• Geomechanics and Engineering
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• 제23권4호
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• pp.313-325
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• 2020

Slope displacement and factor of safety (FOS) of a slope are two aspects that reflect the stability of a slope. However, the traditional limit equilibrium (LE) methods only give the result of the slope FOS and cannot be used to solve for the slope displacement. Therefore, developing a LE method to obtain the results of the slope FOS and slope displacement has significance for engineering applications. Based on a force-displacement coupled mode, this work expands the LE Morgenstern-Price (M-P) method. Except for the mechanical equilibrium conditions of a sliding body adopted in the traditional M-P method, the present method introduces a nonlinear model of the shear stress and shear displacement. Moreover, the energy equation satisfied by a sliding body under a small slope displacement is also applied. Therefore, the double solutions of the slope FOS and horizontal slope displacement are established. Furthermore, the flow chart for the expanded LE M-P method is given. By comparisons and analyses of slope examples, the present method has close results with previous research and numerical simulation methods, thus verifying the feasibility of the present method. Thereafter, from the parametric analysis, the following conclusions are obtained: (1) the shear displacement parameters of the soil affect the horizontal slope displacement but have little effect on the slope FOS; and (2) the curves of the horizontal slope displacement vs. the minimum slope FOS could be fitted by a hyperbolic model, which would be beneficial to obtain the horizontal slope displacement for the slope in the critical state.

• Geomechanics and Engineering
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• 제33권1호
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• pp.77-89
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• 2023

This study aims to establish the correlations between variables related to a slope during rainfall and factor of safety (FOS) and displacement using a coupling analysis method that is designed to consider both in rainfall conditions. With the recent development of measurement technologies, the approach of using the measurement data in the field has become easier. Particularly, they have been obtained in tests to determine the real-time safety and movement of a slope; however, a specific method has not been finalized. In addition, collected measurement data for recognizing the FOS and displacement in real-time with a specific relevance is difficult, and risks of uncertainty, such as in soil parameters and time, exist. In this study, the correlations between various slope-related variables (i.e., rainfall intensity, rainfall duration, angle of the slope, and mechanical properties including strength parameters of selected three types of soil; loamy sand, silt loam, sand) and the FOS and displacement are analyzed in order of seepage analysis, slope stability analysis and slope displacement analysis. Moreover, the methodology of coupling analysis is verified and a fundamental understanding of the factors that need to be considered in real-time observations is gained. The results show that the contributions of the abovementioned variables vary according to the soil type. Thus, the tendency of the displacement also differs by the soil type and variables but not same tendency with FOS. The friction angle and cohesion are negative while the rainfall duration and rainfall intensity are positive with the displacement. This suggests that understanding their correlations is necessary to determine the safety of a slope in real-time using displacement data. Additionally, databases considering rainfall conditions and a wide range of soil characteristics, including hydraulic and mechanical parameters, should be accumulated.

• 한국지반환경공학회 논문집
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• 제8권2호
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• pp.19-27
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• 2007

본 연구에서는 준설에 따른 점토사면의 변형 및 변위양상과 파괴형태를 평가하기 위하여 준설사면의 기울기를 변화시키면서 원심모형실험을 실시하였다. 준설사면의 기울기는 1:2, 1:2.5, 1:3으로 변화시키면서 모형실험을 수행하였다. 실험 결과 기울기 1:3인 경우에는 4개월 경과시점까지 사면부내에서 변위는 발생되었지만, 초기단면과 유사하게 사면을 유지하고 있어 준설후 사면 안정성의 확보에는 문제가 없는 것으로 평가되었다. 준설사면 기울기가 1:2.5인 경우에는 4개월 경과시점에서 사면부내에서 국부적인 사면파괴가 발생하였으며, 기울기가 1:2인 사면의 경우 경과시간 2개월 후 원호파괴형태의 사면내 파괴가 발생되었다. 실험결과 지반의 최대 연직변위는 사면의 비탈머리에서 발생하였으며, 최대 수평변위는 비탈머리를 기준으로 0.5~1H(H : 초기 점토층의 높이) 떨어진 지점의 사면부 아래에서 발생하였으며, 최대 수평변위는 최대연직변위의 약 2배 정도인 것으로 나타났다.

