SPSFC법을 이용한 단계성토 시 침하량 예측

강성현(Seonghyeon Kang),김태형(Taehyung Kim) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.12

현장에서 널리 활용하고 있는 침하예측기법으로는 Hyperbolic법, Hoshino법, Monden법 등이 있다. 이들 기존 침하예측법은 최종침하량 예측이 최종 성토단계가 완료된 이후 가능하다는 단점을 가지고 있다. 본 연구에서는 이와 같은 기존 예측법의 단점을 보완할 수 있는 새로운 침하량 예측법(SPSFC: Settlement Prediction for Staged Filling Construction)을 제안하였다. 이 방법은 연약지반에서 성토 완료 후뿐만 아니라, 초기 성토단계에서 단계성토별 시간-침하곡선을 예측할 수 있다. SPSFC법을 검증하기 위해 연약지반 개량을 위한 배수공법이 적용된 낙동강 하구 지역 두 개 현장에서 계측된 자료를 이용하여 기존 예측기법과 함께 SPSFC법으로 장래침하량을 예측하였다. 비교 결과, SPSFC법으로 예측된 침하량이 기존 예측법과 비교해서 신뢰성이 있음을 확인하였다. 또한 SPSFC법으로 초기 성토 단계에서 침하계측자료를 분석하여 예측에 필요한 지반상수를 구하고 이것을 이용하여 나머지 단계 성토 시 발생할 시간-침하량 곡선을 도시하였다. SPSFC법으로 예측된 침하량이 계측치와 잘 일치하는 것으로 나타나 SPSFC법으로 초기 성토단계의 침하계측 값만을 가지고 장래 침하량 예측이 가능함을 확인하였다. Settlement prediction has been conducted using Hyperbolic, Hoshino, and Monden methods, etc in the fields. These methods are only able to predict settlement after finishing the final filling stage. A new method is proposed to make up for such a weak point. This method was named as SPSFC (Settlement Prediction for Staged Filling Construction) method, which can be able to predict the settlement both the final filling stage and the staged filling from the initial filling stage in soft ground. To verify the applicability of the SPSFC method, firstly. The settlement predicted by the existed methods are compared with that obtained by the SPSFC method. The comparison results indicate the SPSFC has enough reliability to use for prediction of settlement. Secondly. by analyzing the settlement data measured during the initial filling stage, the soil parameters which need to predict the settlement are obtained by the SPSFC method. Then using the obtained soil parameters the time-settlement curve is predicted and compared. The predicted settlement is well matched with the measured one. From the study, the SPSFC method can be possible to predict settlement during the staged filling with only the initial settlement data.

대심도 연약지반의 현장계측을 이용한 장기침하거동특성 분석에 관한 연구

권현욱,임총철,장지건,강상균 한국지반신소재학회 2018 한국지반신소재학회 논문집 Vol.17 No.4

Despite a number of studies on consolidation behavior that have been carried out in the Nakdong River estuary in Busan, these are focused on the prediction of final settlement during ground improvement process, and there is almost no research on the long-term settlement occurring after that. For the practical study on the long-term settlement, the field monitored settlement data that measured over 10 years in the Busan new port facilities area were used, and the final settlement and predicted time-settlement line were constituted by hyperbolic function. As a result, the measured settlements depend on the thickness of clayey soils, and the pattern were similar to each other and good agreement with the predicted time-settlement line using hyperbolic method. Also, the settlement in the lower non-improved layer occupied 62-76% of total settlement. Information about above results would be quite helpful to understand the long-term settlement behaviors as well as the non-improved layer’s settlement is more careful consideration needed at design phase. 대심도 연약지반을 개량하여 상부에 개설되는 도로 등 각종 시설물의 안전을 확보하기 위해서는 공용개시 후 잔류 침하량에대한 명확한 이해를 바탕으로 한 합리적인 설계관리기준의 설정과 예측 값 산정이 매우 중요하다. 그러나 지난 수십 년 동안낙동강 하구 일원 등 대심도 연약지반상의 지반개량을 통해 조성된 부지에서는 설계단계에서 예측한 잔류 침하량을 크게상회하는 침하가 발생하여 많은 시설물의 파손과 아울러 사회적인 논란을 야기되고 있음에도 이에 대한 연구는 거의 전무한실정이다. 본 논문에서는 공용하중 개시 이후 장기간에 걸쳐 발생하는 잔류 침하에 대한 기초적이며 실무적인 연구를 위해, 대심도 연약지반개량을 통해 조성된 부지에서 약 10년에 걸쳐 측정한 침하계측결과를 이용하여 장기 침하거동 양상을 분석하였다. 그 결과 계측된 잔류침하량은 점성토층의 두께의 차이로 지점별로 차이가 있으나 침하양상은 모든 계측결과가 유사하였으며, 쌍곡선 함수식을 이용한 장래 잔류침하 예측결과와는 매우 좋은 일치를 보였다. 또한, 하부 미개량층에서 발생한 침하량이 전체침하량의 대부분(62-76%)을 차지하는 것으로 확인되어 개량층을 대상으로 허용침하량을 규정하고 있는 국내의 현실에좀 더 신중한 고민이 필요한 것으로 나타났다.

