Linear approximation test device and evaluation method for plastic deformation performance of graded crushed stone

Abstract

A linear approximation test device and evaluation method for the plastic deformation performance of graded gravel. The test device includes an engine fixed on a vibration-absorbing table. Impact force; the test mold includes an outer cylinder, and the interior of the outer cylinder is provided with a composite sleeve and a composite cushion; the motor is connected with a servo valve for adjusting the transmission rod to realize waveform control, and the transmission rod is provided with a valve for adjusting the length of the transmission rod itself. lift valve. The evaluation method of the present invention calculates the approximate integral of the plastic deformation curve of the graded crushed stone specimen in the manner of variable time intervals, which can achieve higher accuracy under the same calculation amount, and defines the time interval in the form of a linear function, which can simplify the time The expansion process of the sequence is convenient for application. The present invention uses the PDI index to comprehensively reflect the plastic deformation of the graded crushed stone material at multiple moments.

Description

technical field [0001] The invention relates to the field of highway engineering, in particular to a linear approximation test device and an evaluation method for the plastic deformation performance of graded crushed stones, aiming at quickly and accurately evaluating the plastic deformation performance of graded crushed stones. Background technique [0002] Because of its advantages of easy material acquisition and low cost, graded crushed stone materials were widely used in early road construction in my country. The stone base cannot meet the needs of traffic development. In order to evaluate the deformation performance of graded gravel, the inventor Zhou Gang disclosed a rutting test method (200910103821.7), the basic principle of which is to detect the deformation of the test piece by using wheels to repeatedly walk on the plate-shaped graded gravel test piece Quantity, and the dynamic stability is used to characterize the test results. However, after many rutting tests...

AI Technical Summary

Problems solved by technology

However, after many rutting tests, it was found that when the dynamic stability of two graded gravel materials is the same, their permanent deformations are significantly different or even contradictory

[0003] This is mainly because, in the past, the dynamic stability was mainly calculated based on D45 and D60 (the plastic deformation at the 45th and 60th minutes), but the plastic deformation at other times was ignored, so it often appeared that the deformation resistance was better in the test. The illusion, but in the actual use process produces excessive deformation

In addition, most of the previous tests used rigid test molds, which lead to the complete confinement of graded crushed stones, which is quite different from the actual situation.

Conversely, if the demoulding test is carried out, the graded crushed stone will be in an unconfined state, which is not in line with the actual situation.

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