Basic Geotechnical Earthquake Phần 4 docx

38 Basic Geotechnical Earthquake Engineering

38

DYNAMIC SOIL PROPERTIES

4

CHAPTER

4.1 INTRODUCTION

This book is concerned with geotechnical problems associated with dynamic loads. It

also deals with earthquake related ground motion as well as soil response induced by earthquake

loads. The dynamic response of foundations and structures depends on the magnitude, frequency,

direction, and location of the dynamic loads. Furthermore, it also deals with the geometry of

the soil-foundation contact system, as well as the dynamic properties of the supporting soils

and structures.

Elements in a seismic response analysis are: input motions, site profile, static soil

properties, dynamic soil properties, constitutive models of soil response to loading and methods

of analysis using computer programs. The contents include: earthquake response spectra; site

seismicity; soil response to seismic motion, design earthquake, seismic loads on structures,

liquefaction potential, lateral spread from liquefaction, and foundation base isolation.

Some special problems in geotechnical engineering dealing with soil dynamics and

earthquake aspects are discussed in the later chapters. Its contents include: liquefaction

potential of soil, foundation settlement, dynamic bearing capacity of foundations, stone columns

and displacement piles, dynamic slope stability and dynamic earth pressure in the context of

earthquake loading.

4.2 SOIL PROPERTIES FOR DYNAMIC LOADING

The properties that are most important for dynamic analyses are the stiffness, material

damping, and unit weight. These properties enter directly into the computations of dynamic

response. In addition, the location of the water table, degree of saturation, and grain size

distribution may be important, especially when liquefaction is a potential problem. Since

earthquake induces dynamic kind of loading into the soil, these dynamic soil properties are

quite significant.