Research conclusions: Adopting the crushed stone pile with pipe sinking method to reinforce the soft soil railway foundation in clustered depression at Yanrongfeng is probably difficult to form the pile when encountering the big steep and incline face of solution channel and fluid bowl or encountering the isolated stone of big grain size because of the developments of the solution channel and fluid bowl of lime rock in foundation base．After making comparison，the vibro—replacement stone column with perfect adptability is used．When the abnormal situation of the pile length of crushed stone pile due to the developments of the solution channel and fluid bowl of lime rock in soft foundation base in clustered depression at Yanrongfeng happens，the analysis should be made in combination with the pile length of adjacent pile SO as to eliminate the abnormal situation caused by the isolated stone in soil bed faced by the vibro—replacement head for ensuring the crushed stone pile penetrating into the soft soil bed as required in design．Based on the field tests，thestipulation is offered that the analysis should made in combination with the pile length of the adjacent pile when the pile length is l m shorter than the adjacent pile，and the measure of supplying pile is also presented for the abnormal situation of pile length caused by the isolated stone in soil bed faced by the vibro—replacement head．The application shows the equipment selection，construction technology，key points of quality control of crushed stone pile for the soft railway foundation in clustered depression at Yanrongfeng and its treatment measures are feasible．