A recoverable anchor rod support stress detection method and system

Abstract

The application relates to the technical field of stress detection, in particular to a recoverable anchor rod support stress detection method and system, which comprises the following steps: in the anchor rod drilling process, multiple drilling data of each anchor rod hole are collected in real time; and in the grout solidification process after grouting, part of the anchor rods are selected as monitoring points, stress data of the anchor rods selected as the monitoring points on each section are collected in real time, wherein, the rock layer similarity of any two anchor rods is calculated, all the anchor rods in the same stress area are classified, and the stress abnormality degrees of the anchor rods selected as the monitoring points are obtained; the abnormal increment ratio of adjacent two sections is determined, the stress abnormality degrees of the anchor rods not selected as the monitoring points are estimated, the abnormal evaluation values of each section are calculated, the abnormal conditions of the sections are evaluated, and the anchor rods are recovered. The application can effectively capture the early abnormal change of geological stress, improve the accurate judgment of the recoverable condition of the anchor rods, and ensure the construction safety of the project.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of stress detection, in particular to a recoverable anchor rod support stress detection method and system. BACKGROUND

[0002] Recoverable anchor rod support is a crucial reinforcement means in underground and geotechnical engineering such as tunnels and slopes, mainly by drilling machine to send anchor rods for support into the drilled hole after drilling, and pouring cement slurry or mortar to form a stable support structure. Before the slurry solidifies to form a stable structure, the stress state of the anchor rod needs to be detected to recover the anchor rod.

[0003] When evaluating the stress state of the anchor rod, the stress size of a single anchor rod and its stability over time after the slurry solidifies are mainly used to determine whether to recover the anchor rod. However, in complex geological conditions, the system risk induced by the overall change of the geological structure cannot be effectively perceived. When the rock mass slowly creeps or appears local damage, the mechanical effect produced will be dispersedly applied to multiple anchor rods, causing a collaborative micro change in the group stress, and no sharp stress mutation on a single anchor rod. This distributed and small change is difficult to identify through the stress of a single anchor rod, so that early geological abnormal risks cannot be captured, resulting in misjudgment of the recoverability of the anchor rod and affecting the construction safety of the project. SUMMARY

[0004] In order to solve the above technical problems, a recoverable anchor rod support stress detection method and system are provided to solve the existing problems.

[0005] The technical problem of the application is solved by providing a recoverable anchor rod support stress detection method and system, comprising the following steps:

[0006] In the first aspect, the application provides a recoverable anchor rod support stress detection method, which comprises the following steps:

[0007] During the drilling of the anchor rod, multiple drilling data of each anchor rod hole are collected in real time; and during the solidification of the slurry after grouting, part of the anchor rods are selected as monitoring points, and the stress data of the anchor rods selected as monitoring points on each section are collected in real time, wherein the section includes a conventional section and a reference section;

[0008] According to the geological information of the construction project, the engineering area is divided into different stress regions, the correlation of the drilling data between the anchor rod holes corresponding to any two anchor rods in the same stress region is analyzed, the rock mass similarity of any two anchor rods is calculated, all anchor rods in the same stress region are classified, the difference of the stress data between the anchor rods selected as monitoring points in the same category is evaluated, and the stress abnormality degree of each anchor rod selected as a monitoring point is obtained.

[0009] The abnormal increment ratio of the two adjacent sections is determined by the difference of the stress anomaly degrees of the anchor rods at the same position between the two adjacent sections selected as monitoring points, and the stress anomaly degrees of all anchor rods selected as monitoring points on the reference section are combined to estimate the stress anomaly degrees of the anchor rods on the regular section which are not selected as monitoring points, the abnormal evaluation value of each section is calculated by the cumulative deviation of the stress anomaly degrees of the anchor rods at the symmetrical positions on each section, and the abnormal situation of the section is evaluated to recycle the anchor rods.

[0010] Preferably, the selection of the partial anchor rods as monitoring points comprises: setting multiple sections at a fixed interval along the longitudinal direction of the project, and selecting anchor rods at a plurality of preset key positions on the regular section as monitoring points; and setting a reference section at an interval of a preset number of regular sections, and selecting all anchor rods of the reference section as monitoring points.

