• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.45-52
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• 2014

The tunnel construction is increasing in order to secure a good driving performance of the car and train. A cases of tunnel collapse and the tunnel excessive displacement are increasing with the increase in tunnel construction. In terms of empirical construction methods using the strength characteristics of soil, it is important for tunnel construction to analyze causes of collapse and displacement. In the paper, it was analyzed the causes of collapse and excessive displacement of tunnel in the fractured ground condition. The results of analysis is that the increase of rainfall and lasting increase of displacement and large scale fractured ground are interconnected.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.561-573
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• 2012

Recently, tunnel constructions have been increased in Korea. According to the increment of tunnel constructions, cases of tunnel collapses also have been increased under tunnel construction. Among these tunnel collapses, after a certain amount of time has elapsed due to excessive displacements on slope of tunnel exit or entrance, cases of tunnel collapse have been increased rapidly. Therefore, the case study was conducted in this study to figure out factors effect on the tunnel collapses due to excessive displacements on tunnel exit or entrance slopes. Base on the case study, the fragmental zone of fault and the rainfall were most important factors on the collapse.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2002.10a
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• pp.1-15
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• 2002

동복터널의 현장지질은 편마암과 석탄층(Coal Beds)이 협재된 암질이 매우 불량한 편암으로 구성되어 있으며, 설계 시에는 석탄층의 발달이 확인되지 않아 그 영향을 충분히 고려되지 않았다. 석탄층(두께 2~8m)은 편암의 Rock Cleavage와 같은 방향과 45~55도의 경사를 가지며 pinch out and swelling 형태로 발달이 불규칙하다. 하행선굴착 중 약 290m구간에 걸쳐 석탄층이 나타났으며, 90m 구간은 천단 및 측벽부에서 집중 발달되어 쳐대일변위가 20mm이상인 지점이 발생하는 등 상반굴착 시 111.2mm의 수평방향 내공변위가, 하반굴착 시에는 최대 127.8mm의 내공변위가 발생하였고 하반관통이후 수렴되었다. 내공변위 과다발생에 대한 대책으로 지보타입을 하향 조정하였고 측벽부는 하향 록볼트를 포함한 추가록볼트 보강을 실시하였다. 한편 터널 바닥부의 석탄층은 도로포장 후 침하문제가 예상되어 인버트를 기존 강지보공과 H-beam으로 연결.폐합한 후 콘크리트로 치환(140m구간)하여 추가변위를 최소화하였으며 무근콘크리트로 설계된 라이닝은 철근콘크리트 라이닝으로 변경 시공하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.487-497
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• 2016

If a tunnel is excavated, the released stress is redistributed in the ground around the tunnel face, which lead the stress state of the surrounding ground of the tunnel and the load acting on the tunnel support to change. If the tunnel face deforms, the ground ahead of it is relaxed, and the earth pressure acting on it decreases. And if the displacement increases so much that, the ground ahead of the tunnel face reaches in failure state. At this time, load would be transferred longitudinally in the tunnel, depending on the cover and the face deformations. The longitudinal load transfers in the tunnels induced by the tunnelling has been often studied; however, the relation between the deformation of the tunnel face and the longitudinal load transfer was rarely studied. Therefore in this study assesses the characteristics of the longitudinal load transfer as the face was failed by displacement by conducting a model test in a shallow tunnel. In other words, the longitudinal load transfer of the tunnel with the progress of the face deform was measured by conducting a model test, beginning at the state of earth pressure at rest. As results of this study, most of the longitudinal load transfers occurred drastically at the beginning of the displacement of the tunnel face, and as the displacement of the face approached the ultimate displacement, it converged to the ultimate displacement at a gentler slope. In other words, when the ground ahead of the tunnel face was still in an elastic state, the longitudinally transferred load increased sharply at the beginning stage but it tended to increase gradually if it approached to the ultimate limit. Thus, it was noted that the earth pressure in the face and the longitudinal load transfer of the tunnel had the same decreasing tendency.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.285-294
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• 2005

Drift design is one of the core techniques in the structural design of high-rise buildings and resizing technique is regarded as a practical drift design method for high-rise buildings. In the resizing technique, the structural weight is re-distributed to minimize the target displacement without a change in structural weights. However, the structural weight determined from resizing algorithm is bound to the structural weight based on the preliminary design. Therefore, in this paper, a drift design method that can control the weight of the structure without causing drift control performance to deteriorate is proposed by incorporating the weight control factor in the formulation of resizing algorithm. The proposed drift design method is applied to the drift design of two frame-shear wall systems. The proposed drift design method, in this study, makes it possible to control both the drift and weight of a high-rise building.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.545-553
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• 2009

