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CN-116837809-B - Highway subgrade strength detection method based on semi-empirical correction curve

CN116837809BCN 116837809 BCN116837809 BCN 116837809BCN-116837809-B

Abstract

The invention relates to the field of roadbed intensity, in particular to a highway roadbed intensity detection method based on a semi-empirical correction curve, which records pressure and displacement during impact through a sensor on a drop hammer type deflection meter, calculates the vertical displacement of a road surface, selects a Beckman beam deflection meter and a test vehicle, installs the Beckman beam deflection meter between a rear axle double wheel of the test vehicle, corrects parameters of the test vehicle, calculates deflection values, the diameters of the left tire and the right tire of the correction test vehicle are 22.35cm, the grounding pressure of the left tire and the right tire of the correction test vehicle is 0.75Mpa, the vertical displacement and deflection values measured in the step (2) and the step (3) are recorded and compared with the national highway subgrade strength standard, so that the strength of the subgrade can be rapidly detected, the road structure is not damaged, the road flatness of the selected road can be detected through the test vehicle, and the evaluation is made.

Inventors

  • LUO JUNHUI
  • HUANG XIAOFENG
  • YAN ZENAN
  • CHEN JIANGCAI
  • MO PENG

Assignees

  • 广西北投交通养护科技集团有限公司

Dates

Publication Date
20260505
Application Date
20230517

Claims (6)

  1. 1. The highway subgrade strength detection method based on the semi-empirical correction curve is characterized by comprising the following steps of: (1) Selecting a detected pavement for 1km, and dividing the pavement into 5-10 detection points; (2) Detecting the detection points distinguished in the step (1) by using a drop hammer type deflection meter, calculating the vertical displacement of the road surface, and then testing the strength of the roadbed, wherein the strength test of the roadbed comprises the following steps: S1, digging holes on the detection points selected in the step (1); S2, placing a static load experimental instrument in the hole, and increasing the load in a stage manner; s3, recording data of the load sensor and the sedimentation sensor, and simultaneously recording data of the setting column and the measuring ruler around the hole; S4, after the step S3 is completed, carrying out stage-type load reduction, recording, and calculating the compression modulus and the ultimate bearing capacity; S5, correcting the calculation errors in the S4 by establishing a data model between the roadbed intensity parameters and the test data for the influence of a plurality of environments; the calculation formula of the road surface vertical displacement is as follows: ; wherein: for the vertical displacement to be sought, For the warp direction coordinates, Is a vertical coordinate of the two-dimensional coordinate system, For the radius of the support plate, As the average load pressure (MPa) of the support plate, Is the modulus of elasticity (MPa), For the poisson's coefficient, Is a zero-order bessel function, Is an integral variable; (3) Selecting a Beckman beam deflection instrument and a test vehicle, installing the Beckman beam deflection instrument between two rear axle wheels of the test vehicle, correcting parameters of the test vehicle, and calculating deflection values, wherein the calculation formula of the calculated deflection values is as follows: Wherein: Is a deflection value representative value of the road section, As an average value of rebound deflection values of the road section, In order to ensure that the coefficients are maintained, The standard deviation of the rebound deflection value of the road section; (4) Recording the vertical displacement and deflection values measured in the step (2) and the step (3), and comparing the vertical displacement and deflection values with the national highway subgrade strength standard, wherein the calculation formula of the compression modulus is as follows: In which, in the process, In order to achieve a compressive modulus, In order to be able to carry the load, The calculation formula of the ultimate bearing capacity is as follows: In which, in the process, For the maximum load of the roadbed, Is the stress area of the roadbed.
  2. 2. The method for detecting the intensity of the highway subgrade based on the semi-empirical correction curve according to claim 1, wherein in the step (1), the thickness of the asphalt layer of the detected pavement is 33-35cm, the thickness of the cement layer is 24-26cm, the thickness of the crushed stone layer is 56-57cm, and the detection point is 1m2 in circular area.
  3. 3. The method for detecting the intensity of a highway subgrade based on a semi-empirical correction curve according to claim 1, wherein in step (2), said detecting step comprises: (21) Mounting a supporting plate on the surface of the detection point, and limiting the supporting plate; (22) The supporting plate is impacted through the drop hammer to generate a certain impact force; (23) And recording the pressure and displacement during impact by a sensor on the drop hammer type deflection instrument.
  4. 4. The method for detecting the intensity of a highway subgrade based on a semi-empirical correction curve according to claim 1, characterized in that in step S1, the depth of the holes is 1.2-1.4m, and the diameter of the holes is 0.5-0.7m.
  5. 5. The method for detecting the strength of the highway subgrade based on the semi-empirical correction curve according to claim 1, wherein in step S2, the time for increasing the load stepwise is 11-13min, and the load speed of the load stepwise is 7-9 tons/time.
  6. 6. The method for detecting the intensity of the highway subgrade based on the semi-empirical correction curve according to claim 1, wherein in the step (3), the diameters of the left tire and the right tire of the correction test vehicle are 22.35cm, and the grounding pressure of the left tire and the right tire of the correction test vehicle is 0.75MPa.

