• Title/Summary/Keyword: lateral soil movement

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Case Study for Lateral Displacement of Caisson installed on Deep Soft Soils (대심도 연약지반상에 건설되는 케이슨의 측방변형 사례 연구)

  • Kim, Myung-Hak;Yoon, Min-Seung;Lee, Sang-Wook;Lee, Chea-Kyun;Han, Byoung-Won
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.940-950
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    • 2010
  • In case of uneven surcharge like backfill or embankment after constructing caisson applied on the deep soft marine deposits, lateral deformation of soft soils would happen due to plastic deformation of soil particles by increase of excess pore water pressure. Lateral deformation of soil will result in the caisson displacement which affects soft soil-caisson structure safety. Soft soil was improved by soil compaction pile method, and then gravity caisson was installed. Soil deformations were monitored and analyzed with step by step backfill and embankment behind the caisson. Amount and speed of lateral deformation after the installation of caissons were closely related with the time of backfill and embankment. The relationship between maximum lateral displacement($\Delta_y$) in front of caisson and settlement($\Delta_s$) can be expressed as $\Delta_y=(0.0871)\Delta_s+122.95$. Soft soil depth did not affect the lateral displacement of caisson in this study, which can be explained the soft soil improvement under the caisson by S.C.P. method. Substantially the amount and speed of the lateral deformation of caisson were closely related with the uneven surcharging rate behind caisson.

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A case study on the lateral movement of bridge abutment foundation and repair methods (교대의 측방변위와 대책공법에 대한 사례연구)

  • Lee, Byung-Suk;Lee, Jae-Yeol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.3
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    • pp.1359-1369
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    • 2012
  • In the case of using pile foundation to support bridge abutments on soft ground, the soft ground often causes serious troubles such as lateral movement of bridge abutments by lateral surcharges. In this paper, we investigated and measured the amount of strain of a bridge abutment in the south-western part of Korea. To check the stability and possibility of lateral movement of the bridge abutment, we used the four analysis methods and compared those results; lateral movement index, index for decision of lateral movement and infinite element analysis method. We performed soil and ground tests to fine the causes of the strain and lateral movement. After reviwing several types of repair methods, we suggested the anker reinforcement method along with surcharge process method as a proper repair and rehabilitation of the bridge abutment. Our investigation by through the infinite element analysis method confirmed the effectiveness of the anker reinforcement method allong with the surcharge process method.

Evaluation of Ultimate Lateral Resistance for Single Pile Using Strain Wedge Model in Sand (모래지반에서 쐐기모델을 이용한 단말뚝의 극한수평저항력 산정)

  • Kim, Ji-Seong;Kang, Gi-Chun
    • Journal of the Korean Geotechnical Society
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    • v.32 no.12
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    • pp.15-22
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    • 2016
  • The magnitude of the lateral resistance that resists the lateral movement of the pile is controlled by the amount of the pile movement and the strength and stiffness of soil. In this paper, we proposed an equation which produces the ultimate lateral resistance of the laterally loaded single pile in sand using the strain wedge model of the soil deformation. The ultimate lateral resistance in strain wedge model is composed of earth pressure of wedge rear, the shear resistance on the side of the wedge, and the frictional resistance between pile and ground. The ultimate lateral resistance determined by the proposed equation was compared with the Ashour, F.D.M., field test in sand. As a result, the error of the proposed equation and Ashour theory, field test, F.D.M were respectively 1.03%, 0.40~3.32%, 6.02%.

A Study on Behavior of the Lateral Movement of Breakwater by Centrifuge model Experiments (원심모형실험에 의한 방파제의 수평변위 거동에 관한 연구)

  • Lee, Dong-Won;Kim, Dong-Gun;Jun, Sang-Hyun;Yoo, Nam-Jae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1473-1478
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    • 2010
  • For the cassion type of breakwater under the condition of large wave loads, stability about lateral movement of breakwater was investigated by performing centrifuge model experiments. Prototype of breakwater was modelled by scaling down to centrifuge model and the soft ground reinforced with grouting was also reconstructed in the centrifuge model experiments. Sandy ground beneath breakwater was prepared with a soil sampled in field so that identical value of internal friction angle could be obtained. Centrifuge model experiments were carried out to reconstruct the construction sequence in field. Lateral static wave load was applied to the model caisson after the final stage of construction sequence was rebuilt and the measured lateral movement of caisson was compared with allowable value by the code to assess the stability about lateral movement of the breakwater.

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Application of Piles to Landslides Control (말뚝을 사용한 산사태 억지공법)

  • 홍원표
    • Geotechnical Engineering
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    • v.7 no.4
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    • pp.75-88
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    • 1991
  • A lot of landslides has occurred in rainy seasons beginning at June through September in Korea, where about 70 percent of the total area is mountaneous. Piles can be used as one of the most useful methods to stabilize such landslides. When a row of piles is installed in soil undergoing lateral movement such as landslides, the soil across the open space between the piles can be retained by the arching action of the soil. For the purpose to establish a reasonable design method for stabilizing piles, a method for stability analysis of the slope containing stabilizing piles is presented, using the theoretical equation of the lateral force acting on the piles in soil undergoing lateral movement. In particular, the theoretical equation is arranged by applying the coefcients of lateral force as a simple equation. And also the differential equations proposed in the previous studies for the pile-stability analysis are modified, assumming that the piles above the sliding surface shall be subjected to the lateral reaction from soil in proportion to the pile deflection. Finally, to investigate the effect of stabilizing piles against landslides, an existing landslide slope in Korea is adopted as an example.

