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Trenchless Technology Risk Mitigation Manual

 

Table of Contents

PREFACE

 

Subsurface construction activities throw up several challenges. Further, trenchless projects, on account of being state-of-art, are more challenging and fraught with risks. These risks, if not mitigated adequately and in time, can lead to partial or complete project failure and consequential damages. Such risk mitigation measures can be developed and applied only if the executer is aware of the dangers associated with the complete activity chain. These dangers could result from unregulated or incorrect technique activities, or from site conditions and constraints, or due to human errors, or material failures, or any combinations of these factors. Should such risk factors and their impact be identified completely, one can develop and apply precautionary measures to achieve success in project. One also must remember that the details provided herein are suggestive in nature and there could be several risks resulting due the complex nature of trenchless projects. Usage of the manual, therefore, should be with appropriate caution as it is impossible for the manual to provide complete applicable risk factors and their severity levels

Trenchless Technology provides immense opportunities for developing, maintaining, and managing buried networks in the environmentally sound ways. However due to the unpredictable behavior of subsurface soil matrix there can be several chances of project failure, some due to critical nature of faced risks and others due to mistakes and negligence. As general information about Trenchless is limited due to its state-of-the-art working methodology, risks for each technique will have a different impact compared to conventional methods of project execution. There will be stages in every project’s life cycle where the service provider has to take precautionary measures and a proactive approach is to develop a risk mitigation measures framework. Such framework depends upon the perceived risks and this manual provides inputs on those. For developing an adequate risk mitigation measure framework engineer must be aware of trenchless techniques, their deliverables, and possible failures in such work items. In addition, should the project inspection and supervision processes need to be developed, one would again need the possible failures and the details presented in the manual can also assist the reader. After this he or she will have to draw the prequalification criteria for trenchless activities. Subsequently, when the trenchless technologist is in place and the technique has been selected, the method statement developed by the service provider would need to be evaluated on a particular benchmark. For all these requirements it is vital to have the risk factors documented and the current manual provides these details to assist the project owners.

Manual lays the foundations and provides inputs on the common risk factors expected in trenchless projects. It is structured in six sections. First section deals with the basics and common risk factors. Next four sections deal with technique specific risk factors related to common items, new installation techniques, rehabilitation and finally replacement techniques. Reader has to select the possible failures that s/he can expect in the project and develop a matrix of expected failures in the project. This matrix needs to be evaluated for possible risk mitigation measures and a proper working methodology for doing this is presented in last section. Manual does not provide the actual mitigation measures as that needs to be derived from the respective code of practice/good practice guidelines and instructions from the technique developers and patent holders. Manual is not intended to replace them, it is a compendium of risk related data for quick reference and use for project owners and their engineers.

The manual aims to provide basic understanding of the possible commonly known risk factors of trenchless projects. With this understanding one can proceed to establish the risk mitigation measure framework prior to project execution activities. It is the second part of the multi part trenchless manual series being published by IndSTT and therefore has been structured in almost similar framework as the first part, the IndSTT Trenchless Technology Scope of Works Manual. Next part in the planned series is IndSTT Trenchless Technology Project Supervision Manual to be released in 2012.

Risk mitigation is the process of the management of risk to ensure their reduction to a level 'as low as reasonably practicable' (ALARP). As subsurface constructions are fraught with a substantial amount of risk at various stages, this process needs to be an integral part of planning, design, procurement and construction of subsurface structures. There are enormous benefits of risk mitigation and depending on the desired project objectives, one can plan an appropriate framework of risk mitigation measures and therefore the importance of this manual.

 



Prof. Niranjan Swarup

Executive Director

Indian Society for Trenchless Technology

908, Hemkunt Chambers, 89,

Nehru Place, New Delhi - 110019

 


 


 

Table of Contents

 

Sl. No.
CHAPTERS
1
1.0
Manual Introduction
1.1
The Manual
1.2
Manual Structure
1.3
Manual Deliverables
1.4
Trenchless Operator Qualifications
1.5
Prequalification of Trenchless Technologists
1.6
Exclusions
1.7
Risk Mitigation
1.8
Objectives & Benefits of Risk Mitigation
1.9
Subsurface Construction & Their Risk Levels
1.10
Risk Mitigation for Subsurface Projects
1.11
Project Brief Management
1.12
Trenchless Technology Applications
1.13
Failture of Trenchless Projects
1.14
Consequences of failure in Trenchless Projects
1.15
Common Risks in Trenchless Projects
1.16
Method Specific Risks
1.17
Conclusions
2
2.1
Subsurface survey
2.2
Dewatering
2.3
Excavation of Pits
2.4
Temporary bypassing of Sewer
2.5
CCTV Pipeline Condition Assessment
2.6
Manhole Connection
2.7
Sewer Pipeline Desilting
3
3.1
Moling
3.2
Pipe Ramming
3.3

Horizontal Directional Drilling (for laying HDPE Pipes)
Horizontal Directional Drilling (for laying Steel Pipes)

3.4
Manual Pipe Jacking
3.5
Auger Boring
3.6
Guided Auger Boring
3.7
Tunnel Boring
3.8
Microtunneling
3.9
Rock Boring
4
4.1
Slip Lining
4.2
Cured in Place Pipe
4.3
Sprayed Lining
5
5.1
Pneumatic Pipe Bursting
5.2
Static Pipe Bursting
6
6.1
Introduction
6.2
Definitions of Subsurface Construction Project Risk Mitigation Terms
6.3
Risk Mitigation
6.4
Objectives & Benefits of Risk Mitigation
6.5
Risk Management of Subsurface Construction Works
6.6
Stakeholders Role and Responsibilities
6.7
Deliverable Schedule
6.8
Disclaimer
6.9
Concluding Remarks

 

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