends of the peak response and response time of each monitoring sub-region between two adjacent pre-excitations.

[0043] In this embodiment, the preload excitation is applied by a drop hammer device.

[0044] Specifically, the drop hammer falls from a preset height and impacts the center of the simulated aggregate filling layer within the target detection unit. This allows the impact energy to be transferred through the simulated aggregate to the inner wall of the sheet, creating a stress wave that propagates outwards within the sheet. The mass and fall height of the drop hammer are determined based on the type and particle size of the simulated aggregate. The amplitude of the pre-compression excitation is less than the amplitude of the subsequent cyclic compression load, so as to apply an impact force sufficient to produce a detectable strain response to the sheet while avoiding irreversible deformation of the sheet. The mass and drop height of the falling hammer are used as the starting conditions to test the target detection unit after it is filled and compacted. The strain response signal of each monitoring sub-region is collected by strain gauges. When each monitoring sub-region can collect an effective strain signal higher than the noise level of the strain acquisition instrument, and there is no obvious plastic deformation or crack on the surface of the sheet and the hollow protrusion after the impact, the mass and drop height of the falling hammer are determined as the application parameters for the formal pre-compression excitation. The amplitude of the pre-compression excitation is less than the amplitude of the subsequent cyclic compression load.

[0045] In this embodiment, the pre-compression excitation is applied in the same way for several times, that is, the mass of the falling hammer, the falling height and the impact position are consistent in each pre-compression excitation, wherein the number of pre-compression excitations is at least 3.

[0046] In this embodiment, after all pre-compression excitation is completed and before applying cyclic compression load, the surface of the filling layer of the simulated aggregate in the target detection unit is leveled to restore the surface of the filling layer to a flat state, so as to avoid the local depressions formed by pre-compression excitation from affecting the uniformity of load distribution when subsequent cyclic compression load is applied.

[0047] In this embodiment, the response peak value is the maximum strain value collected by each monitoring sub-region under a single pre-compression excitation, and the response time is the time elapsed from the current application of the pre-compression excitation to the recording of the response peak value in the monitoring sub-region.

[0048] In this embodiment, the trend of response peak change and the trend of response time change are determined by the response peak and response time of each monitoring sub-region between two adjacent pre-pressure excitations.

[0049] Specifically, the response peak value of each monitoring sub-region under the i-th pre-pressure excitation is compared with the response peak value of the same monitoring sub-region under the (i-1)-th pre-pressure excitation to obtain the change in the response peak value of each monitoring sub-region; similarly, the response time of each monitoring sub-region under the i-th pre-pressure excitation is compared with the response time of the same monitoring sub-region under the (i-1)-th pre-pressure excitation to obtain the change in the response time of each monitoring sub-region; i is a positive integer greater than or equal to 2.

[0050] Based on the response peak value change sequence and response time change sequence of each monitoring sub-region obtained under multiple consecutive pre-excitations, the characteristics of the change in response peak value and the change in response time of each monitoring sub-region with the number of pre-excitations are determined: When the response peak value change sequence and response time change sequence of each monitoring sub-region both show a decreasing trend towards zero with the increase of pre-compression excitation times, it is determined that the response peak value and response time of each monitoring sub-region gradually stabilize with the increase of pre-compression excitation times, and the initial performance state of the target detection unit meets the standard. At this time, the simulated aggregate filling is dense and uniform, and the hollow protrusions 4 form effective initial contact with the aggregate in each region, and the initial deformation state of each hollow protrusion 4 is consistent.

[0051] When the response peak change sequence or response time change sequence of one or more monitoring sub-regions shows an increasing trend with the increase of the number of pre-compression excitations, it is determined that the response peak or response time of the monitoring sub-region has not stabilized with the increase of the number of pre-compression excitations, the initial performance state of the target detection unit is not up to standard, the simulated aggregate filling of the inner wall area of ​​the sheet corresponding to the monitoring sub-region is uneven or the hollow protrusion 4 fails to form effective contact with the aggregate due to manufacturing defects, the detection is terminated and the sample is marked as unqualified.

