Transient Surface Wave Exploration

Application of transient surface wave exploration

Surface wave exploration, also known as elastic wave frequency sounding, is a new shallow seismic exploration method developed in recent years. Surface wave is divided into Rayleigh wave (R wave) and Ralph wave (L wave), and R wave has the strongest energy, the largest amplitude and the lowest frequency in the vibration wave group, which is easy to identify and measure. Therefore, surface wave exploration generally refers to Rayleigh surface wave exploration.

(1) Identify the velocity structure of underground medium in the engineering area and divide the stratum;

(2) In situ test the physical and mechanical parameters of rock and soil mass;

(3) Foundation survey of industrial and civil buildings;

Field work method

In order to compare and analyze surface waves, multi-channel geophone is generally used for field test by transient method. When a hammer or a falling weight creates a transient shock force on the ground, a broad band of R-waves can be generated. These r-waves of different frequencies are superimposed on each other and propagate outward in the form of pulse signals. When the multi-channel low-frequency geophone receives the pulse vibration signal, after data acquisition and spectrum analysis, the R wave of each frequency is separated, and the corresponding VR value is obtained, and then the surface wave dispersion curve is drawn.