A wireless transmission pile body internal force test strain sensing system

Abstract

The present application relates to the technical field of strain sensing, in particular to a wireless transmission pile body internal force test strain sensing system, which comprises a pile depth filing module, a frequency band arrangement module, an incremental frequency judgment module, a adjacent frequency checking module and a transmission identification module. In the present application, the sequential relationship of different depth measuring points is established and the depth difference is quantified, the spatial distribution is mapped as the basis for frequency allocation, so that each measuring point forms an ordered and distinguishable frequency interval, reducing the risk of signal aliasing; combined with the continuous calculation and threshold determination of strain change, the transmission frequency is dynamically adjusted according to the stress state, and the perception ability of subtle changes is enhanced; through adjacent frequency difference checking and offset correction, the frequency spectrum interval is maintained stable, and the multi-node concurrent interference is reduced; combined with the frequency matching and sequential identification of the receiving end, the identity and strain state of the measuring point are synchronously analyzed, the manual participation is reduced, and the strain distribution along the depth of the pile body is more continuous and clear.

Description

Technical Field

[0001] This invention relates to the field of strain sensing technology, and in particular to a wireless transmission strain sensing system for testing the internal force of a pile. Background Technology

[0002] The field of strain sensing technology involves acquiring information about the stress state of a structure through strain measurement. It is mainly used in civil engineering structural testing and foundation engineering monitoring. The core aspects of this field include arranging resistance strain gauges or fiber optic strain gauges inside or on the surface of the structure, using changes in resistance or optical signals to reflect the strain distribution of the material under load, and combining static load tests to analyze the axial force transmission process in the pile-soil system. The method includes the process of embedding sensors, fixing wires, connecting signal acquisition instruments, and subsequent data reading and processing. Among them, the traditional wireless transmission strain sensing system for testing the internal force of the pile body refers to the testing method in which resistance strain gauges are welded or tied to the reinforcing cage during the construction of concrete cast-in-place piles and led out to the ground acquisition equipment through wires. It is used to acquire strain data at different depths of the pile body and realize data transmission. The traditional method uses plain round steel bars as the sensor mounting base, fixes the strain gauges by spot welding or wire binding, and uses shielded cables to connect the measuring points in series to the ground static strain gauge for centralized acquisition and recording. At the same time, the test data is manually recorded to complete the internal force analysis.

[0003] Existing technologies rely on traverse wires to bring signals from various measuring points to ground equipment for centralized data acquisition. These traverse wires are numerous and have long paths, making them susceptible to signal attenuation or poor contact due to concrete pouring disturbances or rebar cage deformation during construction. This affects data integrity; for example, in deep pile construction, traverse wires may bend under pressure, resulting in intermittent signals and missing depth data. The traverse wires are connected to the static strain gauge in series, lacking an independent differentiation mechanism between points. Data acquisition relies on manual marking and subsequent processing, which can lead to numbering confusion or recording errors, increasing analytical uncertainty. The transmission method primarily uses fixed signal output, lacking adaptive adjustment capabilities to strain changes. When faced with significant differences in strain amplitude during loading, subtle changes are difficult to identify, making it hard to capture early stress characteristics. Simultaneous acquisition from multiple measuring points lacks effective signal separation methods, leading to signal superposition or interference, especially with a large number of measuring points or similar depths, significantly increasing the difficulty of data differentiation. Data processing relies on manual transcription and organization, which carries the risk of lag and human error. In long-term tests, this can lead to cumulative deviations, affecting the accuracy and reliability of pile axial force distribution analysis. Summary of the Invention

[0004] On the one hand, a wireless transmission strain sensing system for testing the internal force of a pile is provided, the system comprising:

[0005] The pile depth filing module obtains the corresponding installation depth value of the steel cage at the rock and soil layer interface of the concrete cast-in-place pile construction section, sorts the depth values ​​of the strain sensor and establishes the node sequence relationship, calculates the depth difference between adjacent nodes and records the relationship between node number and depth difference, and generates a node depth correspondence table.

[0006] The frequency band arrangement module extracts the adjacent depth difference data of the node depth correspondence table, selects the minimum depth difference as the frequency separation benchmark, obtains the available frequency range of the wireless signal transmission unit, allocates the center frequency according to the node order and limits the upper and lower boundaries, verifies the frequency interval of adjacent nodes, and generates a node frequency interval table.

[0007] The incremental frequency determination module collects the strain values ​​of the strain sensors corresponding to the node frequency interval table at continuous moments during the static load test loading stage, calculates the strain change at adjacent moments to form a change sequence, extracts the change of the steel bar strain measuring point during the unloaded stage and calculates the average change, determines the strain change threshold by combining a set multiple, compares the current change with the strain change threshold, selects the frequency step size according to the change interval and updates the center frequency according to the strain change direction and performs interval verification to generate the node transmission frequency sequence.

[0008] The adjacent frequency verification module calls the node transmission frequency sequence and the node depth correspondence table, calculates the transmission frequency difference of adjacent nodes at the same time, compares the difference with the frequency separation benchmark, performs frequency offset and re-verifies for nodes that do not meet the spacing requirements, and generates a conflict-free frequency sequence.

[0009] The transmission identification module collects the node transmission frequency and arrival order on the ground receiving device based on the conflict-free frequency sequence, matches the received frequency with the node frequency interval table to determine the node number, restores the strain change state according to the frequency offset, and generates a pile strain transmission record.

[0010] As a further embodiment of the present invention, the node depth correspondence table includes a node number sequence, a depth difference distribution set, and a layer identifier set; the node frequency interval table includes a center frequency sequence, a frequency boundary set, and a frequency band interval identifier; the node transmission frequency sequence includes a dynamic frequency trajectory, a change direction marker, and a frequency step size set; the conflict-free frequency sequence includes a correction frequency set, an adjacent frequency interval matrix, and a conflict identifier result; and the pile strain transmission record includes a depth sorting index, a strain state label set, and a frequency matching result.

[0011] As a further aspect of the present invention, the process of calculating the strain change at adjacent time points to form a change sequence specifically involves taking adjacent differences of the strain values ​​at three consecutive time points and performing a moving average to obtain a smooth change sequence. The process of calculating the average change is limited to the arithmetic mean of the changes at no less than five consecutive time points during the no-load stage.

[0012] As a further aspect of the present invention, the set multiple is an integer between 2 and 5 and is fixed within the same test period. The process of comparing the current change with the strain change threshold further includes dividing the current change into three intervals: below the average change, between the average change and the strain change threshold, and above the strain change threshold.

[0013] As a further aspect of the present invention, the pile depth recording module includes:

[0014] The interface depth extraction submodule obtains the installation depth value corresponding to the geotechnical interface position of the rebar cage in the concrete cast-in-place pile construction section, collects the construction section layer record table and rebar cage segment identification data, performs unified conversion on the interface elevation according to the layer number and forms a depth sequence, performs numerical processing on the interface depth and establishes a mapping relationship according to the layer sequence number to generate the interface depth sequence.

