岩土层速度结构回折波探测原理与方法

PRINCIPLE AND METHOD DETECTING VELOCITY STRUCTURE IN ROCK SOIL LAYER BY REVERSE BRANCH

岩上层波速有随深度增加的总趋势。用浅层折射法记录到的折射波均属回折波。本文采用垂向速度梯度为不同正的常数多层水平层状介质模型，推导出回析波正反演公式，有简单解析表达式，据此解释的实测剖面，与验证孔波速测井资料相当吻合。表明在岩土层保持天然结构和横向比较均匀地区，回折波探测方法有良好应用前景。

There exists a general trend which shows that wave velocity increases withdepth in the rock soil layer,All refraction waves recorded by the shallow seismic refractionmethod are reverse branch.The simple analytic expressions of the forward and inversion for-mulas for reverse branch have been derived using the horizontal layered model with verticalvelocity gradients of various positive constances. The measured sections interpreted by themethod fairly fit to logging data of wave velocity in the test bore hok.It is shown that ap-plication of reverse branch method is of a good prospect in the region where the rock soillayers are of original structures and more homogeneous laterally.