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Lee C.-C.,PRO-VISION | Zeng L.-S.,Sino Geotechnology Inc. | Hsieh C.-H.,HCK Geophysical Company | Yu C.-Y.,University of Taipei | Hsieh S.-H.,HCK Geophysical Company
Environmental Earth Sciences | Year: 2012

Electrical resistivity tomography (ERT), single-point-resistance logging with time-lapse, and geological and groundwater level data, are utilized to determine the mechanism of, and a hydrogeological model of, the Gangxianlane landslide in the west-central part of Taiwan. The rock surface and geometry of the colluviums were found by integrating ERT and borehole data. The iso-resistivity line in the bedrock broadly followed the bedding plane, indicating that the contribution of lithology to resistivity exceeds that of groundwater. The results of single-point-resistance logging with time-lapse and borehole data reveal that the bedrock has low permeability, which is associated with poorly developed joints and fractures. The fine grain content part (including the clayey layer), almost parallel to the bedding plane of the bedrock and between the colluvium and the bedrock in the upper part of the landslide, served as the slip surface and is believed to have been recently produced. It can block and retain water in the colluviums. Accordingly, this slip surface has the potential to re-slip in the future. Another slope failure involved rock collapse by a well-developed open release joint close to the Huoshaoping Terrace. It is also related to groundwater flow over a large gradient from the Huoshaoping Terrace. It is a key to determining whether this landslide will expand in the future. © 2012 Springer-Verlag. Source

Yu C.-H.,Sino Geotechnology Inc.
Geotechnical Engineering | Year: 2011

The evenly distributed cast-in-place reinforced concrete group piles with socketed length into soft bedrock of 15 to 33 m were designed as the foundation for Taipei 101. The high-rise building is extremely sensitive to the foundation settlement. Besides, the bearing behavior of a cast-in-place bored pile is largely determined by the way it was installed. Accordingly, the design of pile group foundation for Taipei 101 was based on a series of full scale pile trial installation as well as comprehensive instrumented pile load tests with compressive and pull-out load up to 40 MN and 22 MN respectively. The characteristic t-z curve for each subsurface stratum was evaluated and used to predict the pile load-settlement behavior for the specific soil stratification of each pile located, thus each pile length was determined according to the anticipated loads during service. Besides, the pile group effects, including bearing capacity reduction and settlement increase, were considered in the foundation design. The creep behaviors for piles embedded into bedrock were also analyzed by using the measured results of pile load tests. The superstructures, basement, mat, piles and retaining diaphragm walls were modeled into one integral system for the structural design of foundation, thus the estimation of foundation behavior under various load combinations were conducted using the above mentioned model with the sub-grade reaction under foundation mat. Based on the investigation of trial installations, the construction specification was proposed for the installation of reverse circulation piles. For piles under the main tower, the measures of bottom cleaning and post-grouting were employed to improve the pile bottom sediments and increase end bearing capacity. Both the conventional static and STATNAMIC dynamic loading tests were employed to verify the bearing capacities and behaviors of production piles. Results of the proof load tests met the design requirements well as compared with the simulation using pile ultimate load test results. Source

Yang H.W.,Taiwan High Speed Rail Corporation | Chu D.,Taiwan High Speed Rail Corporation | Wang I.C.,National Taiwan University | Hung C.F.,National Taiwan University | Ho S.K.,Sino Geotechnology Inc.
Civil-Comp Proceedings | Year: 2014

At Taiwan High Speed Rail, we use a track geometry vehicle to measure the track regularity on a periodic regular basis and utilize the on-board patrol installed on the train body to confirm rider's comfort. From the collected data, it was noticed that the track has vertical irregularity occurring at the transition section which is an 8-meter long earthwork section connecting the tunnel with the viaduct structure. This paper presents the results of our work investigating the cause and effect of the track irregularities. It includes monitoring of civil infrastructure, dynamic response measurements on track structure and numerical simulation. The monitoring data indicates the civil infrastructure at the transition section is stable. Dynamic responses of roadbed for tracks were measured and recorded for trains with different operational speeds. The dynamic response data indicates that vibration in the Z direction at the earthwork section is much more significant compared to other check points in tunnel and on viaduct. This could be caused by the 1∼2 mm thin gap observed underneath the roadbed concrete. To verify this postulation, a numerical simulation using the transient dynamic finite element method code - LS-DYNA was performed. Combining the dynamic response measured on site and results of the numerical analysis, we reached the conclusion that the gap between roadbed and the earthwork structure is the root cause of the observed high dynamic response of the track structure. Besides, rail with vertical irregularity could cause significant vibration on train body and this coincides with the measurement of acceleration by the on-board patrol. The results from the numerical simulation suggested that the irregular vertical track geometry may be caused by the repetitive rotation movement of the mass concrete during railway daily operation. A long-term monitoring plan has been implemented to observe the mass concrete movement. Currently, the track geometry can be maintained by adjustment of rail fasteners. © Civil-Comp Press, 2014. Source

Yang S.-H.,National Taiwan University | Chan P.-C.,National Taiwan University | Lin C.-H.,National Taiwan University | Lin H.-H.,National Taiwan University | And 3 more authors.
Journal of Chinese Soil and Water Conservation | Year: 2015

On August 31, 2013, a huge rock driven by torrential rain fell on Provincial Highway No. 2 in Badoutzu and nearly hit a passing car. In Badoutzu, the Da-liao Formation is exposed on the rock slope. The strength of the middle part is greater than that of the lower part; therefore, a notch propagates along the lower part during erosion, resulting in rockfall potential at the middle part. To reduce or avoid rockfall hazard, we recommend a method and associated procedures to analyze the mechanics and the influence area of a rockfall event, that is slope unit division, stereographic projection analysis, stability analysis, and rockfall run-out distance estimation using RocFall Software. The proposed method reveals that the event of August 31 was a tensile-failure-induced toppling. ©, 2015, Chinese Soil and Water Conservation Society. All right reserved. Source

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