[0015] The sensor node sorting submodule obtains the corresponding depth value of the strain sensor based on the interface depth sequence, collects the node number and installation depth data in the sensor installation record table, performs range filtering on the installation depth and retains the data within the construction section, performs ordered arrangement on the filtered depth values ​​and synchronously adjusts the node number order to establish a corresponding relationship, and obtains the node depth sorting.

[0016] The node difference construction submodule sorts the nodes according to their depths, reads the depth data corresponding to the adjacent node numbers, performs difference calculation on the depths of adjacent nodes to form a depth interval sequence, pairs the interval values ​​with the corresponding node numbers and writes them into a structured table, performs sequential merging on all node interval data and establishes a number correspondence relationship, and generates a node depth correspondence table.

[0017] As a further aspect of the present invention, the frequency band arrangement module includes:

[0018] The depth difference benchmark extraction submodule extracts adjacent depth difference data based on the node depth correspondence table, collects the depth difference records corresponding to the node number and reads the adjacent node depth difference data set in sequence, performs filtering on the depth difference data and determines the minimum value as the benchmark data, establishes a correspondence between the benchmark data and the node number and performs unified identification, and generates frequency separation benchmark values.

[0019] The frequency interval allocation submodule obtains the available frequency range of the wireless signal transmitting unit according to the frequency separation reference value, collects the frequency range data of the transmitting unit and allocates the center frequency in the order of node number, performs interval division on the upper and lower boundaries of the node frequency and forms a frequency interval set, and associates and organizes the node number with the corresponding frequency interval to obtain the node frequency interval sequence.

[0020] The interval verification and adjustment submodule calls the node frequency interval sequence, reads the frequency interval data of adjacent nodes and extracts the frequency interval data, performs a consistency judgment between the frequency interval and the frequency separation benchmark value, performs adjustment on the intervals that do not meet the requirements and updates the node interval data, integrates all node frequency intervals in order and establishes a corresponding relationship, and generates a node frequency interval table.

[0021] As a further aspect of the present invention, the incremental frequency determination module includes:

[0022] The strain sequence construction submodule collects strain values ​​of strain sensors at continuous moments during the static load test loading stage according to the node frequency interval table, collects strain records at corresponding moments of measurement points and arranges them in chronological order, performs change calculation on strain values ​​at adjacent moments and forms a change sequence, and simultaneously collects strain records during the no-load stage and extracts change data, performs average calculation on the change amount during the no-load stage and establishes a corresponding relationship to generate a strain change benchmark.

[0023] The threshold determination submodule obtains a set multiple parameter based on the strain change benchmark and performs matching processing. It performs a combined calculation with the strain change benchmark value and the multiple parameter to form threshold data. It aligns the threshold data with the change sequence and establishes a corresponding relationship to obtain a data set for interval determination and generates strain change threshold interval values.

[0024] The frequency update verification submodule reads the change sequence data at the current moment and performs interval matching judgment based on the strain change threshold interval value. It selects frequency step size data according to the change amount interval, extracts the change direction identifier and updates the center frequency data. It performs interval verification on the updated frequency data and performs consistency judgment with the node frequency interval. It integrates the node frequency results in order to generate the node transmission frequency sequence.

[0025] As a further aspect of the present invention, the adjacent frequency verification module includes:

[0026] The frequency difference calculation submodule calls the node transmission frequency sequence and node depth correspondence table, collects the corresponding transmission frequency data of adjacent nodes at the same time and arranges them in node order, performs difference calculation on the transmission frequencies of adjacent nodes and forms a frequency difference sequence, associates and organizes the frequency difference sequence with the node number and establishes an order mapping relationship to generate a node frequency difference sequence.

[0027] The interval determination submodule obtains the frequency separation benchmark based on the node frequency difference sequence and performs matching processing. It compares and judges each node frequency difference data with the frequency separation benchmark item by item, filters out nodes that do not meet the interval requirements and marks the corresponding node number, and associates and organizes the determination results with the node depth correspondence table to generate an interval determination identifier sequence.

[0028] The frequency adjustment verification submodule reads the transmission frequency data corresponding to the nodes that do not meet the interval requirements according to the interval determination identifier sequence, performs frequency offset processing on the associated nodes and updates the transmission frequency sequence, performs difference calculation and consistency verification on the frequency data of adjacent nodes after the update, integrates all node frequency results in order and establishes corresponding relationships to generate a conflict-free frequency sequence.

[0029] As a further aspect of the present invention, the transmission identification module includes:

[0030] The frequency acquisition and matching submodule collects the node transmission frequency and arrival order on the ground receiving device based on the conflict-free frequency sequence, collects the received frequency data and arrival order information at any time in the receiving record, performs interval matching judgment on the received frequency and the node frequency interval table and determines the corresponding node number, associates and organizes the matching result with the arrival order and forms a node identification sequence, and generates a node identification sequence.

[0031] The state restoration submodule obtains the corresponding node transmission frequency data and extracts frequency offset information based on the node identification sequence. It performs matching processing on the frequency offset data and the preset change mapping relationship to restore the strain change state. It associates and organizes the node strain change state with the node number to form a state sequence, thus obtaining the strain change state sequence.

[0032] The depth sorting and recording submodule, based on the strain change state sequence, calls the node depth correspondence table to obtain node depth data, associates the depth corresponding to the node number with the strain change state, sorts the node records according to the depth order to form an ordered record set, writes the sorting result into the structured storage unit and establishes the correspondence between node depth and strain state, and generates the pile strain transmission record.

[0033] As a further aspect of the present invention, the process of selecting the frequency step size according to the range of change specifically involves selecting three discrete frequency step size values ​​that increase arithmetically for each of the three ranges, and the frequency step size value does not exceed half of the frequency separation reference corresponding to the minimum depth difference. The process of updating the center frequency according to the direction of strain change is limited to increasing the center frequency by the frequency step size when the change is positive and decreasing the center frequency by the frequency step size when the change is negative.

[0034] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0035] In this invention, by establishing a sequential relationship between measuring points at different depths and quantifying the depth difference, the spatial distribution is mapped as a basis for frequency allocation, enabling each measuring point to form an orderly and distinguishable frequency range, thus reducing the risk of signal aliasing. By combining continuous calculation of strain changes with threshold determination, the transmission frequency is dynamically adjusted according to the stress state, enhancing the ability to perceive subtle changes. Through adjacent frequency difference verification and offset correction, the spectrum interval is kept stable, reducing multi-node concurrent interference. By combining receiver frequency matching and sequence recognition, the identity of the measuring point and the strain state are synchronously analyzed, reducing manual intervention and making the distribution of pile strain along the depth more continuous and clear. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a system flowchart of the present invention;

[0038] Figure 2 This is a system block diagram of the present invention;

[0039] Figure 3 This is a flowchart of the pile depth documentation module in this invention;

[0040] Figure 4 This is a flowchart of the intermediate frequency band arrangement module of the present invention;

[0041] Figure 5 This is a flowchart of the incremental frequency determination module in this invention;

[0042] Figure 6 This is a flowchart of the adjacent frequency verification module in this invention;

[0043] Figure 7 This is a flowchart of the transmission identification module in this invention. Detailed Implementation

[0044] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0045] This invention provides a wireless transmission strain sensing system for testing the internal force of a pile, such as... Figure 1-2 The diagram shows a wireless transmission strain sensing system for testing the internal force of a pile. The system includes:

[0046] The pile depth filing module obtains the corresponding installation depth value of the reinforcing cage at the rock and soil interface of the concrete cast-in-place pile construction section, sorts the corresponding depth values ​​of the strain sensor and establishes the node sequence relationship, calculates the depth difference between adjacent nodes and records the correspondence between node number and depth difference, and generates a node depth correspondence table.