[0052] Specifically, this invention applies multiple pre-compression excitations to the target detection unit after it has been filled and compacted before applying cyclic compression load, and collects the response peak value and response time of each monitoring sub-region. The change in response peak value and response time between two adjacent excitations decreases and approaches zero with the increase of excitation times as the initial performance state meets the standard. Before loading and testing, the consistency between the uniformity of filling and compaction of the simulated aggregate in each region and the initial contact state of the hollow protrusions is verified. This avoids interference with subsequent test results due to uneven filling or defects in protrusion manufacturing. It overcomes the shortcomings of traditional methods that cannot simultaneously evaluate the uniformity of filling and the contact state of protrusions before loading, resulting in non-unique attributions of abnormalities.

[0053] Please see Figure 5 As shown, this is a flowchart illustrating the process of determining the stress transmission uniformity of the inner wall of the target detection unit according to an embodiment of the present invention. In this embodiment, the process of determining the stress transmission uniformity of the inner wall of the target detection unit based on the strain difference variation trend includes: Under the condition that the initial performance state meets the standard, a cyclic compression load is applied to the target detection unit; During the application of the cyclic compressive load, the strain values ​​of each monitoring sub-region are continuously acquired; Based on the position of each monitoring sub-region in the array, taking each basic analysis unit as a unit, the trend of strain difference between the central monitoring sub-region and the four adjacent monitoring sub-regions on the upper, lower, left and right sides of each basic analysis unit as a function of the number of load cycles is determined. Based on the variation trend of strain differences in the four directions within each basic analysis unit with the number of load cycles, the stress transfer uniformity of the inner wall of the target detection unit is determined.

[0054] In this embodiment, the cyclic compression load is applied by a cyclic loading device.

[0055] Specifically, the loading head of the cyclic loading device applies a cyclic compression load to the surface of the simulated aggregate from above the opening of the target detection unit. The loading waveform is a half-sine wave to simulate the load characteristics of the recycled solid waste aggregate under alternating instantaneous impact and continuous compression during actual service. The loading frequency is determined according to the particle size of the simulated aggregate, with its upper limit determined by the sampling frequency of the strain acquisition instrument. At least 10 data points are collected in each load cycle to ensure accurate capture of strain peaks and waveform characteristics. The lower limit ensures detection efficiency and avoids excessively long single detection times. Under the premise of meeting the constraints, the loading frequency is selected according to the particle size of the simulated aggregate, where large-diameter aggregates correspond to low-frequency loading and small-diameter aggregates correspond to high-frequency loading. The load amplitude is determined according to the amplitude of the pre-compression excitation. The load amplitude is greater than the amplitude of the pre-compression excitation, and the load amplitude is determined by a stepwise increasing method under the premise that no strain signal saturation or visible irreversible deformation of the sheet occurs in each monitoring sub-region.

[0056] In this embodiment, the strain value is continuously acquired by strain gauges 5 deployed in each monitoring sub-region. During the application of cyclic compression load, the strain readings of each strain gauge 5 are continuously read by a strain acquisition instrument.

[0057] In this embodiment, the strain difference between the central monitoring sub-region and the four adjacent monitoring sub-regions within each basic analysis unit is determined by calculating the difference between the strain peak values ​​of the central monitoring sub-region and each adjacent monitoring sub-region within the same load cycle.

[0058] Specifically, within each load cycle, the strain peak value of the central monitoring sub-region and the strain peak values ​​of the four adjacent monitoring sub-regions (upper, lower, left, and right) are obtained respectively. The first difference between the strain peak value of the central monitoring sub-region and the strain peak value of the upper adjacent monitoring sub-region, the second difference between the strain peak value of the central monitoring sub-region and the strain peak value of the lower adjacent monitoring sub-region, the third difference between the strain peak value of the left adjacent monitoring sub-region, and the fourth difference between the strain peak value of the right adjacent monitoring sub-region are calculated as the strain difference values ​​in the four directions under that load cycle.

[0059] In this embodiment, the variation characteristics of strain differences in the four directions within each basic analysis unit with the number of load cycles are determined by arranging the strain difference values ​​in each direction according to the order of load cycles and analyzing their variation trends.