• 한국농공학회논문집
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• 제59권5호
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• pp.101-108
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• 2017

Recently, the occurrence of landslides has been increasing over the years due to the extreme weather event. Developments of landslides monitoring technology that reduce damage caused by landslide are urgently needed. Therefore, in this study, a strain ratio sensor was developed to predict the ground behavior during the slope failure, and the change in surface ground displacement was observed as slope failed on the field model experiment. As a result, in the slope failure, the ground displacement process increases the risk of collapse as the inverse displacement approaches zero. It is closely related to the prediction of precursor. In all cases, increase in displacement and reverse speed of inverse displacement with time was observed during the slope failure, and it is very important event for monitoring collapse phenomenon of risky slopes. In the future, it can be used as disaster prevention technology to contribute in reduction of landslide damage and activation of measurement industry.

• 한국지반공학회논문집
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• 제19권4호
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• pp.23-32
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• 2003

사면지반변위를 측정하기 위한 기존의 시스템은 고가의 장비를 사용함에도 불구하고 설치ㆍ유지가 힘들고 지반지표의 전반적 계측이 힘들며 계측시 위험을 항상 동반한다. 따라서, 이러한 단점을 극복하고 사면의 변위량을 굴착초기부터 굴착단계별 및 유지관리단계까지 쉽게 미숙련자들도 측정할 수 있는 방법이 필요하며 이를 위하여 사진측량 장점을 활용한 소프트카피 사진측량(Softcopy Photogrammetry)의 매카니즘이 사면지반의 변위계측을 위해 적용되었으며 이는 접근하기 어려운 위험 사면의 3차원 지반데이터를 효과적으로 획득ㆍ분석할 수 있는 방법으로 제시하였다. 또한, 기존의 지상사진측량결과 분석과는 다른 등고선 재생성과정을 광속조정프로그램인 DIMA (Digital IMage Analysis)를 개발 적용하여 적용성을 높였다. 사면파괴발생현장 사례를 통해 사면파괴 전후의 계측결과에 대한 사면안정체계 및 기존계측시스템의 단점을 해결할 수 있는 기술적 토대를 마련할 수 있었다.

• Geomechanics and Engineering
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• 제15권4호
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• pp.947-955
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• 2018

In this study, we propose a three-dimensional simplified slope stability analysis using a hybrid-type penalty method (HPM). In this method, a solid element obtained by the HPM is applied to a column that divides the slope into a lattice. Therefore, it can obtain a safety factor in the same way as simplified methods on the slip surface. Furthermore, it can obtain results (displacement and strain) that cannot be obtained by conventional limit equilibrium methods such as the Hovland method. The continuity condition of displacement between adjacent columns and between elements for each depth is considered to incorporate a penalty function and the relative displacement. For a slip surface between the bottom surface and the boundary condition to express the slip of slope, we introduce a penalty function based on the Mohr-Coulomb failure criterion. To compute the state of the slip surface, an r-min method is used in the load incremental method. Using the result of the simple three-dimensional slope stability analysis, we obtain a safety factor that is the same as the conventional method. Furthermore, the movement of the slope was calculated quantitatively and qualitatively because the displacement and strain of each element are obtained.

