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11.
Myint Win Bo Victor Choa Jian Chu Arul Arulrajah 《Marine Georesources & Geotechnology》2017,35(6):847-856
The compressibility characteristics of Singapore marine clay in reconstituted and undisturbed states were studied using oedometer, constant rate of strain, Rowe cell, and isotropic consolidation tests. The intrinsic compression curve of the reconstituted clay was found to be similar to that proposed earlier with some minor deviations at low vertical stresses of less than 100?kPa. The field and laboratory compression behaviors were found to be similar, hence the laboratory curve could be used as a reference for interpreting the field behavior. Factors affecting the measurements of compression index and yield stress were discussed. As the coefficient of lateral earth pressure at the top upper clay was close to 1, the compression curves of vertically and horizontally trimmed samples were almost similar. The yield stress was mainly controlled by the strain rate; i.e., the higher strain rate resulted in the higher yield stress. Constrained modulus as derived from cone penetration tests and flat dilatometer tests were also examined and compared with laboratory test results. The in situ tests showed the decrease in constrained modulus with depth and generally the dilatometer test was found to register a higher modulus value. 相似文献
12.
In-situ testing of Singapore marine clay at Changi 总被引:2,自引:0,他引:2
The Changi East Reclamation Project in the Republic of Singapore comprises of the ground improvement of marine clay with the installation of prefabricated vertical drains and subsequent surcharge placement. Prior to the commencement of land reclamation works, a series of in-situ tests were conducted in marine conditions with the use of various in-situ testing equipment. The In-Situ Testing Site was located in the Northern area of the project where the thickest compressible marine clay layers existed. The in-situ tests carried out were with the field vane, piezocone, flat dilatometer, self-boring pressuremeter and BAT permeameter. In-situ tests were conducted to determine the undrained shear strength and overconsolidation ratio of the marine clay. In-situ dissipation tests provide a means of evaluating the in-situ coefficient of horizontal consolidation and horizontal hydraulic conductivity of soft soil and were used to estimate these properties of Singapore marine clay at Changi. 相似文献
13.
A. Arulrajah M. W. Bo H. Nikraz A. S. Balasubramaniam 《Geotechnical and Geological Engineering》2007,25(6):647-656
In situ dissipation tests provide a means of evaluating the in situ coefficient of consolidation due to horizontal flow and
hydraulic conductivity in horizontal direction in marine clays formation. Dissipation tests by means of piezocone were utilised
in the characterisation of the coefficient of consolidation due to horizontal flow and the hydraulic conductivity in horizontal
direction of Singapore marine clay at Changi. Piezocone dissipation tests were carried out prior to reclamation as well as
after ground improvement with vertical drains to compare the changes in the coefficient of consolidation due to horizontal
flow and hydraulic conductivity in horizontal direction prior to and after ground improvement. The quasi-static piezometric
pressures from the dissipation tests were compared with piezometric pressures from piezometers to determine their possibility
of future use as an alternative to piezometers. Post-improvement CPTU dissipation tests were carried out in the treated “Vertical
Drain Area” as well as in an adjacent untreated “Control Area” for comparison purposes. This study provides support for the
use of piezocone dissipation testing methods for the determination of the coefficient of consolidation due to horizontal flow
and hydraulic conductivity in horizontal direction of marine clays in the region as well as an alternative to piezometer instrumentation
for monitoring of piezometric pressure during consolidation. 相似文献
14.
Yong-Xia Wu Hai-Min Lyu Jack Shuilong Shen Arul Arulrajah 《Environmental Earth Sciences》2018,77(10):392
This paper discusses the geological and hydrogeological features of Quaternary deposits in Tianjin as well as the geohazards related to groundwater hydrology in this region. The soft soil deposits, comprising silt, sand, silty clay and clay, are composed of four aquifer groups. In the first aquifer group, one phreatic aquifer and two confined aquifers have relationships with underground construction in the urban area. These three aquifers are separated by two aquitards and collectively form a multi-aquifer system. During geotechnical construction, potential geohazards present are related to the groundwater, which include water-in-rushing, quicksand and piping hazards. To prevent the aforementioned geohazards, dewatering is conducted; however, groundwater pumping may result in large settlements of the surrounding ground. To reduce pumping-induced settlement, the dewatering–waterproofing system has been adopted. According to the characteristics of the subsoil, excavation depth and the surrounding environment, the dewatering system can be divided into five patterns. In the first four patterns, when pumping is conducted in the excavation pit, the groundwater head in the adjacent aquifers outside the pit decreases due to the leakage effect of the aquitards located between the aquifers. In the fifth pattern, waterproof curtain has cut off the aquifers completely and dewatering in the pit cannot result in settlement around excavation pit. To avoid geohazards related to groundwater hydrology, countermeasures recommended include construction of an effective waterproof curtain, selection of a reasonable excavation dewatering pattern and withdrawal of required groundwater. 相似文献
15.
