Seismic refraction survey (SRS) is a geophysical method of investigation for dam foundation. This method is used to determine depth to bed rock and characteristics of rock mass from P-wave velocity. SRS is generally conducted at the initial stage of Project before doing direct method of investigations (drilling and drifting). Results of SRS can be used for estimating Q-value and deformation modulus (E) of rock mass. SRS was conducted at dam site of Kuri Gongri HE Project along the direction of river in both the banks for evaluating the depth of bed rock and characterizes of rock mass. The total length of survey is 1.35 km in 9 spreads using 24-channel seismograph on ground except one spread in water, where hydrophones were used. Values of Q and E were estimated using the P-wave velocity from SRS.
Seismic refraction survey, dam investigation, hydrophone, shear zone
