Drilling sampling method and sampling device for road and bridge pile foundation

Abstract

The invention relates to the technical field of drilling and sampling, in particular to a drilling and sampling method and device for road and bridge pile foundations. Before drilling sampling, ultrasonic detection signals and all detection sub-sections in the ultrasonic detection signals are obtained, the pressure application adjusting speed of each detection sub-section in the corresponding detection process is further analyzed, and a pressure application prediction model is constructed in combination with the pressure application range of a drill bit; then, in the drilling sampling process, the sudden change coefficient and the sudden change continuous coefficient of the drill bit sensing pressure at each moment are analyzed and obtained, and the drill bit sensing pressure and the prediction pressure applying model are further combined to adjust the drill bit pressure applying in real time. According to the method, before drilling and sampling, ultrasonic waves are used for preliminarily detecting the to-be-detected pile foundation, a prediction pressure applying model of the drill bit is analyzed and constructed, then pressure applying is adjusted according to the real-time pressure condition of the drill bit in the drilling and sampling process, and secondary damage to a sampling sample of the to-be-detected pile foundation in the drilling process due to improper pressure applying is avoided; and the drilling and sampling effect on the road and bridge pile foundation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of drilling sampling, and in particular to a drilling sampling method and a sampling device for road bridge pile foundations. Background Art

[0002] Road and bridge pile foundations are the basic parts used to support road or bridge structures. They are used to transfer the load of the superstructure to the stable stratum to ensure the stability and safety of roads and bridges. Under the long-term influence of the environment and loads, road and bridge pile foundations may have defects, diseases and other safety hazards, so they need to be inspected regularly. Ultrasonic waves, as a non-destructive testing method, can effectively detect the internal conditions of pile foundations, but cannot accurately determine the specific type of defects.

[0003] Existing technologies usually use drilling sampling methods for testing, using a high-speed rotating drill to extract concrete samples from the pile foundation to accurately evaluate the structural performance. However, the geological conditions faced by the pile foundation in the stratum are also different. When using an automatic sampling device to drill and sample, if a constant pressure and rotation speed are maintained, it may cause the sand or mud part to be sampled too quickly, causing secondary damage to the pile foundation, resulting in unnatural cracks or fragmentation of the pile foundation sample, affecting the quality of the pile foundation sample, and further affecting the accuracy of subsequent analysis. Summary of the invention

[0004] In order to solve the technical problem that the existing technology has poor drilling sampling effect on road bridge pile foundations, the purpose of the present invention is to provide a drilling sampling method and sampling device for road bridge pile foundations. The technical scheme adopted is as follows: The present invention provides a drilling sampling method for road bridge pile foundations, the method comprising: Before drilling and sampling the pile foundation to be tested, an ultrasonic detection signal of the pile foundation to be tested is obtained; according to the fluctuation characteristics of the ultrasonic detection signal, the ultrasonic detection signal is segmented to obtain all detection sub-segments; According to the fluctuation stability characteristics of each detection sub-segment and the fluctuation difference between adjacent detection sub-segments, the pressure adjustment speed of each detection sub-segment in the detection process is obtained; according to the pressure adjustment speed and the pressure range of the drill bit in the detection process of all detection sub-segments, a prediction pressure model in the drilling sampling process of the pile foundation to be tested is constructed; During the drilling sampling process of the pile foundation to be tested, a real-time sensing pressure curve of the drill bit is obtained; in the real-time sensing pressure curve, a mutation coefficient of the drill bit sensing pressure at each moment is obtained according to the fluctuation deviation of the drill bit sensing pressure at each moment relative to the drill bit sensing pressure at a historical moment; at the current moment, a mutation continuity coefficient of the drill bit sensing pressure at the current moment is obtained according to the fluctuation of the detection sub-segment to which the detection position of the drill bit belongs and the mutation coefficient of the drill bit sensing pressure at a historical moment; According to the mutation coefficient and the mutation duration coefficient of the drill bit sensor pressure at the current moment, combined with the drill bit sensor pressure at the current moment and the predicted pressure model, the applied pressure of the drill bit at the current moment is adjusted.

[0005] Furthermore, the method for acquiring the detection sub-segment includes: An ultrasonic sequence is constructed based on the ultrasonic detection signal, a first-order difference sequence of the ultrasonic sequence is obtained, all differential values ​​greater than a preset threshold are screened out from the first-order difference sequence, and the sorting sequence number of the differential value in the first-order difference sequence is added with 1 as the time sequence number corresponding to the segmentation point; the ultrasonic detection signal is segmented based on the segmentation point to obtain all signal segments; The segment distribution histogram is fitted with the segment number as the horizontal axis and the segment length as the vertical axis; all signal segments whose length is lower than the average level and whose average amplitude is lower than the overall average amplitude of the signal are regarded as defective segments, and the remaining signal segments are regarded as normal segments; continuous defective segments or continuous normal segments are merged into one detection sub-segment.

[0006] Furthermore, the method for obtaining the pressure adjustment speed includes: The difference between the first signal point of each detection sub-segment and the last signal point of the adjacent previous detection sub-segment is used as the pressure adjustment weight in the detection process corresponding to each detection sub-segment; According to the fluctuation stability and stability continuation of each detection sub-segment, the pressure adjustment parameter of each detection sub-segment in the detection process is obtained; The pressure adjustment parameter is weighted by using the pressure adjustment weight, the weighted result is mapped to the range of [-1, 1], and the mapping value of the preset multiple is used as the pressure adjustment speed in the corresponding detection process of the corresponding detection sub-segment.

[0007] Furthermore, the method for obtaining the pressure adjustment parameter includes: The average amplitude of each signal segment in each detection subsegment is negatively correlated with the amplitude deviation of the average amplitude of the corresponding detection subsegment, and the negative correlation mapping result is used as the fluctuation stability sub-parameter of the corresponding signal segment; the fluctuation stability sub-parameters of all signal segments in the detection subsegment are integrated to obtain the fluctuation stability parameter of the corresponding detection subsegment; the total length of each detection subsegment is used as the stability maintenance parameter of the corresponding detection subsegment; The fluctuation stabilization parameter and the stabilization maintenance parameter are integrated to obtain the pressure adjustment parameter in the corresponding detection process of the corresponding detection sub-segment.