[0047] The frequency band arrangement module extracts adjacent depth difference data based on the node depth correspondence table, selects the minimum depth difference as the frequency separation benchmark, obtains the available frequency range of the wireless signal transmission unit, allocates center frequencies to nodes in sequence and limits the upper and lower boundaries of the frequencies, verifies the frequency intervals of adjacent nodes and adjusts the allocation results, and generates a node frequency interval table.

[0048] The incremental frequency determination module collects strain values ​​from strain sensors at continuous moments during the static load test loading phase based on the node frequency interval table, calculates the strain change at adjacent moments and forms a change sequence, extracts the change of the steel bar strain measuring points during the unloaded phase and calculates the average change, determines the strain change threshold by combining a set multiple, compares the current change with the strain change threshold, selects the frequency step size according to the change interval and updates the center frequency according to the strain change direction, and performs interval verification on the update results to generate a node transmission frequency sequence.

[0049] The adjacent frequency verification module calls the node transmission frequency sequence and node depth correspondence table, calculates the difference between the transmission frequencies of adjacent nodes at the same time, compares the difference with the frequency separation benchmark, performs frequency offset and re-verifies for nodes that do not meet the spacing requirements, and generates a conflict-free frequency sequence.

[0050] The transmission identification module collects the node transmission frequency and arrival order on the ground receiving device based on the collision-free frequency sequence, matches the received frequency with the node frequency interval table to determine the node number, restores the corresponding strain change state according to the frequency offset, and sorts and records the data according to the pile depth position to generate the pile strain transmission record.

[0051] The node depth correspondence table includes a node number sequence, a depth difference distribution set, and a layer identifier set; the node frequency interval table includes a center frequency sequence, a frequency boundary set, and a frequency band interval identifier; the node transmission frequency sequence includes a dynamic frequency trajectory, a change direction marker, and a frequency step size set; the conflict-free frequency sequence includes a correction frequency set, an adjacent frequency interval matrix, and conflict identifier results; and the pile strain transmission record includes a depth sorting index, a strain state label set, and frequency matching results.

[0052] Specifically, such as Figure 2 , 3 As shown, the pile depth documentation module includes:

[0053] The interface depth extraction submodule obtains the installation depth value corresponding to the geotechnical interface position of the rebar cage in the concrete cast-in-place pile construction section, collects the construction section layer record table and rebar cage segment identification data, performs unified conversion on the interface elevation according to the layer number and forms a depth sequence, performs numerical processing on the interface depth and establishes a mapping relationship according to the layer sequence number to generate the interface depth sequence.

[0054] The layer number, interface elevation, and start and end positions of the rebar cage segments in the construction section layer record table were checked line by line. The pile top elevation was used as a unified benchmark to convert the interface elevation. The conversion method was to subtract the interface elevation from the pile top elevation to obtain the interface depth. In the example, the pile top elevation was 34.600 meters, and the four interface elevations in the layer record were 31.800 meters, 27.400 meters, 21.900 meters, and 16.300 meters, respectively, with corresponding interface depths of 2.800 meters, 7.200 meters, 12.700 meters, and 18.300 meters. The collected rebar cage segment identification data was expanded to segment ranges. The segment start depths of 0.000 meters, 12.000 meters, and 24.000 meters were matched with the interface depths. 2.800 meters and 7.200 meters were assigned to segment 1, and 12.700 meters and 18.300 meters were assigned to segment 2. Subsequently, the interface depths are sorted and rearranged, restoring the disordered data in the original records from shallow to deep, and establishing a mapping relationship between layer sequence numbers. For example, layer sequence 1 corresponds to 2.800 meters, layer sequence 2 to 7.200 meters, layer sequence 3 to 12.700 meters, and layer sequence 4 to 18.300 meters. Interval validation is performed on the depth differences between adjacent interfaces. If the difference is less than 0.500 meters, duplicate data is removed; if it is greater than 15.000 meters, a missing layer is marked. In this embodiment, the differences are 4.400 meters, 5.500 meters, and 5.600 meters, all within the allowable range. An interface depth sequence is generated, recording fields including layer sequence number, interface depth, segment number, and material type, which serves as the unified depth benchmark for subsequent node sorting and frequency allocation.

[0055] The sensor node sorting submodule obtains the corresponding depth value of the strain sensor based on the interface depth sequence, collects the node number and installation depth data in the sensor installation record table, performs range filtering on the installation depth and retains the data within the construction section, performs ordered arrangement on the filtered depth values ​​and synchronously adjusts the node number order to establish a corresponding relationship, and obtains the node depth sorting.

[0056] The node numbers and installation depths from the strain sensor installation record table are read, and the data within the construction section is filtered, removing data exceeding the effective depth range of the pile. In this example, the effective depth range is 0.500 meters to 31.500 meters. One node with a depth of 33.400 meters in the original record was removed, while the remaining eight node depths (14.800 meters, 3.200 meters, 18.600 meters, 6.500 meters, 10.900 meters, 22.100 meters, 26.700 meters, and 30.200 meters) were retained. The filtered depths are then sorted in ascending order, and the node number order is adjusted accordingly. The sorted result is that the depths corresponding to nodes 1 to 8 are 3.200 meters, 6.500 meters, 10.900 meters, 14.800 meters, 18.600 meters, 22.100 meters, 26.700 meters, and 30.200 meters. Then, the interface depth sequence is invoked, and the depth of each node is matched with the adjacent interface intervals. For example, 3.200 meters is between 2.800 meters and 7.200 meters, and is marked as the layer sequence 2 interval; 10.900 meters is between 7.200 meters and 12.700 meters, and is marked as the layer sequence 3 interval. The adjacent depth difference is checked on the sorting results, and the minimum difference must not be less than 1.000 meters. In this embodiment, the minimum difference is 3.300 meters, which meets the condition.

[0057] Table 1 Node Depth Sort Table

[0058] Node numbering after sorting Installation depth, meters Sequence interval Segment number Node 1 3.200 sequence 2 interval 1 Node 2 6.500 sequence 2 interval 1 Node 3 10.900 sequence 3 interval 1 Node 4 14.800 sequence 4 interval 2 Node 5 18.600 sequence 5 interval 2 Node 6 22.100 sequence 5 interval 2 Node 7 26.700 sequence 5 interval 3 Node 8 30.200 sequence 5 interval 3

[0059] As shown in Table 1, the node sorting results have formed a one-to-one correspondence between depth and number, providing input for subsequent difference construction.

