scholarly journals Earthquake Induced Liquefaction Analysis and Ground Improvement as a Remedial Measure: A Review

2021 ◽  
Vol 889 (1) ◽  
pp. 012035
Author(s):  
Ubaid Hussain ◽  
Amanpreet Tangri
Keyword(s):  
Dynamic Loading ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Field Studies ◽  
Sudden Increase ◽  
Remedial Measure ◽  
Liquefaction Hazard ◽  
Loss Of Strength ◽  
Liquefaction Analysis

Abstract Liquefaction is the phenomenon in which partially or fully saturated, loose sandy soils behave like a liquid due to loss of strength and rigidity owing to sudden increase in the pore water pressure as a result of dynamic loading such as earthquake. Liquefaction induced by dynamic loading as a result of earthquake is the most destructive feature of earthquake that may results in settlements and collapse of structures. The severity of this phenomenon can be predetermined by the geological and hydro-geological setup of the soil in the study area. The aim of this study is to present a review of various aspects of earthquake induced liquefaction analysis, case evidences from field studies and some of the liquefaction hazards from past earthquakes. Remedial measures using ground improvement techniques to prevent liquefaction hazard is also studied in this paper. Further, investigating the performance of remedial methods against liquefaction is also presented in this paper.

Type of Slope Failure Identified from Pore Water Pressure and Moisture Content Measurements

2015 ◽  
Vol 744-746 ◽  
pp. 690-694
Author(s):  
Muhammad Rehan Hakro ◽  
Indra Sati Hamonangan Harahap
Keyword(s):  
Moisture Content ◽  
Pore Pressure ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Failure Process ◽  
Small Scale ◽  
Content Increase ◽  
Sudden Increase ◽  
Model Slope

Rainfall-induced landslides occur in many parts of the world and causing a lot of the damages. For effective prediction of rainfall-induced landslides the comprehensive understanding of the failure process is necessary. Under different soil and hydrological conditions experiments were conducted to investigate and clarify the mechanism of slope failure. The failure in model slope was induced by sprinkling the rainfall on slope composed of sandy soil in small flume. Series of tests were conducted in small scale flume to better understand the failure process in sandy slopes. The moisture content was measured with advanced Imko TDR (Time Domain Reflectrometry) moisture sensors in addition to measurements of pore pressure with piezometers. The moisture content increase rapidly to reach the maximum possible water content in case of higher intensity of rainfall, and higher intensity of the rainfall causes higher erosion as compared to smaller intensity of the rainfall. The controlling factor for rainfall-induced flowslides was density of the slope, rather than intensity of the rainfall and during the flowslide the sudden increase in pore pressure was observed. Higher pore pressure was observed at the toe of the slope as compared to upper part of the slope.

Geosynthetic Encased Column: comparison between numerical and experimental results

2021 ◽  
Vol 44 (4) ◽  
pp. 1-12
Author(s):  
Nima Alkhorshid ◽  
Gregório Araújo ◽  
Ennio Palmeira
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Experimental Tests ◽  
High Permeability ◽  
Soft Soils ◽  
Column Comparison ◽  
Surrounding Soil ◽  
Granular Column

The use of granular column is one of the ground improvement methods used for soft soils. This method improves the foundation soils mechanical properties by displacing the soft soil with the compacted granular columns. The columns have high permeability that can accelerate the excess pore water pressure produced in soft soils and increase the undrained shear strength. When it comes to very soft soils, the use of granular columns is not of interest since these soils present no significant confinement to the columns. Here comes the encased columns that receive the confinement from the encasement materials. In this study, the influence of the column installation method on the surrounding soil and the encasement effect on the granular column performance were investigated using numerical analyses and experimental tests. The results show that numerical simulations can reasonably predict the behavior of both the encased column and the surrounding soil.

Study on Artificial Island Ground Improvement Method and Effect

2014 ◽  
Vol 1030-1032 ◽  
pp. 1037-1040
Author(s):  
Jin Fang Hou ◽  
Ju Chen ◽  
Jian Yu
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Treatment Method ◽  
Surcharge Preloading ◽  
Porosity Ratio ◽  
Improvement Method ◽  
Consolidation Degree

The artificial island ground on an open sea is covered by thick soft soil. It must be improved before using. In accordance with a designing scheme, the ground treatment method is inserting drain boards on land and jointed dewatering surcharge preloading, the residual settlement is not more than 30cm after improvement and the average consolidation degree is more than 85%. In order to estimate ground improvement effect and construction safety, instruments are buried to monitor the whole ground improving processes. By monitoring settlement and pore water pressure, it is shown that the total ground settlement in construction is 2234mm, its final settlement is 2464mm, and consolidation degree and residual settlement respectively satisfy requirements. In ground improvement, horizontal displacement is small and construction is safe. Meanwhile, the results of soil properties and vane shear strength detection tests show the soft soil ground is greatly reduced in water content and porosity ratio, and improved in strength. It is named that the ground improvement method is reasonable and reaches expected effect.

