Long-term settlement behavior of soft grounds and secondary compression

2017 ◽  
Vol 40 (5) ◽  
pp. 361-369
Author(s):  
Yoshihito Imai ◽  
Masaru Akaishi ◽  
Wen-Chao Huang ◽  
Huei-Wen Chang
Keyword(s):  
Secondary Compression ◽  
Settlement Behavior

Long-Term Settlement Behavior of a Highway in Land Subsidence Area

2018 ◽  
Vol 32 (5) ◽  
pp. 04018063 ◽  
Author(s):  
Yu-Jin Shi ◽  
Ming-Guang Li ◽  
Jin-Jian Chen ◽  
Jian-Hua Wang
Keyword(s):  
Land Subsidence ◽  
Subsidence Area ◽  
Settlement Behavior

Postconstruction settlement of an expressway built on peat by precompression

1985 ◽  
Vol 22 (3) ◽  
pp. 308-312 ◽  
Author(s):  
Laval Samson
Keyword(s):  
Key Words ◽  
Field Observation ◽  
Slow Rate ◽  
Peat Deposit ◽  
Secondary Compression ◽  
Secondary Settlement ◽  
Foundation Movement ◽  
Highway Embankments

This paper presents the analysis of 18 years of settlement observations of two expressway embankments built on a peat deposit with an initial depth of 3.0–5.8 m using the precompression technique. Observations show that upon removal of the temporary surcharge the highway embankments heaved for about 1 year by a total of 4.3–7.9 cm. This foundation movement was followed by slow-rate settlement for a few years and subsequently by additional secondary settlement occurring at a greater rate of settlement versus logarithm of time. Eighteen years after construction, settlements range from 2.7 to 11.9 cm. It is concluded that precompression has been effective in reducing postconstruction settlement by about 65% and its effectiveness on the long-term settlement was experienced for [Formula: see text] years. After that, the rate of settlement became identical to that of the normally consolidated peat. Key words: peat, precompression technique, secondary compression, long-term settlement, field observation, swelling, surcharge.

Creep Characteristics of Organic Soft Clay Soil Using Large–Scale Model

2021 ◽  
Author(s):  
Raid Al-Omari ◽  
◽  
Mohammed Fattah ◽  
Mudhafar Hameedi ◽  
◽  
...  
Keyword(s):  
Large Scale ◽  
Large Fraction ◽  
Soft Clay ◽  
Laboratory Data ◽  
Soil Surface ◽  
Organic Content ◽  
Scale Model ◽  
Secondary Compression ◽  
Large Scale Model

The long-term settlements in organic clay can create a kind of an engineering challenge that appear in most facilities design and construction in areas with deep deposits of soft clay. Peat ground is widely distributed throughout the southern part of Iraq. Peat contains a large amount of organic matter and has a very high natural water content. Three soil samples were collected from depths of 1.5 m, 2.5 m, and 3.5 m, below the soil surface in Halfaya oilfield, which lies east of Missan governorate southern Iraq. A series of tests were conducted in a large-scale model using a plate footing and considering three different percent of organic content. The percent of secondary settlement found is dependent on the stress level applied. A large fraction of the total settlement may be due to secondary compression. The assumption of a constant coefficient of secondary compression, Cα, may not be valid for a long-term settlement of peats. Laboratory data indicate that Cα generally increases with time. Thus, settlement predictions using constant Cα may underestimate field settlement.

Quasi-overconsolidation and creep phenomena in shallow marine and estuarine organo-calcareous silts, Fiji

1995 ◽  
Vol 32 (1) ◽  
pp. 89-105 ◽  
Author(s):  
Graham G. Shorten
Keyword(s):  
Organic Content ◽  
Strain Rates ◽  
Radiocarbon Dates ◽  
Secondary Compression ◽  
Compression Creep ◽  
Preconsolidation Pressure ◽  
Stress Dependent ◽  
Oedometer Tests ◽  
Foundation Failure

Nearshore, estuarine deposits of Holocene organo-calcareous silt provide the most common setting for foundation failure in Fiji. Creep is implicated in long-term settlement. Although the geological history indicates the deposits should be normally consolidated throughout, there is increasing apparent overconsolidation towards the surface. This finding is contrary to what might be expected if delayed compression alone was operating. The phenomenon appears to be related instead to organic content and may be affected by strain rates during consolidation. Oedometer tests extending over 7 months indicate the rate of volume change due to creep follows the Singh–Mitchell relationship, but calculation of secondary compression from radiocarbon dates suggests that the very long-term rate is higher than might be expected. Creep appears to be stress dependent, at least below the preconsolidation pressure, in common with other marine sediments. Key words : silt, organic, preconsolidation pressure, overconsolidation ratio, secondary compression, creep, radiocarbon dating.

scholarly journals Inferring the Creep Settlement Behavior of Rockfill in Reclaimed Lands by Advanced SAR Interferometry and Numerical Modeling: An Example from Arabian Gulf