Acta Geotechnica - The growing rate of plastic waste generation is becoming a global concern due to the adverse impacts of plastics on the environment. Recycling and reusing plastic waste has been... 相似文献
16.
Jagannathan Krishnamurthy Arul Mani Venkatakrishnan Jayaraman M Manivel 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)
To demonstrate the capabilities of remote sensing and Geographic Information System (GIS) techniques for groundwater resources development in hard rock terrains, specifically for the demarcation of suitable sites for artificial recharge of groundwater aquifers, a study was carried out in the Kallar Basin, which is located in parts of the Salem and Tiruchirapalli districts, Tamil Nadu, India. Thematic maps defining lithology, lineaments, landforms, landuse, drainage density, thickness of weathered zone, thickness of fractured zone, hydrological soils, and well yield were prepared from data collected by the Indian Remote Sensing Satellite (IRS) -1C and by conventional methods. All the thematic layers were integrated using a GIS-based model developed specifically for this purpose, enabling a map showing artificial recharge zones to be generated. The exact type of artificial recharge structure, eg, check dam, nallabund, gully plugging and percolation pond, suitable for replenishing groundwater was identified by superposing a drainage network map over an artificial recharge zones map. The GIS-based demarcation of artificial zones developed in the study was based on logical conditions and reasoning, so that the same techniques (with appropriate modifications) could be adopted elsewhere, especially in hard rock terrain, where the occurrence of groundwater is restricted and subject to greater complexity. 相似文献
17.
Natural Hazards - This short communication gives a brief report of a recently anthropic hazard of collapse of a working platform for a cooling tower during construction in the city of Fengcheng in... 相似文献
18.
Factors Affecting Consolidation Related Prediction of Singapore Marine Clay by Observational Methods
The use of prefabricated vertical drains with preloading option is the most widely-used ground improvement method for the
improvement of marine clays in land reclamation projects. The assessment of the degree of consolidation of the marine clay
is of paramount importance prior to the removal of preload in such ground improvement projects. This analysis can be carried
out by means of observational methods with the use of field settlement plates and piezometer monitoring. Field settlement
monitoring data can be used to ascertain the settlement of the reclaimed fill from the time of initial installation. The field
settlement data can be analysed by the Asaoka method to predict the ultimate settlement of the reclaimed land under the surcharge
fill. Back-analysis of the field settlement data will enable the coefficient of consolidation due to horizontal flow to be
closely estimated. Piezometer monitoring data can be analysed to obtain the degree of consolidation of the improved marine
clay. Back-analysis of the piezometer data will also enable the coefficient of consolidation due to horizontal flow to be
estimated. The aim of this paper is to highlight the significance and impact of the various factors that affect prediction
by the Asaoka and piezometer assessment methods. The authors findings of the Asaoka method reveal that the magnitude of ultimate
settlement decreases and the degree of consolidation subsequently increases as a longer period of assessment is used in the
prediction. The degree of consolidation predicted by the piezometers is found to be in good agreement with the Asaoka method
for the early period of assessment. However as the assessment period increases, the piezometer indicates lower degree of consolidation
as compared to field settlement predictions. 相似文献
19.
Baghban Hooman Arulrajah Arul Narsilio Guillermo A. Horpibulsuk Suksun 《Acta Geotechnica》2022,17(5):1681-1697
Acta Geotechnica - This paper studies the effect of various parameters on the effective thermal conductivity (λeff) of the geothermal pavement system when constructed using construction and... 相似文献
20.
Myint Win Bo Ming-Fang Chang A. Arulrajah Victor Choa 《Geotechnical and Geological Engineering》2012,30(1):45-62
Geotechnical ground investigation is important in all construction works particularly, land reclamation projects. The Changi
East reclamation project is a mega project that involves creation of land space as large as 3,000 hectares in multiple phases
between 1991 and 2005. Ground investigation plays a critical role in the Changi project which involved substantial amount
of ground improvement works after reclamation by sand filling. One important aspect of the investigation was to evaluate the
geotechnical characteristics of the underlying compressible soils beneath the original seabed for the selection of suitable
methods of ground improvement. The other important aspect of the investigation was to characterize and verify the compactness
of the reclaimed sand fill. Many types of in situ tests were extensively used in the project. The field vane shear test provides
correlations between the undrained shear strength and depth for the upper and the lower marine clay strata in the Northern
part and the Southern Part of the reclaimed site. Combined with laboratory undrained shear strength tests, the field vane
strength profiles allow the derivation of the undrained shear strength over effective stress ratios for the upper and the
lower marine clays. In addition, results from three other in situ tests, the piezocone cone penetration test, the flat dilatometer
test, and the self boring pressuremeter test provided useful verification of these correlations. A field-performance based
method of assessing degree of consolidation in the underlying clay was developed by combining field monitoring, laboratory
testing and conventional as well as specialized in situ testing. An effective use of in situ testing methods for assessment,
the outcome of ground improvement and for fill quality control in the densification of granular soils is illustrated with
field observation data collected at the project site. 相似文献