In order to operate in narrow place, drill inside buildings and perform tunnelling applications Soilmec has improved one of its top microdrilling rig with electric engine version: the SM-5E. The SM-5E is a 5t class machine. Compact and versatile the rig measure just 2,2 m long by 1,6 m wide giving the possibility to be used in very confined spaces. Four ground stabilizers completed with blocking valve in order to avoid the outflow of hydraulic oil during a break down guarantee safe working even in the toughest soil conditions. The machine body is made with profiles and welded steel sheets and the entire body is protected by guards, grids and doors, especially near hot surfaces and moving parts.
The SM-5E maintains the same high performance and productivity of the diesel rig from which it is derived. Powered by an ABB electric engine (four poles, 50Hz, 380/660V), the machine offers a maximum rated power of 75 kW reducing the exhausted gas emissions. The new special kinematic mechanism, composed by two slew rings, allows a large range of slewing and mast positioning possibilities. One is located on the lower frame to allow drilling over the side of the crawler. It offers rotation of +/-90 degrees with respect to the rig’s longitudinal axis. The second is located on the back of the mast and secures +/-180 degrees rotation for radial drilling. In order to increase the versatility of the drilling unit, SM5 is equipped with telescopic boom of 600mm and sliding mast. Possibility to increase the 1400 mm standard mast stroke thanks to four different mast lengths using special extension of 500 mm, 1000 mm or 2400 mm, allow the rig to be used in low headroom spaces with complete flexibility.
The drilling performance are ensured thanks to a wide range of rotary heads is available from 690-970daNm torque and 98-860rpm drilling speed, to provide excellent productivity in every geological condition. In addition, a hoist force of 51kN ensures the rig offers high performance and greater drilling depths. The rig can be equipped with a hydraulic clamp and breaker of 50-220mm diameter, with a maximum clamping force of 140kN and a top breaking torque of 3,000daNm. For the operator comfort and safety the SM-5E can be radio-controlled reducing costs and time during operation, in either the drilling or in kinematic mechanisms phase. The rig offers numerous safety features as well as easy access for maintenance, and is available in diesel and electric models. Due to these features the rig is of course a multipurpose rig that suits a wide range of civil engineering requirements from micro piling to tunnelling.
The Mosul Dam site
The SM-5E was used in one of the most important project of the last years: the maintenance and safety of Mosul dam in Iraq.
The intervention consist on a series of grout injection to consolidate the Dam’s bottom foundation, the injections were made with the installation of two rows of holes aligned with the dam, grouted with mixtures able to intercept and close fissures and voids deriving from dissolution phenomena. Due both to the stratigraphy and location of the soluble layers, it was necessary to execute and inject holes up to a depth of 200 m. Drilling and grouting activities (including the result control) was carried out in part from the grouting gallery and in part from the dam crest.
The small dimensions of this horseshoe shaped gallery, 3.7 m high and 3 m wide, had not only a considerable impact on the time required for carrying out interventions but also made it necessary to employ small-size rigs. Gallery activities was be further complicated by the need to operate in presence of a significant water head (up to 8-10 bar), making it necessary to carry out drilling and grouting activities using the blow-out preventer. The job site characteristic were very interesting, the SM-5E worked in very confined space with constant and heavy leakage of water. The needs of the personnel was to work with the lowest exhaust emission possible, with a small but powerful rig and the SM-5E has been proven perfect for this job.