Electrical Conductivity for Evaluating Fabric and Mechanical Behavior of Granular Soils

In this study, an auto-compensation conductivity measurement system has been developed. This system is expected to offer a possible means for describing the granular soil fabric and mechanical behaviors. A series of cyclic triaxial compression, extension, and unloading tests with resistance measurement were performed. The correlation between granular soil friction angle φ, and vertical formation factor, Fv under maximum shear stress ratio has been studied. The test results have shown that the electrical conductivity could be used to evaluate the fabric behavior during the process of loading. The fabric ellipsoid function, which has been used to simulate the orientation strength for sedimentation granular soil, was described

The Study of Risk Assessment of Soil Liquefaction on Land Development and Utilization by GIS in Taiwan

The issue of soil liquefaction has been investigated widely in the past 50 years. However, there is no an integrated method have been considered for the factors between regions’ vulnerability of soil liquefaction and resilience capacity to perform the risk assessment of soil liquefaction hazard. This study selects Yunlin and Chiayi County as a demonstration area, and uses Model Builder of geo-processing models to connect multiple analysis processes, the liquefaction risk distribution in Yun-Chia Plain’s area is carried out in 100 × 100 m grid map scale by GIS. The study results could provide the reference of land development and management in Taiwan

Geomehansko obnašanje stisljivih morskih meljev pod obrežnim valovom iz gruščnatega nasipa

In this study, the soft marine silts under a rubble-mound breakwater in Ma-Zu of west Taiwan are adopted as a test sample. The specimens were prepared by a new, remolded method at dry density and consolidated stresses. Tri-axial shear-strength tests were performed to evaluate the pore-water pressure and the shear strength. The test results show that the pore-water pressure increases gradually and is close to the critical values as the axial strain increases. In addition, under isotropic and K0 consolidation, both the c and c\u27 of the soft marine silts were 0 kPa, which means that the silts do not have any shear resistance, just like fluid under a rubble-mound breakwater. Based on the linear-elasticity and the one-dimensional consolidation theory, the model of the settlement and stability was evaluated in SIGMA/W. The results show that the soft marine silts at the breakwater induced a displacement, greatly increasing with the filling rubble-mound loading. The figures and results can be referenced for a stability evaluation of the silt soil deposits under the rubble-mound breakwater. The results are useful for marine silts mechanics and a stability analysis for the planning, design, and related research on near-shore engineering.V pričujoči študiji so obravnavani stisljivi morski melji pod obrežnim valolomom iz gruščnatega nasipa v Ma-Zu-ju na zahodu Tajvana. Preizkušanci so bili pripravljeni z novo metodo, s ponovnim preoblikovanjem vzorcev pri suhi gostoti in konsolidacijskih tlakih. Za določitev pornih vodnih tlakov in parametrov strižne trdnosti so bili izvedeni triaksialni preizkusi strižne trdnosti. Rezultati teh preizkusov so pokazali, da porni vodni tlak postopoma raste in je blizu kritičnih vrednosti, ko raste osna specifična deformacija. Razen tega sta bili, pri izotropni in K0 konsolidaciji, obe vrednosti c in c\u27 stisljivih morskih meljev enaki 0 kPa, kar pomeni da melji nimajo nobene strižne trdnosti, torej se obnašajo kot tekočina pod valolomom iz gruščnatega nasipa. Na osnovi linearne elastičnosti in eno dimenzionalne teorije konsolidacije so bili v programskem orodju SIGMA/W preračunani posedki in preverjena stabilnost. Rezultati teh analiz so pokazali, da so stisljivi morski melji pri valolomu sprožili deformacije, ki so se zelo povečale z obtežbo zaradi izdelave gruščnatega nasipa. Slike in rezultati kažejo zveze za vrednotenje stabilnosti meljastih naplavin pod valolomom iz gruščnatega nasipa. Rezultati so uporabni pri mehaniki morskih meljev in stabilnostnih analizah za planiranje, projektiranje in podobne raziskave v inženirstvu obrežij

Modeling of Load Bearing Characteristics of Jacket Foundation Piles for Offshore Wind Turbines in Taiwan

This paper presents a pioneering study on numerical modeling of load bearing characteristics of the jacket foundation pile for offshore wind turbines on the west coast of Taiwan. Because Taiwan is located in an earthquake prone area, there is significant interest in improving the prediction of the behavior of wind turbine jacket foundations subjected to seismic loading. Investigation of the bearing capacity of the jacket foundation pile for the offshore wind farm using effective stress analysis, with consideration of pore pressure generation and soil/liquid coupled analysis, was conducted. A new procedure to evaluate the design of offshore wind turbine foundation piles in the sand and clay inter-layered soil was also proposed. Static and dynamic analyses of bearing capacity of the jacket foundation pile were conducted. Results obtained demonstrate that the design process for the jacket foundation pile proposed in this study can properly reflect the interaction behavior of the foundation and the soil. In addition, the pore pressure generation model can be used to simulate soil liquefaction. The proposed method is also very useful in the evaluation of the design capabilities of offshore wind turbine jacket foundations

