- Numerical Simulation of Capillary Barrier System under Rainfall Infiltration in Singapore
- Alfrendo Satyanaga ; Harianto Rahardjo ; Chai Juay Hua
- Book Title / Journal: International Journal of Geoengineering Case Histories
- Year: 2019 , Volume: 5
- Numerical & Constitutive Modeling ; Instrumentation
- Keywords: Capillary barrier system ; Fine Sand ; Granite Chips ; finite element ; Rainfall
- Abstract
Rainfall-induced slope failures commonly occur within residual soil slopes. One of the possible systems for slope preventive measure is capillary barrier system. A capillary barrier is a two-layer system of distinct hydraulic properties that is used to prevent water infiltration into the soil below the capillary barrier system by utilizing unsaturated soil mechanics principles. This paper presents the numerical simulation of the capillary barrier system as a slope preventive measure against rainfall-induced slope failures. The capillary barrier was constructed on a slope which experienced several shallow failures due to rainfall. In this study, the capillary barrier system was designed to repair the slope and at the same time to provide preventive measures for further failures due to heavy rainfall conditions of the tropics. The capillary barrier system was constructed using fine sand as the fine-grained layer and granite chips as the coarse-grained layer. Both layers were contained in geocells. The slope was instrumented with tensiometers and piezometers. The tensiometers were installed at different depths from about 0.5 m to 2.0 m below the slope surface. In addition, the adjacent original slope without the capillary barrier system was also instrumented using tensiometers in order to investigate the performance and effectiveness of the capillary barrier system in reducing rainwater infiltration and maintaining negative pore-water pressure in the slope. Results of field measurements from one-year monitoring period and numerical analyses of slope with and without capillary barrier system are presented in the paper. The results of numerical analyses of the slopes with and without capillary barrier system indicated that the capillary barrier system performed well in minimizing rainwater infiltration into the underlying soil layer. In addition, the numerical results showed that the factor of safety of a slope with a capillary barrier system was significantly higher than that of an original slope without the capillary barrier system. The field measurement and numerical analyses results were in good agreement, demonstrating the successful application of unsaturated soil mechanics principles in the design and construction of a capillary barrier system. PDF |
- Geotechnical and Structural Challenges over an Active Landslide
- Konstantinos Seferoglou ; Isabella Vassilopoulou ; Fragiskos Chrysohoidis
- Book Title / Journal: International Journal of Geoengineering Case Histories
- Year: 2018 , Volume: 4
- Landslides ; Instrumentation ; Numerical & Constitutive Modeling
- Keywords: geotechnical and structural design ; deep foundation ; temporary piers ; Geotechnical Monitoring ; active landslide ; sliding movements
- Abstract
The construction of the steel arched Tsakona Bridge, designed to overpass an active landslide, required several temporary projects. Auxiliary steel towers were used for the erection and welding of the arch segments. Most of them had to be founded in the body of the sliding mass. An automated instrumentation and monitoring system was installed on site providing early warning to the engineers in charge in case large displacements were measured. The real-time recording data provided valuable information about the landslide movements. These monitoring results defined the geotechnical and structural design criteria for the deep foundation of the temporary towers. Several 2D and 3D geotechnical and structural models were created to evaluate the sliding effect on the foundation components, finalize their dimensioning and calculate the required reinforcement. The procedure followed for the design of the temporary deep foundation is described based on the criteria devised using the monitoring system, emphasizing on the continuous feedback between the geotechnical and structural design teams. Several key structural design issues required during construction are also presented. PDF |
