• The Journal of Engineering Geology
• /
• v.33 no.1
• /
• pp.189-200
• /
• 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.

• The Journal of Engineering Geology
• /
• v.33 no.2
• /
• pp.229-240
• /
• 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 (AS_i,j) and the slope difference index (SDI_i,j). Plotted in the mean settlement difference index - slope difference index (AS_i,j-SDI_i,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.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.7
• /
• pp.91-105
• /
• 2005

In this study, the deformation behavior of Daegok dam during the construction was analyzed based on the measurement data and a comparative analysis with foreign CFRD measurements was performed. From measuring settlements of Daegok dam with depth, overall behavior was evaluated to be consistent with measured data of other CFRD dams. In addition, construction modulus, void ratio and shape factor were also evaluated to be major factors in predicting the settlement behavior during construction of CFRD-typed dam from measured data of 38 CFRD-typed dams, and the maximum internal settlement is proportional to the void ratio. From the relationship between the maximum internal settlement and the height of a dam, 26 dams were assessed to have its relative modulus ranging between 0.001 and 0.01. In case of general CFRD, the average modulus of maximum internal settlement to the height of a dam is estimated to be 0.005. In case of a low void ratio, the construction modulus was high with its shape factor below 4. On the other hand, in case of a high void ratio, the relative settlement rate was high with its shape factor more than 4.

• The Journal of Engineering Geology
• /
• v.32 no.4
• /
• pp.513-523
• /
• 2022

The purpose of settlement management when treating soft ground through preloading is to determine the amount of settlement, check the progression of consolidation, and compare the settlement with the target settlement amount. Of the various methods available for predicting settlement based on measured data, the hyperbolic method was used in this study to analyze the settlement behavior of soft ground considering the creep behavior resulting from staged fill. Two versions of the method were used: the existing hyperbolic method, and a modified hyperbolic method. The existing hyperbolic method predicts the settlement amount using data for the final settlement section only during soft ground treatment through staged fill, for which the coefficient of consolidation behavior (k) was computed to give a predicted final consolidation settlement amount of S_r = 1.05 cm. In comparison, using the modified method, a predicted final consolidation settlement of S_r = 0.50 cm is obtained by considering the data for each staged fill section. These results show that the modified method considering data from the staged settlement was more accurate than the existing method considering data only from the final settlement section. This modification to the hyperbolic method therefore represents an improvement in performance over the existing method.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.4
• /
• pp.149-156
• /
• 2000

Sedimentation and self-weight consolidation tests in cylinder and large model tank and field measurement such as settlement and pore water pressure at each layer by wireless automatic instrumentation system were carried out to investigate the behaviour of dredged marine clay fill. The consolidation behaviour for each reclaimed layer was analyzed from these measured data and numerical analysis result using finite strain consolidation theory. It was fond from this study that the consolidation behaviour of dredged clay fill is heavily dependent on the filling process.

• Journal of the Korean GEO-environmental Society
• /
• v.6 no.1
• /
• pp.53-62
• /
• 2005

This paper estimates the long-term settlement of Kimpo metropolitan landfill based on measured settlement data from 180 landfill monitors accumulated over a period of 12 years. Comparison of domestic and international settlement records indicate that the domestic compression rate is slightly lower due to greater portion of organic component. Several existing settlement models are used to compare with the observed behavior and also to estimate long-term settlement. The hyperbolic, Gibson & Lo, Bjarngard & Edgers and Power Creep Law models compare well with the measured settlement of the Kimpo metropolitan landfill. The settlement models are further used to estimate long-term settlement. Bjarngard & Edgers and Power Creep Law models result in higher estimates of the long-term settlement compared to the hyperbolic and Gibson & Lo models. Further comparisons indicate that other models, including Sowers and log models, are inapproriate for predicting the long-term settlement of the Kimpo metropolitan landfill.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.4
• /
• pp.61-69
• /
• 2012

A high rock embankment by means of phased dynamic compaction has hardly carried out in Korea. Settlement of each layer is measured in order to verify the settlement behavior of dynamically compacted high rock embankment. A high rock embankment is generally constructed by dividing into several sub-embankments. Such a sub-embankment and dynamic compaction may induce an increase of pressure at the lower part of embankment and cause a different behavior of ground from initial status. In this study, settlement of a high rock embankment is estimated using a hyperbolic model taking into construction history. The results from prediction are compared with those obtained from field measurements. And second creep settlement is predicted using pre-loading test.

• Journal of the Korean GEO-environmental Society
• /
• v.2 no.4
• /
• pp.51-61
• /
• 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.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.1190-1193
• /
• 2010

본 연구에서는 점토층의 자중압밀을 시행하여 현장강도를 구현하기 위하여 1/70로 축소 모델링하여 원심모형실험을 수행하였으며, 점토구간에 PBD 타설시의 연약지반의 압밀침하거동을 분석하기 위하여서는 1/100로 축소모델링하여 원심모형실험과 전산해석을 실시하였다. 전산해석결과 성토체중심아래의 점토지반의 침하량은 1단계 성토제방하중 하에서 4.8개월 경과 후 최대 침하량은 41.1cm, 2단계 성토하중에서 4.2개월 경과 후의 최대침하량은 78.8, 3단계 성토하중에서 6개월 경과후의 침하량은 93.5cm의 침하가 발생하는 것으로 나타나 수치해석 결과와 원심모형실험결과 값의 유사한 경향을 확인하였다.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.3
• /
• pp.393-399
• /
• 2020

In this study, the subsidence behavior caused by groundwater ex-flow in a limestone cavity encountered during tunnel excavation was quantified based on numerical analysis and the effect was analyzed. Based on the groundwater level and surface subsidence surveyed at the site, a numerical analysis technique was applied to analyze the characteristics of the subsidence behavior according to the tunnel passage of the geological vulnerabilities. The results of groundwater seepage-coupled analysis were analyzed to reflect the actual ground subsidence behavior. As a result of the study, it was analyzed that the ground subsidence due to the tunnel excavation in the limestone common section(the geological vulnerable zone) was analyzed that the dramatical decrease in groundwater level was the main cause. As a result of numerical analysis, it was analyzed that the long-term cumulative settlement of the asphalt surface after the groundwater ex-flow was 76~118mm due to the reduction of the volume of the soil layer due to the decrease in the groundwater level, and the settlement amount increased as the depth of the soil layer increased.