[0011] Preferably, the calculation of the rock stratum similarity between the two anchor rods comprises:

[0012] The similarity between the two anchor rods is calculated for each type of drilling data corresponding to the anchor rod holes in the same stress region.

[0013] The rock stratum similarity is a result of forward fusion of the similarities of all types of drilling data of the two anchor rods.

[0014] Preferably, the classification of all anchor rods in the same stress region comprises: randomly selecting an anchor rod as a reference anchor rod from each stress region, and classifying the reference anchor rod and the anchor rods with a rock stratum similarity greater than or equal to a preset first threshold value as a class, and repeating the process for the remaining anchor rods until all anchor rods are classified into multiple classes.

[0015] Preferably, the obtaining of the stress anomaly degrees of the anchor rods selected as monitoring points comprises:

[0016] The difference between the stress data of any anchor rod selected as a monitoring point and the remaining anchor rods selected as monitoring points in the same class to which the anchor rod belongs at all times is calculated as a relative difference.

[0017] The stress anomaly degree is a result of forward fusion of the relative differences of all anchor rods selected as monitoring points in the same class to which the anchor rod belongs.

[0018] Preferably, the determination of the abnormal increment ratio of the two adjacent sections comprises: calculating the relative change rate of the stress anomaly degrees of the anchor rods at the same position between the two adjacent sections selected as monitoring points; and taking the average of all relative change rates between the two adjacent sections as the abnormal increment ratio of the two adjacent sections.

[0019] Preferably, the stress anomaly degree of the anchor rod not selected as the monitoring point on the estimated regular section comprises:

[0020] When the Lth section is the reference section, and the (L+1)th section is the regular section, the calculation formula of the stress anomaly degree of the jth anchor rod not selected as the monitoring point on the (L+1)th section is: wherein, is the stress anomaly degree of the jth anchor rod selected as the monitoring point on the Lth section, is the abnormal increment ratio between the Lth section and the (L+1)th section.

[0021] Based on the stress anomaly degrees of all the anchor rods on the (L+1)th section, the stress anomaly degrees of the anchor rods not selected as the monitoring points on the (L+2)th section are estimated, and the same is sequentially performed until the next section is the reference section.

[0022] Preferably, the calculation of the anomaly evaluation value of each section comprises:

[0023] The difference between the stress anomaly degrees of the two anchor rods at the symmetrical positions on each section is taken as the anomaly deviation.

[0024] The anomaly evaluation value is the result of the positive fusion of the anomaly deviations of all the symmetrical positions on each section.

[0025] Preferably, the evaluation of the anomaly of the section to recover the anchor rod comprises: marking the section with the anomaly evaluation value greater than the preset second threshold value as the abnormal section, otherwise, marking the section as the normal section, and performing the anchor rod recovery operation on the anchor rod on the normal section, and suspending the recovery of the anchor rod on the abnormal section.

[0026] In the second aspect, the embodiments of the present application further provide a recyclable anchor rod support stress detection system, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the recyclable anchor rod support stress detection method according to any one of the above embodiments when the computer program is executed.

[0027] The present application has at least the following beneficial effects:

[0028] ​The application carries out stress monitoring on anchor rods at key positions of conventional sections, carries out stress monitoring on all anchor rods on the reference section, and subsequently estimates the conventional section by using the reference section, so as to ensure the overall evaluation accuracy while realizing low cost; the engineering area is divided into different stress areas, which has the beneficial effect that the areas with different mechanical properties are initially macroscopically distinguished, and the fundamental error caused by comparing anchor rods under completely different stress backgrounds together is avoided; the rock stratum similarity of any two anchor rods is calculated, and all anchor rods in the same stress area are classified, which has the beneficial effect that the similarity of the anchor rods in the same stress area is analyzed on the basis of macroscopic division, so as to secondarily classify the anchor rods, accurately determine the inherent characteristics of the rock stratum where the anchor rod is located, and thus classify the anchor rods in the similar rock stratum into one category; the stress abnormality of each anchor rod selected as a monitoring point is obtained, which has the beneficial effect that the stress data of the anchor rods selected as monitoring points in the same category are compared to evaluate the abnormality of the anchor rods selected as monitoring points, and reflect the possibility that the stress condition of the anchor rod is abnormal; the abnormal increment ratio of two adjacent sections is determined, which has the beneficial effect that the stress abnormality of the anchor rods selected as monitoring points in the two adjacent sections is evaluated to evaluate the abnormal propagation trend of the two adjacent sections, and the dynamic propagation trend of the abnormality along the longitudinal direction of the tunnel is captured; the stress abnormality of the anchor rod not selected as a monitoring point on the conventional section is estimated, which has the beneficial effect that the stress abnormality of the anchor rod not selected as a monitoring point on the entire section is deduced by using the sparse measured points, the probability that the stress of the anchor rod not selected as a monitoring point on the conventional section is in a high abnormal risk state is evaluated, the potential risk evaluation of the position where the monitoring point is not deployed is realized, and the problem caused by the cost limitation and the problem that the steel reinforcement meter cannot be fully laid out are solved; the abnormal evaluation value of each section is calculated, the abnormality of all sections is evaluated, and the anchor rod of the section is recycled, which has the beneficial effect that the abnormal deviation accumulation of the anchor rod at the symmetrical position of each section is considered to evaluate the abnormality of the entire section, the asymmetric deformation or the asymmetric load bearing of the tunnel structure is accurately identified, when the overall stress imbalance of the tunnel is caused by the eccentric pressure, uneven settlement and the like, the mechanical effect cooperatively and asymmetrically acts on the paired symmetrical anchor rods, the early abnormal change of the geological stress is effectively captured by quantifying and accumulating the abnormal deviation of the symmetrical position, the accurate judgment of the recyclable condition of the anchor rod is improved, and the construction safety of the project is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0029] The application further discloses a recyclable anchor rod supporting stress detection method.

[0030] Figure 1 A step flow chart of the recyclable anchor rod supporting stress detection method provided by the application is shown in the figure.

[0031] Figure 2 The step flow chart of the method for obtaining the stress anomaly degree of each anchor rod selected as a monitoring point is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0034] Please refer to Figure 1 which shows the step flow chart of a recoverable anchor rod support stress detection method provided by an embodiment of the present application. The method comprises the following steps:

[0035] Step 1, during the anchor rod drilling process, real-time collection of various drilling data of each anchor rod hole; and after grouting, selection of part of the anchor rods as monitoring points, real-time collection of stress data of the anchor rods selected as monitoring points on each section, wherein the section includes a conventional section and a reference section.

[0036] In tunnel geotechnical engineering, excavation will destroy the stress balance of the original rock-soil body, resulting in deformation, loosening and even collapse of the surrounding rock. Anchor rod is a rod-shaped structure anchored in rock-soil body to maintain the stability of foundation pit or surrounding rock. It is inserted into the rock-soil body through drilling, and the tail is anchored with the external structure to form a stable supporting structure to resist lateral thrust and soil pressure, so as to ensure the stability and safety of underground structure.

[0037] Based on the above analysis, through the geotechnical engineering survey report of the tunnel construction site, the engineering land red line map, topographic map, construction drawing and other construction data, the construction position and design parameters of the anchor rod in the tunnel are determined, and the drilling is completed after the earthwork excavation according to the anchor rod design. During the anchor rod drilling construction process, an intelligent sensor is installed on the drilling machine to real-time collect and record various drilling data of each anchor rod hole, wherein the drilling data includes drilling speed, drill bit torque and vibration signal.

[0038] The anchor rod is installed inside the drilling hole. After the anchor rod is installed and grouting is completed, tensioning and locking are carried out. The steel meter is installed between the anchor rod pad and the nut at the monitoring point, and the stress data of the anchor rod selected as the monitoring point during the grout solidification process are real-time collected.

[0039] The specific process of selecting the anchor rod as the monitoring point is as follows:

[0040] To avoid high monitoring cost, the rebar meter is not installed on all anchor rods, and for the whole tunnel, a monitoring section is set at a fixed interval along the longitudinal direction of the tunnel, and these sections are perpendicular to the longitudinal direction of the tunnel, wherein each section contains a closed support ring composed of a plurality of anchor rods, which are usually arranged in a symmetrical manner at key positions such as the vault, the spandrel, the haunch and the sidewall. It should be noted that the interval between two adjacent sections is 5 meters, and as other embodiments, the implementer can set it according to the actual situation.

