The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature ...The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature and reduced carbon footprint in comparison to conventional open-cut excavation methods.The response of pipes during the jacking process is complex and is governed by several factors,including ground conditions,the amount and distribution of lubrication,pipe and annulus size,pipeline misalignments and jacking force eccentricity,among others.Design practice remains based on empirical equations and previous drives through similar geology,resulting in uncertainty in jacking force estimates,thereby restricting adoption of the technique.In order to improve our understanding of the pipe-jacking process,pipes incorporating sensors providing real-time measurements of earth pressures,pore water pressures,axial strains and hoop strains can be used;but the number of such studies reported in the literature is small and the potential of instrumentation on routine projects is largely untapped.Moreover,jacking pipe monitoring practice lags behind the state-of-the-art instrumentation techniques used for monitoring other geotechnical infrastructure.The purpose of this paper is to provide a thorough review of learnings from instrumented pipe-jacking case studies and other supporting research,as well as to propose potential solutions to research gaps in the current state of design practice and field monitoring of pipe jacking projects.展开更多
In recent years,there has been an increased resort to microtunnelling/pipe-jacking as a means of constructing underground conduits(for water,sewage,gas,and other utilities)to avoid on-street disruption in urban areas....In recent years,there has been an increased resort to microtunnelling/pipe-jacking as a means of constructing underground conduits(for water,sewage,gas,and other utilities)to avoid on-street disruption in urban areas.In this paper,technical details of two 1200 mm internal diameter microtunnels in silty sand totalling over 550 m in length are discussed.While average skin friction values are extremely low for both drives suggesting effective lubrication practice,differences in normalised bentonite volumes appear to be responsible for differences in skin friction.Full or near full buoyancy of the pipeline has been demonstrated for the majority of the drive.The frictional stress increase after a stoppage is shown to depend on not only the stoppage duration but also on the normalised lubrication volume.Interpretation of data in the manner presented in the paper is an important means of assimilating experience of microtunnelling in different ground conditions.展开更多
基金funded by the Science Foundation Ireland Research Centre in Applied Geosciences(SFI-iCRAG),with Ward and Burke Construction Limited as the industry partner.
文摘The popularity of trenchless techniques as a means of utility pipeline installation in urban environments,specifically microtunnelling/pipe-jacking,has increased in recent years due to its minimally-disruptive nature and reduced carbon footprint in comparison to conventional open-cut excavation methods.The response of pipes during the jacking process is complex and is governed by several factors,including ground conditions,the amount and distribution of lubrication,pipe and annulus size,pipeline misalignments and jacking force eccentricity,among others.Design practice remains based on empirical equations and previous drives through similar geology,resulting in uncertainty in jacking force estimates,thereby restricting adoption of the technique.In order to improve our understanding of the pipe-jacking process,pipes incorporating sensors providing real-time measurements of earth pressures,pore water pressures,axial strains and hoop strains can be used;but the number of such studies reported in the literature is small and the potential of instrumentation on routine projects is largely untapped.Moreover,jacking pipe monitoring practice lags behind the state-of-the-art instrumentation techniques used for monitoring other geotechnical infrastructure.The purpose of this paper is to provide a thorough review of learnings from instrumented pipe-jacking case studies and other supporting research,as well as to propose potential solutions to research gaps in the current state of design practice and field monitoring of pipe jacking projects.
基金The first author is funded by an Irish Research Council Enterprise Partnership Scheme(IRC-EPS)Postgraduate Scholarship,with Ward and Burke Construction Limited as the industry partner.The third author is supported by the Royal Academy of Engineering(U.K.)under the Research Fellowship Scheme.
文摘In recent years,there has been an increased resort to microtunnelling/pipe-jacking as a means of constructing underground conduits(for water,sewage,gas,and other utilities)to avoid on-street disruption in urban areas.In this paper,technical details of two 1200 mm internal diameter microtunnels in silty sand totalling over 550 m in length are discussed.While average skin friction values are extremely low for both drives suggesting effective lubrication practice,differences in normalised bentonite volumes appear to be responsible for differences in skin friction.Full or near full buoyancy of the pipeline has been demonstrated for the majority of the drive.The frictional stress increase after a stoppage is shown to depend on not only the stoppage duration but also on the normalised lubrication volume.Interpretation of data in the manner presented in the paper is an important means of assimilating experience of microtunnelling in different ground conditions.
