循环荷载作用下原状花岗岩残积土动力特性

Research purposes: With the rapid development of expressways, railways and subways in southeast coastal areas, it is particularly important to study the dynamic characteristics of undisturbed granite residual soil under long-term cyclic loading in this area. A series of dynamic triaxial tests were carried out on undisturbed granite residual soil in Fuzhou, and the dynamic stress and strain relation, dynamic strength, dynamic shear modulus and damping ratio characteristics of undisturbed granite residual soil under cyclic loading were studied. Research conclusions:(1) The relationship between dynamic strain and vibration number of undisturbed granite residual soil under cyclic loading shows three typical types: stable, destructive and critical. (2) The dynamic strength value of undisturbed granite residual soil decreases with the increase of vibration number, and the relationship between dynamic strength and vibration number is a semi logarithmic function. (3) The dynamic cohesion and the dynamic internal friction angle of granite residual soil both decrease greatly after long-term cyclic loading. (4) The dynamic shear modulus of undisturbed granite residual soil decreases with the increase of vibration number or dynamic shear strain, and the correlation between dynamic shear modulus and dynamic stress amplitude can be described by linear model. (5) With the development of vibration number, the damping ratio of undisturbed granite residual soil under cyclic loading shows three typical types: stable, critical and destructive. (6) The research results have certain reference value for understanding the dynamic characteristics of granite residual soil and selecting the dynamic strength index of soil reasonably.