scholarly journals Effect of Improvement and Application of Composite Prefabricated Vertical Drain Method in Marine Soft Ground: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jianqing Jiang ◽  
Reqiang Liu
Keyword(s):  
High Speed ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Field Monitoring ◽  
Hyperbolic Model ◽  
Soft Ground ◽  
Prefabricated Vertical Drains ◽  
Prefabricated Vertical Drain

One of the commonly used techniques to improve marine soft ground is the drainage consolidation method by plastic board drains (PBDs). But some complex marine soft ground will cause construction inconvenience of PBDs in certain areas of these sites, thus affecting the improvement effect. An alternative possible approach to overcoming these deficiencies may be the combination of PBDs and sand wick drains (SWDs) (i.e., composite prefabricated vertical drains (CPVDs)) as vertical drainage channels in the same site. In order to verify the suitability and performance of this method in marine soft ground improvement, a case study was performed based on the field monitoring and construction of the marine soft ground of an intercity express railway project in China. The construction procedure using the CPVD system, the field monitoring instrumentation scheme, and the design of fill surcharge level were described, and the field monitoring data were presented. The settlement characteristics, dissipation features of pore water pressure, and the horizontal movement pattern were assessed. In addition, predictions of ultimate settlement, postconstruction settlement, and consolidation degree were discussed by applying a modified hyperbolic model. The results show that the marine ground improved by the CPVD system is suitable for the construction of intercity express railway and high-speed railway. The improvement construction period of complex marine soft ground will be greatly shortened by the proposed parallel construction programme. This work will provide technical supports and application reference for the improvement of the similar marine soft ground.

Mitigation of Liquefaction Hazard Using Granular Piles

2011 ◽  
Vol 2 (1) ◽  
pp. 44-66 ◽  
Author(s):  
A. Murali Krishna
Keyword(s):  
Ground Improvement ◽  
Stone Columns ◽  
Loose Sand ◽  
Short Discussion ◽  
Remedial Measure ◽  
Design Concepts ◽  
Liquefaction Mitigation ◽  
Liquefaction Hazard ◽  
Granular Piles ◽  
Surrounding Soil

In this paper, ground improvement techniques are used to mitigate liquefaction hazards. Granular piles are the preferred alternative due to several advantages. Granular piles improve the ground by reinforcing and adding density to the surrounding soil apart from providing drainage. Different mechanisms operate in the function of stone columns/granular piles in liquefaction mitigation, including Drainage, Storage, Dilation, Densification, and Reinforcement. This paper presents an overview of the use of granular piles as a liquefaction remedial measure for sand deposits. A brief description on liquefaction and the associated features is presented. A short discussion on various ground improvement methods available for liquefaction mitigation is discussed in light of the importance of granular piles. Different installation methods and design concepts for granular piles are presented. Various mechanisms of granular piles in mitigating the liquefaction potential of loose sand deposits are discussed and quantified in detail proving their effectiveness in hazard mitigation.

Analyses for the stability of potash tailings piles

1993 ◽  
Vol 30 (3) ◽  
pp. 491-505 ◽  
Author(s):  
Delwyn G. Fredlund ◽  
Zai Ming Zhang ◽  
Karen Macdonald
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Field Studies ◽  
Equilibrium Analysis ◽  
Limit Equilibrium Analysis ◽  
Dissipation Model ◽  
The Stability

The stability of potash tailings piles is investigated using a pore-water pressure generation and dissipation model together with a limit equilibrium analysis. It is found that a shallow toe failure mode is generally the most applicable and that the stability may be influenced by pore-water pressure migration below the pile. It is suggested that field studies would be useful in evaluating stability in the toe region of the pile. Key words : potash tailings, slope stability, pore pressure dissipation, solutioning.

scholarly journals Simple 2D Liquefaction analysis of pore water pressure dissipation method for detached house ground

2018 ◽  
Vol 13 (4) ◽  
pp. 393-401
Author(s):  
Hiroshi YOKAWA ◽  
Hideto NONOYAMA ◽  
Atsushi YASHIMA ◽  
Misko CUBRINOVSKI ◽  
Takayasu YOSHIHARA ◽  
...  
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Detached House ◽  
Liquefaction Analysis