[0060] Specifically, the strain difference values ​​in the same direction under multiple consecutive load cycles are arranged in the order of load cycles to form a strain difference value sequence in that direction. Based on the changing trend of the strain difference value sequence in each direction with the number of load cycles, it is determined whether the strain difference in each direction tends to be consistent, shows an increasing trend, or shows a decreasing trend. When the strain difference value sequence in any direction gradually approaches the strain difference value sequence in other directions with the increase of the number of load cycles, it is determined to be consistent. When the strain difference value sequence in any direction shows an increasing trend with the increase of the number of load cycles, it is determined to be continuously increasing. When the strain difference value sequence in any direction shows a decreasing trend with the increase of the number of load cycles, it is determined to be continuously decreasing.

[0061] In this embodiment, when the strain difference values ​​in the four directions within any basic analysis unit tend to be consistent with the increase of the number of load cycles, it is determined that the stress in the local area corresponding to the basic analysis unit is uniformly transmitted in the four directions, and the stress transmission balance of the local area is qualified.

[0062] When the strain difference value in any direction within any basic analysis unit continues to increase with the increase of the number of load cycles, while the strain difference values ​​in other directions tend to be consistent, it is determined that there is stress transmission hindrance in the local area corresponding to the basic analysis unit in that direction. The hollow protrusions 4 in this local area are defective in that direction, or the distribution density or diameter of the through holes 6 in that direction is too large, resulting in insufficient local stiffness of the sheet in that direction and a decrease in stress transmission efficiency.

[0063] When the strain difference value in any direction within any basic analysis unit continuously decreases to below the strain difference value in other directions as the number of load cycles increases, it is determined that there is excessive stress transmission in the local area corresponding to the basic analysis unit in that direction. The hollow protrusions 4 in that local area are defective in that direction, or the distribution density or diameter of the through holes 6 in that direction is too small, resulting in excessive local stiffness of the sheet in that direction, hindering the deformation of the protrusions, and excessive stress concentration in the sheet body.

[0064] In this embodiment, the process of generating the impact buffering performance test results of the geocell sample based on the stress transfer uniformity includes: Obtain the stress transfer balance determination results for each of the basic analysis units; Based on the stress transmission balance determination results of each of the basic analysis units, the synergistic buffering effect of the local area corresponding to each of the basic analysis units is determined, and the synergistic buffering effect distribution result of the inner wall of the target detection unit is generated. Based on the distribution results of the synergistic buffering effect, the test results of the shock buffering performance of the geocell are generated.

[0065] In this embodiment, the distribution results of the synergistic buffering effect include the location information of the local regions corresponding to each of the basic analysis units and the determination results of their stress transfer balance.

[0066] Specifically, for local areas determined to have satisfactory stress transmission balance, the synergistic buffering effect of the local area is marked as satisfactory; for local areas determined to have stress transmission stagnation, the synergistic buffering effect of the local area is marked as unsatisfactory, and the direction of stress transmission stagnation in the local area is indicated; for local areas determined to have excessive stress transmission, the synergistic buffering effect of the local area is marked as unsatisfactory, and the direction of excessive stress transmission in the local area is indicated.

[0067] In this embodiment, the distribution result of the synergistic buffering effect is based on the array arrangement of the inner wall of the target detection unit. The judgment results of each basic analysis unit are marked according to the position of each basic analysis unit in the array to form a synergistic buffering effect distribution map of the inner wall of the target detection unit. In the synergistic buffering effect distribution map, the first mark represents the local area where the synergistic buffering effect is qualified, the second mark represents the local area where stress transmission is blocked and the direction of blockage is marked, and the third mark represents the local area where stress transmission is excessive and the direction of excess is marked.

[0068] In this embodiment, the impact resistance and buffering performance test results include overall test results and local test results.

[0069] Specifically, the overall test result is determined as follows: when the stress transfer balance judgment result of all basic analysis units is qualified, the overall impact buffering performance of the geocell is determined to be qualified; when the stress transfer balance judgment result of one or more basic analysis units is unqualified, the overall impact buffering performance of the geocell is determined to be unqualified.