- Singapore Case Histories on Performance of Piles Subjected to Tunnelling-Induced Soil Movement
- W M Cham
- Book Title / Journal: International Journal of Geoengineering Case Histories
- Year: 2016 , Volume: 3
- Pile Foundations ; Tunneling in Soils ; Instrumentation
- Keywords: Tunnelling ; Piles
- Abstract
In land scarce Singapore, the development of a comprehensive and efficient underground public transport system is the key to a sustainable transport system. This has resulted in many tunnels being built in densely urbanized areas and at close proximity to buildings and infrastructures. The tunnelling effects on these adjacent structures can be detrimental as problems such as pile settlement and passive loading on the piles could arise. The construction of large scale infrastructure projects such as Circle Line has opened up enormous scope for tunnelling and underground works in Singapore, which offers a great opportunity to study the response of piles to tunnelling. Two case histories are presented and involved the monitoring of 200 buildings located within the influence of tunneling along Circle Line (CCL) 3, 4 and 5. More than 3600 building settlement markers were analyzed and the resulting pile head settlements due to tunnelling were compared with surrounding ground surface movements. The results of the full-scale instrumented piles subjected to the effects of twin tunnel construction on adjacent groups of bored cast in-situ piles are also discussed. PDF |
- Study on Early Warning of Slope Failure by Using Tilt Sensors Installed at Slope Surface
- L.W. Lin ; I. Seko ; T Uchimura ; I. Towhata ; J.P. Qiao
- ICGE Colombo 2015
- Year: 2015
- Landslides ; Instrumentation
PDF |
- Design and Behavior of A Deep Excavation Adjacent to Existing Buildings and Tunnels
- Q. LI ; W.D. Wang ; Z.H. Xu
- ICGE Colombo 2015
- Year: 2015
- Deep Excavations ; Tunneling ; Instrumentation
PDF |
- Monitoring dataset of deformations related to deep excavations for North-South Line in Amsterdam
- M. Korff ; F. J. Kaalberg
- IS SEOUL '14
- Year: 2014
- Deep Excavations ; Underground Structures ; Instrumentation
PDF |
- French Innovations in Geotechnics: the National Research Projects
- C. Bernardini ; B. Simon ; F. Rocher-Lacoste ; H. Gonin ; A. Puech ; R. Frank ; C. Plumelle ; F. Schlosser
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Retaining Walls ; Instrumentation ; Numerical & Constitutive Modeling ; Site Characterization & In-situ Testing (General)
PDF |
- Load transfer mechanisms in geotextile-reinforced embankments overlying voids: experimental and numerical approaches
- G. Auray ; L. Briançon ; P. Villard ; P. Garcin ; A. Huckert
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Geosynthetics for Reinforcement ; Numerical & Constitutive Modeling ; Instrumentation
PDF |
- Performance Assessment of Synthetic Shock Mats and Grids in the Improvement of Ballasted Tracks
- D. Christie ; T. Neville ; C. Rujikiatkamjorn ; S. Nimbalkar ; B. Indraratna
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Railway Geotechnics ; Geosynthetics for Reinforcement ; Laboratory Testing ; Instrumentation
PDF |
- Microseismic Monitoring Developments in Hydraulic Fracture Stimulation
- M. van der Baan ; D. Eaton ; M- Dusseault
- Book Title / Journal: Effective and Sustainable Hydraulic Fracturing
- Year: 2013 , Series: Chapter 21
- Instrumentation ; Mining
- Keywords: microseismic monitoring ; hydraulic fracturing
- Description
- The last decade has seen a significantly increased interest in microseismic monitoring by the hydrocarbon industry due to the recent surge in unconventional resources such as shale-gas
and heavy-oil plays. Both hydraulic fracturing and steam injection create changes in local pore pressures and in situ stresses and thereby brittle failure in intact rock plus additional slip/shearing in naturally fractured rock. Local rock failure or slip yields an acoustic emission, which is also known as a microseismic event. The microseismic cloud represents thus a volumetric map of the extent of induced fracture shearing, opening and closing. Microseismic monitoring can provide pertinent information on in situ reservoir deformation due to fluid stimulation, thus ultimately facilitating reservoir drainage. This paper reviews some of the current key questions and research in microseismicity, ranging from acquisition, processing to interpretation.