Laboratory assessment of electro-osmotic stabilization of soft clay

2011 ◽  
Vol 48 (12) ◽  
pp. 1788-1802 ◽  
Author(s):  
V. Jeyakanthan ◽  
C.T. Gnanendran ◽  
S.-C.R. Lo
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Ground Improvement ◽  
Soft Clay ◽  
Initial Stresses ◽  
Triaxial Tests ◽  
Laboratory Assessment ◽  
Chemical Changes ◽  
Soft Clays ◽  
Electro Osmosis

The application of electro-osmosis (EO) for stabilizing soft clays is receiving more attention in geotechnical engineering. When the application of traditional ground improvement techniques, such as surcharge, pre-loading, wick drains, and vacuum pre-loading, is not appropriate for a particular situation, innovative techniques such as electro-osmosis need to be considered. Although the effectiveness of electro-osmosis has been widely demonstrated in many field applications, geotechnical engineers are still hesitant to apply electro-osmosis due to unknown effects such as electro-chemical changes, which could not be accounted for in the design. This paper presents a design of an electro-osmotic triaxial testing apparatus suitable for electro-osmotic treatment of soft clays and for measuring electro-osmotic permeability and generated pore-water pressure, as well as a testing procedure that accounts for the contribution of electro-chemical changes in the improvement of soil properties. A series of electro-osmotic triaxial tests with various initial stresses and boundary conditions were conducted and the results are presented in the paper.

scholarly journals ANALISIS STABILITAS TIMBUNAN (MAINDAM) BERDASARKAN DATA INSTRUMEN GEOTEKNIK PADA BENDUNGAN SINDANG HEULA SERANG BANTEN

2021 ◽  
Vol 3 (1) ◽  
pp. 48-58
Author(s):  
Nanang Sutisna ◽  
M. Ichwanul Yusup ◽  
Euis Amilia Euis Amilia
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Studies ◽  
Internal Erosion ◽  
Embankment Dam ◽  
Support Tool ◽  
The Core ◽  
Conducting Research ◽  
The Stability

The development of science and technology has obtained supporting technology for monitoring the soil shear force and pore water pressure in the dam, the presence of shear forces against the landfill and pore water pressure through small cavities in the embankment soil in the dam body which can be detected by equipment such as inclinometer and piezometer that have been installed at predetermined points. The application of inclinometer and piezometer technology is used as a support tool for monitoring the movement of landfill and pore water pressure against dams. The embankment dam is the most complex of civilian structures and is very dangerous if damaged. When there is damage to a dam, it will cause a big disaster for the areas that are downstream of the dam. Damage or collapse of a dam can occur due to several things, including overtopping, sliding of the dam slopes (internal erosion or "piping"), and the occurrence of structural degradation of each zone. on the dam body. In the analysis of the stability of the embankment (maindam) which is based on geotechnical instrument data, it must be carried out as carefully and accurately as possible. The purpose of this analysis is to measure the early damage in the main dam (maindam). After conducting research and field studies at the Sindang Heula dam, there were several points of decline at the top of the core embankment (maindam). To find out the cause of the decline, data was taken from measuring geotechnical instruments.

Comparison of two fine sands under torsional loading

2008 ◽  
Vol 45 (12) ◽  
pp. 1659-1672 ◽  
Author(s):  
V. N. Georgiannou ◽  
A. Tsomokos
Keyword(s):  
Phase Transformation ◽  
Cyclic Loading ◽  
Hollow Cylinder ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Strength Reduction ◽  
Monotonic Loading ◽  
Sudden Increase ◽  
Loading Conditions ◽  
Continuous Increase

In this paper the behaviour of two “standard research sands”, widely used for experimental purposes, is compared in a torsional hollow cylinder apparatus under monotonic and cyclic loading conditions. Both sands are fine and uniform with D50 = 0.22 and 0.29 mm, respectively. However, their response to undrained monotonic loading at similar void ratios is dramatically different, with the finer sand showing strength reduction after peak and the coarser sand showing continuous increase in strength with torsional shear. The difference in response is mainly attributed to grain angularity and to a lesser degree to their grading. The results of drained torsional hollow cylinder tests show initial contraction followed by dilation. The stress ratio at phase transformation is uniquely defined by both drained and undrained tests for each sand. Cyclic loading instability is manifested by a sudden increase in shear strain and excess pore-water pressure leading to initial liquefaction. The instability initiates across the instability line for the sand showing strength reduction and across the phase transformation line for the sand showing continuous increase in strength with shearing. Both lines are defined under monotonic loading conditions. The liquefaction, stiffness, and damping characteristics of the sands are given in this paper.

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