제방겸용도로 건설에 따른 제방 안정성 해석에 관한 연구

김성남,이영우 한국도로학회 2008 한국도로학회논문집 Vol.10 No.3

This study analyzes the change of stability of embankment due to the construction of embankment combined used road with two different construction phases. The stabilities have been checked both in the phase of earth banking for a road construction and in the phase of the application of the traffic roads (DB-24). In both cases the factor of safety has been found higher than 1.3 which is the general criterion of the safety of an embankment. The results indicate that the safety of an embankment due to the construction of embankment combined use road is assured, and thus, it is thought that the construction of embankment combined use road can be considered for cutting down on expenses of construction sites for a road construction. However, the pre-examination of stability due to the construction should be carried out because it decreases the factor of safety of an embankment. From this study, it has been found that the factor of safety was dropped most when the water level rose in the transient flow. The result indicates that the stability analysis of a river embankment where the water level changes frequently should be carried out in the condition of transient flow. It is recommended that the inner side of an embankment should have a slope of 1:2 which is identical with the slope of the existing embankment. In addition, the factor of safety also can be decreased due to the traffic loads, and therefore, the effect should also be considered after the construction of embankment combined used road limiting the traffic loads. This study analyzes the change of stability of embankment due to the construction of embankment combined used road with two different construction phases. The stabilities have been checked both in the phase of earth banking for a road construction and in the phase of the application of the traffic roads (DB-24). In both cases the factor of safety has been found higher than 1.3 which is the general criterion of the safety of an embankment. The results indicate that the safety of an embankment due to the construction of embankment combined use road is assured, and thus, it is thought that the construction of embankment combined use road can be considered for cutting down on expenses of construction sites for a road construction. However, the pre-examination of stability due to the construction should be carried out because it decreases the factor of safety of an embankment. From this study, it has been found that the factor of safety was dropped most when the water level rose in the transient flow. The result indicates that the stability analysis of a river embankment where the water level changes frequently should be carried out in the condition of transient flow. It is recommended that the inner side of an embankment should have a slope of 1:2 which is identical with the slope of the existing embankment. In addition, the factor of safety also can be decreased due to the traffic loads, and therefore, the effect should also be considered after the construction of embankment combined used road limiting the traffic loads.

Impact of road embankment construction on groundwater system in alluvial aquifers

김다혜,차범근,여인욱 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.1

This study aims to evaluate the impact of road embankment construction on the groundwater system in alluvial aquifers that have excessively used groundwater. A road embankment was constructed across extensive flat alluvial deposits. Laboratory permeability tests demonstrated that the loading by road embankment significantly reduced the permeability of alluvial sediments, creating an impermeable boundary in the groundwater system. The numerical modeling results showed that road embankment acting as an impermeable boundary caused groundwater levels to rise in the upstream area but decline in the downstream area. However, unlike in other upstream areas, there was no noticeable rise in the groundwater level after the embankment construction in the area where the groundwater was in extensive use. The long-term water level monitoring also confirmed no meaningful change in water level during the road embankment construction. This is because the additional decline of the water level due to the decrease in the influence radius of groundwater pumping by the impermeable boundary offsets the increase in the upstream water level. The flow modeling and the water level monitoring showed that the overall impact of the road embankment construction on the groundwater supplies could be insignificant. However, the numerical modeling indicates that the degree of impact varies with the distance from the road embankment. This study implies that the impact of the road embankment construction on the groundwater supplies in the upstream area will depend on the geological and hydraulic settings, which determine the radius of influence, such as the hydraulic property of the alluvial aquifer, pumping rate, the number and location of pumps, etc.

불포화 도로성토의 내진성 향상을 위한 배수공의 효과

이충원(Lee Chung Won),히고 요스케(Higo Yosuke),오카 후사오(Oka Fusao) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.2

본 연구에서는 동적 원심모형실험을 이용하여 도로성토의 지진시 안정성에 대한 배수공의 효과를 평가하였다. 이를 위하여 지진을 모사한 동적하중 작용시의 변위, 간극수압 및 가속도를 측정하였으며, 그 결과에 근거하여 배수공이 설치된 불포화 도로성토의 동적거동을 검토하였다. 또한, 화상해석을 통하여 본 도로성토 내의 변형율 분포를 확인하였다. 실험 결과, 설계기준을 만족시키는 최소한의 배수공을 설치한 도로성토에서는 침투수량의 저감이 확인되었으며, 그와 같은 경향은 특히 비탈면 선단부에서 현저하게 나타났다. 이는 도로성토의 골격응력 및 강성의 감소를 방지하며, 이에 따라 동적하중 작용시의 변위, 변형율, 간극수압의 증가량 및 가속도 응답이 작게 평가되었다. 실제 도로성토의 시공시에는 도로성토로의 침투를 충분히 방지할 수 있도록 배수공을 비탈면 선단부에서 천단 저부까지 설치하여야 할 것이다. In this study, the effect of the drain for the dynamic stability of the road embankment has been investigated through the centrifugal model tests. Based on the measurement of displacement, the pore water pressure and the acceleration during dynamic loading, dynamic behavior of the unsaturated road embankments with drain has been examined, and an image analysis has revealed the distributions of strains in this road embankment. From the test results, it is clarified that the drain reduces much of the infiltration of water into the embankment, especially at the toe, and prevents from decrease of skeleton stress and stiffness of embankment. Thus, in the dynamic loading process, the displacements, the strain levels, the increase in pore water pressure and the acceleration responses of the case with drain are much less than those of the case without drain, although the drain used in the present study is minimum within the design concept. In the case of real road-embankment construction, the drain should be placed from the toe to the bottom of the crest enough to prevent from the infiltration of water into the embankment.

