• Structural Engineering and Mechanics
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• v.43 no.6
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• pp.835-845
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• 2012

This paper focuses on the stochastic response analysis of industrial masonry chimneys to surface blast-induced random ground motions by using a three dimensional finite element model. Underground blasts induce ground shocks on nearby structures. Depending on the distance between the explosion centre and the structure, masonry structures will be subjected to ground motions due to the surface explosions. Blast-induced random ground motions can be defined in terms of the power spectral density function and applied to each support point of the 3D finite element model of the industrial masonry system. In this paper, mainly a parametric study is conducted to estimate the effect of the blast-induced ground motions on the stochastic response of a chimney type masonry structure. With this purpose, different values of charge weight and distance from the charge centre are considered for the analyses of the chimney. The results of the study underline the remarkable effect of the surface blast-induced ground motions on the stochastic behaviour of industrial masonry type chimneys.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.463-475
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• 2023

Tunnel construction activity, conducted mainly in mountains and within urban centres, causes soil settlement, thus requiring the relevant management of slopes and structures as well as evaluations of risk and stability. Accordingly, in this study we performed a three-dimensional finite element analysis to examine the behaviour of piles and pile cap stability when a tunnel passes near the bottom of the foundation of a pile group connected by a pile cap. We examined the results via numerical analysis considering different conditions for reinforcement of the ground between the tunnel and the pile foundation. The numerical analysis assessed the angular distortion of the pile cap, pile settlement, axial force, shear stress, relative displacement, and volume loss due to tunnel excavation, and pile cap stability was evaluated based on Son and Cording's evaluation criterion for damage to adjacent structures. The pile located closest to the tunnel under the condition of no ground reinforcement exhibited pile head settlement approximately 70% greater than that of the pile located farthest from the tunnel under the condition of greatest ground reinforcement. Additionally, pile head settlement was greatest when the largest volume loss occurred, being approximately 18% greater than pile head settlement under the condition having the smallest volume loss. This paper closely examines the main factors influencing the behaviour of a pile group connected by a pile cap for three ground reinforcement conditions and presents an evaluation of pile cap stability.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.861-868
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• 2018

Recent occurrences of earthquakes in Korea have increased the importance of considering how horizontal loads affect foundation structures as a result of wind and dynamic impact. However, to date, there are few studies on tunnelling-induced behaviour of ground and pile structures simultaneously subjected to horizontal and vertical loads. In this research, therefore, the behaviour of ground and single piles due to tunnelling were investigated through a laboratory model test. Three cases of horizontal loads were applied to the top of the pile. In addition, a numerical analysis was carried out to analyse and compare with the results from the laboratory model test.

• Journal of Korean Port Research
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• v.14 no.4
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• pp.463-473
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• 2000

Reinforcement with geotextiles have been used in the foundation soil to enhance the resistance of embankments to avoid failure through excessive deformation or shear in the foundation. It is improtant to know the amount of the strain and the displacement of buried geotextiles for the verification of the reinforcement behaviour. Full scale trial constructions were performed to check the deformational characteristics of the polyester(PET) mat which was used for the embankment reinforcement. Many instrumentation equipments including surface settlement plates, profile gauges and inclinometer casings were installed to observe the behaviour of the soft ground due to the soil embankment. 60 electrical resistance strain gauges and 9 vibrating wire LVDTs were installed 세 measure the deformation of the polyester mat. Results of various tests and geotextile, waterproofing and protection from the hazard environments were introduced. The proposed instrumentation method was effective for the monitoring or the geotextile behaviour. The direct attachment of electrical resistance strain gauges on the gertextile mat was able to measure small changes of the strain of geotextiles. At the end of the 5 month monitoring, 54 of 60 (93%) strain gauges and 7 of 9 (78%) displacement transducers survived all perils of the compaction impacts and the humidity. And the tensile strain of grotextiles increased as the ground displacement became larger. Though the observed strain of mats under the 3m high embankment load was less than 1%, the magnitudes of the strain according to the mat spreading method were different from each other.

