| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 104 === To improve mass transit construction and the penetration of sewage reticulation, Taiwan's underground excavation works play a critical role. Mechanical excavation projects are increasing with more infrastructure development. However, most of researches emphasis on geotechnical safety or stability without the assessment of efficiency and suitability of the excavation methods. Some of the mechanical excavation systems used are based on studies done in Europe, Japan and elsewhere by foreign manufacturers hence cannot be relied on to give the standards for design and construction in Taiwan as Japan and European experiences are not necessarily appropriate to conditions in Taiwan. Thus to promote the relevant tunneling technology in Taiwan, there is need for more understandings on this topic. This study plan aims at the tunneling excavation with different dig scales. The proposal seeks to establish a novel, general model that considers the vary machines (tunnel boring machine, shield tunnel and pipe jacking ), types (earth pressure balance, slurry pressure balance, thick-mud) and geological cases (soil, gravel and rock) in one unified model to analyze. The straight/curved thrust and torque will be calculated for a blunt/sharp, wedge/cone cutter from global cutting to local dragging/indentation of a tunneling machine respectively.
This study aims at investigation and application for both design and construction such as turnkey project. For “design period”: Besides the traditional equations, the study examined more key factors: single cutter to doubled-cutters, the axial gradient of tunnel, floating power and different working condition (active or passive earth pressure, machine or pipe touch tight or densification by geological gable). For “construction period”: By using dimensional analysis, the proposed model generalizes geological characteristics corresponding to two types of cutting forces (thrust and torque) to evaluate their excavation progress with penetration rate. Furthermore, the normalizedSuitable Indices: can be used not only to estimate the functionality and efficiency of cutting machine adopted for tunnel project, but also to offer a warning information for inadequate cutting strategy. To obtain feasibility of normalizedSuitable Indices: applied to geological prediction by using data mining.
This research obtained the following results with two study cases in Taipei:
Design parts:
(1) Low plasticity clay from first case studies, thrust has been approaching the lower bound at 0k + 398 m, namely in near field generating active earth pressure failure; and settlement may be happened in the far field.
(2) Sandstone and shale interbed from first case studies, thrust maximum occurs at 1k + 342 m, the outer cutters due to wear, excavation the aperture and shield machine shell the outer diameter are almost the same, resulting in shield machine were shackled in the underground.
Construction parts: Combined previous literatures and this research, as long as the approximate geological materials will cluster is closer either: ductile (soil) thrust index between 10^1 to 10^2, brittle materials (rock-like) between 10^0 and 10^-2, composite material (gravel) between 10^-3 and 10^-1.
Data mining: WEKA analysis showed that the difference rings parameters between previous and now value can be predicted geology about the front of 2 times shield machine diameter, two case studies above 80% high accuracy.
|
|---|
