Double rotary drilling

Transcription

1 Double rotary drilling

2 Double rotary drilling Description With pile production using double rotary drilling, an outer casing and an inner auger (hollow auger) are driven in counter-rotation by two independant rotary drives which are mounted on a common carriage. The outer casing provides support for the ground, while the auger removes drilling cuttings up through the casing. Once the final depth is reached, a concrete pump is used to pump pumpable concrete via the hollow stem of the auger inside the outer casing to the bottom of the borehole. More concrete is pumped in under simultaneous extraction of the casing and the auger filled with drilling cuttings. The extraction speed is selected as a function of the quantity of concrete and the concrete pressure. In a further step a reinforcement cage can then be inserted into the liquid concrete. Soil types Double rotary drilling is suitable for noncohesive soils up to maximum density as well as cohesive soils up to stiff consistency. Advantages Suitable for nearly all soil types High productivity Very precise drilling Low noise level Low vibration Adjustment of casing and auger possible Drilling does not have to be carried out with water injection 2

3 Double rotary drilling Equipment technology Because of their high engine power, the carrier machines of the LRB-series are especially suitable for pile production with double rotary drilling. The double rotary drives DBA 80, DBA 200 and DBA 300 have sliding cylinders for the relative adjustment of casing and auger. This means that the casing can either run ahead of the auger to prevent cave-in, or the auger can drill ahead as a pilot to break up hard soil. Double rotary drives Model Max. speed Max. torque Casing Auger Casing Auger Max. relative adjustment DBA 80 on LRB kw DBA 200 on LRB kw DBA 300 on LRB kw 18 / 36 rpm 24 / 48 rpm 80 / 40 knm 60 / 30 knm +/- 150 mm 7 / 14 rpm 15 / 30 rpm 196 / 98 knm 98 / 49 knm +/- 150 mm 10 / 23 rpm 14 / 29 rpm 300 / 128 knm 150 / 72 knm +/- 350 mm Application limits* Carrier machine, rotary drive Max. drilling depths Max. drilling diameter LRB 125 with DBA 80 approx. 13 m 610 mm LRB 155 with DBA 200 approx. 17 m 750 mm LRB 255 with DBA 300 approx. 18 m 900 mm * Depending on soil conditions. 3

4 Double rotary drilling Production Positioning at the drilling point. Combined drilling of casing and auger to the bottom of the borehole. Concrete is pumped t stem of the auger fillin up. At the same time extracted. 4

5 4 5 hrough the hollow g it from the bottom uger and casing are Inserting the reinforcement. Finished pile. Concrete 5

6 The ideal drilling rig Sheave head Rope crowd system Flushing head Sliding cylinder for relative adjustment Drive II Drive I Auxiliary winch Lateral inclination device Leader Leader support arm Longitudinal inclination device Vertical travel device Support arm brace Leader swing device Radius adjustment device Basic machine High engine output with automatic engine speed control Controlled entirely from cab Sturdy and solid rig design Wide longitudinal and lateral supporting system on the basic machine through triangles High push and pull forces High torque Completely self-rigging (no auxiliary machines required) Large range of working tools (all common pile driving, drilling and pressing works can be performed) Leader swing range +/- 90 Stepless inclination 1:6 forward 1:3 backward depending on type of equipment Increase of effective leader length (3 m) via vertical travel device Automatic vertical alignment High alignment forces Simultaneous control of several movements via Load-sensing multi-circuit hydraulics Quick change of equipment possible through quick connection Equipment design according to latest European regulations and standards High manufacturing quality through quality control by PDE-system 6

7 Notes 7

8 LWN /2010 Subject to change without notice. 8 BVV Spezialtiefbautechnik Vertriebs GmbH Bleibtreustrasse 9, D Munich/Germany Tel.: Fax: info@bvv.by Liebherr-Werk Nenzing GmbH P.O. Box 10, A-6710 Nenzing/Austria Tel.: Fax: crawler.crane@liebherr.com