지중연속벽 시공을 위한 트렌치 굴착시 지반변형에 관한 모형실험

홍원표,이문구,이재호 한국지반공학회 2006 한국지반공학회논문집 Vol.22 No.12

A series of model tests were performed to investigate the ground deformation during trench excavation for diaphragm walls. An apparatus was manufactured to observe the failure pattern of a slurry-supported trench in sandy ground. Ground deformations including settlement and lateral displacement of the surrounding ground adjacent to the trench were carefully monitored during excavation. Experimental observations indicated that the settlement of the adjacent ground increased with closing to the trench. Especially, the considerable settlement occurred at the distance which was equal to 40% of the excavation depth. And, the higher settlement was obtained when the relative density of ground was looser and the ground water table was higher. Also, the lateral wall face of excavated trench was bulged with lowering the slurry level in stages and then the upper part of trench failed finally. The envelope of ground surface settlement could be represented as a hyperbolic line and the measured settlement was smaller than those predicted by Clough and O’Rourke (1990).

Centrifuge Modelling and Analysis of Ground Reaction of High-speed Railway Embankments over Medium Compressibility Ground

Chong-lei Zhang,Guan-lu Jiang,Xian-feng Liu,Li-jun Su 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.12

The objective of this study is to verify the feasibility of using centrifugal model tests to characterize the ground reaction response of a high-speed railway embankment to predict its ground settlement. To do so, a series of Centrifugal Model Tests (CMTs) of the embankment were performed to investigate the variation of ground reaction and corresponding derived modulus at different embankment ratios. The ground reaction determined from the CMTs was compared with those obtained from corresponding fullscale field tests of instrumented embankment. The results show that the ground reaction at the embankment centreline gradually approaches the embankment weight (γH) with increasing embankment ratio. Considering the embankment filling process with different embankment ratios, it seems inappropriate to employ the value of γH as the ground reaction without any correction in settlement prediction. Finally, the predictive capability of the proposed approach for embankment settlement estimation was assessed against the corresponding field measurements and those determined based on the calculation methods suggested in the current design standard in China. The results show that the proposed simple approach satisfactorily estimates the ground settlement of HSR embankments and its deviation of predicted settlements is below 11.9% compared with the data obtained from the field full-scale tests. However, the deviation of the result calculated by the current recommend design standard is 17.7%-148.3%.

서해안 중부지역 연약지반의 침하특성 분석을 위한 실험적 연구

김준석 한국재난정보학회 2021 한국재난정보학회 논문집 Vol.17 No.4

연구목적: 실트질 함유가 높으며 다양한 응력이력 때문에 침하량 예측에 어려움이 있는 우리나라의 서 해안 중부지역의 연약점토지반의 침하량 특성을 분석하기 위하여 실험을 실시하였다. 연구방법: 3개의 경우에 대한 현장실험을 실시하였다. 각각의 경우에 대하여 침하판 침하량을 계측하였으며 Terzaghi의 일차원 압밀침하량, 쌍곡선법(hyperbolic method)과 Asaoka법을 모두 분석하여 실무에 유용한 결론을 도출하였다. 연구결과: Terzaghi에 의한 예측값이 모든 경우에서 가장 큰 것으로 분석되었으며 침하판 침하값에 비하여 111%~187%로 크게 예측하였다. 즉, 실제 지반의 침하량인 침하판 침하값이 Terzaghi 의 예측값에 비하여 53.4~89.9% 의 침하를 나타내었다. 따라서, 우리나라 중부 서해안 점토질 연약지반 에서 Terzaghi방법에 의한 예상침하량은 실제 침하량보다 과다하게 예상하는 것으로 분석되었다. 결 론: Asaoka방법과 쌍곡선 방법은 비교적 유사한 결과를 제시한 것으로 분석되었으며, 실무에서는 실제 침하량 보다 작게 침하량을 예측할 경우 위험을 초래할 수 있으므로 실제 침하량보다 6~14% 크게 예측 한 쌍곡선 분석법이 안전측으로 사용될 수 있을 것으로 판단된다. Purpose: An experiment was conducted to analyze the characteristics of the settlement of soft clay soil in the central region of the west coast of Korea, which has a high silt content and is difficult to predict settlement due to various stress histories. Method: Field experiments were conducted for three cases. The settlement amount of the subsidence plate was measured in each case, and the following conclusions were drawn by analyzing Terzaghi's one-dimensional consolidation settlement amount, both the hyperbolic method and the Asaoka method. Result: The predicted value by Terzaghi was analyzed to be the largest in all cases, and it was predicted to be 111% to 187% larger than the subsidence plate settlement value. That is, the subsidence plate settlement value, which is the amount of settlement of the actual ground, showed a settlement of 53.4~89.9% compared to the predicted value of Terzaghi. Therefore, it was analyzed that the expected settlement of the Terzaghi method in the clay soft ground of the central west coast of Korea is more than the actual settlement. Conclusion: It was analyzed that the Asaoka method and the hyperbolic method presented relatively similar results, and in practice, predicting the settlement amount smaller than the actual settlement amount may cause a risk, so the hyperbola analysis method predicted 6~14% larger than the actual settlement amount can be used as a safety side.

