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CN-121978761-A - Method for detecting grouting piles of mould bags based on resistivity method

CN121978761ACN 121978761 ACN121978761 ACN 121978761ACN-121978761-A

Abstract

The invention relates to the technical field of pile foundation detection and discloses a detection method of a grouting pile of a mould bag based on a resistivity method, which comprises the following steps of S1, collecting data before detection, performing site investigation and debugging, S2, arranging electrodes in an array mode, S3, applying low-frequency alternating current, synchronously recording M-N electrode opposite potential data, marking electrode coordinates and time stamps when storing original data, S4, preprocessing the data, establishing a three-layer medium model, S5, performing feature recognition on the mould bag, and grading pile quality according to breakage degree. The invention effectively solves the problem that the traditional detection method needs to break a road or pre-embed a device, so that the requirement of 'detection while passing through a vehicle' is difficult to meet, and simultaneously improves the detection efficiency, increases the detection precision and has strong practicability.

Inventors

  • CHEN BIN
  • CHEN HONGPING
  • JIANG SHENGWEN
  • FU XIANGBIN
  • LI JINHUA
  • ZHANG SONG
  • LIN SHUAI
  • ZHANG YUANTONG
  • WANG QUAN

Assignees

  • 长大市政工程(广东)有限公司
  • 广东长大工程检测有限公司

Dates

Publication Date
20260505
Application Date
20260123

Claims (10)

  1. 1. The detection method of the molded bag grouting pile based on the resistivity method is characterized by comprising the following steps of: s1, collecting data before detection, performing on-site investigation and debugging equipment; s2, arranging electrodes in an array manner; S3, applying low-frequency alternating current, synchronously recording M-N electrode pair potential data, and marking electrode coordinates and a time stamp when the original data are stored; s4, preprocessing data and establishing a three-layer medium model; and S5, carrying out feature recognition on the die bags and grading pile forming quality according to the damage degree.
  2. 2. The method for detecting the grouting pile of the mould bag based on the resistivity method according to claim 1, wherein the data collection comprises the steps of obtaining a design drawing, construction records, and defining the diameter and the length of a pile body of the grouting pile of the mould bag.
  3. 3. A method of detecting a molded bag grouting pile based on resistivity method as defined in claim 2, wherein the in-situ survey includes detecting a road surface structure, a position of an underground pipeline and measuring an elevation of the ground surface, the in-situ survey being positioned using a geological radar or pipeline gauge.
  4. 4. A method for detecting a grouting pile of a mould bag based on a resistivity method as claimed in claim 3, wherein the equipment debugging comprises a check resistivity meter, electrodes and a multi-channel acquisition system.
  5. 5. The method for detecting the grouting pile of the mould bag based on the resistivity method as claimed in claim 4, wherein the specific process of arranging the electrodes in an array is as follows: Detecting the region by adopting a temperature nano device or a dipole device, wherein the transverse/longitudinal distance delta x=delta y=0.5-2 m of the detection device, the distance between power supply electrodes is 1.5-2 times of the detection depth, and 3-5 rows of pile bodies are covered; Single pile encryption, namely arranging 3-5 circles of electrodes in a radius of 1-3m by taking a pile center as an origin, wherein the inner circle spacing is 0.5m, and the outer circle spacing is 1-2m; the grounding optimization, namely, electrodes are inserted into the ground surface for 20-30cm, conductive paste or saturated brine is filled around the electrodes, the grounding resistance is ensured to be less than or equal to 100 omega, and the distance between adjacent electrodes is more than or equal to 3 times the length of the electrodes.
  6. 6. The method for detecting a grouting pile of a mould bag based on a resistivity method as claimed in claim 5, wherein the preprocessing of the data comprises: removing abnormal data with the ground resistance of more than 100 omega, and filtering high-frequency noise through wavelet transformation; and carrying out terrain correction based on the surface elevation data to compensate the influence of the gradient on the resistivity distribution.
  7. 7. The method for detecting the grouting pile of the mould bag based on the resistivity method, which is characterized in that the three-layer medium for establishing the three-layer medium model comprises mould bags, cement paste concretes and peripheral soil bodies, the number of data iteration is more than or equal to 200 by adopting a regularization inversion algorithm, and meanwhile, the fitting error is less than or equal to 5 percent to generate the three-dimensional resistivity distribution model.
  8. 8. The method for detecting grouting piles of a mold bag based on a resistivity method as claimed in claim 7, wherein the characteristic recognition of the mold bag comprises: The normal pile body is that the resistivity image shows that the central low-resistance area is wrapped by a continuous high-resistance ring, and the error between the boundary and the designed pile diameter is less than or equal to 5%; Breakage judgment, namely interrupting the high-resistance ring, wherein the resistivity of the peripheral soil body is less than or equal to 80 omega M, an abnormally low resistance region.
  9. 9. The method for detecting a grouting pile by using a mould bag based on a resistivity method as claimed in claim 8, wherein the pile forming quality grading comprises the following steps: The class I (preferred) has no dissipation, complete high-resistance ring and uniform low-resistance area; Grade II (qualification) the area of the escape area is less than 15 percent of the pile body cross section area, and no continuous channel is formed; grade III (failure) with dissipation area not less than 15% or channel length not less than 50cm, and pile repair.
  10. 10. The method for detecting the grouting pile of the mould bag based on the resistivity method, according to claim 9, is characterized in that a phase-locked amplification technology is adopted to filter out 50Hz power frequency noise when the coordinates and the time stamp of the time scale grouting electrode of the original data are stored.

