Remediation against floatation of underground structures

Chian, Siau Chen; Madabhushi, Spg

doi:10.1680/grim.11.00030

Cited by 9 publications

(3 citation statements)

References 15 publications

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“…Based on the above force equilibrium, the uplift displacement of the underground structure can be estimated based on simple mechanical equations. The estimated uplift response computed was found to coincide with experimental results from 13 centrifuge tests under different soil and earthquake conditions, including relative density, hydraulic conductivity, sand type, magnitude, frequency and duration of earthquakes (Chian, 2012).…”

Section: Theoretical Force Mechanism Of Buoyant Structures Under Stat...supporting

confidence: 54%

Excess Pore Pressures Around Underground Structures Following Earthquake Induced Liquefaction

Chian

Madabhushi

2012

International Journal of Geotechnical Earthquake Engineering

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Underground structures located in liquefiable soil deposits are susceptible to floatation following an earthquake event due to their lower unit weight relative to the surrounding saturated soil. This inherent buoyancy may cause lightweight structures to float when the soil liquefies. Centrifuge tests have been carried out to study the excess pore pressure generation and dissipation in liquefiable soils. In these tests, near full liquefaction conditions were attained within a few cycles of the earthquake loading. In the case of high hydraulic conductivity sands, significant dissipation could take place even during the earthquake loading which inhibits full liquefaction from occurring. In the case of excess pore pressure generation and dissipation around a floating structure, the cyclic response of the structure may lead to the reduction in excess pore pressure near the face of the structure as compared to the far field. This reduction in excess pore pressure is due to shear-induced dilation and suction pressures arising from extensile stresses at the soil-structure interface. Given the lower excess pore pressure around the structure; the soil around the structure retains a portion of this shear strength which in turn can discourage significant uplift of the underground structure.

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Section: Theoretical Force Mechanism Of Buoyant Structures Under Stat...supporting

confidence: 54%

Excess Pore Pressures Around Underground Structures Following Earthquake Induced Liquefaction

Chian

Madabhushi

2012

International Journal of Geotechnical Earthquake Engineering

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“…Pipeline uplift in liquefied soil is due to the buoyant force being greater than the resistance against it. This resistance consists of the weight of pipeline, the weight of overlying soil and the shear resistance of soil (Chian & Madabhushi, 2013). In this study, the pipeline model was identical and the weight of overlying soil was not significantly increased by introducing the root systems.…”

Section: Excess Pore Pressure Generation Under Pipelinementioning

confidence: 97%

Centrifuge modelling of remediation of liquefaction-induced pipeline uplift using model root systems

Wang¹,

Brennan²,

Knappett³

et al. 2018

Physical Modelling in Geotechnics

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Buried pipelines are susceptible to floatation within liquefiable soil after earthquakes. When soil liquefies, its shear strength is significantly reduced due to generation of excess pore pressure. A buried pipeline within such soil can then uplift due to a combination of (i) an upwards pore pressure gradient across the pipe and (ii) the resisting force contributed from soil shear strength being significantly reduced. Roots have been confirmed to increase the shear resistance of soil, so they can potentially be used as a new countermeasure against pipeline uplift, in locations where there is no above-ground infrastructure (i.e. where uplift is most likely). Three centrifuge tests have been conducted in this study to evaluate this potential. One was performed as a benchmark and the other two included one of two overlying model shallow root systems (either fibrous roots only, or fibrous and large structural roots) respectively. The results show that roots can be used as a remediation method against pipeline uplift induced by soil liquefaction. Model fibrous roots were shown to reduce uplift displacements by 15% while the model system consisting of both large structural and fibrous roots further reduced uplift to approximately 28%.

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“…The underground structure, together with water and soil, form a complex triadic system of interactions. Groundwater creates many geotechnical problems [ [1] , [2] , [3] ] and it is difficult to properly calculate the buoyancy of underground structures in clay soils [ 4 , 5 ]. For a foundation with strong permeability, such as sand or gravel soil, buoyancy is calculated according to the anti-floating fortification water level without reduction.…”

Section: Introductionmentioning

confidence: 99%

Buoyancy of underground structures and pore water pressure conduction law in silty clay strata

Guo,

Zhou,

Sun

et al. 2024

Heliyon

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Remediation against floatation of underground structures

Cited by 9 publications

References 15 publications

Excess Pore Pressures Around Underground Structures Following Earthquake Induced Liquefaction

Excess Pore Pressures Around Underground Structures Following Earthquake Induced Liquefaction

Centrifuge modelling of remediation of liquefaction-induced pipeline uplift using model root systems

Buoyancy of underground structures and pore water pressure conduction law in silty clay strata

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