[0008] Furthermore, the method for obtaining the predicted pressure model includes: Obtain the detection depth interval corresponding to each detection sub-segment; take the detection depth as the horizontal axis, take the drill bit applied pressure as the vertical axis, start the applied pressure from zero, take the pressure adjustment speed of the first detection sub-segment as the slope, and fit the applied pressure change sub-segment corresponding to the first detection sub-segment within the detection depth interval; Taking the end point of the applied pressure change sub-segment corresponding to the first detection sub-segment as a new starting point, taking the pressure adjustment speed of the second detection sub-segment as a slope, fitting the applied pressure change sub-segment corresponding to the second detection sub-segment within the detection depth interval; taking the end point of the applied pressure change sub-segment corresponding to the second detection sub-segment as a new starting point, iterating continuously until the corresponding applied pressure change sub-segments within all detection depth intervals are obtained; Among them, when the applied pressure in the applied pressure change sub-segment corresponding to a non-first detection sub-segment is equal to the lower limit of the preset range for the first time, then after the applied pressure is equal to the lower limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment is set to the lower limit of the preset range; when the applied pressure in the applied pressure change sub-segment corresponding to any detection sub-segment is equal to the upper limit of the preset range for the first time, then after the applied pressure is equal to the upper limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment is set to the upper limit of the preset range.

[0009] Furthermore, the method for obtaining the mutation coefficient includes: At each moment, the upper envelope of the real-time sensor pressure curve of the drill bit is obtained; the upper envelope is subjected to adaptive mean filtering to determine whether the drill bit sensor pressure at each moment belongs to the historical filtering window corresponding to the previous adjacent historical moment; If it is, the mutation coefficient of the drill bit sensor pressure at the corresponding moment is set to 0; If it does not, then the mutation coefficient of the drill bit sensor pressure at each moment is obtained based on the deviation of the drill bit sensor pressure in a preset number of adjacent historical filtering windows on the upper envelope, combined with the fluctuation similarity and fluctuation stability of the drill bit sensor pressure in a preset number of adjacent historical filtering windows.

[0010] Furthermore, the method for obtaining the mutation coefficient of the drill bit sensor pressure at each moment according to the drill bit sensor pressure at each moment, relative to the deviation of the drill bit sensor pressure in the adjacent preset number of historical filter windows on the upper envelope, combined with the fluctuation similarity and fluctuation stability of the drill bit sensor pressure in the adjacent preset number of historical filter windows, includes: Taking the drill bit sensing pressure at each moment, a preset number of adjacent historical filtering windows on the upper envelope as target windows; The difference between the drill bit sensor pressure at each moment and the average level of the drill bit sensor pressure in each target window is taken as the mutation sub-deviation; the cumulative sum of all the mutation sub-deviations of the drill bit sensor pressure at each moment is taken as the mutation deviation; The ratio of the intersection of the drill bit sensor pressure values ​​in all target windows to the union of the corresponding values, multiplied by the corresponding time length of all target windows, is used as the reference weight of the sudden change of the drill bit sensor pressure at each moment; The mutation deviation is weighted by using the mutation reference weight, and a normalized result of the weighted result is used as the mutation coefficient of the drill bit sensor pressure at each moment.

[0011] Furthermore, the method for obtaining the mutation persistence coefficient includes: Based on the drilling sampling feed rate of the drill bit at the current moment, the signal segment corresponding to the drilling process of the drill bit at the current moment in the ultrasonic detection signal is matched, and the detection sub-segment to which the corresponding signal segment belongs is obtained; the difference between the length of the signal segment matched at the current moment and the length of the corresponding detection sub-segment is used as the mutation maintenance weight; The mutation maintenance weight is used to weight the mean of the mutation coefficient of the drill bit sensor pressure at each moment in the preset historical time domain at the current moment, the weighted result is normalized, and the normalized result is used as the mutation persistence coefficient of the drill bit sensor pressure at the current moment.

[0012] Furthermore, the method for adjusting the applied pressure of the drill bit at the current moment includes: The applied pressure corresponding to the drilling sampling feed rate of the drill bit at the current moment in the preset pressure model is used as the predicted applied pressure of the drill bit at the current moment; The difference sign between the drill bit sensor pressure at the current moment and the drill bit sensor pressure at the previous adjacent historical moment is used as the adjustment direction, and the normalized result of the absolute value of the difference is used as the first parameter; the product of the mutation coefficient and the mutation duration coefficient of the drill bit sensor pressure at the current moment is used as the second parameter; The adjustment direction, the first parameter and the second parameter are integrated to obtain an adjustment amplitude parameter; the adjustment amplitude parameter is added with a constant 1 to obtain an adjustment weight; the predicted applied pressure is weighted using the adjustment weight, and the weighted result is used as the applied pressure of the drill bit at the current moment.

[0013] The present invention also proposes a drilling sampling device for road bridge pile foundations, comprising a device body, and the device implements the steps of a drilling sampling method for road bridge pile foundations.

[0014] The present invention has the following beneficial effects: Before drilling and sampling the pile foundation to be tested, the present invention obtains the ultrasonic detection signal of the pile foundation to be tested and all the detection sub-segments therein, so as to provide data preparation for subsequent analysis and construction of a predictive pressure model; then, the fluctuation stability characteristics of each detection sub-segment and the fluctuation difference between adjacent detection sub-segments are analyzed, the internal texture distribution of the pile foundation to be tested during the ultrasonic detection process is roughly evaluated, the pressure adjustment speed of each detection sub-segment in the corresponding detection process is obtained, and then, combined with the pressure range of the drill bit, a predictive pressure model is constructed during the drilling and sampling process of the pile foundation to be tested; further, during the drilling and sampling process of the pile foundation to be tested, the pressure sensor pressure at each moment is used to adjust the pressure adjustment speed of each detection sub-segment. The force is relative to the fluctuation deviation of the drill bit sensor pressure at the historical moment, and the mutation coefficient of the drill bit sensor pressure at each moment is obtained; at the current moment, according to the fluctuation of the detection sub-segment to which the detection position of the drill bit belongs and the mutation coefficient of the drill bit sensor pressure at the historical moment, the mutation continuity coefficient of the drill bit sensor pressure at the current moment is obtained; based on the real-time mutation of the sensor pressure during the drilling sampling process and the amplitude change in the ultrasonic signal at the same detection depth, the possibility of change in the detection part is evaluated, and then the drill bit sensor pressure at the current moment and the predicted pressure model are combined to adjust the applied pressure of the drill bit at the current moment in real time. The present invention first uses ultrasound to preliminarily detect the pile foundation to be tested before drilling and sampling the pile foundation to be tested, analyzes and constructs a predicted pressure model of the drill bit, and then adjusts the pressure in combination with the real-time pressure of the drill bit during the drilling sampling process, so as to avoid secondary damage to the sampled sample of the pile foundation to be tested during the drilling process due to improper pressure, thereby improving the drilling sampling effect of the pile foundation of roads and bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flow chart of a drilling sampling method for road bridge pile foundations provided by one embodiment of the present invention; Figure 2 A segmented distribution histogram provided by an embodiment of the present invention; Figure 3 A prediction pressure model is provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a drilling sampling method and sampling device for road bridge pile foundations proposed by the present invention, its specific implementation method, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] The following is a detailed description of a specific scheme of a drilling sampling method and a sampling device for road bridge pile foundations provided by the present invention in conjunction with the accompanying drawings.