Description

Highway subgrade strength detection method based on semi-empirical correction curve Technical Field The invention relates to the technical field of roadbed strength, in particular to a highway roadbed strength detection method based on a semi-empirical correction curve. Background The roadbed has various cross sections according to the filling height and the terrain, and the roadbed design mainly comprises a roadbed body engineering design, a roadbed protection and reinforcement engineering design and a roadbed retaining engineering design. For example, the Chinese patent publication No. CN104499473A discloses a highway subgrade strength detection method based on a semi-empirical correction curve, which comprises the following steps of firstly measuring penetration resistance qd of road foundation soil with different depths by using a PANDA2 variable energy penetrometer, secondly dividing the road bed depth into two sections according to the measured different depths, calculating the average value of the penetration resistance qd of each section, and thirdly obtaining road foundation soil strength corresponding to different road bed depths according to the relation between the penetration resistance qd and a CBR value, wherein the penetration resistance qd and the CBR value meet the following conditions that lgCBR =0.352+1.057. The highway subgrade strength detection method based on the semi-empirical correction curve disclosed by the invention not only can be used for effectively detecting the highway subgrade strength, but also can be used for rapidly and effectively detecting the road foundation soil strength (CBR value), does not need larger load and more equipment in the detection process, has the advantages of rapidness and effectiveness, and can provide scientific basis and technical guidance for the establishment of a subgrade maintenance management scheme. However, when the road is detected by the method, the road structure is required to be damaged, and the road is difficult to detect. In summary, developing a highway subgrade strength detection method based on a semi-empirical correction curve is still a critical problem to be solved in the subgrade strength field. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a highway subgrade strength detection method based on a semi-empirical correction curve, which is characterized in that the thickness of an asphalt layer of a detected pavement is 33-35cm, the thickness of a cement layer is 24-26cm, the thickness of a rubble layer is 56-57cm, the detected pavement is 1m < 2 >, the pavement is divided into 5-10 detected points, a supporting plate is mounted on the detected points by using a drop hammer type deflection meter, the supporting plate is limited, the supporting plate is impacted by a drop hammer to generate a certain impact force, the pressure and displacement during impact are recorded by a drop hammer type deflection meter upper sensor, the vertical displacement of the pavement is calculated, a Beckman beam deflection meter and a test vehicle are selected, the Beckman beam deflection meter is mounted between a rear axle double wheel of the test vehicle, the parameter of the test vehicle is corrected, the deflection value is calculated, the diameters of a left tire and a right tire of the test vehicle are 22.35cm, the left tire and the right tire of the test vehicle are grounded to be 0.75Mpa, the pressure and the deflection value during impact can be measured by the drop hammer type deflection meter upper sensor, the step (2) and the vertical displacement of the test vehicle can be compared with the detected pavement strength, the road strength can be evaluated, the road strength can be compared with the road strength and the road strength can not be evaluated, and the road strength can be measured, and the road strength can be well be measured. In order to achieve the above purpose, the present invention provides the following technical solutions: (1) Selecting a detected pavement for 1km, and dividing the pavement into 5-10 detection points; (2) Detecting the detection points distinguished in the step (1) by using a drop hammer type deflection meter, calculating the vertical displacement of the road surface, and then testing the strength of the roadbed; (3) Selecting a Beckman beam deflection instrument and a test vehicle, installing the Beckman beam deflection instrument between the Beckman beam deflection instrument and a rear axle double wheel of the test vehicle, correcting parameters of the test vehicle, and calculating deflection values; (4) And (3) recording the vertical displacement and deflection values measured in the step (2) and the step (3), and comparing the vertical displacement and deflection values with the national highway subgrade strength standard. The invention is further arranged that in the step (1), the thickness of the asphalt layer of the selected detection pavement is