Recently, it is more concerned about securing of its seismic safety, as underground structures are significantly recognized. Especially, it is very important that underground structures such as the tunnel of urban railroad or subway ensure the seismic safety of its, because it can be caused an enormous loss of lives and a economical damage by earthquake. When the subway tunnel of cut-and-cover box type is constructed, grounds are excavated and refilled. In this study, the parametric study is performed and analyzed about factors affecting seismic analysis of cut-and-cover tunnel, such as soil type, refilled range, tunnel location, etc. Consequently, it is hoped to provide the preliminary data for a better reasonable review on seismic design and seismic performance assessment of underground structures.

With the recent decreasing of available land, the usage of underground for constructing underground parking lots, subway, underground shopping centers and roads is becoming more frequent than before. Subsequently, due to the changes of the ecosystems and the depletion of ground water in the underground environments are being negatively affected due to coming into contact with corrosive and hazardous substances. In particular, the durability, safety and convenience of the people who reside or utilize these underground structures are reduced by the environmental problems originating from underground ecosystems. Currently there exist a large number of on-going topics of discussion intended to solve the problems, but in order to consolidate a proper and standardized procedure of maintaining waterproofing techniques for these underground structures, a testing method to evaluate the performance of waterproofing and waterleakage resistance in underground structures is necessary.

In light of the maintenance of underground structures, the evaluation scope of precise inspection for safety and diagnosis have been revised. Crack, leakage, deterioration, and drainage system are evaluated with field inspection in maintenance manner. It also proposed that the additional revision of the precise inspection for safety and diagnosis.

Reinforced concrete structures are deteriorated in a few decades due to various causes, such as carbonation. Therefore it is important to evaluate the accurate carbonation depth in order to secure the durability of the structure. In this paper, carbonation depth by drilling excavation and splitting core sample are compared. Also, the procedure for estimating the appropriate repair zone is proposed, with the result of carbonation depth and steel bar detection.

To investigate earthquake responses of structures with basements and soil deposits, centrifuge tests using an in-flight earthquake simulator were performed. The fixed and embedded basements did not reduce the earthquake responses of SDOF structures due to the dynamic behaviors of massive soil deposits.

The priority order about a rational repair and reinforcement is generally decided by subjective decision of engineer. An appearance investigation carried out to decide about a rational repair and reinforcement through systematic and objective analysis in tunnel. we could prevent expecting leakage through several improvements in the aspects of design, materials and site implementation.

To evaluate underground behavior characteristic according to the ground water level variation, displacement and bending moment using FEM(Plaxis) were analyzed. When the ground water level difference is more than 10m, it were analyzed that effects on underground structures was great

This research was intended to confirm the reducing effects water leakage of the acicular thaumasite as admixture for mixing concrete structure, in case of the water leakage on underground structure

This study examines preventive technology that is to control the leak by rebuilding the waterproofing layer using adhesive gel for the damaged area expected to raise any disaster if there are making leakage in an underground structure.

The more durability of structures has been concerned, the more attention of maintenance has been given. Durability index is introduced to evaluate the state assessment in the precise safety of diagnosis in this paper. Two field data have been implemented to this proposal method. The priority of maintenance is also suggested using by this application.

본 연구에서는 구조물에 발생하는 변상 진전 특성을 수치 해석적으로 평가할 수 있는 기법을 새롭게 개발하기 위한 연구를 수행한 것이다. 이를 위해서, 변상발생 메커니즘을 토대로 하여, 인장균열 발생 후, 휨압축에 의한 압축손상까지를 해석에 반영하였다. 특히 인장균열이 발생하고나서 압축손상이 발생하기까지의 해석단계를 위해서는, 등가소성힌지길이 개념을 새롭게 도입하여, 균열의 진전을 해석하게 된다. 등가소성힌지 길이개념을 도입함으로써, 균열발생단면에 대한 단면력, 즉, 축력과 모멘트를 균열폭과 관계지어 균열폭의 확장을 추적해 나가게 된다.