[0041] On the conventional section, the anchor rods at the three key positions of the vault, the left spandrel (or the left haunch) and the right spandrel (or the right haunch) are selected as monitoring points; at the same time, a reference section is set every interval of a predetermined number of conventional sections, and all anchor rods on the support ring of the reference section are selected as monitoring points.

[0042] In this embodiment, a reference section is set every interval of 3 conventional sections, and as other embodiments, the implementer can set it according to the actual situation.

[0043] Thus, the stress data of each anchor rod selected as a monitoring point on each section at different times during the setting process of the slurry is obtained, wherein the section includes the conventional section and the reference section.

[0044] It should be noted that all anchor rods have the same length, anchoring force, anchoring parameters, etc. Secondly, the rebar meter is installed on the surface of the tunnel, not inside the borehole.

[0045] At this point, a variety of drilling data for each anchor rod hole and stress data of each anchor rod selected as a monitoring point on each section at different times during the setting process of the slurry are obtained.

[0046] Step 2, according to the geological information of the construction project, the engineering area is divided into different stress regions, the correlation of the drilling data between the anchor rod holes corresponding to any two anchor rods in the same stress region is analyzed, the rock similarity of any two anchor rods is calculated, all anchor rods in the same stress region are classified, the difference of the stress data between the anchor rods selected as monitoring points in the same category is evaluated, and the stress abnormality of each anchor rod selected as a monitoring point is obtained.

[0047] Further, the step flow chart of the method for obtaining the stress abnormality of each anchor rod selected as a monitoring point provided by the embodiment of the application is shown in Figure 2 .

[0048] .The supporting structure formed by the anchor rod increases the tensile capacity of the rock mass itself, improves the bearing capacity thereof, and reinforces the tunnel spandrel. However, before the supporting structure reaches the specified hardness, the supporting stability thereof is insufficient, and generally needs to be supported by the anchor rod. When the mud gradually solidifies and the supporting structure gradually stabilizes, the supporting stress is gradually transferred to the stable supporting structure, and the stress borne by the anchor rod gradually decreases. Then, the anchor rod is recovered according to the unlocking device. During the solidification of the mud, the decay change of the bearing stress of the anchor rod and the supporting structure needs to be monitored in real time, so as to determine whether the anchor rod reaches the recoverable condition, and to evaluate whether the geological structure changes and whether the tunnel engineering is safe.

[0049] Due to the action of the geological structure, the place where the stress of the mud changes is generally concentrated on the interface of the geological structure layer, such as the interface between soft rock and hard rock. The stronger the change rate of the interface is, the more complex the geological force acting on the anchor rod during the penetration thereof is, and the more intense the change of the stress data is. Therefore, the geological condition of the position where the anchor rod is located can be determined according to the drilling data during drilling. If the drilling data of the positions where two anchor rods are located are similar, the geological conditions of the positions are similar.

[0050] Based on the above analysis, the surface of the tunnel is divided into different stress regions in the longitudinal direction of the tunnel according to the geological structure in the geological exploration report of the tunnel construction site.

[0051] It should be noted that the stratigraphic lithology, mechanical parameters and geological structure information of the tunnel along the line are obtained from the geological exploration report. The side of the tunnel bearing the main load is identified as a high stress region, which usually corresponds to the side of the mountain with a larger buried depth and a higher terrain. The other side is identified as a low stress region, which usually corresponds to the side of the mountain with a shallower buried depth and a lower terrain. The region located at the interface of different rock layers, i.e. the interface of different rock layers, is recorded as a mutation region.

[0052] Further, based on the similarity of the drilling data of the anchor holes corresponding to all anchor rods in the same stress region, the anchor rods are classified, specifically:

[0053] The similarity degree of each kind of drilling data of the anchor holes corresponding to any two anchor rods in the same stress region is calculated.

[0054] The similarity degree of all kinds of drilling data of any two anchor rods is fused in a positive direction, and the result is taken as the similarity degree of the rock layers corresponding to any two anchor rods.