[0020] See also Figure 1 , which shows a flow chart of a drilling sampling method for road bridge pile foundation provided by an embodiment of the present invention, specifically comprising: Step S1, before drilling and sampling the pile foundation to be tested, obtain the ultrasonic detection signal of the pile foundation to be tested; according to the fluctuation characteristics of the ultrasonic detection signal, segment the ultrasonic detection signal to obtain all detection sub-segments.

[0021] It should be noted that the drilling sampling process for each road and bridge pile foundation is the same. Here, only any road and bridge pile foundation is taken as the pile foundation to be tested for analysis and drilling sampling. The drilling sampling position of the pile foundation to be tested needs to be determined based on the ultrasonic signal. That is, since the cross-sectional area of ​​the pile foundation to be tested is large, drilling sampling can only sample its local samples, so it is necessary to perform multiple ultrasonic detections at different positions of the pile foundation to be tested. Then, the emission position where all ultrasonic detection signals are most obviously attenuated is used as the drilling sampling position of the pile foundation to be tested, and the ultrasonic detection signal analyzed later is also the ultrasonic detection signal emitted at this position.

[0022] In one embodiment of the present invention, before drilling and sampling the pile foundation to be tested, an ultrasonic detection device is used to preliminarily detect the pile foundation to be tested, and a high-precision receiving system is used to record and obtain an ultrasonic detection signal reflecting the internal composition distribution of the pile foundation to be tested, so as to subsequently analyze and construct a predictive pressure model of the drill bit, and adjust the pressure in combination with the real-time pressure of the drill bit during the drilling sampling process to avoid secondary damage to the sampled sample of the pile foundation to be tested during the drilling process due to improper pressure application; It should be noted that the acquisition of ultrasonic detection signals is an existing technology well known to those skilled in the art and will not be described in detail.

[0023] Taking into account that when there are defects such as looseness, honeycombs, and voids in the pile foundation to be tested, the sound wave will attenuate in the ultrasonic detection signal, which also indirectly reflects that the fluctuation characteristics of the ultrasonic wave corresponding to different sample states in the pile foundation are inconsistent; therefore, in one embodiment of the present invention, the ultrasonic detection signal is further segmented according to the fluctuation characteristics of the ultrasonic detection signal to obtain all detection sub-segments; wherein different detection sub-segments can be regarded as corresponding ultrasonic segments at different detection depths, providing data preparation for subsequent analysis.

[0024] Preferably, in one embodiment of the present invention, considering that ultrasonic segments with similar amplitudes are more likely to correspond to similar pile foundation sampling states, the ultrasonic detection signal can be segmented first, and the ultrasonic segments with similar amplitudes can be divided into a signal segment; considering that the states of normal sampling samples of the pile foundation to be tested may be different in different strata, even if there may be slight fluctuation differences in continuous signal segments, they may all be ultrasonic vibration characteristics of normal sampling samples or defective sampling samples corresponding to the detection process, and the normal sampling samples of the pile foundation to be tested should be far more than the defective sampling samples, which indirectly indicates that there are also large differences in the lengths of the corresponding signal segments, so the detection sub-segment can be further obtained based on the length of the signal segment and the characteristics of amplitude attenuation caused by defects; based on this, the method for obtaining the detection sub-segment includes: An ultrasonic sequence is constructed based on the ultrasonic detection signal, a first-order difference sequence of the ultrasonic sequence is obtained, all differential values ​​greater than a preset threshold are screened out from the first-order difference sequence, and the sorting sequence number of the differential value in the first-order difference sequence is added with 1 as the time sequence number corresponding to the segmentation point; the ultrasonic detection signal is segmented based on the segmentation point to obtain all signal segments; The segment distribution histogram is fitted with the segment number as the horizontal axis and the segment length as the vertical axis; all signal segments whose length is lower than the average level and whose average amplitude is lower than the overall average amplitude of the signal are regarded as defective segments, and the remaining signal segments are regarded as normal segments; continuous defective segments or continuous normal segments are merged into one detection sub-segment.

[0025] As an example, the preset threshold is set to 10. When the difference value is greater than 10, it can be considered that there is a large fluctuation mutation. Then, the sorting number of the difference value in the first-order difference sequence plus 1 is used as the time sequence number corresponding to the segmentation point, and the segmentation point is used as the end signal point of the signal segment, and the segmentation point is adjacent to the starting signal point of the next signal segment; assuming that an ultrasonic sequence is {10, 12, 16, 14, 13, 29, 26, 19, 15}, the corresponding first-order difference sequence is {2, 4, -2, -1, 16, -3, -7, -4}, and the fifth sorting number in the first-order difference sequence corresponds to a difference value greater than 10, then the sixth ultrasonic signal point in the ultrasonic sequence is used as a segmentation point, and the corresponding signal segments are {10, 12, 16, 14, 13} and {29, 26, 19, 15}; according to the method described in this example, all signal segments in the ultrasonic detection signal can be obtained; See also Figure 2 , which shows a segmented distribution histogram provided by an embodiment of the present invention; Figure 2 L in the figure is the average length of all signal segments. All signal segments corresponding to the histogram blocks below the dotted line corresponding to L in the segment distribution histogram are taken as preliminary defect segments. The amplitude mean of the ultrasonic detection signal is taken as the overall average amplitude. All preliminary defect segments whose amplitude mean in the segment is lower than the overall average amplitude are taken as defect segments, and all other signal segments are taken as normal segments. Further, continuous defect segments or continuous normal segments are merged into a detection subsegment. For example, there are 5 signal segments, namely normal segment a, defect segment b, normal segment c, normal segment d, and defect segment e. Then, the continuous normal segment c and normal segment d are merged to obtain 4 detection subsegments in total.

[0026] Step S2, according to the fluctuation stability characteristics of each detection sub-segment and the fluctuation difference between adjacent detection sub-segments, obtain the pressure adjustment speed of each detection sub-segment in the corresponding detection process; according to the pressure adjustment speed of all detection sub-segments in the corresponding detection process and the pressure range of the drill bit, construct a predicted pressure model in the drilling sampling process of the pile foundation to be tested.

