There are few systematical formulas to calculate the roller number and the distances between rollers in crawler travel system of rotary pile drill.

Crawler hydraulic drill, and USES the new type of hydraulic technology, low gas consumption, rotary torque, move the hole deflection is convenient.

The newly developed drill, XPL-20, for rotary jetting and anchor is introduced. The main features, technical data, application and structure of drill and its caterpillar chassis are briefly mentioned.