Supported excavations in soft soil deposits

2006 ◽  
pp. 117-273
Keyword(s):  
Soft Soil ◽  
Soil Deposits

scholarly journals Uncertainty Analysis in Prediction of Settlements for Spatial Prefabricated Vertical Drains Improved Soft Soil Sites

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 42
Author(s):  
Jemal Jibril Muhammed ◽  
Priyantha W. Jayawickrama ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Granular Layer ◽  
Soft Soil ◽  
Contributing Factors ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Class A ◽  
Numerical Predictions ◽  
Soil Deposits ◽  
Class C ◽  
Test Embankment

This paper presents the quantification of uncertainties in the prediction of settlements of embankments built on prefabricated vertical drains (PVDs) improved soft soil deposits based on data collected from two well-documented projects, located in Karakore, Ethiopia, and Ballina, Australia. For this purpose, settlement prediction biases and settlement distributions were statistically computed based on analyses conducted on two Class A and Class C numerical predictions made using PLAXIS 2D finite element modelling. From the results of prediction bias, Class C predictions agreed well with the field measured settlements at both sites. In Class C predictions, the computed settlements were biased to the measured values. For Class A predictions, the calculated settlement values were in the range of mean and mean minus 3SD (standard deviations) for Karakore clay, and they were within mean and mean minus 2SD limit for the Ballina soil. The contributing factors to the settlement uncertainties of the Karakore site may include variability within the soil profile of the alluvial deposit, particularly the presence of interbedded granular layer within the soft layers, and the high embankment fills, and the limited number of samples available for laboratory testing. At the Ballina test embankment site, the uncertainties may have been associated with the presence of transitional layers at the bottom of estuarine clay and sensitivity of soft soil to sample disturbances and limitations in representing all the site conditions.

Investigation of field-installation effects of horizontal twin-jet grouting in Shanghai soft soil deposits

2013 ◽  
Vol 50 (3) ◽  
pp. 288-297 ◽  
Author(s):  
Zhi-Feng Wang ◽  
Shui-Long Shen ◽  
Chu-Eu Ho ◽  
Yong-Hyun Kim
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Ground Surface ◽  
Prediction Methods ◽  
Jet Grouting ◽  
Soil Deposits ◽  
Lateral Displacements ◽  
Surface Heave

This paper presents a case study of an investigation into the responses of the surrounding ground to the horizontal twin-jet grouting method (HTJGM) in soft soil deposits of Shanghai. During the field test, the variation of pore-water pressure, lateral earth pressure, lateral displacements of the subsurface soils, and ground surface heave induced by the installation of five horizontal jet-grouted columns were monitored. The monitoring results indicate that the excess pore-water pressure reached 4 to 6 times the undrained shear strength of the soils, while maximum lateral displacements and ground surface heave were up to 80 and 17 mm, respectively. The influence range due to the installation of jet-grouted columns was between 15 and 20 times the nominal column radius. The development of prediction methods for lateral displacements and ground surface heave induced by the HTJGM installation process are presented and discussed. Results from the investigation suggest that the proposed prediction methods can be used to provide reasonable estimates of ground response and influence range of horizontal jet grouting.

Geotechnical characterization of soft soil deposits in Northern Poland

2019 ◽  
Vol 259 ◽  
pp. 105187 ◽  
Author(s):  
J. Konkol ◽  
K. Międlarz ◽  
L. Bałachowski
Keyword(s):  
Soft Soil ◽  
Geotechnical Characterization ◽  
Northern Poland ◽  
Soil Deposits

Field performance of the port of Sepetiba test fills

1995 ◽  
Vol 32 (1) ◽  
pp. 106-121 ◽  
Author(s):  
Vinod K. Garga ◽  
Luciano V. Medeiros
Keyword(s):  
Ground Improvement ◽  
Soft Soil ◽  
Soft Clay ◽  
Field Performance ◽  
Stone Columns ◽  
Field Investigations ◽  
Large Program ◽  
Soil Deposits ◽  
Load Tests ◽  
The Cost

The design of the industrial port of Sepetiba, 50 km south of Rio de Janeiro, Brazil, required a detailed evaluation of the underlying soft soil deposits. Initially, on the basis of laboratory tests, it was proposed to remove approximately 3.7 × 106 m3 of the very soft deposits in the stockpile area by dredging and substitute with hydraulic sand fill. Subsequently, in view of the cost of such a measure, a large program of field investigations was initiated to study the in situ characteristics of the soft clay to evaluate whether replacement of this material and (or) ground improvement was necessary. As part of this investigation, two large identically instrumented test fills (test fills B and D), each 65 m2 in plan and 5 m high, with 3:1 slopes were constructed. Test fill B was constructed over natural ground, whereas the subsoil beneath test fill D was treated with stone columns. The instrumentation for each test fill consisted of piezometers, deep settlement plates, surface settlement plates, and inclinometers. This paper provides a description of the field investigations, observations on installation of stone columns, analysis of instrumentation, a comparison of the behaviour of the two test fills, and a discussion on load tests on individual stone columns. Key words : case history, embankment, ground improvement, instrumentation, soft clay, stone columns.