[0027] Considering that in the process of drilling and sampling of the pile foundation to be tested, the drill bit will enter the sample area corresponding to each detection sub-segment in turn during operation. If the stable fluctuation of the detection sub-segment is maintained for a longer time, it means that the texture of the corresponding sample is more uniform and the deterioration is less likely, which further indicates that the probability that the detection sub-segment corresponds to a normal sample is greater. In this case, the applied pressure and pressure change speed of the drill bit in the detection process corresponding to the detection sub-segment can be appropriately increased to ensure its drilling sampling efficiency. On the contrary, when the fluctuation of the detection sub-segment is kept smaller and there is obvious amplitude attenuation and mutation relative to the adjacent previous detection sub-segment, it indicates that the texture of the corresponding sample has changed relatively, which further indicates that the probability that the detection sub-segment corresponds to a defective sample is greater. In this case, the pressure applied by the drill bit and the pressure change speed in the detection process of the detection sub-segment should be appropriately reduced to ensure the sample quality. Therefore, the embodiment of the present invention will obtain the pressure adjustment speed of each detection sub-segment in the detection process according to the fluctuation stability characteristics of each detection sub-segment and the fluctuation difference between adjacent detection sub-segments; based on the internal texture distribution of the pile foundation to be tested during the ultrasonic detection process, a preliminary analysis is performed to determine the pressure adjustment speed corresponding to each detection process, and then combined with the drill bit pressure range of the automatic drilling sampling device, a preliminarily predicted pressure model for the drilling sampling process of the pile foundation to be tested can be constructed, so as to subsequently adjust the drill bit pressure and ensure the efficiency and quality of drilling sampling.

[0028] Preferably, in one embodiment of the present invention, considering that pile foundation defects may cause ultrasonic amplitude attenuation or wave velocity change, when there is an obvious amplitude difference or mutation between adjacent detection sub-segments, it indicates that the texture of the sample has changed relatively. If the amplitude between the detection sub-segments is in an attenuated state and the more obvious it is, the pressure applied by the drill bit should be appropriately reduced when drilling and sampling to the detection depth corresponding to the detection sub-segment, otherwise the pressure applied can be increased; considering that the more stable the fluctuation of the detection sub-segment and the longer the stable process lasts, the greater the possibility that the detection sub-segment corresponds to a normal sampling sample, the longer the detection process of maintaining the normal sampling sample, the lower the possibility of sample texture change, and the smaller the possibility of reducing the pressure, the pressure can be appropriately increased and the pressure can also be accelerated; therefore, the method for obtaining the pressure adjustment speed includes: The difference between the first signal point of each detection sub-segment and the last signal point of the adjacent previous detection sub-segment is used as the pressure adjustment weight in the detection process corresponding to each detection sub-segment; According to the fluctuation stability and stability continuation of each detection sub-segment, the pressure adjustment parameter of each detection sub-segment in the detection process is obtained; The pressure adjustment parameter is weighted by using the pressure adjustment weight, the weighted result is mapped to the range of [-1, 1], and the mapping value of the preset multiple is used as the pressure adjustment speed in the corresponding detection process of the corresponding detection sub-segment.

[0029] The method for obtaining the pressure adjustment parameter includes: The average amplitude of each signal segment in each detection sub-segment is negatively correlated with the amplitude deviation of the average amplitude of the corresponding detection sub-segment, and the negative correlation mapping result is used as the fluctuation stability sub-parameter of the corresponding signal segment; the fluctuation stability sub-parameters of all signal segments in the detection sub-segment are combined to obtain the fluctuation stability parameter of the corresponding detection sub-segment; the total length of each detection sub-segment is used as the stability maintenance parameter of the corresponding detection sub-segment; the fluctuation stability parameter and the stability maintenance parameter are integrated to obtain the pressure adjustment parameter of the corresponding detection sub-segment during the detection process.

[0030] As an example, the pressure adjustment speed is calculated as: ; Where i is the serial number of the detection sub-segment; is the pressure adjustment parameter corresponding to the detection process of the i-th detection sub-segment; is the preset multiple; is the hyperbolic tangent function; is the difference between the first signal point in the i-th detection subsegment and the last signal point in the i-1-th detection subsegment, and is also the pressure adjustment weight in the detection process corresponding to the i-th detection subsegment; j is the sequence number of the signal segment in the i-th detection subsegment; is the total number of signal segments in the i-th detection subsegment; is the average amplitude of the signal points in the jth signal segment in the i-th detection subsegment; is the average amplitude of the signal points in the i-th detection subsegment; is the fluctuation stability sub-parameter of the j-th signal segment in the i-th detection sub-segment; is the fluctuation stability parameter of the i-th detection sub-segment; is the total length of the i-th detection sub-segment, and is also the stability maintenance parameter; is the pressure adjustment parameter corresponding to the detection process of the i-th detection sub-segment.

[0031] In the calculation formula of the pressure adjustment speed, the absolute value of the difference between the average amplitude of each signal segment and the average amplitude of the corresponding detection sub-segment is negatively correlated and mapped to the exponential function, so that the smaller the absolute value of the difference, the larger the fluctuation stability sub-parameter, and then all the fluctuation stability sub-parameters are accumulated to obtain the fluctuation stability parameter; then the fluctuation stability parameter is multiplied and combined with the stability maintenance parameter, so that the more stable the fluctuation and the longer the fluctuation stability is maintained, the faster the pressure can be adjusted and the larger the pressure adjustment parameter; then the pressure adjustment weight is multiplied and combined with the pressure adjustment parameter, where the pressure adjustment weight may be negative, so the sign of the corresponding product may also be negative, so its negative correlation is mapped to the tanh() function, so that its value range becomes [-1, 1], and it is further multiplied by a preset multiple to adjust the value. In this example, the preset multiple is 10, and the implementer can also determine it according to the specific application to obtain the pressure adjustment speed.

[0032] At this point, the pressure adjustment speeds corresponding to the detection process of all detection sub-segments are obtained, and the pressure range of the drill bit can be further combined to construct a predictive pressure model during the drilling sampling process of the pile foundation to be tested.

[0033] Preferably, in one embodiment of the present invention, the method for obtaining the predictive pressure model includes: Obtain the detection depth interval corresponding to each detection sub-segment; take the detection depth as the horizontal axis, the drill bit applied pressure as the vertical axis, the applied pressure starts from zero, and the pressure adjustment speed of the first detection sub-segment is used as the slope to fit the applied pressure change sub-segment within the detection depth interval corresponding to the first detection sub-segment; Taking the end point of the applied pressure change subsegment corresponding to the first detection subsegment as a new starting point, taking the pressure adjustment speed of the second detection subsegment as a slope, fitting the applied pressure change subsegment within the detection depth interval corresponding to the second detection subsegment; taking the end point of the applied pressure change subsegment corresponding to the second detection subsegment as a new starting point, iterating continuously until the corresponding applied pressure change subsegments within all detection depth intervals are obtained; Among them, when the applied pressure in the applied pressure change sub-segment corresponding to a non-first detection sub-segment is equal to the lower limit of the preset range for the first time, then after the applied pressure is equal to the lower limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment will be set to the lower limit of the preset range; when the applied pressure in the applied pressure change sub-segment corresponding to any detection sub-segment is equal to the upper limit of the preset range for the first time, then after the applied pressure is equal to the upper limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment will be set to the upper limit of the preset range.

