• Title/Summary/Keyword: 상대 침하

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An Experimental Study on the Relationship between Deformation and Relative Settlement for Weathered-granite (화강풍화토의 변형계수와 상대침하 관계식에 관한 실험적 연구)

  • Park, Yong-Boo
    • Land and Housing Review
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    • v.4 no.1
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    • pp.125-131
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    • 2013
  • To predict the real bearing capacity and settlement of the shallow foundation the plate load test results were used. But there is no field estimation method about igneous weathered soil and rock. Therefore, to predict the settlement equation, the plate load test about igneous weathered soil and rock was done in this study. To analyze the load ~ relative settlement curve by normalization, it did not use normal analysis method, but the load ~ relative settlement (s/B, s : settlement, B : breadth of plate) was used. As a result of normalization by load ~ relative settlement conception, the curve was regular regardless of plate diameter and it was suggested the relationship of in-situ soil condition and results.

Relative Settlement Analysis of Soft Ground (연약지반의 상대적 침하 거동 분석)

  • Young-Jun Kwack;Heui-Soo Han
    • The Journal of Engineering Geology
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    • v.33 no.2
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    • pp.229-240
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    • 2023
  • Instruments are installed in soft ground improvement projects to manage economic and safe construction. When analyzing data, the amount of settlement data over time can be used to understand the overall ground settlement behavior, but it is difficult to analyze the interrelatedness between measurement points. Therefore, to analyze the relative compressive settlement behavior between measurement points, the settlement amount and velocity were processed and defined as the mean settlement difference index (ASi,j) and the slope difference index (SDIi,j). Plotted in the mean settlement difference index - slope difference index (ASi,j-SDIi,j) coordinate system. As a result of the analysis of the relative compaction subsidence behavior between the measuring points, the relationship between the measuring points in the average subsidence difference index - slope difference index coordinate system moved to area 1 as the compaction was completed. By continuously plotting the movement path of the observation point in the corresponding coordinate system, the relative settlement behavior between the measurement points was analyzed, and it was possible to check whether the settlement behavior of the two measurement points was stable or unstable depending on the direction of the path.

The Experimental Study on the Long-term Creep Settlements of Nam-Hae Sands (남해안 모래의 장기 크리프 침하 특성에 관한 실험적 연구)

  • Park, Eonsang
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.9
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    • pp.21-28
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    • 2018
  • In this study, a standard consolidation test (Oedometer) was performed on the relative density of sand in the south coast to evaluate long-term creep settlement characteristics. Experimental results show that the cumulative settlement at the final loading stage decreases as the relative density increases and the variation of the void ratio decreases. As a result of analyzing the settlement rate of long-term creep of sand, creep settlement of 4.7~11.0% occurred depending on relative density with respect to total settlement. The creep parameter, Beta, of Schmertmann et al. (1978) was estimated to be 0.17~0.40 (average 0.21), and it tended to converge to a certain value when the load step becomes more than a certain level. It was found that there is no significant difference in the creep parameter depending on the layer thickness, and it was confirmed that the creep parameter could be applied regardless of the field layer thickness.

Analysis of Relative Settlement Behavior of Retaining Wall Backside Ground Using Clustering (군집분류를 이용한 흙막이 벽체 배면 지반의 상대적 침하거동 분석)

  • Young-Jun Kwack;Heui-Soo Han
    • The Journal of Engineering Geology
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    • v.33 no.1
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    • pp.189-200
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    • 2023
  • As urbanization and industrialization increase development in downtown areas, damage due to ground settlement continues to occur. Building collapse in urban has a high risk of leading to large-scale damage to life and property. However, there has rarely been studied on measurement data analysis methods when uneven loads are applied to the excavated ground and no prior knowledge of the ground. Accordingly, it was attempted to analyze the relative settlement behavior and correlation by processing the time-series surface settlement of construction sites in the urban. In this paper, the average index of difference in settlement and average of relative difference in settlement are defined and calculated, then plotted in the coordinate system to analyze the relative settlement behavior over time. In addition, since there was no prior knowledge of the ground, a standard to classify the clusters was needed, and the observation points were classified into using k-means clustering and Dunn Index. As a result of the analysis, it was confirmed that all the clusters moved to the stable region as the settlement amount converges. The clusters were segmented. Based on the analysis results, it was possible to distinguish between the independent displacement area and same behavior area by analyzing the correlation between measurement points. If possible to analyze the relative settlement behavior between the stations and classify the behavior areas, it can be helpful in settlement and stability management, such as uplift of the surrounding area, prediction of ground failure area, and prevention of activity failure.

A Study on the Behaviour of Single Piles to Adjacent Tunnelling in Stiff Clay (견고한 점토층에서 실시된 터널근접시공으로 인한 단독말뚝의 거동에 대한 연구)

  • Jeon, Youngjin;Lee, Cheolju
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.6
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    • pp.13-22
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    • 2015
  • In the current work, a series of three-dimensional (3D) numerical modelling has been performed in order to study the effects of the relative locations of tunnels with respect to the position of pile tips which governs the behaviour of pre-existing, adjacent single piles. In the numerical analyses, several governing factors, such as tunnelling-induced pile head settlements, relative displacements, volume losses, axial pile forces, interface shear stresses and apparent factors of safety have been analysed. When the pile tips are inside the tunnelling influence zone, of which the pile tip location is considered with respect to the tunnel position, tunnelling-induced pile head settlements are larger than the ground surface settlements, resulting in tunnelling-induced tensile pile forces. On the contrary, when the pile tips are outside the influence zone, compressive pile forces associated with downward shear stresses at the upper part of the piles are developed. Based on computed load and displacement relation of the pile, the apparent factors of safety of the piles inside the tunnelling influence zone have been reduced by 36% in average. The shear transfer mechanism based on the relative tunnel locations has been analysed in great detail by considering tunnelling-induced pile forces, interface shear stresses and the apparent factors of safety.

