Rapid prediction method of dynamic rebound modulus of graded crushed stone considering particle breakage

Abstract

The invention discloses a method for quickly predicting the dynamic rebound modulus of graded crushed stones considering particle crushing, specifically: determining the physical property parameters of multiple groups of graded crushed stones under the conditions of different gradations, different compaction degrees, and different water contents ;According to the dynamic triaxial test, the dynamic rebound modulus of multiple groups of graded crushed stones were measured respectively, and the three-parameter model was used to predict, and the dynamic rebound modulus of each group of graded crushed stones obtained based on the dynamic triaxial test , fit the three-parameter model to get the model fitting coefficient k 1 、k 2 and k 3 ; Determine the fitting parameter k of all physical parameters of each group of graded crushed stones to the three-parameter model 1 、k 2 、k 3 The contribution ratio of , using stepwise multiple regression analysis method to determine the fitting parameter k of the model 1 ~k 3 Respectively with the correlation of each physical parameter, the rapid prediction formula is obtained. The invention can conveniently and accurately obtain the dynamic rebound modulus of the graded crushed stone, scientifically guide the design and construction of the graded crushed stone in the pavement structure, and ensure the engineering quality.

Description

technical field [0001] The invention belongs to the technical field of road engineering, and relates to a method for quickly predicting the dynamic rebound modulus of graded crushed stones considering particle crushing. Background technique [0002] As the graded crushed stone material for the subgrade transition layer and cushion layer, due to the relatively uniform gradation and the relatively small contact area between particles, particle breakage is prone to occur under the combined action of load stress and environmental factors, resulting in the deterioration of the crushed stone gradation and mechanical properties. The properties are attenuated, and its ability to resist deformation is reduced accordingly. If gravel materials with unreasonable gradation, poor angularity, and severe crushing are selected, the subgrade structure after overlaying will experience different degrees of settlement and deformation, which will not only fail to improve the performance of the su...

AI Technical Summary

Problems solved by technology

Due to the essential difference between the static calculation and the dynamic response of the structure, the fast prediction results such as the CBR conversion and the look-up table method proposed earlier based on the static modulus are no longer applicable to the current road design, and it is impossible to accurately control the site construction. guide

At the same time, the test method for the elastic modulus of granular materials (Appendix D) proposed in the new version of the specification requires the use of an expensive dynamic triaxial tester; in addition, the gravel material used for the test is loose, the preparation of the specimen is difficult, and the results are highly discrete. These factors limit the application of dynamic triaxial tester in road engineering

In the existing literature (such as the mesoscopic thermodynamic mechanism of the crushing evolution path of granular materials, Shen Chaomin et al., 2019.1), the research on the evolution law of the elastic modulus of graded gravel under different molding methods and moisture content conditions is not in-depth, and it is difficult to accurately and quickly Prediction of Dynamic Resilience Modulus of Graded Crushed Stone

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