[0055] In the embodiment, the maximum-minimum value normalization method is used to normalize each kind of drilling data, and then the reciprocal of the DTW distance of each kind of drilling data corresponding to the anchor hole of any two anchors in the same stress region is calculated to measure the similarity, wherein the calculation process of the DTW distance is a known technology, and will not be described here. As other embodiments, the implementer can measure the similarity by the Pearson correlation coefficient, and the embodiment does not specially limit this. Secondly, the specific process of the positive fusion is that the sum of the similarities of all kinds of drilling data of any two anchors is taken as the rock similarity corresponding to the two anchors. As other embodiments, the implementer can also calculate the mean of the similarities of all kinds of drilling data of any two anchors as the rock similarity corresponding to the two anchors.

[0056] It should be noted that when calculating the reciprocal of the DTW distance, a preset value greater than 0 is added to the denominator to avoid the denominator being 0. In the embodiment, the preset value greater than 0 is 1, and as other embodiments, the implementer can set it according to the actual situation.

[0057] It should be noted that the greater the rock similarity, the more similar the geological state inside the drilling corresponding to the two anchors, and the more similar the geological form.

[0058] A random anchor is selected from each stress region as a reference anchor, and the reference anchor and the anchors with a rock similarity greater than or equal to a preset first threshold value are classified into a category. For the remaining anchors, the process is repeated until all anchors are classified into multiple categories.

[0059] In the embodiment, the preset first threshold value is 0.8, and as other embodiments, the implementer can set it according to the actual situation.

[0060] It should be noted that if the rock similarity between the finally remaining anchors is less than the preset first threshold value, it indicates that the threshold condition is not met. If there are anchors that do not meet the threshold condition in the classification process, the anchors that do not meet the threshold condition are marked as suspected abnormal anchors.

[0061] Further, since the actual reinforcement meter can only sense the longitudinal axial tension of the supporting structure, under normal circumstances, the supporting structure inside the drilling will be deformed due to similar stress changes, and will pull the reinforcement. Therefore, the stress changes caused by the geological conditions represented by the same category to the supporting and anchoring structures are usually similar, that is, the stress size and change difference of different anchors in the same category are relatively small. If the stress changes at different anchors in the same category have significant differences, it indicates that the support stress of the anchor is more likely to be abnormal, and local geological subsidence, displacement and other phenomena are more likely to occur, and the possibility of not meeting the recovery condition is higher.

[0062] Based on the above analysis, the anchor rod selected as a monitoring point in the same category is analyzed for outlier analysis. The anchor rod with significant outlier characteristics is more likely to have abnormalities. Therefore, the difference in stress data of the anchor rod selected as a monitoring point in the same category is analyzed, and the stress abnormality degree is calculated. Specifically,

[0063] For each category, the difference between the stress data of any anchor rod selected as a monitoring point and the stress data of each anchor rod selected as a monitoring point at all times is calculated, and is denoted as a relative difference.

[0064] In this embodiment, the DTW distance between the stress data of any anchor rod selected as a monitoring point and the stress data of each anchor rod selected as a monitoring point at all times is calculated, and is denoted as a relative difference. The DTW distance is a known technology and will not be described here. As other embodiments, the implementer can use other methods of existing technology, such as Euclidean distance, and this embodiment does not make special restrictions.

[0065] The result of forward fusion of the relative difference between the any anchor rod selected as a monitoring point and all anchor rods selected as a monitoring point is used as the stress abnormality degree of the any anchor rod.

[0066] In this embodiment, the specific process of forward fusion is as follows: After normalizing the sum of the relative differences between the any anchor rod selected as a monitoring point and all anchor rods selected as a monitoring point, the stress abnormality degree of the any anchor rod is obtained. As other embodiments, the implementer can also normalize the mean of the relative differences between the any anchor rod and all anchor rods by calculating the mean of the relative differences between the any anchor rod and all anchor rods, and then use the result as the abnormality degree of the any anchor rod. The maximum and minimum value normalization method is used for normalization, and the maximum and minimum value normalization method is a known technology and will not be described here. As other embodiments, the implementer can use other methods of existing technology, such as Z-score standardization method, and this embodiment does not make special restrictions.

[0067] It should be noted that the stress abnormality degree of the suspected abnormal anchor rod selected as a monitoring point is assigned a value of 1. As an embodiment, the implementer can set it according to the actual situation.

