含硬包体试样在破裂孕育过程中波速场的变化

THE VARIATION IN VELOCITY FIELD OF THE SAMPLE INCLUDING HARD INCLUSION IN RUPTURE PREPARATION PROCESS

含硬包体混凝土试样在底面支撑侧面双轴加压至主破裂的情况下波速场的变化图象为：加压初期，试样上的纵波平均速度在４１７５～４６１５ｍ／ｓ之间变化，随着压力升高，出现小于４１７５ｍ／ｓ的低速区，但范围甚小，位置在两个包体之间。随后出现大于４６１５ｍ／ｓ的高速区，范围大致与包体位置一致。随着σ１的增加，低速区在逐渐变大，高速区逐步减小后又重新变大，高速区与低速区在平面上相互重叠，在空间上看，高速区被低速区包围着。临近主破裂时，低速区变小并逐步形成条带，高速区也变小，主要集中在靠近未来出现破裂的一个包体位置上。最终的破裂面出现在此高速区与低速条带交界附近，包体也局部破裂了。

The variation process of the velocity field of the concrete sample including the hard inclusion under double-axis pressurization until main rupture from both sides with bottom supporting is as follows: the average velocity of longitudinal wave in the sample varied from 4175 m/s to 4615 m/s at the initial stage of the pressurization and a low velocity area with less than 4175m/s and extremly small size appeared between two inclusions with rise in pressure; then the high velocity area with more than 4615m/s appeared and its rang was roughly the same with the location of inclusion; with increase of σ 1, the low velocity area gradually enlarged, and the high velocity area again enlarged after reducing gradually, was superimposed on the low velocity area in plane and was surrounded by the low velocity area in space; closing on main rupture, the low velocity area reduced and qradually formed a banding area, and the high velocity area reduced too and was concentrated near the inclusion which will rupture in future, and the final rupture surface appered near the juncture of the high velocity area and the low velocity banding area, and the inclusion ruptured locally.