UNCERTAINTY AND RELIABILITY - Introduction to Soft Soil Geotechnique: Content, Context and Application - page 121

min were directly processed and sent to a database, that facilitated direct access to
all parties involved: client, contractor, consultant, local authority and insurance
company. Easy visualization by coloured maps indicated normal, alert and critical
levels, in the last case automatically sending emails and SMSs. This 'dynamic'
warning system comprised permanent “virtual” specialist's eye on site and
provided the proper conditions to complete the construction safely in 2004.
Lower uncertainty but safe margins shorten construction time 38
The Betuwe route, a double track freight railway of 160 km connecting
Rotterdam harbour with Germany, is completed at 4.5 billion euro in 2007. The
embankment of this railway leads into the western part of the Netherlands through
an area of extremely soft soils. In particular, consolidation time and residual
settlements composed a serious risk to the progress of the project. The high risk
profile of the Sliedrecht-Gorinchem section of the Betuwe line, characterised by
peat soil, a high water table, a short construction time, various subsidence-sensitive
objects in the direct proximity and inflexible links with existing infrastructure (Fig
8.9), formed the start of the formation of the 'Waardse Alliance', a special and new
type of alliance between the contractor and the client. Together they took on the
challenge to redesign and build this section within the tight time schedule and the
appointed budget. Both parties agreed to share the costs of identified risks
including unexpected soil conditions and possible damage to existing
infrastructures.
Figure 8.9 The new Betuwe line runs close to existing infrastructure; by applying a
monitoring concept to the largest risk factor: the subsidence, a new type of PPS contract
could be established, leading to significant cost reduction and an excellent project result.
The alliance provided a unique opportunity to optimize the design, to maintain a
constant watch on the unseen and to act swiftly to compensate for any unexpected
situation. The risk on excessive settlement and instability was controlled by on-line
38 In his Terzaghi Oration, Barends introduced the slogan: from uncertain safety to safe
uncertainty , marking the awareness of dealing with large margins in soil mechanics.