PBD공법이 적용된 연약지반에서 운용 중인 시설물의 잔류침하거동

강기천(Gichun Kang),김태형(Taehyung Kim),정충기(Choonggi Jeong) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.8

항만 터미널 부두 지역의 연약지반 개량을 위해 PBD가 적용되었다. 본 논문은 PBD가 적용된 연약지반에서 PBD가 설치된 직후부터 상부 구조물 운용 후의 잔류침하거동에 대해서 다루고 있다. 기존의 연구는 개량공법 시공 중에 발생하는 침하, 즉 PBD개량 효과에 대해 주로 이루어졌다. 실제 시설물의 운용 중에 발생하는 잔류침하는 시설물의 유지 및 운용을 위해서는 아주 중요한 요소이나 이 부분에 대한 연구는 매우 부족한 실정이다. 본 연구에서는 실제로 운용 중에 있는 항만 터미널 부두의 침하량 계측결과를 분석하여 운용 중에 발생한 침하량은 PBD 개량층에서 발생하는 것을 확인하였다. 또한 계측값과 수치해석 값을 비교한 결과 계측값이 수치해석에 의해 예측된 잔류침하량 내에서 수렴하는 것도 확인하였다. The Plastic Board Drain is used to improve soft soils deposited in container terminal area at a port. This paper describes settlement behavior of soft ground in this area from PBD installation to the time of operating facilities. Previous researches focused on soil improvement effect of PBD, that is, the settlement occurred during ground improvement period. The residual settlement occurred during operating the facility is very important from the maintenance and management point of view. However, the study of this residual settlement has been rarely conducted. In this study, by analyzing the measured settlement data obtained from the container terminal area at the port, it was verified that the residual settlement induced during operating facilities occurred in a layer with PBD improvement. In addition, by comparison the settlement predicted by a numerical analysis with the settlement measured in the field, it was confirmed that the actual settlement is in the range of predicted settlement.

수치해석을 통한 연약지반을 고려한 철도노반 침하 특성에 대한 고찰

오동욱,김규화,윤환희,정혁상 한국철도학회 2023 한국철도학회논문집 Vol.26 No.2

This paper presents quantitative numerical analysis results of effects of underground water level and train load on subsidence of rail trackbed in soft ground. Although the railway subgrade strictly limits the allowable residual settlement to 30mm through the railroad design standards and specifications, it is reported that subsidence occurs continuously in some sections of the Honam high-speed rail and Gyeongbu high-speed rail 2nd phase. The causes of subsidence of the rail trackbed include the groundwater level, height of embankment, and soft ground, and although studies on causes of each type of subsidence have been conducted, research on the complex causes of subsidence have been insufficient. Therefore, in this study, the effects of soft ground conditions, groundwater level, fill height, and train load, the main causes of subsidence of railway subgrade, on residual subsidence of soft ground were analyzed. Secondary compaction was considered to simulate soft ground. Soil Soft Creep Model was used. As a result of the analysis, it was confirmed that the rate of residual settlement increased significantly as the liquid limit of the silt layer increased. In addition, the factors of greatest influence on increase of residual settlement were found to be, in order, liquidity of soft ground, thickness of soft ground, and location of groundwater level were determined.