[0034] See also Figure 3 , which shows a prediction pressure model provided by an embodiment of the present invention, wherein the horizontal axis is the detection depth, wherein the detection depth can also be understood as the drill position or feed rate during the drilling sampling process, the vertical axis is the drill pressure, N1 is the upper limit of the drill pressure, N0 is the lower limit of the drill pressure, and the curve segment reflects the change of the applied pressure corresponding to the detection process or detection depth of each detection sub-segment; Figure 3 When the applied pressure in the second applied pressure change sub-segment reaches the upper limit of the preset range, the upper limit of the preset range is maintained until the applied pressure in the fourth applied pressure change sub-segment decreases; the change of the lower limit of the preset range is maintained in the same way and will not be repeated.

[0035] It should be noted that, in this example, the upper limit of the preset range is set to 200KN, and the lower limit of the preset range is set to the lower limit of the critical pressure for the drill bit to damage the pile foundation; the upper limit of the preset range and the lower limit of the preset range in the drill bit pressure range need to be determined based on the material properties of the pile foundation to be tested and the relevant design parameters of the automatic sampling device.

[0036] Step S3, during the drilling sampling process of the pile foundation to be tested, obtain the real-time sensor pressure curve of the drill bit; in the real-time sensor pressure curve, obtain the mutation coefficient of the drill bit sensor pressure at each moment according to the fluctuation deviation of the drill bit sensor pressure at each moment relative to the drill bit sensor pressure at the historical moment; at the current moment, obtain the mutation continuity coefficient of the drill bit sensor pressure at the current moment according to the fluctuation of the detection sub-segment to which the detection position of the drill bit belongs and the mutation coefficient of the drill bit sensor pressure at the historical moment.

[0037] In one embodiment of the present invention, after obtaining the predicted pressure model, drilling sampling is started on the pile foundation to be tested, and the real-time sensor pressure of the drill bit in the automatic drilling sampling device during the drilling sampling process is collected, wherein the real-time sensor pressure is not the actual pressure applied by the drill bit, but the sensor pressure collected when the drill bit contacts the pile foundation, and the collection frequency is 2 seconds each time, and the cumulative feed amount of the drill bit at each collection moment, and the drilling depth or detection depth of the drill bit are recorded at the same time; the real-time collected drill bit sensor pressure is mapped to the timestamp, and a real-time sensor pressure curve is constructed, that is, each moment corresponds to a real-time sensor pressure curve.

[0038] It should be noted that collecting the real-time sensing pressure and cumulative feed rate of the drill bit is an existing technology well known to those skilled in the art, and can also be obtained based on the data integration system of the automatic drilling sampling device, which will not be described here; implementers can also define the sampling frequency by themselves.

[0039] Considering that the drill bit sensing pressure will suddenly drop after the drill bit drills into the defective part of the pile foundation to be tested, the embodiment of the present invention will obtain the mutation coefficient of the drill bit sensing pressure at each moment in the real-time sensing pressure curve according to the fluctuation deviation of the drill bit sensing pressure at each moment relative to the drill bit sensing pressure at the historical moment; the mutation coefficient indirectly reflects the possibility that the drill bit is located at the defective part of the pile foundation to be tested, so as to prepare for the subsequent real-time adjustment of the drill bit pressure.

[0040] Preferably, in one embodiment of the present invention, considering that even in the normal part of the pile foundation to be tested, after the drill bit drills and destroys a part of the pile foundation structure, there will be some debris or dust accumulation, which will cause the drill bit sensing pressure to suddenly decrease. Therefore, the sensing pressure mutation in the real-time sensing pressure curve may not be caused by defects, and the upper envelope of the curve can roughly reflect the approximate fluctuation of the sensing pressure curve, based on which the upper envelope can be analyzed; considering that the adaptive mean filter usually uses the local statistical characteristics of the input signal to adjust the filter window size, the mutation at each moment can be evaluated according to the filter window in the adaptive filtering process, and then combined with the signal fluctuation in the filter window, the mutation can be evaluated; therefore, the method for obtaining the mutation coefficient includes: At each moment, the upper envelope of the real-time sensor pressure curve of the drill bit is obtained; the upper envelope is subjected to adaptive mean filtering to determine whether the sensor pressure of the drill bit at each moment belongs to the historical filtering window corresponding to the previous adjacent historical moment; If it is, the mutation coefficient of the drill bit sensor pressure at the corresponding moment is set to 0; If it does not, then the mutation coefficient of the drill bit sensor pressure at each moment is obtained based on the deviation of the drill bit sensor pressure in a preset number of adjacent historical filtering windows on the upper envelope, combined with the fluctuation similarity and fluctuation stability of the drill bit sensor pressure in a preset number of adjacent historical filtering windows.

[0041] It should be noted that the method for obtaining the upper envelope, the adaptive mean filtering and the corresponding filtering window are already existing technologies well known to those skilled in the art and will not be elaborated on herein; in the process of analyzing the mutation coefficient of the drill bit sensor pressure at each moment, each moment can be regarded as the last moment in the real-time sensor pressure curve, and the historical moment refers to the historical moment before this moment.

[0042] Among them, considering that the drill bit sensor pressure at each moment has a large deviation from the drill bit sensor pressure at all its historical moments, it means that the drill bit sensor pressure at this moment is more likely to change suddenly; and when the drill bit sensor pressure changes at all its historical moments are also similar and last longer, it means that when comparing whether there is a deviation, its reference value is greater; then when each moment does not belong to the same filtering window as the previous adjacent historical moment, the method for obtaining the mutation coefficient is: The preset number of adjacent historical filter windows of the drill bit sensor pressure on the upper envelope at each moment are used as target windows; The difference between the drill bit sensor pressure at each moment and the average level of the drill bit sensor pressure in each target window is taken as the mutation deviation; the cumulative sum of all mutation deviations of the drill bit sensor pressure at each moment is taken as the mutation deviation; The ratio of the intersection of the drill bit sensor pressure values ​​in all target windows to the union of the corresponding values, multiplied by the corresponding time length of all target windows, is used as the reference weight of the sudden change of the drill bit sensor pressure at each moment; The mutation deviation is weighted by using the mutation reference weight, and the normalized result of the weighted result is used as the mutation coefficient of the drill bit sensor pressure at each moment.

