Descriptions
As the soil or rock deforms the distances between the in-hole anchors change, as do the distances between the individual in-hole anchors and the reference head. The magnitude, distribution and rate of deformation can be accurately measured at the reference head.
The GEO-XB2 rod type extensometer range is available in a wide range of reference heads, anchors, rods and measuring sensors.
Case Studies
Percy Road, Bournemouth
Despite its appearance as a small, local street, Percy Road is one of the busiest roads in Bournemouth, located in the Boscombe area.
Settlement at different rates had been happening on a short stretch, approximately 100 yards, of Percy Road, over several months, starting in September 2016.
This settlement was associated with a sewer located 18 meters below ground level. It was observed that groundwater was entering a section of the sewer and subsidence was taking place at the surface.
Wessex Water completed the repair works and the road re-opened to traffic in February 2018.
Wessex Water project manager Joe Edmunds said: “We will continue to monitor Percy Road regularly.”
Daily Echo, 5th February 2018
Percy Road, Bournemouth Case Study
Bucharest Metro Line 5
Bucharest has four metro lines (Metro Lines 1, 2, 3 and 4) consisting of 70km of double track, 49 stations and four depots. The network handles about 600,000 passengers per weekday and the modernisation project is jointly funded by the European Investment Bank (EIB) and the Romanian Government.
Bucharest Metro Line 5 is part of the latest phase IV upgrade and extension of the existing metro network being constructed by Societatea Comerciala de Transport cu Metroul (Metrorex), a metro operating company in Romania. The 17.7km-long underground metro will operate from Drumul Taberei in the south-west zone of Bucharest to Pantelimon in the eastern side through twin track tunnels. It is being constructed in two sections and the contract for Section 1 (known as Raul Doamnei-Eroilor) started in the second quarter of 2011 and is expected to last for about 25 months under the supervision of Metroul – Systra.
Section 1 involves construction of two underground parallel tunnels each of 5.7m-diameter and 7km-long. A third tunnel measuring 260m-long will be excavated to link Metro Lines 1 and 5 at Eroilor station. A total of 240,000m3 of earth and rock will be excavated to construct the tunnels.
Bucharest Metro Line 5 Case Study
Jakarta Mass Rapid Rail Transport, Phase 1, CP104/5
The CP104 and CP105 construction sections include a total of 3.89 kms of 6.05m twin tube tunnelling, four underground stations – Senayan, Istora, Bendungan Hilir, and Setiabudi – and a cut-and-cover transition structure of almost 500m in length to connect the below and above ground sections.
Two special challenges were posed by this project: It was Indonesia’s first shield tunnel construction and the construction of underground stations using the cut-and-cover and top-down method on Sudirman Street, a major street consisting of 12 lanes.
Diaphragm walls were installed to form the station boxes followed by excavation and construction of the slabs from roof downwards as excavation progressed.
Entrances and ventilation shafts were constructed using bottom up construction method and steel struts and walers used to prop open the excavation
Jakarta Mass Rapid Rail Transport, Phase 1, CP104/5 Case Study