• Structural Engineering and Mechanics
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• v.22 no.3
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• pp.293-310
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• 2006

In seismic prone areas it is possible to meet very different objects (equipment components, on shelf artefacts, simple architectural elements) that can be modelled as a rigid body rocking on a rigid foundation. The interest in their behaviour can have different reasons: seismological, in order to estimate the ground motion intensity, or more strictly mechanical, in order to limit the response severity and to avoid overturning. The behaviour of many rigid bodies subjected to twenty wide ranging acceleration recordings is studied here. The response of the blocks is described using kinematic and energy parameters. A condition under which a so called scale effect is tangible is highlighted. The capacity of the signals to produce overturning is compared to different ground motion parameters, and a good correlation with the Peak Ground Velocity is unveiled.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.136-142
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• 1997

The behaviour of ground movement during the construction of two parallel tunnels in weathered zone and soft rock has been investigated. All the influencing factors for the behaviour of twin tunnel such as tunnel size, ground conditions, tunnel depth, pillar width and initial state of ground stresses were examined The results of FEM nonlinear analysis were compared with some of model test results in weathered zone to verify the numerical method. It was found that minimum interference was obtained in the parallel construction case when the twin tunnel distance (pillar width) is just over the twice of tunnel diameter. Guide line for the interference of twin tunnelling has been introduced for the ground of weathered zone and soft rock.

• Land and Housing Review
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• v.2 no.1
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• pp.79-85
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• 2011

The bearing capacity of a soil can be improved by conventional ground improvement techniques such as stabilization and compaction methods. Recently, the use of geotextiles in improving the bearing capacity of soils has become popular because of the availability of durable and strong geosynthetic materials. In this paper, through the laboratory model tests on sandy ground reinforced by geotextiles with the strip footing under plane strain condition, the effects of bearing capacity improvement on the sandy ground and its behaviour were investigated.

• Wind and Structures
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• v.22 no.3
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• pp.369-391
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• 2016

Electricity is transmitted by transmission lines from the source of production to the distribution system and then to the end users. Failure of a transmission line can lead to devastating economic losses and to negative social consequences resulting from the interruption of electricity. A comprehensive in-house numerical model that combines the data of computational fluid dynamic simulations of tornado wind fields with three dimensional nonlinear structural analysis modelling of the transmission lines (conductors and ground-wire) is used in the current study. Many codes of practice recommend neglecting the tornado forces acting on the conductors and ground-wires because of the complexity in predicting the conductors' response to such loads. As such, real transmission line systems are numerically simulated and then analyzed with and without the inclusion of the lines to assess the effect of tornado loads acting on conductors on the overall response of transmission towers. In addition, the behaviour of the conductors under the most critical tornado configuration is described. The sensitivity of the lines' behaviour to the magnitude of tornado loading, the level of initial sag, the insulator's length, and lines self-weight is investigated. Based on the current study results, a recommendation is made to consider conductors and ground-wires in the analysis and design of transmission towers under the effect of tornado wind loads.

• Geomechanics and Engineering
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• v.24 no.5
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• pp.443-456
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• 2021

Structural design of the vertical displacements and shear strains in the earth fill (EF) dams has great importance in the structural engineering problems. Moreover, far fault earthquakes have significant seismic effects on seismic damage performance of EF dams like the near fault earthquakes. For this reason, three dimensional (3D) earthquake damage performance of Oroville dam is assessed considering different far-fault ground motions in this study. Oroville Dam was built in United States of America-California and its height is 234.7 m (770 ft.). 3D model of Oroville dam is modelled using FLAC3D software based on finite difference approach. In order to represent interaction condition between discrete surfaces, special interface elements are used between dam body and foundation. Non-reflecting seismic boundary conditions (free field and quiet) are defined to the main surfaces of the dam for the nonlinear seismic analyses. 6 different far-fault ground motions are taken into account for the full reservoir condition of Oroville dam. According to nonlinear seismic analysis results, the effects of far-fault ground motions on the nonlinear seismic settlement and shear strain behaviour of Oroville EF dam are determined and evaluated in detail. It is clearly seen that far-fault earthquakes have very significant seismic effects on the settlement-shear strain behaviour of EF dams and these earthquakes create vital important seismic damages on the swelling behaviour of dam body surface. Moreover, it is proposed that far-fault ground motions should not be ignored while modelling EF dams.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.225-232
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• 2003

The behaviour of ground induced by tunneling of 2arch tunnels may differ from the one caused by usual type tunnels. This paper describe the behaviour created by the size of pilot tunnel and the condition on the construction method of center piller Also, loads acting on the supports of the first tunnel and the center pillar during the excavation of second tunnel is investigated by numerical analyses. The results of numerical analyses are compared to the data records of measurement results, i.e. force on the support system and ground displacement.