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Estimation Method of Earth Pressures Acting on a Row of Piles due to Lateral Soil Movements (측방변형지반속 줄말뚝에 작용하는 토압의 산정법)

  • 홍원표;송영석
    • Journal of the Korean Geotechnical Society
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    • v.20 no.3
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    • pp.13-22
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    • 2004
  • In case of the lateral movement accurring at soft ground where a row of piles are installed, the crown failure at external arch zone of soil arching is firstly developed, and the cap failure at wedge zone in front of piles is lastly developed. Therefore, the lateral earth pressure acting on a row of piles due to soil movement should be calculated in each condition of crown and cap failures around piles. A theoretical equation of crown failure can be proposed using a cylindrical cavity expansion theory. The theoretical equation of crown failure is mainly affected by two factors. One is related to soil properties such as internal friction angle, cohesion and horizontal pressure, and the other is related to pile factors such as diameter, installation interval. Meanwhile, the yield range of lateral earth pressure is established in the estimation of theoretical equation based on crown and cap failures around piles. The theoretical values based on crown and cap failures are compared with the experimental values. The experimental values are located in the range proposed by theoretical values. Thus, it is confirmed that the theoretical values proposed in the study are very reasonable.

Centrifuge modelling of pile-soil interaction in liquefiable slopes

  • Haigh, Stuart K.;Gopal Madabhushi, S.P.
    • Geomechanics and Engineering
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    • v.3 no.1
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    • pp.1-16
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    • 2011
  • Piles passing through sloping liquefiable deposits are prone to lateral loading if these deposits liquefy and flow during earthquakes. These lateral loads caused by the relative soil-pile movement will induce bending in the piles and may result in failure of the piles or excessive pile-head displacement. Whilst the weak nature of the flowing liquefied soil would suggest that only small loads would be exerted on the piles, it is known from case histories that piles do fail owing to the influence of laterally spreading soils. It will be shown, based on dynamic centrifuge test data, that dilatant behaviour of soil close to the pile is the major cause of these considerable transient lateral loads which are transferred to the pile. This paper reports the results of geotechnical centrifuge tests in which models of gently sloping liquefiable sand with pile foundations passing through them were subjected to earthquake excitation. The soil close to the pile was instrumented with pore-pressure transducers and contact stress cells in order to monitor the interaction between soil and pile and to track the soil stress state both upslope and downslope of the pile. The presence of instrumentation measuring pore-pressure and lateral stress close to the pile in the research described in this paper gives the opportunity to better study the soil stress state close to the pile and to compare the loads measured as being applied to the piles by the laterally spreading soils with those suggested by the JRA design code. This test data shows that lateral stresses much greater than one might expect from calculations based on the residual strength of liquefied soil may be applied to piles in flowing liquefied slopes owing to the dilative behaviour of the liquefied soil. It is shown at least for the particular geometry studied that the current JRA design code can be un-conservative by a factor of three for these dilation-affected transient lateral loads.

Study on Application of Criteria of Lateral Flow in Soft Soils (측방유동 판정기준의 적용성 연구)

  • Chae, Young-Soo;Moon, Han-Joong;Kim, Dae-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.2
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    • pp.219-223
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    • 2006
  • In this paper, the criteria of the lateral displacement in soft soil due to embankment were evaluated. The lateral displacement was measured at a pier structure in a new harbor construction site, and the measurement was compared with the criteria. The results by the measurement such as the critical pressure causing lateral movement in terms of undrained strength, the lateral movement index by Japan Highway Co., the lateral displacement index by Japan Construction Ministry, the modified index by Korean Highway Co. were estimated to be lower than the respective index values.

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Lateral Resistance Analysis of Single Pile Using Strain Wedge Model in Sand (모래지반에서 쐐기모델을 이용한 단독말뚝의 수평저항력 해석)

  • Bae, Jong-Soon;Kim, Ji-Seong;Kim, Sung-Ho
    • Journal of the Korean Geotechnical Society
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    • v.26 no.11
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    • pp.39-46
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    • 2010
  • The magnitude of the lateral resistance that resists the lateral movement of the pile is controlled by the amount of the pile movement and the strength and stiffness of soil. In this paper, we proposed an equation which produces the lateral resistance of the laterally loaded single pile using the strain wedge model of the soil deformation. The results of this equation is compared with results of model test, field test, p-y curve and other methods. It is found that the result of proposed equation is smaller than the result of model test. The results of loading test considerably coincide with those of proposed equation; however, a few of deviations are generated as the displacement of pile head increases. Moreover, coincidences exist between the results of the proposed equation and those of finite difference method.

A study on the stability of pile bridge abutment on soft ground undergoing lateral flow (연약지반에서의 말뚝기초 교대의 측방유동 대책공법 적용에 관한 연구)

  • 오일록;채영수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.753-760
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    • 2003
  • An existing studies concern about movement of pile bridge abutments. However, lateral displacement cause the serious failure of bridge by embankment under soft soil lateral flow A intention is obtained by analyzing the relationship between the safety factor of evaluation for lateral movements. Precise investigation and analysis are performed, in which the lateral movement of bridge abutments has occurred, and construct design strut-slab between bridge abutments in order to restraint lateral flow. As a result of this study, it was found that when evaluation for lateral movements is allowed to use Tschebotarioff's method and lateral flow decision number (I) and revision lateral flow decision number (M$_{I}$) by Korea Highway Corporation. Most important thing is decision of pressure of lateral flow at this case. Tschebotarioff's isoscales triangle method have no trouble analysis of pressure of lateral flow. Strut-slab method are nearly not have constructed case in this field site study that applied method. The method are between abutments combined steel strut and reinforced concrete slab. This method are effective restraint lateral flow but have little difficulty if long span bridge between abutments.s.

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