Numerical Simulation of Bored Pile on Foundation Pit Support in Soft Soil Deposits

2014 ◽  
Vol 884-885 ◽  
pp. 679-684
Author(s):  
Jing Wang ◽  
Xiao Qing Liu ◽  
Xiao Chen Xie ◽  
Hui Jun Qi
Keyword(s):  
Numerical Simulation ◽  
Soft Soil ◽  
Pile Group ◽  
Beam Element ◽  
The Finite Element Method ◽  
Foundation Pit ◽  
Bored Pile ◽  
Soil Deposits ◽  
Bored Piles ◽  
Displacement Effects

To the supporting method of bored cast-in-place piles on foundation pit support in soft soil deposits, using the finite element method and considering the interaction between pile group, respectively, bored piles with compound foundation and entitative beam element are numerically simulated in two ways; Compared two kinds of method to calculate the displacement effects of adjacent pipeline to the actual monitoring data, the results show that using entitative beam element are adopted to simulate the piles is more reasonable.

scholarly journals The Impact of Using Different Types of Soft Soils Treated by Stone Columns on Creep Behavior

2022 ◽  
Vol 961 (1) ◽  
pp. 012052
Author(s):  
Sura Tawfeeq Al-Auqbi ◽  
Nahla M. Salim ◽  
Mahmood R. Mahmood
Keyword(s):  
Soft Soil ◽  
Horizontal Displacement ◽  
Cohesive Soil ◽  
Stone Columns ◽  
Stone Column ◽  
Geometric Conditions ◽  
Improvement Factor ◽  
Soil Deposits ◽  
Different Types ◽  
The Impact

Abstract The stone column technique is an effective method to increase the strength of soft cohesive soil, which results in a reduction in foundation settlement and an increase in bearing capacity. The topic of restraining creep settlement through the use of stone columns techniques has gained increasing attention and consideration; because stone columns are widely used to treat soft soil deposits, caution should be applied in estimating creep settlement. We discovered a reversible relation between shear parameters and the creep settlement in floating stone columns; while, in case of end-bearing stone columns shows a direct positive relation between shear parameters and the creep settlement, and the creep settlement began at the primary settlement. The shear parameters affected the improvement factor (n) of creep settlement in both floating and end-bearing stone columns. The standard creep coefficient’s n values in floating and end-bearing conditions were more significant than the low creep coefficient’s n values in forwarded geometric conditions. The stress in both floating and end-bearing stone columns was increasing and uniformly distributed along the length of the floating stone column and in the case of end-bearing stone column was limited to the stiffness layer; the maximum vertical stress was in the central point of the embankment. The embankment’s maximum horizontal displacement occurred on the edge.

Selection of optimal intensity measures for fragility assessment of circular tunnels in soft soil deposits

2021 ◽  
Vol 145 ◽  
pp. 106724
Author(s):  
Zhong-Kai Huang ◽  
Kyriazis Pitilakis ◽  
Sotirios Argyroudis ◽  
Grigorios Tsinidis ◽  
Dong-Mei Zhang
Keyword(s):  
Soft Soil ◽  
Intensity Measures ◽  
Soil Deposits ◽  
Optimal Intensity ◽  
Selection Of

Liquefaction Hazard Mapping of Lucknow

2013 ◽  
Vol 4 (1) ◽  
pp. 17-41 ◽  
Author(s):  
Abhishek Kumar ◽  
P. Anbazhagan ◽  
T. G. Sitharam
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Soft Soil ◽  
Hazard Mapping ◽  
Ground Acceleration ◽  
Subsurface Characterization ◽  
Local Site ◽  
Liquefaction Hazard ◽  
Soil Deposits

Even though the size of the earthquake is moderate, presence of soft soil near the surface can cause devastating damage due to local site and induced effects like liquefaction. Evidence of liquefaction due to past Indian earthquakes was highlighted in many Paleo-seismic studies, particularly in the Himalayan region. The objective of this paper is subsurface characterization of part Indo-Gangetic Basin (IGB) and estimation of liquefaction hazards for the possible surface ground motions based on the region seismic study. Drilling of boreholes and measurement of standard penetration N values are carried out at selected locations for subsurface characterization. Possibility of liquefaction for soil deposits are assessed by comparing the grain size distribution curves obtained from laboratory tests with the range of grain size distribution curves of potentially liquefiable soils. The minimum factor of safety values has been identified for each location and presented in the form of maps showing FOS against liquefaction for average and maximum amplified peak ground acceleration (PGA) values. These maps have highlighted that the northern, western and central parts of Lucknow fall under very critical to critical for liquefaction while southern parts shows moderate to low critical area.

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