[0068] It should be noted that the greater the relative difference, the greater the difference in stress change between the two anchor rods under the same category of geological conditions. The greater the stress abnormality degree, the greater the significant difference in stress data between the anchor rod and all other anchor rods in the same category, and the greater the possibility of abnormal stress at the anchor rod.

[0069] Thus, the stress abnormality degree of each anchor rod selected as a monitoring point is obtained.

[0070] Step 3, the abnormal increment ratio of the two adjacent sections is determined by the difference of the stress abnormality of the anchor rods selected as the monitoring points at the same position between the two adjacent sections, and the stress abnormality of the anchor rods not selected as the monitoring points on the regular section is estimated by combining the stress abnormality of all the anchor rods selected as the monitoring points on the reference section, the abnormal evaluation value of each section is calculated by the cumulative deviation of the stress abnormality of the anchor rods at the symmetrical positions on each section, the abnormal condition of the section is evaluated, and the anchor rod is recycled.

[0071] Further, since the change of the geological anomaly is usually continuous, the stress abnormality of the anchor rod not selected as the monitoring point can be estimated according to the stress abnormality of the anchor rod selected as the monitoring point, specifically:

[0072] The relative change rate of the stress abnormality of the anchor rod selected as the monitoring point at the same position between the two adjacent sections is calculated, and the average of all the relative change rates between the two adjacent sections is taken as the abnormal increment ratio of the two adjacent sections.

[0073] In this embodiment, the relative change rate is calculated by the known technology, which will not be described here; the calculation formula of the abnormal increment ratio of the two adjacent sections is:

[0074]

[0075] Wherein, is the abnormal increment ratio of the Lth section to the L+1th section, is the stress abnormality of the i th anchor rod selected as the monitoring point on the L+1th section, is the stress abnormality of the i th anchor rod selected as the monitoring point on the Lth section, is the number of anchor rods with strain gauges installed at the same position on the Lth section and the L+1th section, wherein, is the relative change rate.

[0076] In this embodiment, since only three anchor rods on the regular section are installed with strain gauges, The value is 3.

[0077] Taking the reference section as the starting point, the stress abnormality of the anchor rod not selected as the monitoring point on the next section is estimated, assuming that the Lth section is the reference section, specifically:

[0078]

[0079] Wherein, is the stress abnormality corresponding to the j th anchor rod not selected as the monitoring point on the L+1th section, is the stress abnormality corresponding to the j th anchor rod selected as the monitoring point on the Lth section, anomaly increment ratio between the Lth section and the L+1th section;

[0080] Based on the stress anomaly degree of the anchor rod selected as the monitoring point on the L+1th section and the estimated stress anomaly degree of the anchor rod not selected as the monitoring point on the L+1th section, the stress anomaly degree of the anchor rod not selected as the monitoring point on the L+2th section is estimated, and the same is sequentially performed until the next section is the reference section.

[0081] It should be noted that since the stress anomaly degree exists in all anchor rods on the L+1th section, based on the anomaly increment ratio between the L+1th section and the L+2th section, in combination with the stress anomaly degree of all anchor rods on the L+1th section, the stress anomaly degree of the anchor rod not selected as the monitoring point on the L+2th section is estimated, and based on the stress anomaly degree of all anchor rods on the L+2th section, the stress anomaly degree of the anchor rod not selected as the monitoring point on the L+3th section is estimated. In this embodiment, every interval of 3 normal sections is set as a reference section, therefore, 3 sections are contained between the adjacent two reference sections, and the L+4th section is the reference section, and no estimation is needed. The stress anomaly degree of the anchor rod not selected as the monitoring point on the L+5th section is estimated from the L+4th section as the starting point, and the same is sequentially performed.

[0082] It should be noted that the greater the anomaly increment ratio is, the more rapidly the stress anomaly condition is intensified along the tunnel excavation direction, and the more continuous the geological anomaly zone is, for example, the tunnel is entering a settlement zone, a slip zone or a huge stress concentration zone. The greater the stress anomaly degree is, the higher the probability of the anchor rod not selected as the monitoring point being in a high abnormal risk state is according to the trend prediction.

