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Adaptive Design of Supported Excavations - Dr Giovanna Biscontin

This project aims to fully document and make available the automated back analysis tool developed by Ms Jin to support commercial implementation, as well as investigate barriers to the adoption of data-driven adaptive design in practice through a targeted workshop. It will also provide guidance on future research developments needed to promote data-driven design in practice; promote provisions on adaptive design to be included in standards and guidance documents.

[Final Report]

The Observational Method (OM) is included as a design option both in EC7 and the CIRIA 760 guide. The OM is most often invoked during construction as a ‘best way out’ process to optimise the design or mitigate impacts when the wall monitoring shows triggers are exceeded. Rapid redesign is then required to provide new construction plans. The newest version of CIRIA 760 clearly outlines a process for using the OM from the start as a pro-active measure allowing greater savings in materials and programme by reducing the excessive conservatism of the initial design as construction progresses. The approach is seldom used in practice due to barriers in contractual design, monitoring, construction management (risk control, time and cost) and training. 

2018 Biscontin Image

A workshop on ‘The observational method for supported excavations: research challenges for removing barriers’ was held in Cambridge on March 28, 2018 to identify major challenges to the practical application of the OM. A total of 28 invited participants were selected to represent all the expertise and functions that interact on excavation projects: designers, contractors, and project owners. A number of common themes emerged from the discussions on barriers to the implementation of the OM: 

  1. Monitoring: instrumentation and monitoring planning; types and accuracy of instruments; interpretation and quality of data; sharing, transferring and preserving information. 
  2. Demonstrating benefits: successful case histories, client education 
  3. Contractual relations: sharing responsibilities, risks and seamless cooperation. 
  4. Modelling tools: availability, transparency, accuracy 

The following activities are proposed to help in supporting practical implementation of the OM: 

  1. Publish and disseminate widely a convincing set of case histories clearly illustrating savings in costs and schedule, as well best practices to ensure productive interactions of all parties. 
  2. Establish information needed for the implementation of the OM, tools that are most effective for back analysis, and truly effective on-site practices. 
  3. Publish guidelines on the most effective approaches to instrumentation and monitoring, clearly outlining advantages, disadvantages, technical specifications of instruments. Sample monitoring plans should be developed to suit a number of different excavation types and project scales. 
  4. Develop standard on data collection and sharing, i.e., recommended data formats and meta-data information labels, data storage and long term preservation, as well as security. 
  5. Develop tools to capture information from different sources and of different types in one common database: monitoring data and construction progress should be linked and stored together. 
  6. Develop visualisation tools that can easily combine monitoring data and back analysis. 
  7. Provide guidance and/or training on numerical methods for back analysis that addresses challenges in capturing soil behaviour (constitutive modelling) and problem response (type and complexity of analysis) specifically aimed at practicing engineers and application to excavations. 
  8. Engage a diverse group to explore possible contractual agreements or project organisation to ensure maximum freedom to adopt the OM ab initio. 
  9. Develop more robust tools for automated back-analysis through machine learning techniques, incorporating probabilistic approaches, including impact on schedule, costs and risks. 

The enthusiasm demonstrated by the workshop participants indicates there is quite a lot of interest in moving forward on the OM. After circulating the report on the workshop outcomes we will engage with industrial partners to develop a plan for future work and strategies for engagement of relevant academic partners, industrial sponsors and agencies. 

[Final Report]

Researcher:


Department of Engineering


Department of Engineering

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The Centre for Digital Built Britain is a partnership between the Department of Business, Energy & Industrial Strategy and the University of Cambridge to deliver a smart digital economy for infrastructure and construction for the future and transform the UK construction industry’s approach to the way we plan, build, maintain and use our social and economic infrastructure.