Method for testing soil constitutive relation and dynamic strength parameter

Abstract

The invention relates to a method for testing a soil constitutive relation and a dynamic strength parameter. The method comprises the following steps of: placing a soil sample in a dynamic triaxial test machine and consolidating; determining vibration frequency, vibration wave type, vibration times and applied external force; applying continuously-increased external force for vibrating; keeping in the same vibration times; stopping testing while straining to reach some degree (5 to 8% in general); processing the last three vibrations under the same dynamic stress; averaging the strains; drawing a relation curve with the dynamic stress and dynamic strain serving as the coordinates under the same coordinate system; arranging strength indexes according to a total stress way; calculating the corresponding main stress under such power condition; drawing a total stress morh stress circle for the dynamic strength; drawing the stress circles under different confining pressures in the same coordinate; calculating a common tangent of the three circles; and determining a vertical intercept and a gradient which are respectively the dynamic cohesive force and dynamic friction angle under a power condition. The method is simple and accurate in result, greatly simplifies the workload of the test, and is the best choice for the engineering test with requirement on time.

Description

technical field [0001] The invention belongs to a test method for testing the strength of soil, in particular to a method for testing soil dynamic constitutive relation, dynamic strength parameter and damping ratio with a simple method. Background technique [0002] Vibration triaxial test belongs to the dynamic test content of soil, and it is a method commonly used in the determination of dynamic characteristics of soil indoors. The research on the deformation and stability of soil under earthquakes in my country mainly uses the vibration triaxial test method to study the liquefaction resistance stability of foundations and slopes. Experimental study of dynamic characteristics. However, so far there is no more unified testing method. At present, in the construction industry standards, only the "Soil Engineering Test Regulations" of the Ministry of Water Resources has some introductions to the vibration triaxial test. The test equipment is an electromagnetic vibration triax...

AI Technical Summary

Problems solved by technology

This method requires more test pieces, 27-36 samples, and cannot guarantee that the experimental data has a more regular pattern

For each specimen, the complete stress-strain curve cannot be obtained, and the curve is a function of different vibration times, which cannot be compared with the static stress-strain, only the dynamic strength can be obtained

Since the specimens are not exactly the same, it may not be possible to obtain a single law that the dynamic strength increases with the increase of the consolidation ratio, and the results cannot be normalized

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