This paper describes the result of study on measurement of displacement of structure by means of non-contacting method, close-range digital photogrammetry using digital camera. To apply close-range digital photogrammetry to displacement measurement of structure, correction of lens distortion that interferes geometrical analysis has been carried out and then measuring displacement was performed on load regulated-rahmen. For enhanced applicability of displacement measurement, MIDAS which is a structural analysis program was used for modeling and the result was taken from comparative analysis. As a result of the study, it is showed that close-range digital photogrammetry could supplement several weaknesses of LVDT and cable displacement meter and, especially, economy in the perspective of measuring time could be realized. Close-range digital photogrammetry using digital camera can be applied to the area where requires visual analysis such as 3D modeling of structure, profile replication of measurement of structure as well as measurement of displacement of structure.

• Journal of the Korean GEO-environmental Society
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• v.12 no.2
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• pp.45-53
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• 2011

Soil nailing method was often designed by the slope stability analysis based on limit equilibrium. However, in the case of shorten length of nails, although the calculated factor of safety is within the design factor of safety, the horizontal displacement of soil nailed walls occurred above the allowable limit. In this study, relationship between the load and factor of safety, and relationship between the load and displacement ratio based on the test results were analysed. From the analysed results, the relationship between factor of safety and displacement ratio was estimated. For the mobilized horizontal displacement of the walls within the serviceability limit corresponding to the displacement of less than 0.3% displacement ratio, the calculated factor of safety by limit equilibrium analysis had to satisfy above 1.35. Also, although the minimum factor of safety is estimated above 1.35, the maximum horizontal displacement is often mobilized above 0.3% of excavation height. Therefore, it is necessary to perform the numerical analysis of soil nailed walls in the case of low shear strength or high excavation.

• Computational Structural Engineering
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• v.2 no.1
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• pp.71-78
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• 1989

In this paper a computer program for displacement control method was developed, in which a certain displacement of the structure is increased and the applied loads and another displacements are obtained. To simplify the nonlinear structural analysis, the relationships of moment-curvature were linearized as elasto-softening model for over-reinforced concrete beam and as elasto-plastic-softening model for under-reinforced concrete beam. Since the result of the analysis of reinforced concrete beam depended on the element size beyond elastic zone, the relationship of moment-curvature was modified for each element by using the concept of fracture energy approach. Overall, analytical results accurately predicted the load-displacement behavior of reinforced concrete beams.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.71-77
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• 2014

Heavy rainfall induces many disasters including slope failure and infrastructure collapse. In this point of view, rainfall-simulated centrifugal model test can be a reasonable tool to evaluate the stability of geotechnical structure. In order to obtain the displacements of a model in centrifugal model test, in general, LVDT and laser displacement sensor are used. However, when the rainfall is simulated, the LVDT has the problem of excessive infiltration into the model ground, and the laser displacement sensor provides the measuring result with inaccuracy due to the dispersion of the laser radiation. Hence, in this study, horizontal displacement sensor for rainfall-simulated centrifugal model test was developed. This sensor produced with a thin elastic steel plate and gave the accurate relationship between the displacement and the strain.

• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.123-134
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• 2005

A coupled three-dimensional pile group analysis method (YSGroup) was developed considering nonlinear pile head stiffness matrices and compared with other analytical methods (elastic displacement method, Group 6.0 and FBPier 3.0). In this method, a pile cap was modelled by four-node flat shell element, a pier was modelled using 3 dimensional beam element, and individual piles were modelled as beam-column elements. Through the comparative studies on a piled pie. subjected to lateral loads in linear soil, it was found that present method (YSGroup), elastic displacement method and Group 6.0 gave similar results of lateral pile head displacement, but FBPier 3.0 was estimated to show somewhat larger displacements than those from the three methods. Displacements of superstructure (pier), including nonlinear soil behavior, could be estimated by present method (YSGroup) and FBPier 3.0 because these two methods modelled the superstructure directly by finite element techniques. It was found that pile groups in pinned pile head condition had a tendency to cause excessive rotation of the pile cap.