New expansive soil expansibility measuring method

Abstract

The invention discloses a new expansive soil expansibility measuring method, which comprises the following steps of: performing consolidation and expansion deformation tests on the same expansive soilsample under multi-stage load; establishing a relation curve of a porosity ratio and overburden pressure of the same consolidation and expansion deformation; researching a relationship between initial states and the overburden pressure of an intersection point of expansion and consolidation deformation curves in different initial states; and determining the expansibility of the expansive soil inother different initial states through adopting a graph look-up method. Compared with a traditional expansibility measuring method, the expansive soil expansibility measuring method has the advantagesthat the test convenience degree and the deformation control difficulty in the test process are improved to a large extent, the test conforms to the expansibility generation mechanism, the randomnessof expansive soil expansibility measuring results can be effectively reduced, errors of the expansibility measuring results are reduced, and the expansive soil expansibility measurement result accuracy is improved.

Description

technical field [0001] The invention relates to a new method for measuring the swelling force of expansive soil. Background technique [0002] The swelling force of expansive soil is one of the most important indicators to judge the expansion and deformation characteristics of expansive soil. The accuracy of the expansion force measurement is directly related to the engineering application of expansive soil and the rationality of the selection of engineering treatment measures. Therefore, how to accurately measure soil expansion Force is of great significance to engineering construction. [0003] At present, there are two main methods for measuring expansion force in my country: [0004] One is the balanced loading method in the geotechnical test regulations, which is mainly to keep the height of the expansive soil soil sample constant by adding water and loading at the same time, and calculate the size of the load required to keep the soil height constant during the expans...

AI Technical Summary

Problems solved by technology

The test procedure of this method is simple, but there are also relatively large shortcomings, which are mainly reflected in: 1) During the expansion and deformation test process of the soil, it is extremely difficult to maintain the original height stability, and the soil sample produces slight deformation during the test process not easy to see

2) There are problems in the mechanism of the test. From the actual operation of the test method of the geotechnical test regulations, the soil is loaded and compressed back to the original height after a certain amount of expansion is generated. The measured force is actually the consolidation after the expansion is stable. There is a certain difference in the mechanism of pressure and expansion force

3) The expansion force measurement method in the geotechnical test regulations uses a single sample to test to determine the expansion force of the soil. External factors have a greater influence on the test results, the test results are more random, and the accuracy of the results is insufficient.

There are also some problems with this method, which are mainly manifested in: 1) The expansion and deformation characteristics of the soil are closely related to factors such as soil properties and the initial state of the soil, and there are certain differences in the "equivalent" soil samples produced by this method , the properties of the sample are not only related to the initial state, but also have a certain relationship with the compaction work in the production process, the operator and technical level, and the operation method. Therefore, the variability of "equivalent" samples is large

2) For the determination of the linear expansion rate of a single sample, external factors have a greater impact on the test results, and it is consistent with the principle of the expansion force measurement of the geotechnical test regulations. The linear expansion rate cannot reflect the essential cause of the soil expansion force

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