1) No mud discharge, truly green and environmental protection;

2) Solve the problem of the wall protection and drilling of the rotary drilling rig in the complex sand layer, fluid plastic silt layer, backfill layer, pebble layer, etc;

3) The guiding effect of the casing itself can be used to control the verticality of the pile;

4) There is no effect of mud and sediment caused by mud wall protection on the weakening of the bearing capacity of the bored pile, so that the lateral friction resistance and bearing capacity of the pile are greatly improved compared with other pile types;

5) Avoid the quality problems such as shrinkage, broken piles and concrete segregation that may occur in general cast-in-place piles.

6) The problem of hole wall collapse of the upper unstable section caused by suction and disturbance during drilling is completely avoided.