Study on Influence of Confining Pressure on Strength Characteristics of Pressurised Frozen Sand

In order to reveal the influence law of freezing pressure and confining pressure on the strength characteristics of frozen sand, with the self-developed high-pressure frozen soil triaxial instrument, the triaxial compression tests of frozen sand under different freezing pressures and confining pressures were carried out. The test results show that the freezing pressure will not change the stress-strain curve of the frozen sand. Similar to the confining pressure, the freezing pressure influences the strength of the frozen soil in two ways: strengthening and weakening. The threshold confining pressure resulting from the test was about 45 MPa. Through comparison of the initial elastic modulus with the secant elastic modulus at 0.5 times the strength, it is found that the initial elastic modulus is more appropriate to use in engineering calculations. The internal friction angle is greatly affected by the freezing pressure, and cohesion shows little change with the freezing pressure. Compared with the test results and other constitutive equations, it is found that the constitutive equation established in this paper considering the effect of freezing pressure can better describe the stress-strain relationship of the pressurised frozen sand.

Automated summary

This research aims to reveal the influence of freezing pressure and confining pressure on the strength characteristics of frozen sand. Triaxial compression tests were conducted using a self-developed high-pressure frozen soil triaxial instrument. The results show that freezing pressure affects the strength of the frozen soil in both strengthening and weakening ways. Compared to confining pressure, freezing pressure has a greater impact on the frozen soil. The comparison of elastic moduli suggests that the initial elastic modulus is more suitable for engineering calculations. In addition, freezing pressure greatly affects the internal friction angle, while cohesion shows little change.