Warning Model for Shallow Landslides Induced by Extreme Rainfall

In this study, the geophysical properties of the landslide-prone catchment of the Gaoping River in Taiwan were investigated using zones based on landslide history in conjunction with landslide analysis using a deterministic approach based on the TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability) model. Typhoon Morakot in 2009 was selected as a simulation scenario to calibrate the combination of geophysical parameters in each zone before analyzing changes in the factor of safety (FS). Considering the amount of response time required for typhoons, suitable FS thresholds for landslide warnings are proposed for each town in the catchment area. Typhoon Fanapi of 2010 was used as a test scenario to verify the applicability of the FS as well as the efficacy of the cumulative rainfall thresholds derived in this study. Finally, the amount of response time provided by the FS thresholds in cases of yellow and red alerts was determined. All five of the landslide events reported by the Soil and Water Conservation Bureau were listed among the unstable sites identified in the proposed model, thereby demonstrating its effectiveness and accuracy in determining unstable areas and areas that require evacuation. These cumulative rainfall thresholds provide a valuable reference to guide disaster prevention authorities in the issuance of yellow and red alerts with the ability to reduce losses and save lives

NUMERICAL ANALYSES OF PILE FOUNDATION FOR SUPPORT STRUCTURE OF OFFSHORE WIND TURBINE AT CHANGHUA COAST IN TAIWAN

This study investigates the bearing capacities of group pile foundation (jacket foundation) installed on the seabed of offshore wind farm (OWF) at the Changhua coast of Western Taiwan for the jacket support structure of offshore wind turbine (OWT) using three-dimensional (3-D) finite element method (FEM). The jacket foundations are subjected to a combined Vertical-Horizontal-Moment (V-H-M) loading for the operational period. The responses of installed group pile foundations are investigated under the combined loading in marine silty sand-low plasticity silt & clay (SM-ML-CL) layers determined by 19 offshore boring logs. The validity of numerical procedures was verified by a large-scale lateral loading test of steel tubular model pile in laboratory. A systematic parametric study was performed to investigate the effects of the pile length L, pile diameter D, and pile spacing S on the ultimate bearing (or load) capacity behavior of the foundation. The effect of pile length is significant on the vertical bearing capacity (Vult) whereas pile diameter and pile spacing on the ultimate horizontal and moment loads bearing capacities (Hult and Mult). The normalized V-H and V-H-M failure envelopes of bearing capacity for the jacket foundations subjected to combined loadings can be expressed as functions of L, D, and S and fitted by elliptical shape curves. The V-H-M failure envelopes and approximated expressions are proposed to evaluate the mechanical stability of the group pile foundations for the jacket support structure of OWT under the combined loading condition

The Chemokine CCL4 Stimulates Angiopoietin-2 Expression and Angiogenesis via the MEK/ERK/STAT3 Pathway in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignant tumor with a poor prognosis and is a major public health burden in Taiwan. Angiogenesis, the formation of new blood vessels, promotes tumor proliferation, maintenance, and metastasis. Angiopoietin 2 (Angpt2), a mitogen with a strong angiogenic effect, is highly specific to endothelial cells and a key player in angiogenesis. The inflammatory chemokine (C-C motif) ligand 4 (CCL4) is also important in the pathogenesis and progression of cancer. In this study, an analysis of records from The Cancer Genome Atlas (TCGA) database found higher CCL4 expression in oral cancer tissue than in normal healthy tissue. CCL4 treatment of oral cancer cells upregulated Angpt2 expression and stimulated mitogen-activated protein kinase kinase (MEK), extracellular signal-regulated kinase 1/2 (ERK), and signal transducer and activator of transcription 3 (STAT3) phosphorylation. Transfection of oral cancer cells with MEK, ERK, and STAT3 inhibitors and their small interfering RNAs inhibited CCL4-induced promotion of Angpt2 expression and angiogenesis. In a mouse model of OSCC, CCL4-treated cells promoted neovascularization in implanted Matrigel plugs, whereas inhibiting CCL4 expression suppressed Angpt2 expression and angiogenesis. CCL4 shows promise as a new molecular therapeutic target for inhibiting angiogenesis and metastasis in OSCC