[0060] The node difference construction submodule sorts the nodes by depth, reads the depth data corresponding to the adjacent node numbers, performs difference calculation on the depths of adjacent nodes to form a depth interval sequence, pairs the interval values ​​with the corresponding node numbers and writes them into a structured table, performs sequential merging on all node interval data and establishes the number correspondence relationship, and generates a node depth correspondence table.

[0061] Based on the sorted node depth sequence, the depths of adjacent nodes are read pair by pair and the difference is calculated to form a depth interval sequence. In this embodiment, the depth differences between adjacent nodes are 3.300 meters, 4.400 meters, 3.900 meters, 3.800 meters, 3.500 meters, 4.600 meters, and 3.500 meters, respectively. Each difference is paired with the corresponding preceding and following node numbers. For example, node 1 to node 2 corresponds to 3.300 meters, and node 2 to node 3 corresponds to 4.400 meters. All differences are sequentially merged to generate a sequence structure with interval numbers. Then, the interval values ​​are classified into intervals: less than 2.000 meters are marked as adjacent intervals, 2.000 meters to 4.500 meters are marked as regular intervals, and greater than 4.500 meters are marked as extended intervals. In this embodiment, only the 4.600-meter interval between nodes 6 and 7 belongs to the extended interval; the rest are regular intervals. The difference data, node depth, and sequence information are jointly written to form a node depth correspondence table. Each record in this table contains the preceding node number, the following node number, the preceding node depth, the following node depth, and the interval value, providing a direct data source for subsequent frequency separation benchmark extraction.

[0062] Specifically, such as Figure 2 , 4 As shown, the frequency band arrangement module includes:

[0063] The depth difference benchmark extraction submodule extracts adjacent depth difference data based on the node depth correspondence table, collects the depth difference records corresponding to the node number and reads the adjacent node depth difference data set in sequence, performs filtering on the depth difference data and determines the minimum value as the benchmark data, establishes a correspondence between the benchmark data and the node number and performs unified identification, and generates frequency separation benchmark values.

[0064] The depth difference data between adjacent nodes is read one by one from the node depth correspondence table, and a depth difference data set is constructed according to the node number order. In this example, seven sets of adjacent difference data are read from the node depth correspondence table, namely 3.300 meters, 4.400 meters, 3.900 meters, 3.800 meters, 3.500 meters, 4.600 meters, and 3.500 meters. First, the data set is filtered by range, and the filtering rule is to retain only the data within the range of 2.000 meters to exclude abnormally close or excessively large interval data. In this example, all seven sets of data meet the condition. Then, the minimum value extraction operation is performed on the filtered data. The size of each difference is compared in turn, and the minimum value is determined to be 3.300 meters. This value is used as the candidate value for the depth difference benchmark of the current construction section. To ensure the validity of the reference value, the actual depths of nodes 1 and 2 were further verified by referring to the node installation record table. The measured actual depths of node 1 were 3.220 meters and node 2 were 6.510 meters, with deviations from the recorded values ​​of 0.020 meters and 0.010 meters, respectively, both less than the allowable error of 0.050 meters. Therefore, 3.300 meters was confirmed as the depth difference reference value. Subsequently, the depth difference reference value was converted into a frequency separation reference value. Using the engineering calibration ratio, each 1.000 meters corresponds to 1.000 MHz, and 3.300 meters was converted to 3.300 MHz. The value was then processed to ensure accuracy, retaining the value to the 0.100 MHz level, resulting in the frequency separation reference value of 3.300 MHz. This ratio was obtained through field comparative tests. At a ratio of 0.500 MHz, the frequency aliasing between adjacent nodes occurred 7 times; at a ratio of 1.000 MHz, the aliasing decreased to 1 time; and at a ratio of 1.500 MHz, although there was no aliasing, the number of usable nodes decreased. Therefore, 1.000 MHz was determined as the implementation ratio. The frequency separation reference value was mapped to the node number and written into a reference data table for subsequent frequency interval allocation.

[0065] The frequency interval allocation submodule obtains the available frequency range of the wireless signal transmitting unit based on the frequency separation reference value, collects the frequency range data of the transmitting unit and allocates the center frequency in the order of node number, performs interval division on the upper and lower boundaries of the node frequency and forms a set of frequency intervals, and associates and organizes the node number with the corresponding frequency interval to obtain the node frequency interval sequence.

[0066] Based on the frequency separation reference value of 3.300 MHz, the available frequency range of the wireless transmitting unit is read as 470.300 MHz to 489.300 MHz. Boundary reservation processing is performed on this range, with a 0.500 MHz guard band reserved above and below, forming an effective bandwidth of 18.000 MHz. Subsequently, the center frequency allocation operation is performed according to the node number sequence, with nodes arranged one by one at a fixed interval of 3.400 MHz, resulting in center frequencies of 470.800 MHz, 474.200 MHz, 477.600 MHz, 481.000 MHz, 484.400 MHz, 487.800 MHz, 491.200 MHz, and 494.600 MHz respectively. After center frequency allocation, interval boundaries are defined for each node, forming frequency intervals of 0.600 MHz to the left and right. For example, the interval for node 1 is 470.200 MHz to 471.400 MHz, and the interval for node 2 is 473.600 MHz to 474.800 MHz. Then, interval calculation is performed on adjacent node intervals, calculated by subtracting the upper boundary of the preceding node from the lower boundary of the subsequent node. In this embodiment, all intervals are 2.200 MHz. This interval value is compared with the minimum interval of 2.100 MHz after conversion based on the frequency separation reference, confirming that all requirements are met.

[0067] Table 2 Node Frequency Range Table

[0068] Node number Center frequency, megahertz Lower boundary, megahertz Upper boundary, megahertz Adjacent center frequency difference, megahertz Node 1 470.800 470.200 471.400 3.400 Node 2 474.200 473.600 474.800 3.400 Node 3 477.600 477.000 478.200 3.400 Node 4 481.000 480.400 481.600 3.400 Node 5 484.400 483.800 485.000 3.400 Node 6 487.800 487.200 488.400 3.400 Node 7 491.200 490.600 491.800 3.400 Node 8 494.600 494.000 495.200 3.400

[0069] As shown in Table 2, the node frequency interval sequence has formed a complete mapping relationship.

[0070] The interval verification and adjustment submodule calls the node frequency interval sequence, reads the frequency interval data of adjacent nodes and extracts the frequency interval data, performs consistency judgment between the frequency interval and the frequency separation benchmark value, performs adjustment on the intervals that do not meet the requirements and updates the node interval data, integrates all node frequency intervals in order and establishes corresponding relationships, and generates a node frequency interval table.

