The wave speeds reflecting mechanical properties of media are measured in Φ900 plane blast load generator. This paper investigates the time characteristics of explosive wave propagation in saturated soils. The experiment results indicate that the velocity of stress propagation can increase from 50 m/sec to 475 m/sec under relatively small loading in saturated soils

and consequently the volumetric stress strain relation presents the character of increasing hardening; these phenomena are greatly different from that of unsaturated soils. All these results are helpful to studying the constitutive relation and the wave propagation regularity

and conduce to obtaining the design loading on the underground structures in the saturated soils. For the first loading

the rise time decreases with the increasing of the depth firstly

and then the rise time increases with the increasing of the depth. For the other three loading

the rise time decreases monotonously

with the increasing of the depth

and the trend of the turning to shock wave exists. This phenomenon differs greatly from that of elastic-plastic geo-materials such as unsaturated soils and sands. For the latter materials

the rise time always increases in the direction of the wave propagation because of its plasticity. In addition

the greater of the overpressure on the ground

the shorter of the rise time.During the loading

the mechanical properties could be drawn by using the wave velocity in most cases. In this paper

three types of wave velocity are discussed: the initial stress propagation velocity C

0

the incident wave peak stress propagation velocity C

1

and the peak reflected stress propagation velocity C

2

.The variation regularity of C

1

is the same as that of C

0

. Further more

the comparison of C

0

and C

1

in the same time of loading show that C

0

is less than C

1

above a certain depth

and the value of C

0

is larger than C

1

under the depth.The value of C

2

is monotone increasing with the increasing of the depth

the maximum of C

2

appears in the bottom

and equal to 475 m/sec

greater than those of C

0

and C

1

.Through comparing of C

0

C

1

and C

2

an especial phenomenon can be deduced: the wave velocity isn’t proportional to stress in soils directly

on condition that the density can be considered as the constant approximately. The compression modulus E can be calculated

and has the character: the compression modulus during the early stages of small loading is greater than that under moderate loading

and with the further increasing of loading the compression modulus increases remarkably. This is the main reason why it is easy to generate the shock wave or discontinuous wave in partially saturated soils.