함수비에 따른 불포화 도로성토의 동적 안정성 평가

이충원,히고 요스케,오카 후사오 한국지반공학회 2014 한국지반공학회논문집 Vol.30 No.6

It has been pointed out that the collapses of unsaturated road embankments caused by earthquake are attributed tohigh water content owing to the seepage of the underground water and/or the rainfall infiltration. Hence, it is importantto study influences of water content on the dynamic stability and deformation mode of unsaturated road embankmentsfor development of a proper design scheme including an effective reinforcement to prevent from severe damage. Thisstudy demonstrates dynamic centrifugal model tests with different water contents to investigate the effect of water contenton deformation and failure behaviors of unsaturated road embankments. Based on the measurement of displacement,the pore water pressure and the acceleration during dynamic loading, dynamic behavior of the unsaturated roadembankments with about optimum water content and the higher water content than the optimum one have been examined. In addition, an image analysis has revealed the displacement field and the distributions of strains in the road embankment,by which deformation mode of the road embankment with the higher water content has been clarified. It has beenconfirmed that in the case of higher water content the settlement of the crown is large mainly owing to the volumecompression underneath the crown, while the small confining pressure at the toe and near the slope surface induceslarge shear deformation with volume expansion.

대심도 연약지반 도로확장 공사에서의 설계 개선

김태형,박태영,김성렬,유상호,김국한,김윤태 한국지반공학회 2012 한국지반공학회논문집 Vol.28 No.8

The expansion of a road on soft ground could induce an additional settlement to the existing road because of the consolidation characteristics of the soft soil layer subjected to additional load by an adjacent banking. In such case,the existing road could be faced with various problems during the stages of the construction and maintenance, such as deterioration of not only the surface smoothness yielding the decrease in automobile performance safety but also the structural stability of the embankment. These kinds of problems are expected to occur more freguently especially for the deep ground level with a fairly thick soft soil layer. Therefore, they should be examined and studied adequately during the design stage. As a reference case study, this paper deals with the project named Namhae Expressway of 2nd Branch with the soft soil layer with the thickness upto about 50m. After a lengthy review of the original design,an improved design is proposed.

침투가 일어나는 불포화 도로성토의 동적 변형거동

이충원,히고 요스케,오카 후사오 한국방재학회 2016 한국방재학회논문집 Vol.16 No.6

Seismic vulnerability of road embankments is significant geotechnical problem. In this sense, this study demonstrates dynamic centrifugal model tests considering seepage flow to investigate the effect of seepage water on deformation and failure behaviors of unsaturated road embankments. Based on the measurement of displacement, the pore water pressure and the acceleration during dynamic loading, dynamic behavior of the unsaturated road embankments subjected to seepage flow has been examined. Amplitudes of the acceleration responses of all the measuring points are larger than the input wave, and maximum acceleration close to the surface is relatively larger than that inside embankment. Also, large volume compression occurs underneath the crest which results in the large settlement at the crest due to dynamic loading. Including this part, shear strain localizes at rather lower part of the model, and rather large shear strain with expansive volumetric strain can be observed at the toe of the slope. In addition, large deformation is likely to occur at the lower part in the case with seepage water, whereas the soils close to the surface largely deforms with high water content and without seepage flow. 지반공학 분야에서 도로성토의 동적 취약성은 중요한 현안 사항이며, 이러한 관점에서 본 연구에서는 불포화 도로성토의 변형 및 파괴거동에 대한 침투수의 영향 고찰을 목적으로 동적원심모형실험을 실시하였다. 이를 위하여 동적과정 중의 변위, 간극수압 및 가속도의 계측에 근거하여 침투가 발생하는 불포화 도로성토의 동적거동을 분석하였다. 실험 결과, 가속도 응답은 모든 측정점에서 입력파보다 증폭되었으며, 최대가속도는 성토 내부에 비해 표면 부근에서 더욱 크게 나타났다. 또한, 동적과정 중 큰 체적압축이 도로성토의 천단 하부에서 발생하며 이는 천단부의 큰 침하를 유발하였다. 이 부분을 포함하여 전단변형율이 도로성토의 저부로 집중되었으며, 체적팽창을 수반하는 큰 전단변형율이 사면 선단부에서 관찰되었다. 이와 함께, 도로성토에 침투가 발생하는 경우에는 침투가 발생하지 않는 고함수비 조건에 비해 대변형이 상대적으로 낮은 곳에서 발생하는 경향이 있음을 알 수 있었다.