[0083] In the tunnel structure, the support forms of the symmetric positions are generally similar. If the local geological structures of the tunnel are similar and uniform, the support stresses of the symmetric positions are generally similar, that is, the stress changes of the anchor rods at the symmetric positions are close. If the stress of the anchor rod is abnormal, it may be that the local geological structure changes. Since the abnormal change of the geological structure is usually continuous, it is reflected on multiple support structures, so when the stress changes of the anchor rods at the symmetric positions are inconsistent, it may be caused by the unqualified single anchor support structure.

[0084] Based on the above analysis, the abnormal evaluation value of each section is calculated by analyzing the difference of the stress anomaly degrees of the anchor rods at the symmetric positions on each section, and the specific method is as follows:

[0085] The difference of the stress anomaly degrees of the two anchor rods at the symmetric positions on both sides of the vault on each section is taken as the abnormal deviation, with the anchor rod at the vault on each section as the symmetric point.

[0086] The result of forward fusion of abnormal deviations at all symmetrical positions on each cross section is used as the abnormality assessment value for each cross section.

[0087] In this embodiment, the absolute value of the difference in stress anomaly between two anchor bolts at symmetrical positions on both sides of the arch on each cross-section is taken as the anomaly deviation. Secondly, the specific process of forward fusion is as follows: the normalized result of the sum of the anomaly deviations at all symmetrical positions on each cross-section is taken as the anomaly assessment value for each cross-section. Alternatively, the implementer can calculate the normalized result of the mean of the anomaly deviations at all symmetrical positions on each cross-section as the anomaly assessment value for each cross-section. Furthermore, the maximum-minimum normalization method is used for normalization processing; this method is a well-known technique and will not be elaborated upon here.

[0088] It should be noted that for anchor bolts selected as monitoring points, the stress anomaly is calculated from the actual measured data, while for anchor bolts not selected as monitoring points, the stress anomaly is an estimated result.

[0089] It should be noted that the larger the abnormal deviation, the larger the obtained abnormal assessment value, indicating that the stress anomaly degree of the two anchors at symmetrical positions is much different, reflecting a more significant asymmetry in the force on both sides. This suggests that the cross-section may have undergone geological anomalies, and the anchors at this cross-section are more likely to require secondary construction.

[0090] Based on the anomaly assessment values, the anomalies of the anchor bolts on the cross-section are evaluated, specifically as follows:

[0091] Cross sections with abnormal assessment values ​​greater than a preset second threshold are marked as abnormal cross sections, and those with values ​​less than a preset second threshold are marked as normal cross sections.

[0092] In this embodiment, the process of obtaining the preset second threshold is as follows: by collecting stress data of anchor bolts when they are retrievable during tunnel construction in historical periods, the abnormal evaluation value of each section is calculated, and the maximum value of all abnormal evaluation values ​​is taken as the preset second threshold. In this embodiment, the preset second threshold is 0.35. As for other implementation methods, the implementer can set it according to the actual situation.

[0093] For anchor bolts on normal cross-sections, anchor bolt retrieval is carried out. For anchor bolts on abnormal cross-sections, retrieval is suspended, and they are manually identified a second time to confirm the cause of the abnormality. After taking remedial and reinforcement measures, the stability of the support structure of the cross-section is reassessed. Once the safety standard is met, anchor bolt retrieval is carried out on the anchor bolts on the abnormal cross-sections.

[0094] Based on the same inventive concept as the above method, the embodiments of the present application also provide a recoverable anchor rod support stress detection system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the above recoverable anchor rod support stress detection methods when executing the computer program.

[0095] It should be understood that, although Figure 1 The steps in the flowchart of the above embodiment are displayed in sequence according to the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, Figure 1 At least part of the steps in the above embodiment can include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but can be executed in rotation or alternation with other steps or sub-steps or stages of other steps.

[0096] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present application.

[0097] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation of the present application. It should be pointed out that, for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solution of the present application, all belong to the protection scope of the technical solution of the present application.

