On the premise that before secondary change the bed thickness changes gradually and the rock volume is constant,the au- thor uses translational iteration to eiiminate the secondary change of bed thickness.

• 本文在未发生次生变化前地层厚度是渐变的和地层在次生变化前后其岩体体积不变的前提下,提出了用平移迭代法消去地层次生变化的方法。