Description

Method for detecting grouting piles of mould bags based on resistivity method Technical Field The invention relates to the technical field of pile foundation detection, in particular to a detection method of a molded bag grouting pile based on a resistivity method. Background The mould bag grouting is a foundation treatment or seepage-proofing and leakage-stopping technology, and is characterized by that the specially-made mould bag is placed into stratum gap, drilling hole or karst cave, then the grout such as cement paste is injected, and the filtration action of mould bag is used to implement consolidation. After the grouting of the mould bags is finished, pile foundations need to be detected, so that a special detection method is needed. At present, a core drilling method, an acoustic wave transmission method and the like are commonly used in the field of pile foundation detection to detect the pile foundation, but the method has obvious defects for a mould bag grouting pile, such as easy drilling deviation caused by pile shape interference in the core drilling method, low detection efficiency, incapability of embedding an acoustic detection tube in the acoustic wave transmission method, difficulty in detection due to the influence of a working interface in the high/low strain method, long static load test period, high cost and inapplicability to large-area detection, and meanwhile, the method needs to damage a pavement or an embedded detection device, and cannot meet the requirements of 'low damage and rapid detection' of the existing road. Disclosure of Invention In order to solve the problem that the traditional detection method in the background technology needs a road breaking or pre-embedding device, so that the requirement of 'detection while driving and detecting at the same time' is difficult to meet, the invention provides a detection method for a grouting pile of a mould bag based on a resistivity method. The invention adopts the following technical scheme that the method for detecting the grouting pile of the mould bag based on the resistivity method comprises the following steps: s1, collecting data before detection, performing on-site investigation and debugging equipment; s2, arranging electrodes in an array manner; S3, applying low-frequency alternating current, synchronously recording M-N electrode pair potential data, and marking electrode coordinates and a time stamp when the original data are stored; s4, preprocessing data and establishing a three-layer medium model; and S5, carrying out feature recognition on the die bags and grading pile forming quality according to the damage degree. As a further improvement of the scheme, the data collection comprises the steps of obtaining a mould bag grouting pile design drawing, construction records, and defining the diameter and the length of a pile body. As a further improvement of the above, the on-site survey includes detecting road surface structure, underground pipeline location, and measuring ground level elevation, and the on-site survey is positioned using geological radar or pipeline gauges. As a further improvement of the above solution, the device commissioning includes verifying the resistivity meter, the electrodes and the multi-channel acquisition system. As a further improvement of the above scheme, the specific process of arranging the counter electrodes in an array is as follows: Detecting the region by adopting a temperature nano device or a dipole device, wherein the transverse/longitudinal distance delta x=delta y=0.5-2 m of the detection device, the distance between power supply electrodes is 1.5-2 times of the detection depth, and 3-5 rows of pile bodies are covered; Single pile encryption, namely arranging 3-5 circles of electrodes in a radius of 1-3m by taking a pile center as an origin, wherein the inner circle spacing is 0.5m, and the outer circle spacing is 1-2m; the grounding optimization, namely, electrodes are inserted into the ground surface for 20-30cm, conductive paste or saturated brine is filled around the electrodes, the grounding resistance is ensured to be less than or equal to 100 omega, and the distance between adjacent electrodes is more than or equal to 3 times the length of the electrodes. As a further improvement of the above, the preprocessing of the data includes: removing abnormal data with the ground resistance of more than 100 omega, and filtering high-frequency noise through wavelet transformation; and carrying out terrain correction based on the surface elevation data to compensate the influence of the gradient on the resistivity distribution. As a further improvement of the scheme, the three-layer medium for establishing the three-layer medium model comprises a mould bag, cement slurry concretes and peripheral soil bodies, the number of data iteration is more than or equal to 200 by adopting a regularization inversion algorithm, and meanwhile, the fitting error is less than or equal to 5% to