在轴向应力-应变下海底沉积物声速及其变化

对南海南部海域海底浅表层沉积物短柱状样进行轴向应力-应变/声学测量,结果表明沉积物纵波声速有三种不同的变化结果:(1)声速从应变过程开始随应力-应变曲线变化,在最大应力时声速同时也是最大值,结束时可能高于或低于开始时的声速;(2)声速从应变过程开始逐渐减小,结束时是最小值;(3)声速从应变过程开始逐渐增大,最大值出现在结束时.这些结果与海底浅表层沉积物的物理力学性质、颗粒接触状态、颗粒的微结构等特征有关.研究结果可为深入认识南海南部各种海底沉积物作为承载界面的可靠性、声遥测遥感海底沉积物的工程力学性质等科学目的提供理论依据.

The sound velocity variation in seafloor sediments on its axial stress-strain course

Data from measuring experiments on the axial stress-strain/sound velocity are reported and analyzed for the short columnar samples of seafloor surface sediments of the southern South China Sea,the result shows that there are three types on the variance of sedimental compressional wave velocity:(1) following the stress-strain curve variance the sound velocity varies from the strain beginning,the sound velocity values come out maximum when the stress value reaches maximum, at the strain ending,the sound velocity value is higher or lower than that of the strain beginning;(2) the sound velocity decreases with the strain increase and the sound velocity minimum values come out at the strain ending;(3) the sound velocity increases with the strain increase and maximnm values come out at the end of the course of the stress-strain.These results are related to the characteristics of seafloor surface sediments such as physical-mechanical features,grain contact state and sediment microstructure,etc.These research results will contribute to evaluating the basic stabilization of seafloor engineering in a bearing capacity state,and survey seafloor sediment engineering-mechanical characteristics by the acoustic remote sensing method.