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Four-layer pavement modulus back calculation method based on FWD deflection basin geometrical characteristics

A technology of geometric features and deflection basins, applied in the field of four-layer modulus back calculation, can solve problems such as large differences, large errors, and non-convergence of back calculation results, and achieve the effect of small calculation value error and numerical stability

Pending Publication Date: 2020-02-07
RES INST OF HIGHWAY MINIST OF TRANSPORT
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Problems solved by technology

If there is a large difference between the measured deflection basin and the theoretical deflection basin, there is no solution to the back calculation of the measured deflection basin; less consideration is given to the geometric characteristics of the deflection basin, resulting in non-convergence of the back calculation results and large errors.

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  • Four-layer pavement modulus back calculation method based on FWD deflection basin geometrical characteristics
  • Four-layer pavement modulus back calculation method based on FWD deflection basin geometrical characteristics
  • Four-layer pavement modulus back calculation method based on FWD deflection basin geometrical characteristics

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Embodiment Construction

[0037] Table 1 shows a FWD deflection basin measured for a pavement structure, based on which the modulus back calculation of the 4-layer structure is carried out.

[0038] Table 1 FWD measured deflection basin

[0039]

[0040] 1. Calculation of theoretical deflection basin and extraction of geometric eigenvalues

[0041] Taking a typical asphalt pavement structure as an example, according to the material characteristics of each layer of the structure and engineering experience, set a wide modulus range, such as: the modulus of the asphalt mixture of the surface layer is set to 15000-1000MPa, and the base cement is stable The modulus of the graded crushed stone is set at 20000-3000MPa, the modulus of the subbase cement soil is set at 6000-1000MPa, and the modulus of the soil foundation is set at 400-100MPa, see Table 2.

[0042] Table 2: Summary of calculation parameters for an asphalt pavement structure

[0043] structural layer Thickness / m Modulus / MPa Poi...

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Abstract

The invention discloses a four-layer pavement modulus back calculation method based on FWD deflection basin geometrical characteristics. The four-layer pavement modulus back calculation method comprises the following steps: 1, calculating a theoretical deflection basin and corresponding characteristic values of a pavement to be subjected to back calculation by adopting an elastic layered system mechanical model; 2, establishing a relation model of an equivalent far-end deflection point and a soil foundation modulus by adopting a nonlinear function; 3, establishing a relation model of the deflection ratio of the central point and the modulus ratios of the surface layer and the base layer by adopting a nonlinear function; 4, establishing a relation model between the deflection ratio of the fourth point and the central point and the modulus ratio of the surface layer and the subbase layer by adopting a nonlinear function; and 5, extracting a geometrical characteristic value of the actually measured deflection basin according to the constructed relation model, and respectively and reversely calculating modulus parameters of each structural layer corresponding to the actually measured FWD deflection basin according to two different convergence discrimination modes of central point deflection and deflection basin area. The four-layer modulus back calculation result is stable, the difference between the four-layer modulus back calculation result and a theoretical calculation value is small, and a reliable basis can be provided for evaluating the actual modulus state of each structural layer of an in-service pavement.

Description

technical field [0001] The invention relates to a four-layer modulus inversion method based on the geometric characteristics of a FWD deflection basin, belonging to the technical field of road engineering. Background technique [0002] FWD (Falling Weight Deflectometer) is one of the most advanced pavement non-destructive testing equipment in the world at present. The pavement deflection basin detected by FWD is obtained by a modulus inversion method to obtain the different structural layers. The modulus parameter is an effective method to evaluate the service state of each structural layer of the pavement in service. [0003] The existing modulus inversion methods mainly include iterative method and database search method, which have been widely used in pavement engineering, but both have certain limitations. For example, the difference between the measured deflection basin and the theoretical deflection basin is large, and the back calculation of the measured deflection b...

Claims

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Application Information

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IPC IPC(8): G06F30/23
Inventor 王旭东杨光周兴业吴将丰张蕾肖倩
Owner RES INST OF HIGHWAY MINIST OF TRANSPORT
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