2020 ◽  
Vol 12 (3) ◽  
pp. 527 ◽  
Author(s):  
Michele Di Lisa ◽  
Hossam Eldin A. Ali ◽  
Paolo Mazzanti ◽  
Serena Moretto
Keyword(s):  
Creep Rate ◽  
Arabian Gulf ◽  
Time Frame ◽  
Sar Interferometry ◽  
Wave Forces ◽  
Reclaimed Land ◽  
Static Compression ◽  
Ground Deformations ◽  
Settlement Behavior

Satellite Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) is becaming a key-technique for monitoring ground deformations. The potential of A-DInSAR for settlement monitoring is exploited in this paper through the investigation of a reclaimed land in Dubai (UAE). Time histories of displacements were obtained from COSMO-SkyMed satellite images over the period between 2011 to 2016, allowing to derive the long-term deformation of the entire artificial island. Special attention was paid on long-term settlement of the hydraulically-placed rockfill of the peripheral rubble-mound revetments. The A-DInSAR results have been compared with results derived from numerical analyses and with field surveys, proving the relation between observed and modeled displacements. The study has also revealed that rockfill long-term settlement (creep) rate is significantly dependent on the aging (time since placement). In the analyzed time-frame (2011–2016) it has been observed that recently placed rockfill experienced creep rate up to ten times higher than the creep rate measured for similar rockfill structures placed 30 years earlier. Furthermore, it has been demonstrated that static compression by preloading and dynamic or impact densification induced by wave forces proved to have also a significant impact on reducing the creep rate of the rockfill.

Application of the Cα/Cc concept to secondary compression of sabkha soils

1998 ◽  
Vol 35 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Mosleh A Al-Shamrani
Keyword(s):  
Appreciable Amount ◽  
Silty Clay ◽  
Soil Behavior ◽  
Compression Behavior ◽  
Clay Particles ◽  
Secondary Compression ◽  
Undisturbed Samples ◽  
Consolidation Coefficient ◽  
Test Embankment

Sabkha soils are coastal and inland saline deposits of arid climates consisting mainly of loosely cemented sandy silt to silty clay particles. Invariably the soils contain an appreciable amount of organic material and are characterized as being highly compressible. Despite increased interest in various aspects of sabkha soil behavior, little is yet known about the nature and magnitude of secondary compression of these distinct sediments. In this paper, the secondary compression behavior of a typical sabkha formation from the southwestern coast of Saudi Arabia was investigated. Series of conventional and long-term, one-dimensional consolidation tests were conducted on natural and preloaded undisturbed samples taken from the compressible sabkha layer. The results of the laboratory investigation, substantiated by existing field data, indicated that a significant portion of sabkha settlements takes place as a secondary compression. The coefficient of secondary compression, Cα, was found to be constant, and the ratio of Cα to the compression index, Cc, is within the range reported in the published literature for various geotechnical materials. The applicability of the Cα /Cc concept to sabkha soils was further ascertained by comparing the secondary settlements estimated based on this concept with those measured directly in the field under an instrumented test embankment. Reasonable agreement was found between predictions and field observations.Key words: sabkhas, consolidation, coefficient of secondary compression, preloading, test embankment.

scholarly journals Study on long-term settlement behavior of reclaimed land based on the observed data in Hiroshima Bay

2017 ◽  
Vol 12 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Naoki KUMAMOTO ◽  
Takashi TSUCHIDA ◽  
Kazuaki FUKUHARA ◽  
Naoyoshi KITAYAMA
Keyword(s):  
Reclaimed Land ◽  
Settlement Behavior

Records of settlement of the M5 motorway over the Somerset Levels

1991 ◽  
Vol 7 (1) ◽  
pp. 627-635 ◽  
Author(s):  
D. Cook ◽  
G. Pereira
Keyword(s):  
Laboratory Tests ◽  
Data File ◽  
Operative Field ◽  
Alluvial Deposits ◽  
Low Level ◽  
Secondary Compression ◽  
Key Features ◽  
Statistical Relationships ◽  
Complex Deposition

AbstractAn account is given of the secondary consolidation characteristics of recent alluvial deposits under the line of the M5 motor-way where it crosses the Somerset levels. It uses a group of 161 long term settlement records between East Clevedon and St George which were maintained after contract completion in 1973 as the instrumentation installed during construction had .predicted continued settlement. The records were combined with a data file of soils information from the same area compiled by the first author in 1984. The key features of secondary consolidation are reviewed as a guide to the analysis of the records, which are examined for statistical relationships between the measured rates of secondary compression and the operative field variables namely, the embankment loading, the depth of consolidating material and its light preconsolidation. Because of the complex deposition sequence it was only found possible to follow trends. These showed that secondary consolidation was most sensitive to the loading relative to the preconsolidation, or thresh-hold pressure. They also gave some indication of decreasing overall rates of secondary strain with increasing thickness of deposit. Laboratory tests significantly underestimated the field rates of secondary consolidation in all cases. It was reckoned that persistent low level vibrations from heavy traffie contribute to the variations, affecting the shallower layers by a greater amount.

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