Claims

1. A method of detecting stress in a recoverable anchor rod, characterized by, The method comprises the following steps: In the anchor rod drilling process, multiple drilling data of each anchor rod hole are collected in real time; and in the grouting body solidification process after grouting, part of the anchor rods are selected as monitoring points, and stress data of the anchor rods selected as monitoring points on each section are collected in real time, wherein the section includes a conventional section and a reference section; According to geological information of the construction project, the engineering area is divided into different stress regions, the correlation of drilling data between anchor rod holes corresponding to any two anchor rods in the same stress region is analyzed, the rock stratum similarity of the any two anchor rods is calculated, all anchor rods in the same stress region are classified, the difference of stress data between the anchor rods selected as monitoring points in the same category is evaluated, and the stress abnormality of each anchor rod selected as a monitoring point is obtained. The abnormal increment ratio of the adjacent two sections is determined by using the difference change of the stress abnormality of the anchor rods selected as monitoring points at the same position between the adjacent two sections, and the stress abnormality of the anchor rods not selected as monitoring points on the conventional section is estimated in combination with the stress abnormality of all anchor rods selected as monitoring points on the reference section; the abnormal evaluation value of each section is calculated through the cumulative deviation of the stress abnormality of the anchor rods at the symmetrical positions on each section, the abnormality of the section is evaluated, and the anchor rod is recycled.

2. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The selecting part of the anchor rods as monitoring points comprises: setting multiple sections at a fixed interval along the longitudinal direction of the project, and selecting anchor rods at a plurality of key positions as monitoring points on the conventional section; setting a reference section at an interval of a preset number of conventional sections, and selecting all anchor rods of the reference section as monitoring points.

3. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The calculating the rock stratum similarity of the any two anchor rods comprises: calculating the similarity of each kind of drilling data of the anchor rod holes corresponding to the any two anchor rods in the same stress region; The rock stratum similarity is a result of forward fusion of the similarity of all kinds of drilling data of the any two anchor rods.

4. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The classifying all anchor rods in the same stress region comprises: randomly selecting an anchor rod as a reference anchor rod from each stress region, classifying the reference anchor rod and the anchor rods with a rock stratum similarity greater than or equal to a preset first threshold value as a category, and repeating the process for the remaining anchor rods until all anchor rods are divided into multiple categories.

5. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The obtaining the stress abnormality of each anchor rod selected as a monitoring point comprises: calculating the difference of stress data between any anchor rod selected as a monitoring point and each anchor rod selected as a monitoring point in the same category to which the any anchor rod belongs at all times, and recording the difference as a relative difference; The stress abnormality is a result of forward fusion of the relative differences of all anchor rods selected as monitoring points in the same category to which the any anchor rod belongs.

6. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The determining the abnormal increment ratio of the adjacent two sections comprises: calculating the relative change rate of the stress abnormality of the anchor rods selected as monitoring points at the same position between the adjacent two sections; and taking the average of all relative change rates between the adjacent two sections as the abnormal increment ratio of the adjacent two sections.

7. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The estimating the stress abnormality of the anchor rods not selected as monitoring points on the conventional section comprises: When the Lth section is the reference section and the (L+1)th section is the regular section, the stress anomaly degree of the jth anchor rod not selected as the monitoring point on the (L+1)th section is calculated by the formula: wherein, is the stress anomaly degree of the jth anchor rod selected as the monitoring point on the Lth section, is the abnormal increment ratio between the Lth section and the (L+1)th section. Based on the stress anomaly degrees of all the anchor rods on the L+1 section, the stress anomaly degrees of the anchor rods on the L+2 section which are not selected as the monitoring points are estimated, and the estimation is sequentially performed until the next section is the reference section.

8. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The calculation of the anomaly evaluation value of each section comprises: The difference between the stress anomaly degrees of the two anchor rods at the symmetrical positions on each section is taken as the anomaly deviation. The anomaly evaluation value is the result of the positive fusion of the anomaly deviations of all the symmetrical positions on each section.

9. A recoverable anchor rod support stress detection method according to claim 1, characterized in that, The anomaly evaluation value of each section is calculated, and the anomaly evaluation value of each section is calculated.

10. A recyclable anchor rod support stress detection system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, The anomaly evaluation value of each section is calculated, and the anomaly evaluation value of each section is calculated. The anomaly evaluation value of each section is calculated, and the anomaly evaluation value of each section is calculated. The processor executes the computer program to realize the steps of the recoverable anchor rod support stress detection method according to any one of claims 1-9. The processor executes the computer program to realize the steps of the recoverable anchor rod support stress detection method according to any one of claims 1-9.

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