[0071] The node frequency interval sequence is invoked, and adjacent node interval data is read pair by pair and interval calculation is performed. The obtained interval interval is compared with the minimum allowable interval of 2.100 MHz. In this embodiment, the interval between node 1 and node 2 is 2.200 MHz, the interval between node 2 and node 3 is 2.200 MHz, and the interval of the remaining nodes is 2.200 MHz, all meeting the requirements. To verify the check logic, a simulated abnormal scenario is set up, and the center frequency of node 3 is lowered by 0.300 MHz to 477.300 MHz. At this time, the interval between node 2 and node 3 decreases to 1.900 MHz, which is less than 2.100 MHz, triggering the adjustment mechanism. The adjustment method is to move the center frequency of node 3 up by 0.200 MHz to 477.500 MHz, and the interval is recalculated to 2.100 MHz, meeting the requirements. If a single adjustment does not meet the standard, up to 3 more translation operations are performed; if it still does not meet the standard, the node interval boundary is compressed, reducing it by 0.100 MHz on each side. In this embodiment, boundary compression is not triggered. Generate a table of node frequency ranges that have passed verification, and record the adjustment flag as "no adjustment".

[0072] Specifically, such as Figure 2 , 5 As shown, the incremental frequency determination module includes:

[0073] The strain sequence construction submodule collects strain values ​​of strain sensors at continuous moments during the static load test loading phase according to the node frequency interval table, collects strain records at corresponding moments of measurement points and arranges them in chronological order, performs change calculation on strain values ​​at adjacent moments and forms a change sequence, and simultaneously collects strain records during the no-load phase and extracts change data, performs average calculation on the change amount during the no-load phase and establishes a corresponding relationship to generate a strain change benchmark.

[0074] According to the node frequency interval table, strain sensors are called to collect data node by node. The data source is resistance or vibrating wire strain gauges embedded in the steel cage. The strain values ​​of each node during the loading stage are continuously recorded by a data acquisition instrument at a sampling interval of 1 second. In this embodiment, nodes 1 to 6 are selected as the analysis objects. Strain values ​​are recorded at five time nodes: 0 kN, 2000 kN, 4000 kN, 6000 kN, and 8000 kN during the static load test loading stage. Taking node 3 as an example, its collected values ​​are 15 microstrain, 162 microstrain, 358 microstrain, 547 microstrain, and 731 microstrain, respectively. The collected data are then arranged in chronological order, and the change in strain value at adjacent time points is calculated by subtracting the previous time point value from the later time point value, resulting in a change sequence of 147 microstrain, 196 microstrain, 189 microstrain, and 184 microstrain. Simultaneously, independent data collection was performed during the no-load phase, acquiring 10 sets of steady-state data. The no-load data for node 3 were 12 microstrain, 13 microstrain, 12 microstrain, 14 microstrain, 13 microstrain, 12 microstrain, 13 microstrain, 13 microstrain, 12 microstrain, and 14 microstrain. The same change was calculated on these data, yielding 1 microstrain, 1 microstrain, 2 microstrain, 1 microstrain, 1 microstrain, 1 microstrain, 0 microstrain, 1 microstrain, and 2 microstrain. The absolute values ​​of this sequence were taken and averaged to obtain the no-load change baseline of 1.100 microstrain. During data processing, outlier removal rules were implemented. An outlier was identified when a change exceeded five times the average change of the previous three changes and then decreased by more than 80% of that change at the next moment. In this example, node 5 exhibited an outlier of 412 microstrain at the 4000 kN stage, with normal values ​​of 211 and 228 microstrains before and after it, meeting the outlier criteria. Therefore, the average of the two adjacent valid data points, 219.500 microstrain, was used to replace the outlier. The same process was performed on all nodes to obtain the unloaded variation reference values ​​of nodes 1 to 6 as 0.900 microstrain, 1.000 microstrain, 1.100 microstrain, 1.200 microstrain, 1.000 microstrain, and 0.800 microstrain, respectively. These values ​​were written into the strain sequence data table along with the loading variation sequence as input data for subsequent threshold determination.

[0075] The threshold determination submodule obtains a set multiple parameter based on the strain change benchmark and performs matching processing. It combines the strain change benchmark value and the multiple parameter to form threshold data. It aligns the threshold data with the change sequence range and establishes a correspondence to obtain a data set for interval determination and generates strain change threshold interval values.

[0076] The system reads the set of strain variation benchmarks and calculates threshold data for each node using a multiplier parameter. In this example, the multiplier parameter is experimentally determined to be 6.000. The benchmark value of 1.100 microstrain at node 3 is multiplied by the multiplier parameter to obtain a threshold of 6.600 microstrain. The threshold is then divided into four zones: stable zone, first-level zone, second-level zone, and third-level zone. The division rule is as follows: values ​​below the threshold are considered stable; values ​​from the threshold to 10 times the threshold are considered first-level zone; values ​​from 10 times the threshold to 20 times the threshold are considered second-level zone; and values ​​exceeding 20 times the threshold are considered third-level zone. Taking node 3 as an example, its threshold is 6.600 microstrain. Therefore, 6.600 microstrain to 65.999 microstrain is the first-level zone, 66.000 microstrain to 131.999 microstrain is the second-level zone, and values ​​above 132.000 microstrain are the third-level zone. The strain changes of 147, 196, 189, and 184 microstrains at node 3 all fell within the third-level variation zone. The multiplier parameter was determined through comparative experiments, with four sets of test conditions: 4.000, 5.000, 6.000, and 7.000. The no-load false trigger rate and loading recognition rate were recorded.

[0077] Table 3. Results of Threshold Multiple Test

[0078] Multiple parameter No-load false trigger rate, percentage Loading recognition rate, percentage Number of frequency overlaps between adjacent nodes 4.000 6.8 99.4 5 5.000 3.1 99.2 3 6.000 1.2 98.9 1 7.000 0.8 95.7 1

[0079] As shown in Table 3, when the multiplier is 6.000, the no-load false trigger rate drops to 1.2%, while the recognition rate remains at 98.9%. Therefore, 6.000 was selected as the implementation value. A set of strain change threshold intervals for each node was generated, and a correspondence was established with the change sequence.

[0080] The frequency update verification submodule reads the change sequence data at the current moment and performs interval matching judgment based on the strain change threshold interval. It selects the frequency step size data according to the change amount interval, extracts the change direction identifier and updates the center frequency data. It performs interval verification on the updated frequency data and performs consistency judgment with the node frequency interval. It integrates the node frequency results in order to generate the node transmission frequency sequence.

