Based on analyzing and summing up the cause and type of stria produced in the pittsburgh process, the author presents a method to avoid production of stria by improving structure of bridge wall and strengthening operation.

• 作者分析归纳了无槽垂直引上作业中线道产生的原因和种类；提出改进桥砖结构和加强操作防止线道产生的方法.