LAUSR

In the present study, the non-metal acoustic waves 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 with increasing the cyclic number and tends to be stable. Also, under the conditions of equivalent control moisture rate and cyclic number, the cyclic amplitude has a great effect on the P-wave velocity of expansive soil. Thus, with increase in the cyclic amplitude, the P-wave velocity is decreased. 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 in cyclic amplitude