인천시 안전한 도로환경조성을 위한 정책 제언: 지반침하 관리 대책을 중심으로

김은경 (재) 인천연구원 2018 도시연구 Vol.- No.13

Ground settlement-related safety accidents are gradually increasing at home and abroad. The reason why the underground space that cannot be seen directly by the eyes is especially dangerous is that there is no way to prevent a tragic disaster if it is a road and sidewalk on which cars or people come and go. In Incheon City in February 2012, a collapse occurred at the center of a six-lane road near the construction site of Incheon Metro Line 2, and in July 2014, next year, there was a phenomenon in which the ground near the construction site of Yeongjong Sky City Sinmyeong Skyview sank in an earthquake-like shape. Like this, in Incheon City, too, accidents related to ground settlement continuously occur, and there is a limitation in the parts that can be solved based on an analysis of the natural topography of Incheon. This study benchmarked the road safety environment policy related to a ground settlement based on the current management system related to the ground settlement of Incheon and domestic and foreign preceding case analysis. Finally, this study would seek a long-term measure for road safety management to promote the improvement of the road safety environment of Incheon City. As a result of the study, it is noted that Incheon City would need to get 3D ground/underground space information that can add more accurate underground location and ground information by integrating the Pavement Management System (PMS) introduced in 2012 with the latest technology. Besides, it is necessary to reflect this more actively in administrative practice and also to improve the legal system for this system. It is judged that Incheon City will create a safer road environment than it is now, when improvements of the system and the road environment are made, utilizing time-series data. 국내외에서 지반침하와 관련된 안전사고는 점차 증가하고 있는 실정이다. 눈으로 직접 볼 수 없는 지하의 빈 공간이 특히 위험한 이유는 그 위로차나 사람이 오가는 도로 및 보도일 경우 대형 참사를 막을 길이 없기 때문이다. 인천시는 2012년 2월, 인천지하철 2호선 공사현장 주변 왕복 6차선 도로 한 가운데서 붕괴가 발생하였고, 이듬해 2014년 7월에는 영종하늘도시신명스카이뷰 공사장 주변이 지진이 난 듯한 형상으로 땅이 꺼지는 현상을 보였다. 이처럼 인천시 역시 지반 침하에 관련한 사고가 끊이지 않고 있으며, 인천의 자연지형 분석을 토대로 해결할 수 있는 부분에 한계가 존재한다. 본고에서는 인천의 지반침하와 관련된 현 시점의 관리체계 및 국내외선행 사례 분석을 바탕으로 지반침하 관련 도로 안전환경 정책을 벤치마킹하였다. 최종적으로 인천시의 도로안전 환경 개선을 도모하기 위한 장기적인 도로안전 관리 방안을 모색하고자 한다. 연구 결과, 인천시는 2012년 도입된 도로포장관리시스템(PMS)을 최신기술과 접목하여 더욱 정확한 지하 위치와 지상 정보를 더할 수 있는 3차원 지상지하 공간정보를 취득할 필요가 있겠다. 뿐만 아니라 이를 더욱 적극적으로 행정 실무에 반영하고, 이러한 체계를 위한 법제도 개선이 함께이루어질 필요가 있다. 이 같은 제도 개선 및 시계열적 자료를 활용한 도로환경 개선이 이루어 질 때, 인천시는 지금보다 더 안전한 도로환경 조성을 이룰 것으로 판단된다

PVD 적용지반에서 단계성토시 침하량 예측

강성현(Seong-Hyeon Kang),김태형(Tae-Hyung Kim) 한국지반신소재학회 2014 한국토목섬유학회 학술발표회 Vol.2014 No.11

Settlement prediction has been conducted using Hyperbolic, Hoshino, and Monden methods, etc in the fields. These methods are only able to predict settlement after finishing the final filling stage. A new method is proposed to make up for such a weak point. This method was named as Kang"s method, which can be able to predict the settlement both the final filling stage and the staged filling from the initial filling stage in soft ground. To verify the applicability of this method, the measured settlement curve history was compared with the predicted one. The predicted settlement is well matched with the measured one. From the study, the Kang"s method can be possible to predict settlement during the staged filling with only the initial settlement data.

지하수위 변동에 따른 응력과 간극수압 변화에 의한 성토체 즉시침하 해석

이민수(Min-Soo Lee),이일화(Il-Wha Lee),이강명(Kang-Myuong Lee) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10

연약지반에 구조물을 건설할 경우, 지반침하가 발생하는 여러 가지 원인 중 하나는 지하수위에 있다. 지반침하를 예측하기 위해서는, 지하수위 변동에 의한 응력과 간극수압이 지반에 어떠한 영향을 미치는지 파악하기 위한 연구가 필요한 실정이다. 본 논문은 연약지반층에서 지하수위 변동에 따른 응력과 간극수압 변화를 분석하여 즉시침하에 미치는 영향을 검토하였다. 연약지반과 성토체를 구현하기 위해 유한요소해석 프로그램을 사용하였고, 해석 매개변수로 지하수위를 저하시키고, 조건변화에 따라 간극수압과 응력변화에 의한 즉시침하량을 검토하였다. One of the reason to occur subsidence of ground is the water layer in case of constructing structure on the soft soil. The research of effect on the ground about stress and pore pressure is needed to know subsidence of ground by fluctuations of ground water level to predict subsidence of ground. This paper confirmed the immediate settlement on the soft soil layer of changing stress and pore pressure by fluctuations of ground water level. It used Finite Element Method (FEM), made reduction of the water layer as a parameter and debated the immediate settlement of the effect about changing condition of pore pressure and stress to express soft soil and embankment.