[0043] As an example, the preset number is set to 3, and the target window is the three historical filter windows closest to it in the historical time domain at that moment; the implementer can also set the preset number by himself; and then obtain the mutation coefficient based on the calculation formula of the mutation coefficient; the calculation formula of the mutation coefficient is: ; Where t is the time sequence number during the drilling sampling process; is the mutation coefficient of the drill bit sensing pressure at the tth moment; is a linear normalization function; c is the serial number of the target window; C is the total number of target windows, which is also the preset number; is the drill bit sensor pressure at the tth moment; is the mean value of the drill bit sensor pressure in the cth target window; is the mutant bias; is mutation bias; is an exponential function with the natural constant e as base; is the sequence of drill bit sensing pressure in the cth target window; is the sequence intersection of the drill bit sensing pressure in all target windows; is the sequence union of the drill bit sensing pressure in all target windows; is the mean duration of all target windows; is the sudden change reference weight of the drill bit sensor pressure at the tth moment.

[0044] In the calculation formula of the mutation coefficient, the difference is measured in the form of the absolute value of the difference to obtain the mutation sub-deviation, and then the mutation deviation is obtained, which reflects the mutation of the drill bit sensor pressure at each moment relative to the drill bit sensor pressure in the historical time domain; the intersection and union ratio of the drill bit sensor pressure in the target window is used to evaluate the similarity of the fluctuation of the drill bit sensor pressure in the historical time domain, and then the intersection and union ratio is multiplied and combined with the corresponding duration of the target window. The larger the intersection and union ratio and the longer the duration of the target window, the more similar the fluctuation is and the longer it lasts, the greater the reference significance is, and the larger the corresponding mutation reference weight is; then the mutation reference weight is multiplied and combined with the mutation deviation and normalized to obtain the mutation coefficient.

[0045] Considering that at the current moment, if there are continuous sudden changes in the drill bit sensor pressure in the historical time domain, it further indicates that the drill bit sensor pressure has maintained a sudden change for a certain period of time, and it is possible that a defective part is currently detected, and the subsequent pressure adjustment degree should be greater; considering that when the ultrasonic signal detects a defective part, its amplitude suddenly drops and attenuates, and there may be continuous fluctuation and sudden drop segments, if the duration of each fluctuation and sudden drop segment is shorter than the duration of the remaining signal segments in the detection sub-segment to which it belongs, it means that the sudden drop degree is higher, and the pressure adjustment degree should also be greater; therefore, the embodiment of the present invention will, at the current moment, obtain the sudden change duration coefficient of the drill bit sensor pressure at the current moment according to the fluctuation of the detection sub-segment to which the drill bit is located at the detection position, and the sudden change coefficient of the drill bit sensor pressure at the historical moment.

[0046] Preferably, in one embodiment of the present invention, the method for obtaining the mutation persistence coefficient includes: Based on the drilling sampling feed rate of the drill bit at the current moment, the signal segment corresponding to the drilling process of the drill bit at the current moment in the ultrasonic detection signal is matched, and the detection sub-segment to which the corresponding signal segment belongs is obtained; the difference between the length of the signal segment matched at the current moment and the length of the corresponding detection sub-segment is used as the mutation maintenance weight; The mutation maintenance weight is used to weight the mean of the mutation coefficient of the drill bit sensor pressure at each moment in the preset historical time domain at the current moment, the weighted result is normalized, and the normalized result is used as the mutation persistence coefficient of the drill bit sensor pressure at the current moment.

[0047] It should be noted that obtaining the corresponding detection depth of each signal point during the detection process based on the ultrasonic detection signal is an existing technology well known to those skilled in the art and will not be elaborated here. Furthermore, after the detection depth of each signal point in the ultrasonic signal at the corresponding moment is known, the signal segment at the current moment can be matched based on the drilling sampling feed rate of the drill bit at the current moment, that is, the detection depth, to prepare for subsequent analysis.

[0048] As an example, the preset historical neighborhood is set to the five historical moments of the current moment, and the implementer can also set it by himself; The calculation formula of mutation maintenance coefficient is: ; Where T is the serial number of the current moment; is the sudden change duration coefficient of the drill bit sensing pressure at the current moment; is a linear normalization function; is the length of the signal segment in the ultrasonic detection signal corresponding to the drilling process of the drill bit at the current moment; is the length of the detection sub-segment corresponding to the signal segment in the ultrasonic detection signal during the drilling process of the drill bit at the current moment; Maintain weights for mutations; It is the mean value of the mutation coefficient of the drill bit sensor pressure at each moment in the preset historical time domain at the current moment.

[0049] In the calculation formula of the mutation maintenance coefficient, the larger the mean value of the mutation coefficient in the preset historical neighborhood, the more likely it is that there may be continuous mutations. At the same time, if the difference is measured in the form of the absolute value of the difference to obtain the mutation maintenance weight, the smaller the difference is, the more different the fluctuation continuity of the corresponding signal segment at the current moment is from that of the other signal segments in the corresponding detection sub-segment. The greater the possibility that the corresponding signal segment at the current moment is a defect causing a sudden drop in amplitude, the greater the possibility that the drill bit sensor pressure at the current moment is a defect causing a mutation. Therefore, the mutation maintenance weight is used to weight the mean value, and the weighted result is normalized to obtain the mutation continuity coefficient of the drill bit sensor pressure at the current moment.

[0050] Step S4, adjusting the applied pressure of the drill bit at the current moment according to the mutation coefficient and mutation duration coefficient of the drill bit sensor pressure at the current moment, combined with the drill bit sensor pressure at the current moment and the predicted pressure model.

[0051] After obtaining the mutation coefficient and mutation duration coefficient of the drill bit sensor pressure at the current moment, that is, after real-time evaluation of the drilling environment in which the drill bit is located, the drill bit sensor pressure at the current moment and the predicted pressure model can be further combined to adjust the applied pressure of the drill bit at the current moment, thereby ensuring the efficiency and effect of drilling sampling.