• Geomechanics and Engineering
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• 제6권6호
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• pp.561-575
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• 2014

Estimating seismic displacements has a great importance for foundations on or adjacent to slope surfaces. However, dynamic solution of the problem has received little attention by previous researchers. This paper presents a new analytical model to determine seismic displacements of the shallow foundations adjacent to slopes. For this purpose, a dynamic equilibrium equation is written for the foundation with failure wedge. Stiffness and damping at the sliding surface are considered variable and a simple method is proposed for its estimation. Finally, for different failure surfaces, the calculated dynamic displacement and the surfaces with maximum strain are selected as the critical failure surface. Analysis results are presented as curves for different slope angles and different foundation distances from edge of the slope and are then compared with the experimental studies and software results. The comparison shows that the proposed model is capable of estimating seismic displacement of the shallow foundations adjacent to slopes. Also, the results demonstrate that, with increased slope angle and decreased foundation distances from the slope edge, seismic displacement increases in a non-linear trend. With increasing the slope angle and failure wedge angle, maximum strain of failure wedge increases. In addition, effect of slope on foundation settlement could be neglected for the foundation distances over 3B to 5B.

• 지질공학
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• 제19권4호
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• pp.475-482
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• 2009

절토사면에 설치된 흙막이벽의 거동은 도심지 굴착공사에 적용된 흙막이벽의 거동과는 다를 것이다. 배면경사지에 설치된 흙막이벽 설계법을 확립하기 위하여는 흙막이벽 및 배면지반의 변형거동을 상세히 규명할 필요가 있다. 따라서, 본 연구에서는 아파트 신축부지 절개사면의 보강을 위하여 앵커지지 흙막이벽과 억지말뚝이 설치된 사면을 대상으로 계측을 수행하였다. 계측결과 굴착초기에는 흙막이벽의 변형이 배면경사지반의 변형보다는 크게 발생되나, 굴착깊이가 깊어짐에 따라 배면경사지반의 변형이 크게 발생되었다. 이는 굴착으로 인한 흙막이벽의 변형이 흙막이말뚝의 강성과 앵커인장력에 의하여 억제되었기 때문으로 판단된다. 앵커에 도입된 선행인장력은 흙막이벽의 거동에만 큰 영향을 미치며, 강우로 인한 흙막이벽의 변형은 지하수위의 변화보다 지표부근에서 침투된 침투수의 영향이 큰 것으로 나타났다. 한편, 굴착배면의 경사진 사면에 설치된 앵커지지 흙막이벽의 수평변위는 굴착배면지반이 수평인 흙막이 굴착의 경우 보다 2~6배 정도 크게 발생하였다.

• 한국환경복원기술학회지
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• 제4권3호
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• pp.10-18
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• 2001

The existing measurement system to ground-surface displacement survey of the slope has been including the hazard for the measure in site and the difficulty for install, maintenance and control of expensive instruments, which are impossible of whole survey on the slope surface. To overcome of those defects, Softcopy Photogrammertry method is used, which can measure displacement of ground-surface on the slope and structure deformation vectors. Recently, the survey methods applying the advantages of Photogrammetry and Digital Photogrammetry Survey are widely used. In this study, therefore, the development and application of the new instrument mechanism on the the site example are studied. Through the application of Softcopy Photogrammetry, the 3-D data of ground surface on the dangerous slope could be effectively obtained at the long distance, which are obtained through the reform process of contour line. Those are different to the results of the Close-Range Photogrammetry analysis. In ground instrumentation parts, the new practical system shall be the technical base to improve of the instrument machine as well as can be widely applied in civil engineering and others branch.

• 대한공간정보학회지
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• 제16권4호
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• pp.17-23
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• 2008

산사태의 발생 징후를 효율적으로 사전에 감지하기 위한 방법을 도출하기 위하여 모형사면을 제작하여 지상LiDAR 장비로 사면의 변위를 파악하고자 모니터링 분석을 실시하였다. 그 결과 신속하게 사면 변위에 대한 영상을 모니터링 할 수 있었으며, 사면에 대한 모니터링 분석 정확도는 변위 전을 기준으로 1차,2차,3차 변위 후에 대하여 각각 평균 0.007m, 0.006m, 0.006m편차로 매우 적은 편차가 나타난 것이 입증 되었기에 향후 실제 사면의 변위 측정에 유용하게 이용될 수 있다.