Application of waste rubber to reduce the settlement of road embankment

Tafreshi, S.N. Moghaddas,Norouzi, A.H. Techno-Press 2015 Geomechanics & engineering Vol.9 No.2

In this paper, a series of repeated load tests were carried out on a 150 mm diameter plate simulative of vehicle passes, to demonstrate the benefits of soil-rubber shred mixture in decreasing the soil surface settlement of road embankment. The results show that the efficiency of rubber reinforcement is significantly a function of the rubber content, thickness of rubber-soil mixture and soil cap thickness over the mixture. Minimum surface settlement is provided by 2.5% of rubber in rubber-soil mixture, the thickness of mixture layer and soil cap of 0.5 times the loading surface diameter, giving values of 0.32-0.68 times those obtained in the unreinforced system for low and high values of amplitude of repeated load. In this installation, in contrast with unreinforced bed that shows unstable response, the rate of enhancement in settlement decreases significantly as the number of loading cycles increase and system behaves resiliently without undergoing plastic deformation. The findings encourage the use of rubber shreds obtained from non-reusable tires as a viable material in road works.

준설토를 활용한 도로 성토 기술개발을 위한 지오텍스타일 튜브의 국내외 시공현황 분석

성현종(Hyun-Jong Sung),김형주(Hyeong-Joo Kim),고정희(Jeong-Hee Ko) 한국지반신소재학회 2013 한국지반신소재학회 학술발표회 Vol.2013 No.4

This Embankment technology using Geotextile tube presented in this study was first introduced in Korea Ilsan Bridge Project by TENCATE’s technology. As the transportation distance from the quarry location to the construction site of the coastal area roads and embankments is far, the cost of transporting these fill materials is expensive and engineers had encountered construction difficulties, hence, conventional embankment technology must be furthered researched. In this study, we can obtain the basic data for the development of road embankment technology with geotextile tube utilizing dredged soil based on the geotextile tube construction cases being applied practical alternative to the conventional embankment technology, domestically and internationally.

한계평형해석에 의한 연약지반 위의 철도노반 고성토를 위한 직포 보강 효과

김유성(Kim You-Seong),최재선(Choi Jae-Seon) 한국토목섬유학회 2010 한국지반신소재학회 논문집 Vol.9 No.4

직포 보강재는 연약지반 성토시 장비주행성, 지지력 및 활동안정성 개선 등을 목적으로 활발하게 적용되고 있다. 이 논문에서는 연약지반 위에 고강도의 직포를 2층 보강하여 철도제방을 성공적으로 구축한 사례를 소개하였다. 한계평형해석에 근거한 비탈면 활동안정분석결과 연약지반 위에 고강도의 직포를 2층 보강하고 흙쌓기를 수행하였을 때 제체의 활동에 대한 안전율은 0.91에서 l.14로 약 25%증가하고, 2개월 이상의 공기단축효과가 있는 것으로 나타났다. 따라서, 공기가 촉박하거나, 안전율이 다소 부족한 현장의 경우 고강도 직포보강에 의한 연약지반처리공법은 유용한 것으로 판단된다. Woven geotextiles (polyester mats) reinforcement is generally used to improve traffic ability, bearing capacity, and slope stability for embankment construction on soft ground. Cases of two high-strength woven georextiles reinforcement layers are introduced in the present paper, which has been successfully constructed for rail road embankment on soft ground. According to the case results based on the limit equilibrium analyses of slope stability, the two high-strength woven georexriles reinforcement layers on the soft ground can substantially increase the stability of the embankment by about 25%, improve the safety factor from 0.91 to 1.14, and significantly reduce the embankment construction duration at least 2 months. Therefore, the application of high-strength woven geotextiles is found to be useful for in-situ cases having the lack of construction duration and stability, as a soft ground improvement.

성토체 및 모래매트의 강성이 하부지반의 변형과 성토체의 안전에 미치는 영향에 대한 유한요소해석

배우석 ( Woo Seok Bae ),김종우 ( Jong Woo Kim ),권영철 ( Young Cheul Kwon ) 한국안전학회 2007 한국안전학회지 Vol.22 No.4