TRENCH CONSTRUCTION METHOD BASED ON PILOT WELL AND WORKING WELLS, AS WELL AS ROTARY DRILLING RIG FOR TRENCH CONSTRUCTION AND CALIBRATOR Russian patent published in 2006 - IPC E21B3/00 E02D17/06 E02F5/20 

FIELD: mining and building, particularly to construct trench adapted for further wall erection in densely built-up urban and industrial areas and to construct trench under difficult hydrogeological conditions, namely in watered unstable ground.

SUBSTANCE: method involves forming a row of pilot wells spaced equal distances one from another and having diameters lesser than design trench width; forming working wells having diameters equal to design trench width by widening pilot wells along with simultaneously cutting bridges between working wells and removing the cut ground. The pilot wells are vertical or inclined and drilled under thixotropic mix protection. Distance between the pilot well axes is less than design trench width. The pilot wells are drilled in anti-phase one with another by inner and outer columns to provide ten-fold outer column strength in comparison with that of inner column. The pilot well is widened by removing outer column from it and providing the column with hollow reamer having cutting tool diameter equal to design trench width. Removable section of outer column is installed under the reamer. The removable section is provided with through receiving orifices and has height measured from lower end thereof to lower cutting tool plane enough for section advancing for pilot well widening and to prevent working well axis deviation from drilling axis and to provide section disconnection from reamer when reamer reaches trench bottom. After working well collision hollow calibrator body is installed on outer column. Outer and inner columns are brought into rotary-reciprocal movement and the calibrator is moved along trench length to remove cut ground from trench through calibrator interior.

EFFECT: increased technological efficiency of trench having different profiles and different direction construction.

14 cl, 9 dwg, 2 ex