[0070] The local detection result is, when the overall detection result is unqualified, outputting the synergistic buffering effect distribution map to indicate the location and defect type of the unqualified local area, wherein, The defect types include stress transmission obstruction and stress transmission overload. Stress transmission obstruction is a defect in which the hollow protrusions 4 in a local area are arranged with excessively large spacing or insufficient number in that direction, or the distribution density or diameter of the through holes 6 in that direction is too large, resulting in stress not being effectively transmitted along that direction. Stress transmission overload is a defect in which the hollow protrusions 4 in a local area are arranged with excessively small spacing or excessive number in that direction, or the distribution density or diameter of the through holes 6 in that direction is too small, resulting in excessive concentration and transmission of stress along that direction.

[0071] Specifically, this invention uses the difference between the strain peak values ​​of the central monitoring sub-region and the adjacent monitoring sub-regions in the four directions (upper, lower, left, and right) within the basic analysis unit as the strain difference value in each direction during the application of cyclic compression load. The strain difference values ​​in the same direction under multiple consecutive load cycles are arranged in cyclic order to form a strain difference value sequence. A uniform stress transmission is determined by the consistency of the four-directional strain difference value sequence with increasing load cycles; a continuously increasing strain difference value sequence in a certain direction indicates stress transmission stagnation in that direction; and a continuously decreasing strain difference value sequence in a certain direction indicates excessive stress transmission in that direction. During the application of cyclic load, the stress transmission balance in different directions of each local area is simultaneously evaluated, and further, detection results are generated that include overall pass / fail determination and indications of the location and defect type of unqualified local areas. This overcomes the shortcomings of traditional methods, which can only determine overall pass / fail status and cannot identify the direction and specific location of stress anomalies, providing directional guidance for the local optimization of hollow protrusion arrangement and through-hole distribution.

[0072] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for testing the performance of geocells used for filling with recycled solid waste aggregate, characterized in that, include: Provide a geocell sample to be tested, determine the target detection unit of the sample, and divide the inner wall of the target detection unit into several monitoring sub-regions to construct a basic analysis unit; Simulated aggregate is filled into the target detection unit and its surrounding cells. During the filling process, the height of the filling layer in the target detection unit is continuously monitored. The filling density of the simulated aggregate in the target detection unit is determined based on the height change trend during the filling process. The target detection unit is subjected to a number of pre-pressure excitations to determine the peak response and response time of each monitoring sub-region to the pre-pressure excitation. The initial performance state of the target detection unit is determined based on the trend of the change in the peak response and the trend of the change in the response time of each monitoring sub-region. A cyclic compression load is applied to the target detection unit, and the strain value of each monitoring sub-region is continuously acquired. Based on the position of each monitoring sub-region in the array, the trend of strain difference between the monitoring sub-regions in each basic analysis unit with the number of load cycles is determined on a per-basic analysis unit basis. The stress transmission balance of the inner wall of the target detection unit is determined based on the trend of strain difference. The impact buffering performance test results of the geocell sample are generated based on the stress transfer uniformity.

2. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 1, characterized in that, The process of determining the target detection unit of the sample and constructing the basic analysis unit includes: Samples were taken from the geocell to be tested; A cell unit located in the central region of the sample is used as the target detection unit; The inner wall of the target detection unit is divided into several monitoring sub-regions arranged in an array along the length and width directions of the inner wall. A single monitoring sub-region in the array is used as the central monitoring sub-region, and several adjacent monitoring sub-regions of the central monitoring sub-region are used to jointly construct a basic analysis unit, wherein the basic analysis units overlap with each other.

3. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 2, characterized in that, The sample comprises several interconnected complete cell units. Each complete cell unit is formed by connecting multiple sheets to form a grid structure, and the inner wall surface of a single cell unit is provided with several staggered hollow protrusions and several uniformly distributed through holes.

4. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 3, characterized in that, The process of determining the filling density state of the simulated aggregate within the target detection unit includes: Simulated aggregate is filled into the target detection unit and its surrounding cell units; Vibration is applied to the simulated aggregate during the filling process; During the continuous application of vibration, the height of the filling layer within the target detection unit is continuously monitored; Based on the filling layer height value when the continuous vibration is in a non-decreasing state, it is determined that the simulated aggregate in the target detection unit has reached a dense filling state.

5. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 4, characterized in that, The process of determining the initial performance state of the target detection unit includes: Several pre-compression excitations are continuously applied to the surface of the simulated aggregate from above the opening of the target detection unit, and the response peak value and response time of each monitoring sub-region under each pre-compression excitation are collected respectively. Based on the response peak value and response time of each monitoring sub-region collected under several consecutive pre-pressure excitations, the change in response peak value and the change in response time of each monitoring sub-region are determined respectively, and a sequence of response peak value change and a sequence of response time change are constructed. When the response peak change sequence and response time change sequence of each monitoring sub-region both show a decrease and approach zero with the increase of the number of pre-excitations, it is determined that the initial performance state of the target detection unit meets the standard. Based on the fact that the response peak value change sequence or response time change sequence of one or more of the monitoring sub-regions shows a trend of increasing with the increase of the number of pre-excitations, it is determined that the response peak value or response time of the current monitoring sub-region has not stabilized, the initial performance state of the target detection unit is not up to standard, and the detection is terminated.

6. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 5, characterized in that, The process of determining the response peak change sequence and the response time change sequence includes: By comparing the response peak values ​​of each monitoring sub-region under two adjacent pre-pressure excitations, the change in the response peak value of each monitoring sub-region is obtained; By comparing the response times of each monitoring sub-region under two adjacent pre-pressure excitations, the change in the response time of each monitoring sub-region is obtained; The response peak change of each monitoring sub-region determined under several consecutive pre-pressure excitations is arranged in the order of pre-pressure excitation to form a sequence of response peak change of each monitoring sub-region; The response time changes of each monitoring sub-region determined under several consecutive pre-pressure excitations are arranged in the order of pre-pressure excitation to form a sequence of response time changes of each monitoring sub-region.

7. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 6, characterized in that, The process of determining the trend of strain differences between monitoring sub-regions within each basic analysis unit as a function of load cycles includes: Within each load cycle, the strain peak value of the central monitoring sub-region and the strain peak values ​​of several adjacent monitoring sub-regions are obtained respectively. The difference between the strain peak value of the central monitoring sub-region and the strain peak value of the adjacent monitoring sub-regions in each direction is calculated to determine the strain difference value in different directions under load cycle. The strain difference values ​​in the same direction under multiple consecutive load cycles are arranged in the order of load cycles to form a sequence of strain difference values ​​in the current direction.

8. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 7, characterized in that, The process of determining the trend of strain differences between monitoring sub-regions within each of the basic analysis units as a function of the number of load cycles also includes: Based on the variation trend of the strain difference value sequence in each direction with the number of load cycles, the variation trend of strain difference in each direction is determined. When the strain difference value sequence in any direction gradually approaches the strain difference value sequence in other directions as the number of load cycles increases, the strain difference change trend is determined to be consistent. When the strain difference value sequence in any direction shows an increasing trend with the number of load cycles, the strain difference change trend is determined to be a continuous increase. When the strain difference value sequence in any direction shows a decreasing trend with the increase of the number of load cycles, the strain difference change trend is determined to be a continuous decrease.

9. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 8, characterized in that, The process of determining the stress transmission uniformity of the inner wall of the target detection unit includes: When the strain difference value sequence in different directions within any basic analysis unit tends to be consistent with the increase of the number of load cycles, the stress transfer balance of the local area corresponding to the basic analysis unit is determined to be qualified. Based on the fact that the strain difference value sequence in any direction within any basic analysis unit shows an increasing trend with the increase of the number of load cycles, while the strain difference value sequence in other directions tends to be consistent, it is determined that there is stress transmission hindrance in the local area corresponding to the basic analysis unit in that direction. When the strain difference value sequence in any direction within any basic analysis unit shows a decreasing trend with the increase of the number of load cycles, it is determined that there is excessive stress transmission in the local area corresponding to the basic analysis unit in that direction.

10. The performance testing method for geocells used for filling with recycled solid waste aggregate according to claim 9, characterized in that, The process of generating the impact buffering performance test results of the geocell sample based on the stress transfer uniformity includes: Based on the stress transmission balance determination results of each of the basic analysis units, the synergistic buffering effect of the local area corresponding to each of the basic analysis units is determined, and the synergistic buffering effect distribution result of the inner wall of the target detection unit is generated. Based on the distribution results of the synergistic buffering effect, the test results of the shock buffering performance of the geocell are generated, wherein the test results include overall test results and local test results.

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