Research

Design and fabrication of a principal stress testing apparatus (三主應力試驗機之設計與製作)

Dynamic triaxial testing system (動態三軸試驗儀)

This study investigates the arching effect in embankments subjected to basal settlement and water infiltration through dynamic centrifuge model tests. Embankments are critical geotechnical structures that often face challenges from seismic activities and subsidence of underlying soil layers. The research aims to understand the mechanisms of soil arching, its stability, and its interaction with liquefaction, focusing on improving the seismic resilience of embankments built on deformable foundations. Two experimental cases were analyzed: an unreinforced embankment (Case 1) and a reinforced embankment with soil nails (Case 2).  The tests utilized a centrifugal shaking table with a flexible and impervious base to simulate non-liquefiable soft ground.  A liquid supply system introduced Metolose-based fluid into the embankment during centrifugal loading to study the effects of water infiltration and saturation on soil arching. Dynamic loading was applied to induce soil liquefaction, and the relationship between arching and liquefaction was examined. The results revealed that basal settlement leads to soil arching, redistributing loads laterally and creating a loosened zone beneath the arch, which is highly susceptible to liquefaction under water infiltration and dynamic loading.  While soil arching remains stable under static conditions, it may weaken or collapse under seismic loading, causing significant damage such as lateral spreading, crest subsidence, and slope bulging. To mitigate these vulnerabilities, a novel reinforcement approach inspired by the New Austrian Tunneling Method (NATM) was proposed.  Soil nails were employed to reinforce the soil arch, stabilizing the embankment under dynamic conditions.  The reinforced embankment maintained the arching effect during seismic loading, exhibiting improved resistance to deformation and liquefaction-induced damage.  The findings confirm that reinforcing soil arching with soil nails is an effective strategy to enhance the seismic resilience of embankments and levees on soft ground or deformable foundations, particularly in seismically active regions.

本研究通過動態離心模型試驗探討了在基底沉陷和水滲透作用下堤壩中的土拱效應。堤壩是重要的大地工程結構，常面臨地震活動和基底土層沉陷的挑戰。本研究旨在深入了解土拱效應的機制、穩定性及其與液化的相互作用，重點研究如何提高建於可變形地基上的堤壩的抗震能力。研究設計了兩種實驗案例：未加固的堤壩（Case 1）和使用土釘加固的堤壩（Case 2）。試驗使用離心振動台進行，基底為柔性且不透水的材料，以模擬不可液化的軟弱地基。在離心加載過程中，通過液體供應系統向堤壩中引入基於Metolose的液體，研究水滲透和飽和對土拱效應的影響。隨後施加動態載荷以誘發土壤液化，並分析土拱效應與液化之間的關係。結果表明，基底沉陷會導致土拱效應的形成，從而將荷載側向重分布，並在拱下方形成鬆散區域。該區域在水滲透和動態載荷作用下極易發生液化。雖然土拱效應在靜態條件下保持穩定，但在地震載荷下可能會削弱或崩塌，導致嚴重損害，例如側向擴展、堤頂沉陷和坡面隆起。為應對這些脆弱性，研究提出了一種受新奧地利隧道法（NATM）啟發的創新加固方法。通過使用土釘加固土拱，穩定堤壩在動態條件下的結構。加固後的堤壩在地震載荷下保持了土拱效應，顯示出更強的抗變形和抗液化損害能力。研究結果證實，使用土釘加固土拱是一種有效的策略，可提高建於軟弱地基或可變形地基上的堤壩和堤防的抗震能力，特別是在地震活躍地區。

This study focuses on dip slopes that are prone to failure, with particular attention to groundwater infiltration. Through the development of theoretical models and physical model experiments, the research aims to clarify the failure mechanisms and establish a refined evaluation method that improves upon conventional slope stability analysis techniques. Model experiments conducted under gravitational and centrifugal fields successfully reproduced slope failure mechanisms and enabled the assessment of various factors affecting slope stability. The results confirmed the emergence of two distinct failure modes, toe sliding and thrust failure, and identified the reverse toe angle as a critical factor influencing the bifurcation between these modes. Furthermore, the study proposes counterweight embankments as an effective measure to mitigate instability in dip slopes. Based on theoretical analysis and experimental results, it was demonstrated that counterweight fills can shift the failure mode from toe sliding to thrust failure, thereby enhancing slope stability. These findings suggest that, for improving the stability of the southeast pit wall in the Mae Moh open-pit mine in northern Thailand, implementing counterweight embankments and shortening the slope length are effective countermeasures.

本研究以易於發生斜坡破壞之順向坡為研究對象，著重於地下水滲透的影響，透過理論模型的構築與物理模型試驗，釐清破壞機制並建立改良傳統斜坡穩定解析法的精確評估手法。藉由在重力場及離心場下進行的模型試驗，成功再現斜坡破壞機制，並評估各種影響斜坡穩定性的因素。結果確認了坡趾滑動與推擠破壞兩種不同的破壞模式之出現，並揭示反向坡趾角是影響破壞模式分歧的重要因子。此外，本研究提出押重填土作為緩解流向盤斜坡不穩定性的有效對策。根據理論分析與試驗結果，加重填土能使破壞模式由坡趾滑動轉移至推擠破壞，進而提升斜坡穩定性。基於上述成果，對於改善泰國北部Mae Moh露天礦南東部礦坑壁之穩定性，施工加重填土並縮短斜坡長度為有效之對策。

Stress measurement method based on tomography (トモグラフィーに基づく応力測定法)

Surface velocity during and after failure (破壞中及破壞後的表面速 )

Preparation of embankment model in a soil chamber subjected to 50g acceleration  (準備在50G離心加速度實驗的堤壩模型)