For a pipejacking, the jacking force is critical to balance the resistance force and to move the pipe string forwards. The driving mechanism of a curved pipejacking is more complicated than a straight-line pipejacking...For a pipejacking, the jacking force is critical to balance the resistance force and to move the pipe string forwards. The driving mechanism of a curved pipejacking is more complicated than a straight-line pipejacking, and its jacking force is also more difficult to be determined. The paper theoretically studies the jacking force of a curved pipejacking by considering the static equilibrium of earth pressure, resistance at cutting face, friction at pipe surface, and the driving force behind the pipe string. The derived theoretical formula can be used to estimate the driving forces of a straight-line or a curved pipejacking. Case study was performed by applying the theoretical and empirical formulae. After calibration, the corrected formula is more accurate and more applicable.展开更多
The mechanical properties of colluvium strongly govern the stability of colluvial slopes, and they arc essential for the related analysis and design. Nevertheless, their measurement is not easy on account of heterogen...The mechanical properties of colluvium strongly govern the stability of colluvial slopes, and they arc essential for the related analysis and design. Nevertheless, their measurement is not easy on account of heterogeneity in property and difficulty of sampling. This study attempted to evaluate the shear strength of remolded colluvium by means of a simple direct shear test in the field. A portable direct shear tester was designed to overcome the inconvenience and expensiveness of the conventional large-scale in-situ direct shear test. It can be easily assembled and applied for the silnplc field direct shear test. For calibration, the results of the portable direct shear tester were compared with the results of the laboratory direct shear tester for four different types of soil samples, i.e. standard sand, slate debris, arenaceous shale debris and mixture of gravel and sand. Correlation formulas were established based on the calibration, enabling the portable direct shear tester to measure and estimate the shear strength of remoldcd colluvium in field. This study primarily focuses on the colluvium in Central Taiwan, including the lateritic Dadu Terrace and the arcnaceous shale of Taiping-Wufcng mounts. The portable direct shear tester was applied to sites selected in these areas, and the results were furthcr analyzed and discussed.展开更多
Underground pipelines are prone to damage by corrosion in Taiwan due to the humid climate and the aging and overuse of pipelines.No-dig technologies are necessary,as the cities in Taiwan are highly populated.Rehabilit...Underground pipelines are prone to damage by corrosion in Taiwan due to the humid climate and the aging and overuse of pipelines.No-dig technologies are necessary,as the cities in Taiwan are highly populated.Rehabilitation methods,including the cured-in-place pipe(CIPP)method,provide an alternative to the new no-dig installation methods,which are comparatively more expensive.In this study,the numerical analysis software ABAQUS was used to simulate straight-line and curved underground pipelines damaged by corrosion.After calibration by small-scale physical modeling in the laboratory,numerical models were applied to the analysis of the mechanical behavior of straight-line and curved underground pipelines.To analyze the performance of the CIPP rehabilitation method,different scenarios for straight-line and curved pipelines were considered.These included before-and after-rehabilitation,different internal pressures and surface loading conditions,and different liner deformabilities and pipe-liner interface strengths.The results suggest that the CIPP method can reinforce damaged pipes by reducing stress concentration and differential displacement near the corrosion void.However,proper liner thickness,liner material properties,and pipe-liner interface strength are essential for well-designed CIPP rehabilitation.展开更多
文摘For a pipejacking, the jacking force is critical to balance the resistance force and to move the pipe string forwards. The driving mechanism of a curved pipejacking is more complicated than a straight-line pipejacking, and its jacking force is also more difficult to be determined. The paper theoretically studies the jacking force of a curved pipejacking by considering the static equilibrium of earth pressure, resistance at cutting face, friction at pipe surface, and the driving force behind the pipe string. The derived theoretical formula can be used to estimate the driving forces of a straight-line or a curved pipejacking. Case study was performed by applying the theoretical and empirical formulae. After calibration, the corrected formula is more accurate and more applicable.
基金support of the National Science Counci(NSC94-2211-E-005-022),Taiwan,China
文摘The mechanical properties of colluvium strongly govern the stability of colluvial slopes, and they arc essential for the related analysis and design. Nevertheless, their measurement is not easy on account of heterogeneity in property and difficulty of sampling. This study attempted to evaluate the shear strength of remolded colluvium by means of a simple direct shear test in the field. A portable direct shear tester was designed to overcome the inconvenience and expensiveness of the conventional large-scale in-situ direct shear test. It can be easily assembled and applied for the silnplc field direct shear test. For calibration, the results of the portable direct shear tester were compared with the results of the laboratory direct shear tester for four different types of soil samples, i.e. standard sand, slate debris, arenaceous shale debris and mixture of gravel and sand. Correlation formulas were established based on the calibration, enabling the portable direct shear tester to measure and estimate the shear strength of remoldcd colluvium in field. This study primarily focuses on the colluvium in Central Taiwan, including the lateritic Dadu Terrace and the arcnaceous shale of Taiping-Wufcng mounts. The portable direct shear tester was applied to sites selected in these areas, and the results were furthcr analyzed and discussed.
基金This research was made possible by financial support from the Ministry of Science and Technology of Taiwan(Project No.105-2625-M-005-011)CECI Engineering Consultants,Inc.We also appreciate the Ashimori Industry Co.for providing the data for CIPP liners.
文摘Underground pipelines are prone to damage by corrosion in Taiwan due to the humid climate and the aging and overuse of pipelines.No-dig technologies are necessary,as the cities in Taiwan are highly populated.Rehabilitation methods,including the cured-in-place pipe(CIPP)method,provide an alternative to the new no-dig installation methods,which are comparatively more expensive.In this study,the numerical analysis software ABAQUS was used to simulate straight-line and curved underground pipelines damaged by corrosion.After calibration by small-scale physical modeling in the laboratory,numerical models were applied to the analysis of the mechanical behavior of straight-line and curved underground pipelines.To analyze the performance of the CIPP rehabilitation method,different scenarios for straight-line and curved pipelines were considered.These included before-and after-rehabilitation,different internal pressures and surface loading conditions,and different liner deformabilities and pipe-liner interface strengths.The results suggest that the CIPP method can reinforce damaged pipes by reducing stress concentration and differential displacement near the corrosion void.However,proper liner thickness,liner material properties,and pipe-liner interface strength are essential for well-designed CIPP rehabilitation.
