Research on shear particle system method of natural frequency of horizontal layered soils

Natural frequency is one of the most important dynamic characteristics of field soil layers. In order to avoid the resonance between structure and ground, the natural frequency of engineering establishments should be different from that of ground. On the basis of traditional shear particle system method based on lumped mass matrix (lumped mass method), a new shear particle system method based on consistent mass matrix (consistent mass method) is developed. Then, influencing factors on computing precision of shear particle system method are analyzed. The three aspects of soil delamination, mass matrix form and material damping are mainly considered. The analysis indicates: the more layer numbers we divide, the more precise the results will be and from the standpoint of practice engineering, when layer number is more than three, a subdivision is needless; layer thickness has very small effect on computing results; the result of consistent mass method is superior to that of lumped mass method and has the property of upper bound solution; in small damping circumstance, the material damping has small influence on natural frequency.