Characteristics of Load-Settlement Behaviour for Embeded Piles Using Load-Transfer Mechanism (하중전이기법을 이용한 매입말뚝의 하중-침하 거동특성)

  • Oh, Se Wook
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.4
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    • pp.51-61
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    • 2001
  • A series of model tests and analyses by load transfer function were performed to study load-settlement behaviour with relative compaction ratio of soil and embeded depth of pile. In the model tests, embeded depth ratio(L/D) of pile were installed 15, 20, 25 and relative compaction of soil(RC) is 85%, 95% and then cement were injected at around perimeter of pile. For analysis of embedded pile, the paper were compared results of model tests with analysis results by Vijayvergiya model and Castelli model, Gwizdala model of elastic plasticity-perfect plastic model and then the fitness load transfer mechanism was proposed to predict load-settlement behaviour of embeded pile. The analysis results of predicted bearing capacity by load transfer function, ultimate bearing capacity of embeded pile were approached to measured value and behaviour of initial load-settlement curve were estimated that load transfer function by Castelli were similar to measured value. The result of axial load analysis of bored pile shows that skin friction estimated by load transfer mechanism is investigated more a little than that of measured values.

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Influence of Saturation and Soil Density on the Ground Subsidence Using Distinct Element Method (개별요소법을 통한 지반의 포화도와 밀도가 함몰에 미치는 영향 평가)

  • Kim, Yeonho;Kim, Hyunbin;Park, Seong-Wan
    • Journal of the Korean Geotechnical Society
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    • v.34 no.8
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    • pp.27-36
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    • 2018
  • The collapse behavior of ground subsidence caused by continuous loss of particles depends on the saturated condition and density of the ground. In this study, types of ground subsidence were classified based on the saturated condition and each type was performed on the different relative density to analyze the influence factors on the collapse behavior by distinct element method. According to analysis results, the relatively small amount of settlement occurred on the dense ground and a cavity was created under dense-unsaturated ground. In contrast, loose ground showed the large amount of settlement and collapsed immediately without cavity formation even if the unsaturated ground was simulated. The results demonstrated that because the relative density has influence on the mechanical interlocking and saturated condition has influence on the inter-particle force, these are important factors to change the collapse behavior.

Ground Stability Interpretation of the Five-storied Stone Pagoda at the Muryangsa Temple, Korea; An Examined by the Nondestructive Survey (비파괴 탐사를 이용한 무량사오층석탑 지반안정해석)

  • Chae, Sang-Jeong;Suh, Man-Cheol
    • Journal of Conservation Science
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    • v.20
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    • pp.43-54
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    • 2007
  • The Muryangsa temple five-storied stone pagoda (Treasure No. 185) was geographically located in the area of the Baekje Kingdom. The architectural style of the Muryangsa temple five-storied stone pagoda is the pagoda at the early Goryeo Dynasty that was succeeded technique of the Baekje Kingdom and form of the Shilla Kingdom. Because this pagoda is located outside during old time that it received serious petrological and biological weathering in rock blocks and occurred the center subsidence in the upper capstone. This study executed ground stability interpretation in order to know what central subsidence in the upper capstone occurred for soft ground. The ground stability interpretation used seismic survey, electrical resistivity survey and GPR survey by non-destructive method. As the result, the ground appeared in the condition which is good. Specially, high resistance zone appeared from electric resistivity survey which come to seem with ground reinforcement harden. Consequently, central subsidence condition in the upper capstone is not by the instability of ground, and is judged with the thing by the structure instability in rock blocks over the upper capstone. This will be applied basic data with the long-term monitoring or preservation countermeasure of the pagoda.

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Analysis of Sand Compaction Piles Under Flexible Surcharge Loading (연성하중을 받는 모래다짐말뚝(SCP)의 거동분석)

  • 홍의준;김재권;정상섬;김수일
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.223-233
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    • 2003
  • Sand compaction pile (SCP) is one of the ground improvement techniques which are being used for not only accelerating consolidation but also increasing bearing capacity of loose sands or soft clay grounds. In this study, laboratory model tests and 3-D finite element analyses were performed to investigate the interaction between sand compaction piles and surrounding soft soils. Based on the results obtained, as the area replacement ratio increases, the stress concentration ratio increases at the pile point, the settlement decreases, and the relative displacement between column and soil also decreases. It is also found that numerical study is illustrated by good comparison with model test results, and the numerical analysis revealed slip effects which could not be specifically identified in the model tests.

Behavior of Underground Flexible Pipe According to Ground Characteristics (지반특성에 따른 지중 연성관의 거동특성)

  • Chang, Yongchai;Kim, Yonghyu;Lee, Seungeun;Park, Kichul;No, Jinsuk
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.4
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    • pp.41-48
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    • 2009
  • A flexible pipe was buried 10cm below the ground formed with standard sand to observe changes in the shape of the pipe according to the behavior of ground at each relative density. Changes in the shape of the pipe in each ground were observed to examine the behavior of the pipe under the state of reinforced ground after installing geogrid under the pipe. Ground reinforced using geogrid formed tensile force on the reinforcement material with increase in the vertical load and showed reduction in settlement under identical vertical load with existence of reinforcement. Distributions of ground deformation of 100% relative density and 70% relative density had clear difference. Reinforced ground with 70% density converged to the ground reaction of final settlement of non-reinforced ground with 100% density at final settlement of 100 mm. Because the shape of lower part strain of the buried pipe is similar to that of un-reinforced ground with relative density of 100%, reinforcement effect by geogrid in soft ground can be anticipated.

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