[0052] Preferably, in one embodiment of the present invention, the method for adjusting the applied pressure of the drill bit at the current moment includes: The applied pressure corresponding to the drilling sampling feed rate of the drill bit at the current moment in the preset pressure model is used as the predicted applied pressure of the drill bit at the current moment; The difference sign between the drill bit sensor pressure at the current moment and the drill bit sensor pressure at the previous adjacent historical moment is used as the adjustment direction, and the normalized result of the absolute value of the difference is used as the first parameter; the product of the mutation coefficient and the mutation duration coefficient of the drill bit sensor pressure at the current moment is used as the second parameter; The adjustment direction, the first parameter and the second parameter are integrated to obtain the adjustment amplitude parameter; the adjustment amplitude parameter is added with a constant 1 to obtain the adjustment weight; the predicted applied pressure is weighted using the adjustment weight, and the weighted result is used as the applied pressure of the drill bit at the current moment.

[0053] As an example, the calculation formula for the applied pressure of the drill bit after adjustment at the current moment is: ; Where T is the serial number of the current moment; The applied pressure of the drill bit after adjustment at the current moment; To predict the applied pressure at the current moment corresponding to the feeding depth or the detection depth in the pressure model; The drill bit sensing pressure at the current moment; is the drill bit sensor pressure at the previous adjacent historical moment at the current moment; is the sudden change duration coefficient of the drill bit sensing pressure at the current moment; is the mutation coefficient of the drill bit sensor pressure at the current moment; is the adjustment direction at the current moment, and its value is +1 or -1; is the first parameter; is the second parameter; is the adjustment amplitude parameter; To adjust the weight.

[0054] It should be noted that the mutation coefficient and the mutation maintenance coefficient are both normalized, and their value ranges are both from 0 to 1, and the value range of the adjustment amplitude parameter is from -1 to 1.

[0055] In the above formula, when the drill bit sensor pressure at the current moment is greater than the drill bit sensor pressure at the previous adjacent moment and the difference is larger, the adjustment direction is negative, that is, the applied pressure needs to be reduced, and the adjustment amplitude should also be larger, and the corresponding first parameter is larger; when the mutation coefficient and mutation duration coefficient of the drill bit sensor pressure at the current moment are larger, the possibility that the drill bit is in a transition change of sample texture is greater, and the corresponding second parameter is also larger; the adjustment direction, the first parameter and the second parameter are multiplied and combined to obtain the adjustment amplitude parameter, and then the adjustment weight is obtained by adding the constant 1, and the adjustment weight is multiplied and combined with the drill bit applied pressure at the current moment to obtain the adjusted applied pressure; specifically, the applied pressure in the predicted pressure model is adjusted based on the fluctuation, so that when the drill bit transitions from the normal part of the pile foundation to the defective part, the applied pressure is appropriately reduced to improve the sampling quality, and when the drill bit transitions from the defective part of the pile foundation to the normal part, the applied pressure is appropriately increased to improve the sampling efficiency.

[0056] As the drilling sampling process changes, that is, as time changes, the pressure applied by the drill bit during the drilling sampling process can be adjusted, thereby regulating the entire drilling sampling process and improving the drilling sampling effect on the pile foundation to be tested.

[0057] The present invention also proposes a drilling sampling device for road bridge pile foundations, comprising a device body, and the device can implement the steps of a drilling sampling method for road bridge pile foundations.

[0058] In summary, before the drilling sampling of the pile foundation to be tested, the present invention obtains the ultrasonic detection signal of the pile foundation to be tested and all the detection sub-segments therein, further analyzes and obtains the pressure adjustment speed of each detection sub-segment in the corresponding detection process, and combines the pressure range of the drill bit to construct a predictive pressure model in the drilling sampling process of the pile foundation to be tested; then, during the drilling sampling process of the pile foundation to be tested, the mutation coefficient and mutation duration coefficient of the drill bit sensor pressure at the current moment are analyzed and obtained, and further combined with the drill bit sensor pressure at the current moment and the predictive pressure model, the pressure applied by the drill bit at the current moment is adjusted. The present invention first uses ultrasound to preliminarily detect the pile foundation to be tested before the drilling sampling of the pile foundation to be tested, analyzes and constructs a predictive pressure model of the drill bit, and then adjusts the pressure in combination with the real-time pressure of the drill bit during the drilling sampling process, so as to avoid secondary damage to the sampled sample of the pile foundation to be tested during the drilling process due to improper pressure, thereby improving the drilling sampling effect of the pile foundation of roads and bridges.

[0059] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0060] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A drilling sampling method for road and bridge pile foundations, characterized in that: The method comprises: Before drilling and sampling the pile foundation to be tested, an ultrasonic detection signal of the pile foundation to be tested is obtained; according to the fluctuation characteristics of the ultrasonic detection signal, the ultrasonic detection signal is segmented to obtain all detection sub-segments; According to the fluctuation stability characteristics of each detection sub-segment and the fluctuation difference between adjacent detection sub-segments, the pressure adjustment speed of each detection sub-segment in the detection process is obtained; according to the pressure adjustment speed and the pressure range of the drill bit in the detection process of all detection sub-segments, a prediction pressure model in the drilling sampling process of the pile foundation to be tested is constructed; During the drilling sampling process of the pile foundation to be tested, a real-time sensing pressure curve of the drill bit is obtained; in the real-time sensing pressure curve, a mutation coefficient of the drill bit sensing pressure at each moment is obtained according to the fluctuation deviation of the drill bit sensing pressure at each moment relative to the drill bit sensing pressure at a historical moment; at the current moment, a mutation continuity coefficient of the drill bit sensing pressure at the current moment is obtained according to the fluctuation of the detection sub-segment to which the detection position of the drill bit belongs and the mutation coefficient of the drill bit sensing pressure at a historical moment; According to the mutation coefficient and the mutation duration coefficient of the drill bit sensor pressure at the current moment, combined with the drill bit sensor pressure at the current moment and the predicted pressure model, the applied pressure of the drill bit at the current moment is adjusted.

2. A drilling sampling method for road and bridge pile foundations according to claim 1, characterized in that: The method for acquiring the detection sub-segment includes: An ultrasonic sequence is constructed based on the ultrasonic detection signal, a first-order difference sequence of the ultrasonic sequence is obtained, all differential values ​​greater than a preset threshold are screened out from the first-order difference sequence, and the sorting sequence number of the differential value in the first-order difference sequence is added with 1 as the time sequence number corresponding to the segmentation point; the ultrasonic detection signal is segmented based on the segmentation point to obtain all signal segments; The segment distribution histogram is fitted with the segment number as the horizontal axis and the segment length as the vertical axis; all signal segments whose length is lower than the average level and whose average amplitude is lower than the overall average amplitude of the signal are regarded as defective segments, and the remaining signal segments are regarded as normal segments; continuous defective segments or continuous normal segments are merged into one detection sub-segment.

