初勘阶段 meaning in English

preliminary phase

This author discusses the application of multi - electrode resistivity imaging method and refraction survey to find out the crack and structure in the country rock , to classify the rock according to the wave velocity , and to offer corresponding geological data for engineering design in the anjin highway exploration
摘要在安景高速公路初勘阶段，利用高密度电法及地震折射波物探方法，查明隧道围岩裂隙、构造发育情况，根据波速对围岩分类，配合钻探为工程设计提供相应的基础地质资料。