[0081] The frequency update verification submodule reads the current change value node by node according to the strain change threshold range and performs interval matching judgment. In the embodiment, the current change value of node 3 is 147 microstrain, which falls into the third-level change zone. Therefore, a frequency step size of 0.600 MHz is selected, and the change direction is read as rising. This step size is added to the original center frequency of node 3, 477.600 MHz, to obtain the updated frequency of 478.200 MHz. Then, an interval verification is performed on the updated frequency, comparing it with the interval of node 3 from 477.000 MHz to 478.200 MHz. It is found that the updated value is equal to the upper boundary, so the value is retained. If the updated value exceeds the upper limit of the interval, the upper boundary is directly taken as the frequency. Taking node 2 as an example, its change value is 58 microstrain, which falls into the first-level change zone. The corresponding step size is 0.200 MHz, so 474.200 MHz is updated to 474.400 MHz. Taking node 6 as an example, its change in strain is 96 microstrains, falling into the third-level change region, corresponding to a step size of 0.600 MHz. The frequency is updated from 487.800 MHz to 488.400 MHz. After performing the same operation on all nodes, a node transmission frequency sequence is formed: 470.800 MHz, 474.400 MHz, 478.200 MHz, 481.600 MHz, 485.000 MHz, and 488.400 MHz. This sequence simultaneously reflects the direction and level of node change, providing a basic input for adjacent-channel verification.

[0082] Specifically, such as Figure 2 , 6 As shown, the adjacent frequency verification module includes:

[0083] The frequency difference calculation submodule calls the node transmission frequency sequence and node depth correspondence table, collects the corresponding transmission frequency data of adjacent nodes at the same time and arranges them in node order, performs difference calculation on the transmission frequencies of adjacent nodes and forms a frequency difference sequence, associates and organizes the frequency difference sequence with the node number and establishes an order mapping relationship to generate the node frequency difference sequence.

[0084] The module calls the node transmission frequency sequence and node depth correspondence table, reads the transmission frequency data of adjacent nodes one by one in node number order, and performs difference calculation to form a frequency difference sequence. In this embodiment, the node transmission frequency sequence at the current time is 470.800 MHz, 474.400 MHz, 478.200 MHz, 481.600 MHz, 485.000 MHz, and 488.400 MHz. This submodule first reads the frequency values ​​of adjacent nodes in the order of nodes 1 to 6. For nodes 1 and 2, it performs frequency difference calculation, subtracting the frequency of node 1 (470.800 MHz) from the frequency of node 2 (474.400 MHz) to obtain a frequency difference of 3.600 MHz; the same calculation is performed for nodes 2 and 3 to obtain 3.800 MHz; for nodes 3 and 4, it obtains 3.400 MHz; for nodes 4 and 5, it obtains 3.400 MHz; and for nodes 5 and 6, it obtains 3.400 MHz. Before performing the difference calculation, the validity of each node's frequency data is verified. The verification rule is that the frequency must be within the frequency range of its respective node, and the received timestamp must be within the current sampling period. In this example, node 3 receives a frequency of 478.200 MHz, which falls within the range of 477.000 MHz to 478.200 MHz, meeting the range condition, and therefore participates in the calculation. If a node's frequency is missing, the frequency from the previous moment is used as a substitute, allowing only one consecutive substitution. If this is exceeded, the node is removed from the current frequency difference calculation. After completing the frequency difference calculation, each set of frequency differences is associated with the corresponding node number pair and node depth pair. For example, the frequency difference between node 1 and node 2 is 3.600 MHz, and the depth difference is 3.300 meters; the frequency difference between node 2 and node 3 is 3.800 MHz, and the depth difference is 4.400 meters. Subsequently, a frequency difference sequence record is generated according to the node order. The record fields include the previous node number, the next node number, the previous node depth, the next node depth, and the frequency difference value. To facilitate subsequent calls, this submodule also performs sequential numbering on the frequency difference sequence, forming a continuous record structure with frequency difference numbers 1 to 5. Regarding data consistency, the correspondence between frequency difference and depth difference is synchronously verified. If the ratio of frequency difference to depth difference significantly deviates from the historical statistical range, it is marked as abnormal. In this example, a depth difference of 3.300 meters corresponds to a frequency difference of 3.600 MHz, a ratio of approximately 1.090 MHz per meter, which is within the allowable range of 0.800 to 1.200 MHz per meter, therefore no adjustment is made. A node frequency difference sequence is generated and used as direct input data for the subsequent interval determination submodule.

[0085] The interval determination submodule obtains the frequency separation benchmark and performs matching processing based on the node frequency difference sequence. It compares and judges each node frequency difference data with the frequency separation benchmark item by item, filters out nodes that do not meet the interval requirements and marks the corresponding node number, and associates and organizes the determination results with the node depth correspondence table to generate an interval determination identifier sequence.

[0086] The frequency difference data is read item by item based on the node frequency difference sequence, and a frequency separation reference value of 3.300 MHz is used for item-by-item comparison and judgment. In this embodiment, the frequency difference sequence read is 3.600 MHz, 3.800 MHz, 3.400 MHz, 3.400 MHz, and 3.400 MHz. This submodule performs a comparison operation on each frequency difference. When the frequency difference is greater than or equal to 3.300 MHz, it is marked as meeting the spacing requirement; when the frequency difference is less than 3.300 MHz, it is marked as not meeting the spacing requirement. In this embodiment, all frequency differences are greater than the reference value, so all are marked as meeting the requirement. However, to verify the judgment logic, a simulated operating condition is set, and the frequency of node 3 is reduced from 478.200 MHz to 477.800 MHz. At this time, the frequency difference between node 3 and node 4 becomes 3.200 MHz. The submodule detects that this frequency difference is lower than the reference value of 3.300 MHz and immediately marks node 3 and node 4 as not meeting the spacing requirement. Subsequently, risk levels are assigned to frequency offsets that do not meet the spacing requirements. Frequency offsets between 3.000 MHz and 3.299 MHz are marked as moderate risk, while those below 3.000 MHz are marked as high risk. The aforementioned 3.200 MHz is classified as moderate risk. This submodule also calls the node depth mapping table, writing the depths of node 3 (10.900 meters) and node 4 (14.800 meters) into the identification records, forming a spacing determination identification sequence containing node number, depth, frequency offset, and risk level. After generating the identification sequence, a complete scan of all node pairs is performed to ensure no node pairs are missed or duplicate records are recorded. The spacing determination identification sequence is output, providing precise location information for subsequent frequency adjustment verification.

[0087] The frequency adjustment and verification submodule reads the corresponding transmission frequency data of nodes that do not meet the interval requirements according to the interval judgment identifier sequence, performs frequency offset processing on the associated nodes and updates the transmission frequency sequence, performs difference calculation and consistency verification on the frequency data of adjacent nodes after the update, integrates all node frequency results in order and establishes corresponding relationships to generate a conflict-free frequency sequence.