3. A drilling sampling method for road and bridge pile foundations according to claim 2, characterized in that: The method for obtaining the pressure adjustment speed includes: The difference between the first signal point of each detection sub-segment and the last signal point of the adjacent previous detection sub-segment is used as the pressure adjustment weight in the detection process corresponding to each detection sub-segment; According to the fluctuation stability and stability continuation of each detection sub-segment, the pressure adjustment parameter of each detection sub-segment in the detection process is obtained; The pressure adjustment parameter is weighted by using the pressure adjustment weight, the weighted result is mapped to the range of [-1, 1], and the mapping value of the preset multiple is used as the pressure adjustment speed in the corresponding detection process of the corresponding detection sub-segment.

4. A drilling sampling method for road and bridge pile foundations according to claim 3, characterized in that: The method for obtaining the pressure adjustment parameter includes: The average amplitude of each signal segment in each detection subsegment is negatively correlated with the amplitude deviation of the average amplitude of the corresponding detection subsegment, and the negative correlation mapping result is used as the fluctuation stability sub-parameter of the corresponding signal segment; the fluctuation stability sub-parameters of all signal segments in the detection subsegment are integrated to obtain the fluctuation stability parameter of the corresponding detection subsegment; the total length of each detection subsegment is used as the stability maintenance parameter of the corresponding detection subsegment; The fluctuation stabilization parameter and the stabilization maintenance parameter are integrated to obtain the pressure adjustment parameter in the corresponding detection process of the corresponding detection sub-segment.

5. The drilling sampling method for road and bridge pile foundation according to claim 1, characterized in that: The method for obtaining the predicted pressure model includes: Obtain the detection depth interval corresponding to each detection sub-segment; take the detection depth as the horizontal axis, take the drill bit applied pressure as the vertical axis, start the applied pressure from zero, take the pressure adjustment speed of the first detection sub-segment as the slope, and fit the applied pressure change sub-segment corresponding to the first detection sub-segment within the detection depth interval; Taking the end point of the applied pressure change sub-segment corresponding to the first detection sub-segment as a new starting point, taking the pressure adjustment speed of the second detection sub-segment as a slope, fitting the applied pressure change sub-segment corresponding to the second detection sub-segment within the detection depth interval; taking the end point of the applied pressure change sub-segment corresponding to the second detection sub-segment as a new starting point, iterating continuously until the corresponding applied pressure change sub-segments within all detection depth intervals are obtained; Among them, when the applied pressure in the applied pressure change sub-segment corresponding to a non-first detection sub-segment is equal to the lower limit of the preset range for the first time, then after the applied pressure is equal to the lower limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment is set to the lower limit of the preset range; when the applied pressure in the applied pressure change sub-segment corresponding to any detection sub-segment is equal to the upper limit of the preset range for the first time, then after the applied pressure is equal to the upper limit of the preset range for the first time, the applied pressure in the corresponding applied pressure change sub-segment is set to the upper limit of the preset range.

6. A drilling sampling method for road and bridge pile foundations according to claim 1, characterized in that: The method for obtaining the mutation coefficient includes: At each moment, the upper envelope of the real-time sensor pressure curve of the drill bit is obtained; the upper envelope is subjected to adaptive mean filtering to determine whether the drill bit sensor pressure at each moment belongs to the historical filtering window corresponding to the previous adjacent historical moment; If it is, the mutation coefficient of the drill bit sensor pressure at the corresponding moment is set to 0; If it does not, then the mutation coefficient of the drill bit sensor pressure at each moment is obtained based on the deviation of the drill bit sensor pressure in a preset number of adjacent historical filtering windows on the upper envelope, combined with the fluctuation similarity and fluctuation stability of the drill bit sensor pressure in a preset number of adjacent historical filtering windows.

7. A drilling sampling method for road and bridge pile foundations according to claim 6, characterized in that: The method for obtaining the mutation coefficient of the drill bit sensor pressure at each moment according to the drill bit sensor pressure at each moment, relative to the deviation of the drill bit sensor pressure in the adjacent preset number of historical filter windows on the upper envelope, and in combination with the fluctuation similarity and fluctuation stability of the drill bit sensor pressure in the adjacent preset number of historical filter windows, comprises: Taking the drill bit sensing pressure at each moment, a preset number of adjacent historical filtering windows on the upper envelope as target windows; The difference between the drill bit sensor pressure at each moment and the average level of the drill bit sensor pressure in each target window is taken as the mutation sub-deviation; the cumulative sum of all the mutation sub-deviations of the drill bit sensor pressure at each moment is taken as the mutation deviation; The ratio of the intersection of the drill bit sensor pressure values ​​in all target windows to the union of the corresponding values, multiplied by the corresponding time length of all target windows, is used as the reference weight of the sudden change of the drill bit sensor pressure at each moment; The mutation deviation is weighted by using the mutation reference weight, and a normalized result of the weighted result is used as the mutation coefficient of the drill bit sensor pressure at each moment.

8. A drilling sampling method for road and bridge pile foundations according to claim 2, characterized in that: The method for obtaining the mutation persistence coefficient includes: Based on the drilling sampling feed rate of the drill bit at the current moment, the signal segment corresponding to the drilling process of the drill bit at the current moment in the ultrasonic detection signal is matched, and the detection sub-segment to which the corresponding signal segment belongs is obtained; the difference between the length of the signal segment matched at the current moment and the length of the corresponding detection sub-segment is used as the mutation maintenance weight; The mutation maintenance weight is used to weight the mean of the mutation coefficient of the drill bit sensor pressure at each moment in the preset historical time domain at the current moment, the weighted result is normalized, and the normalized result is used as the mutation persistence coefficient of the drill bit sensor pressure at the current moment.

9. A drilling sampling method for road and bridge pile foundations according to claim 1, characterized in that: The method for adjusting the applied pressure of the drill bit at the current moment includes: The applied pressure corresponding to the drilling sampling feed rate of the drill bit at the current moment in the preset pressure model is used as the predicted applied pressure of the drill bit at the current moment; The difference sign between the drill bit sensor pressure at the current moment and the drill bit sensor pressure at the previous adjacent historical moment is used as the adjustment direction, and the normalized result of the absolute value of the difference is used as the first parameter; the product of the mutation coefficient and the mutation duration coefficient of the drill bit sensor pressure at the current moment is used as the second parameter; The adjustment direction, the first parameter and the second parameter are integrated to obtain an adjustment amplitude parameter; the adjustment amplitude parameter is added with a constant 1 to obtain an adjustment weight; the predicted applied pressure is weighted using the adjustment weight, and the weighted result is used as the applied pressure of the drill bit at the current moment.

10. A drilling sampling device for road and bridge pile foundations, comprising a device body, characterized in that: The device implements the steps of a drilling sampling method for road bridge pile foundations as described in any one of claims 1 to 9.

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