Assessment of change in acoustic wave velocity of compacted expansive soil through experiments

Abstract. In the present study, the non-metal acoustic wave monitor, TH204, has been used to determine P-wave velocity of compacted expansive soil under the condition of drying-wetting cycles with constant amplitude to explore the change in P-wave velocity of compacted expansive soil with the cyclic number, cyclic amplitude and control moisture content. The results show that the P-wave velocity of the compacted expansive soil follows a non-linear decrease rate with increasing the cyclic number, while it tends to be stable. Also, under the conditions of equivalent control moisture rate and cyclic number, the cyclic amplitude has great effect on the P-wave velocity of expansive soil. Thus, with increase in the cyclic amplitude, the P-wave velocity decrease. Secondly, under the same cyclic number, the P-wave velocity changes with the control moisture rate monotonously. Further, the study shows that the peak values of P-wave velocity appear near the optimum moisture rate, and the peak value position remains unaltered with change of cyclic amplitude.