PDF |
- Performance verification of a geogrid mechanically stabilised layer
- J. Kwon ; B. Reall ; I. Fraser ; M. Wayne
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Pavement ; Geosynthetics ; Geosynthetics for Reinforcement ; Instrumentation
PDF |
- Comparison of Static and Dynamic Pile Load Tests at Thi Vai International Port in Viet Nam
- Le Phan Ta ; Tatsunori Matsumoto ; Ha Nguyen Hoang
- Book Title / Journal: International Journal of Geoengineering Case Histories
- Year: 2013 , Volume: 3
- Site Characterization & In-situ Testing (General) ; Instrumentation ; Pile Foundations ; Soil Dynamics In-Situ
- Keywords: static load test ; dynamic load test ; steel pipe pile ; spun concrete pile ; wave matching analysis ; pile foundation quality control ; berth area
- Abstract
A berth structure, 600 m long and 60 m wide, for handing of loaded containers was completed in early 2013 as one of the facilities of Thi Vai International Port located on the bank of the Cai Mep river in Viet Nam. The berth is a quay structure supported by 885 driven spun concrete piles and 156 driven steel pipe piles. Four test piles, named TSC1, TSC2, TSP1 and TSP2, with different pile lengths and diameters were driven at the project site in 2011 prior to construction of working piles. Static load tests (SLTs) were conducted for the test piles to determine the design pile capacity. Dynamic load tests (DLTs) were also carried out for the TSC1 and TSP1 in order to obtain information for selecting the pile driving system used for the working piles and to examine the applicability of wave matching analysis (WMA) to derive the static load-displacement curves. A wave matching analysis program developed by the authors was employed in the WMAs. Good agreement between the derived and measured static responses was obtained for the TSC1 and TSP1. The identified soil parameters obtained from the final WMA of the TSC1 and TSP1 were used to predict the static responses of the TSC2 and TSP2. The predicted load-displacement curves were reasonable matches to the measured ones, indicating that the identified soil parameters of the test piles could be used for prediction of the static responses of other constructed piles. Moreover, pile driving termination criterion in this site was examined through the test piling. PDF |
- Importance of Fracture Closure to Cuttings Injection Efficiency
- M. Bai ; A. Diaz ; J. McLennan ; Ju Reyna
- Book Title / Journal: Effective and Sustainable Hydraulic Fracturing
- Year: 2013 , Series: Chapter 39
- Instrumentation
- Keywords: fracture closure
- Description
- The major benefit of adequate fracture closure is to release injection pressure and restore it to its initial magnitude during the shut-in period to prevent gradual pressure build-up over the injection batches that follow. This paper examines a number of injection cases where the
benefits of adequate fracture closure and the detrimental impacts of insufficient fracture closure are respectively revealed.
In-depth examination of fracture closure impact can be set for short durations with relatively fewer injection batches, as well as for long periods with numerous batch injections. The former scenario focuses on determining the physics of the individual fracture closure, while the latter situation emphasizes the general trend with respect to peak pressure at the end of injection and terminal pressure at the end of the shut-in period.
In addition, this paper addresses the added complexities during fracture closing after shut-in
that can be identified from the relationship between injection pressure and the G function
superposition derivative. Straight-line behavior usually indicates that the formation is homogeneous and leak-off from the fracture into the formation is linear. Other responses such
as concave or convex shapes of the G superposition derivative relationship may indicate the formation is either naturally fractured or tight (i.e., low permeability). Or, the pressure decline
shapes may imply fracture tip extension, or fracture height recession. Direct examination of
the pressure decline curves may reveal the relationship between the fracture responses and
formation characteristics.
PDF |
- Timber pile load test instrumented with removable extensometers
- F. Rocher-Lacoste ; P. Reiffsteck ; Kouby El ; J. Christin
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Pile Foundations ; Instrumentation
PDF |
- Monitoring and Instrumentation of demonstrators storage cells (CMHM)
- J. Morel ; F. Bumbieler ; P. Teixeira ; O. Gay
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
- Instrumentation ; Underground Structures
PDF |