[0088] The node pairs that do not meet the interval requirement are read according to the interval determination identifier sequence, and frequency offset processing is performed on them. In the example, for the case where the frequency difference between node 3 and node 4 is insufficient, the current center frequency of node 4 (481.000 MHz) and its interval boundary (480.400 MHz to 481.600 MHz) are read first. An upward offset operation is performed first, increasing the frequency of node 4 by 0.200 MHz to 481.200 MHz. The frequency difference between node 3 and node 4 is recalculated to be 3.400 MHz, which meets the baseline requirement. At the same time, the frequency difference between node 4 and node 5 is calculated to be 3.800 MHz, which also meets the requirement, so the adjustment result is retained. If a single offset does not meet the requirement, a second offset is performed, with a step size of 0.200 MHz each time, for a maximum of 3 times. If three consecutive offsets still do not meet the requirement, the offset is performed on the next node, or the reverse offset processing is performed on both nodes simultaneously. Multiple adjustments were not triggered in the example. After adjustment, the frequency difference is recalculated for all nodes, resulting in an updated frequency difference sequence of 3.600 MHz, 3.800 MHz, 3.400 MHz, 3.400 MHz, and 3.400 MHz, all greater than the baseline value. The adjusted frequencies are then written into a collision-free frequency sequence, yielding 470.800 MHz, 474.400 MHz, 477.800 MHz, 481.200 MHz, 484.600 MHz, and 488.400 MHz. This submodule performs a consistency check before writing the results, ensuring that each node's frequency remains within its interval boundaries and guaranteeing that the frequencies of nodes not involved in the adjustment remain unchanged. A collision-free frequency sequence is generated for subsequent use by the transmission identification module.

[0089] Specifically, such as Figure 2 , 7 As shown, the transmission identification module includes:

[0090] The frequency acquisition and matching submodule collects the node transmission frequency and arrival order on the ground receiving device based on the conflict-free frequency sequence, collects the received frequency data and arrival order information in the receiving record, performs interval matching judgment on the received frequency and the node frequency interval table and determines the corresponding node number, associates and organizes the matching result with the arrival order and forms a node identification sequence, and generates the node identification sequence.

[0091] Based on a collision-free frequency sequence, the ground receiving device collects node transmission frequencies and arrival order data. In this embodiment, the receiving device collects frequency data of 470.790 MHz, 474.415 MHz, 477.788 MHz, 481.196 MHz, 484.612 MHz, and 488.395 MHz within the same sampling period. This submodule first performs spectral smoothing on the collected data, taking the average of three adjacent sampling points as the stable frequency value. For example, the frequency of node 3 is smoothed to 477.788 MHz. Subsequently, the processed frequency data is compared item by item with the node frequency interval table to determine the node number. In this embodiment, 477.788 MHz falls within the node 3 interval of 477.000 MHz to 478.200 MHz, and is therefore identified as node 3. If a frequency falls into two intervals simultaneously, it is determined according to the principle of minimizing its distance from the center frequency. No overlap occurs in this embodiment. The node numbers are then associated with arrival order information; for example, node 1 corresponds to order 1, and node 2 corresponds to order 2. This forms a node identification sequence, with recorded fields including node number, receiving frequency, and arrival order, providing input for state reconstruction.

[0092] The state restoration submodule obtains the corresponding node's transmission frequency data and extracts the frequency offset information based on the node identification sequence. It performs matching processing on the frequency offset data and the preset change mapping relationship to restore the strain change state. It associates and organizes the node strain change state with the node number to form a state sequence, thus obtaining the strain change state sequence.

[0093] The current receiving frequency of each node is read based on the node identification sequence, and the static center frequency in the conflict-free frequency sequence is used for offset calculation. In this example, the static center frequency of node 3 is 477.600 MHz, and the current receiving frequency is 477.800 MHz, with a difference of 0.200 MHz. This submodule performs state mapping processing based on the frequency offset. An offset of 0.200 MHz corresponds to a first-level change state, 0.400 MHz corresponds to a second-level change state, and 0.600 MHz corresponds to a third-level change state. In this example, node 3 is determined to be in a first-level rising state, and node 6 rises from 487.800 MHz to 488.400 MHz, with an offset of 0.600 MHz, and is determined to be in a third-level rising state. If the frequency is lower than the static center frequency, it is marked as a falling state and classified into levels according to the same step size. This submodule associates the node number with the state level to generate a strain change state sequence, for example, node 1 is stable, node 2 is in a first-level rising state, and node 6 is in a third-level rising state. This sequence is used to express the strain change trend at different depths of the pile.

[0094] The depth sorting and recording submodule is based on the strain change state sequence. It calls the node depth correspondence table to obtain node depth data, associates the depth corresponding to the node number with the strain change state, sorts the node records according to the depth order and forms an ordered record set, writes the sorting result into the structured storage unit and establishes the correspondence between node depth and strain state, and generates the pile strain transmission record.

[0095] Based on the strain change state sequence, the node depth correspondence table is invoked to obtain the installation depth data of each node, and correlation processing is performed. In this embodiment, node 6 with a depth of 22.100 meters corresponds to the third-level rising state, and node 1 with a depth of 3.200 meters corresponds to the stable state. Subsequently, all node records are sorted from shallowest to deepest, resulting in the following sorting order: node 1, node 2, node 3, node 4, node 5, and node 6. The sorted node depth and state information are written into a structured storage unit, with record fields including node number, node depth, state level, and receiving frequency. Integrity verification is performed during the writing process to ensure that the node number is unique, the depth increases sequentially, and the state level conforms to the preset range. A pile strain transmission record is generated, realizing a complete closed-loop data chain mapping from frequency signal to structural state.

[0096] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wireless transmission strain sensing system for testing internal forces in piles, characterized in that, The system includes: The pile depth filing module obtains the corresponding installation depth value of the steel cage at the rock and soil layer interface of the concrete cast-in-place pile construction section, sorts the depth values ​​of the strain sensor and establishes the node sequence relationship, calculates the depth difference between adjacent nodes and records the relationship between node number and depth difference, and generates a node depth correspondence table. The frequency band arrangement module extracts the adjacent depth difference data of the node depth correspondence table, selects the minimum depth difference as the frequency separation benchmark, obtains the available frequency range of the wireless signal transmission unit, allocates the center frequency according to the node order and limits the upper and lower boundaries, verifies the frequency interval of adjacent nodes, and generates a node frequency interval table. The incremental frequency determination module collects the strain values ​​of the strain sensors corresponding to the node frequency interval table at continuous moments during the static load test loading stage, calculates the strain change at adjacent moments to form a change sequence, extracts the change of the steel bar strain measuring point during the unloaded stage and calculates the average change, determines the strain change threshold by combining a set multiple, compares the current change with the strain change threshold, selects the frequency step size according to the change interval and updates the center frequency according to the strain change direction and performs interval verification to generate the node transmission frequency sequence. The adjacent frequency verification module calls the node transmission frequency sequence and the node depth correspondence table, calculates the transmission frequency difference of adjacent nodes at the same time, compares the difference with the frequency separation benchmark, performs frequency offset and re-verifies for nodes that do not meet the spacing requirements, and generates a conflict-free frequency sequence. The transmission identification module collects the node transmission frequency and arrival order on the ground receiving device based on the conflict-free frequency sequence, matches the received frequency with the node frequency interval table to determine the node number, restores the strain change state according to the frequency offset, and generates a pile strain transmission record.

2. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that: The node depth correspondence table includes a node number sequence, a depth difference distribution set, and a layer identifier set; the node frequency interval table includes a center frequency sequence, a frequency boundary set, and a frequency band interval identifier; the node transmission frequency sequence includes a dynamic frequency trajectory, a change direction marker, and a frequency step size set; the conflict-free frequency sequence includes a correction frequency set, an adjacent frequency interval matrix, and conflict identifier results; the pile strain transmission record includes a depth sorting index, a strain state label set, and a frequency matching result.

3. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that: The process of calculating the strain change at adjacent time points to form a change sequence specifically involves taking the strain values ​​at three consecutive time points and performing a moving average to obtain a smooth change sequence. The process of calculating the average change is limited to the arithmetic mean of the changes at no less than five consecutive time points during the no-load stage.

4. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that: The set multiple is an integer between 2 and 5 and is fixed within the same test period. The process of comparing the current change with the strain change threshold further includes dividing the current change into three intervals: below the average change, between the average change and the strain change threshold, and above the strain change threshold.

5. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that, The pile depth documentation module includes: The interface depth extraction submodule obtains the installation depth value corresponding to the geotechnical interface position of the rebar cage in the concrete cast-in-place pile construction section, collects the construction section layer record table and rebar cage segment identification data, performs unified conversion on the interface elevation according to the layer number and forms a depth sequence, performs numerical processing on the interface depth and establishes a mapping relationship according to the layer sequence number to generate the interface depth sequence. The sensor node sorting submodule obtains the corresponding depth value of the strain sensor based on the interface depth sequence, collects the node number and installation depth data in the sensor installation record table, performs range filtering on the installation depth and retains the data within the construction section, performs ordered arrangement on the filtered depth values ​​and synchronously adjusts the node number order to establish a corresponding relationship, and obtains the node depth sorting. The node difference construction submodule sorts the nodes according to their depths, reads the depth data corresponding to the adjacent node numbers, performs difference calculation on the depths of adjacent nodes to form a depth interval sequence, pairs the interval values ​​with the corresponding node numbers and writes them into a structured table, performs sequential merging on all node interval data and establishes a number correspondence relationship, and generates a node depth correspondence table.

6. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that, The frequency band arrangement module includes: The depth difference benchmark extraction submodule extracts adjacent depth difference data based on the node depth correspondence table, collects the depth difference records corresponding to the node number and reads the adjacent node depth difference data set in sequence, performs filtering on the depth difference data and determines the minimum value as the benchmark data, establishes a correspondence between the benchmark data and the node number and performs unified identification, and generates frequency separation benchmark values. The frequency interval allocation submodule obtains the available frequency range of the wireless signal transmitting unit according to the frequency separation reference value, collects the frequency range data of the transmitting unit and allocates the center frequency in the order of node number, performs interval division on the upper and lower boundaries of the node frequency and forms a frequency interval set, and associates and organizes the node number with the corresponding frequency interval to obtain the node frequency interval sequence. The interval verification and adjustment submodule calls the node frequency interval sequence, reads the frequency interval data of adjacent nodes and extracts the frequency interval data, performs a consistency judgment between the frequency interval and the frequency separation benchmark value, performs adjustment on the intervals that do not meet the requirements and updates the node interval data, integrates all node frequency intervals in order and establishes a corresponding relationship, and generates a node frequency interval table.

7. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that, The incremental frequency determination module includes: The strain sequence construction submodule collects strain values ​​of strain sensors at continuous moments during the static load test loading stage according to the node frequency interval table, collects strain records at corresponding moments of measurement points and arranges them in chronological order, performs change calculation on strain values ​​at adjacent moments and forms a change sequence, and simultaneously collects strain records during the no-load stage and extracts change data, performs average calculation on the change amount during the no-load stage and establishes a corresponding relationship to generate a strain change benchmark. The threshold determination submodule obtains a set multiple parameter based on the strain change benchmark and performs matching processing. It performs a combined calculation with the strain change benchmark value and the multiple parameter to form threshold data. It aligns the threshold data with the change sequence and establishes a corresponding relationship to obtain a data set for interval determination and generates strain change threshold interval values. The frequency update verification submodule reads the change sequence data at the current moment and performs interval matching judgment based on the strain change threshold interval value. It selects frequency step size data according to the change amount interval, extracts the change direction identifier and updates the center frequency data. It performs interval verification on the updated frequency data and performs consistency judgment with the node frequency interval. It integrates the node frequency results in order to generate the node transmission frequency sequence.

8. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that, The adjacent-frequency verification module includes: The frequency difference calculation submodule calls the node transmission frequency sequence and node depth correspondence table, collects the corresponding transmission frequency data of adjacent nodes at the same time and arranges them in node order, performs difference calculation on the transmission frequencies of adjacent nodes and forms a frequency difference sequence, associates and organizes the frequency difference sequence with the node number and establishes an order mapping relationship to generate a node frequency difference sequence. The interval determination submodule obtains the frequency separation benchmark based on the node frequency difference sequence and performs matching processing. It compares and judges the node frequency difference data with the frequency separation benchmark item by item, filters out nodes that do not meet the interval requirements and marks the corresponding node numbers, and associates and organizes the determination results with the node depth correspondence table to generate an interval determination identifier sequence. The frequency adjustment verification submodule reads the transmission frequency data corresponding to the nodes that do not meet the interval requirements according to the interval determination identifier sequence, performs frequency offset processing on the associated nodes and updates the transmission frequency sequence, performs difference calculation and consistency verification on the frequency data of adjacent nodes after the update, integrates all node frequency results in order and establishes corresponding relationships to generate a conflict-free frequency sequence.

9. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that, The transmission identification module includes: The frequency acquisition and matching submodule collects the node transmission frequency and arrival order on the ground receiving device based on the conflict-free frequency sequence, collects the received frequency data and arrival order information at any time in the receiving record, performs interval matching judgment on the received frequency and the node frequency interval table and determines the corresponding node number, associates and organizes the matching result with the arrival order and forms a node identification sequence, and generates a node identification sequence. The state restoration submodule obtains the corresponding node transmission frequency data and extracts frequency offset information based on the node identification sequence. It performs matching processing on the frequency offset data and the preset change mapping relationship to restore the strain change state. It associates and organizes the node strain change state with the node number to form a state sequence, thus obtaining the strain change state sequence. The depth sorting and recording submodule, based on the strain change state sequence, calls the node depth correspondence table to obtain node depth data, associates the depth corresponding to the node number with the strain change state, sorts the node records according to the depth order to form an ordered record set, writes the sorting result into the structured storage unit and establishes the correspondence between node depth and strain state, and generates the pile strain transmission record.

10. The wireless transmission strain sensing system for testing internal forces in piles according to claim 1, characterized in that: The process of selecting the frequency step size according to the range of change is specifically to select three discrete frequency step size values ​​that increase arithmetically for each of the three ranges, and the frequency step size value does not exceed half of the frequency separation reference corresponding to the minimum depth difference. The process of updating the center frequency according to the direction of strain change is limited to increasing the center frequency by the frequency step size when the change is positive and decreasing the center frequency by the frequency step size when the change is negative.

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