Maxa Rockdrills has developed advanced DTH techniques for demanding special applications, like:
- INTERLOCKING STEEL PIPES CURTAINS
Contiguous or Secant Piles are commonly used to construct continuous CURTAIN WALLS, and DTH Systems are very suitable for this applications, in difficult ground Conditions a/o when Rock socketing is required. Normally Cased drilling is required, in order to grant proper verticality and alignment of the curtain.
Maxa DTH Casing Systems are frequently utilized for this purpose.
MOREOVER MAXA HAS DEVELOPED A SPECIAL APPLICATION, CALLED “INTERLOCKING STEEL PIPES CURTAIN”, WHICH IT HAS PIONEERED YEARS AGO and then successfully implemented globally.
THIS TECHNOLOGY CONSISTS OF DRIVING STEEL PIPES OF UP TO 1.200MM DIAMETER BY MEANS OF DTH SPECIAL CASING SYSTEM, GRANTING A PERFECT INTERCONNECTION BETWEEN THE STEEL PIPES BY MEANS OF VERTICAL JOINTS WELDED ALONG THE SAME.
SIMULTANEOUSLY TO THE DRILLING (BY MEANS OF SPECIAL OVERSIZED DTH BIT SET, WHICH IS ALLOWING FOR THE REQUIRED EXTRA DRILLING SPACE REQUIRED FOR INCORPORATING THE JOINTS), THE M/F JOINTS ARE SLIDED INTO EACH OTHER AND THE CURTAIN IS COMPLETED.
IN ADDITION TO VERY HIGH PRODUCTIVE RATES, this solution allows to drill any required length of Rock Socketing, which is essential for an efficient static behavior of the Curtain.
THIS METHOD IS ALSO OVERCOMING ALL THE POSSIBLE PROBLEMS DUE TO LACK OF PRECISION IN CASE OF TRADITIONAL CONTIGUOUS OR SECANT PILES CURTAINS (gaps between the piles, causing leakage of material and inaccurate curtain alignement, requiring extra mending works, etc.).
Maxa is able to provide not only the MOST SUITABLE DRILLING SETS FOR THIS KIND OF APPLICATIONS, but also on request THE VERTICAL M/F JOINTS OF ITS OWN DESIGN and STEEL PIPES of the required diameter and Steel Grade.
- HORIZONTAL “HD” and “HDD” Large Dia.Drilling (Minitunneling)
a) Maxa has been pioneering in “HD” type of application (straight drilling, without Directionality function), which is consisting of DIRECT PLACING OF STEEL PIPES, up to 1.200mm dia., Horizontally or inclined, through ANY KIND OF GROUND FORMATIONS, including hardest Rock, to a max. length of approx. 120m.
This is achieved by special DTH Hammers, as standard DTH Hammers would be unable to restart operation whenever stopped (the hammer’s piston is not re-positioned by gravity as during vertical drilling) and reinforced Bit sets.
This application is normally mounted on “pipe jacking” types of HD Drilling rigs.
Productivity is extremely high, compared to any other HD method in difficult ground conditions.
b) Usually when Horizontal HDD (Horizontal Directional Drilling) rigs and tools are utilized for Large Diameters, it is necessary to start the hole with a smaller diameter and then to carry out (often Multiple steps of) REAMING by suitable tools in order to achieve the final diameter.
Recently some technologically advanced solution has been developed by a German rigs manufacturer IN ORDER TO MAKE POSSIBLE DIRECT STEERING OF LARGE DIAMETER HORIZONTAL HOLES, without needing further Reaming operations.
HOWEVER SPECIALLY ADAPTED DTH HAMMERS AND BIT SETS HAD TO BE DESIGNED IN ORDER TO MATCH WITH THE RIGS’ FEATURES.
Maxa has provided the German Company with the optimal type of Hammers and Bits for this kind of application.
The result of this combination of technologies, using the German Chief Technical Manager’s own words, was “Very successful, and the steering of our (combined) System was perfect!”
Therefore we can now offer, in cooperation with the German rigs’ Manufacturer, the optimal solution for FULL DIRECTIONAL DRILLING up to 1.200mm dia. and over 100m length.
Applications include placing of Facilities across roads, rivers, etc. and “Roof Top” fore-poling treatment to protect excavation of tunnels.
The lattest was commonly used for shorter lengths (10-15m) and small diameters (3″-6″), but now it is applied to much larger parameters!
- CASING DRIVING BY TRADITIONAL METHODS + DTH SYSTEM FOR ROCK SOCKETING
WHEN CASING IS PLACED BY VIBRATORY OR IMPACT HAMMER THROUGH OVERBURDEN STRATA, UP TO THE MAX PRACTICAL DRIVING LENGTH, THE FIRM BEDROCK IS OFTEN DIFFICULT TO ACHIEVE, AS THE CASING CANNOT PENETRATE HARD SOIL AND WEATHERED ROCK STRATA. For such cases MAXA HAS DEVELOPED A SPECIAL (and economic) SOLUTION, called “ALE” SYSTEM, eliminating the risk of jamming the drill string in case of unstable, fractured rock strata or even loose ground.
