Compact CPT crawler rig

Projects

Restricted Access Contracts

During December 2003, Lankelma CPT Ltd mobilised its ‘Mini-Crawler’ restricted access unit to complete three jobs that required its specialist capabilities.

1) Sheltered Housing

The Mini-Crawler went on to perform tests at an extremely difficult access location for Mouchel Parkman at Gale Farm, Sheltered Housing complex near York.

The rig was required to manoeuvre through a 1.2m wide passageway to reach a central courtyard where it performed five tests (using its ground anchors to produce a 20 Tonne reaction force) to a depth of ≈18.0m. Piezometer standpipes were pushed to a depth of 7.0 and 8.0 metres respectively to allow measurement of ground water levels.

2) Flood Defences

At the request of Norwest Holst, The rig performed tests to a maximum requested depth of ≈15.0m on a flood defence embankment at Goole on Humberside.

Scaffold platforms had been built to allow testing ‘over water’ from a stable, level platform. The reduced weight of the rig was ideal for access to this narrow platform and performance was outstanding giving maximum penetration with minimum disruption to other site works.

3) Lock Farm

The third job reverted back to flood defences, this time at the request of Allied Exploration & Geotechnics Ltd at Lock Farm near Pontefract, at an embankment.

Access to this embankment was narrow but well within the capabilities of the rig. Lankelma produced ≈45.0m of quality data, identifying various units along the profile of the embankment that correlated well with samples performed by others.

Flying High.....Pushing Deep

What do you do if you have a job beneath a rail bridge, with no access in or out; full of piles that can’t be touched and you need some ground investigation? You call Lankelma and their Minicrawler CPT rig!

Recently, Lankelma was approached to come up with a method of testing the ground beneath a railway bridge on the CTRL. The ground had been capped with concrete and grout pipes were sticking out of the surface which couldn’t be damaged. The underlying soils needed to be tested before it was treated with ground improvement methods, and then tested afterwards to verify that the ground improvement had worked.

Because of the access problems posed by the sites location, Lankelma sent its 3.5 tonne Minicrawler along to do the job. It was craned down onto the site using an onsite crawler crane. Once the rig had landed, it had to move carefully through the maze of pipes that covered the floor. Due to the rig only weighing 3,5 tonnes, extra reaction force was gained by bolting the rig down to the concrete floor.

The Mincrawler was able to carry out 5 tests over the two day period down to a depth of 5 to 10 metres.

The Minicrawler is a versatile CPT rig. Due to its size, it is able to work on sites where a standard CPT rig would not be able to gain access. With its multi-angle rams, it is designed for slope and embankment work. The reaction force of the rig can be increased by screw picks in the soil, bolting it down to concrete, or by adding kentledge weights.