Disposal cover as an engineered barrier of a near-surface disposal facility for low and very low-level radioactive waste is composed of a multi-layer to isolate radioactive waste from environmental influences for the long term. To acquire a realistic forecast for the post-closure period of the disposal facility, it is essential to carry out long-term experimental research in a similar condition to the actual disposal environment. Hence, a performance test facility of the disposal cover was constructed in Gyeongju low and intermediate level radioactive waste disposal center in 2022. The constructed performance test facility has differences from the material properties presented in the design. These differences are factors that affect the prevent rainfall infiltration, which is one of the important roles of the disposal cover. Therefore, in this study, a numerical simulation of rainfall infiltration into the performance test facility was performed for the designed case and the actual constructed case. To simulate the behavior of water infiltration, the FEFLOW software based on the finite element method is used. Through the analysis of numerical simulation results, it is confirmed that the hydraulic conductivity of the material constituting the multi-layer of the disposal cover greatly influences the amount of water infiltration.

목 적: 본 연구는 허쉬버그검사와 교대프리즘가림검사에 의한 편위각을 알아보고자 하였다. 방 법: 21세 이상~25세 이하(평균 23.14±1.25세) 대학생 22명을 대상으로 허쉬버그검사와 교대프리즘가림검사로 카파각과 전체 편위각을 측정하였다. 결 과: 근거리에서 교대프리즘가림검사에 의한 편위각은 좌,우안의 카파각과 매우 유의한 상관관계(r=0.755, r=0.730)를 나타냈으며 양성(+) 카파각 값들과의 관계에서는 관계식 y=3.954+0.063χ으로 양의 기울기 값이 측정되었다. 그리고 폭주근점과 조절력은 선형관계인 y=10.603-0.667χ의 관계식으로 음의 기울기 값과 높은 음의 연관성(r=-0.646, p=0.001)을 보였고, 통계적으로도 유의한 차이(t=14.973, p=0.000)가 있는 것으로 분석되었다. 결 론: 카파각과 교대프리즘가림검사에 의한 편위각은 상관관계가 높았으며 편위를 진단하는 참고적인 자료로 활용이 가능하다.

Domestic urban railway underground station structures, which were built in the 1970s ad 1980s, had been constructed as Cut-and-Cover construction system without seismic design. Because the trends of earthquake occurrence is constantly increasing all over the world as well as the Korean Peninsula, massive human casualties and severe properties and structures damage might be occurred in an non-retrofitted underground station during an earthquake above a certain scale. Therefore, to evaluate the retrofit effect and soil-structure interaction of seismic retrofitted underground station, a centrifugal shaking table test with enhanced stiffness on its structural main member are carried out on 1/60 scaled model using the Kobe and Northridge earthquakes. The seismic retrofitted members, which are columns, side walls, and slabs, are evaluated to comparing with existing non-retrofitted centrifuge test results Also, to simulate the scaled ground using variation of shear velocity according to site conditions such as ground depth and density, resonant column test is performed. From the test results, the relative displacement behavior between ground and structures shows comparatively similar in ground, but is increased on ground surface. The seismic retrofit effects were measured using relative displacements and moment behavior of column and side walls rather than slabs. Additionally, earthquake wave can be used to main design factor due to large structural deformation on Kobe earthquake wave than Norhridge earthquake wave.

In this study, a full-scale test was conducted to analyze the behavior characteristics which are related to roadbed according to steel pipe press-in excavation during construction of underground railway crossing. the value of depth of soil cover that is the most sensitive element gets to increase gradually by 1.0, 1.5, and 2.0(H/D). Then we performed press-in excavation and measured the displacements of roadbed with LVDT. When the depth of soil cover level is 1.0(H/D), the maximum value of 5.2mm were seen at the point of 2mm for pipe press. Also, when depth of soil cover had increased, Uplift decreased more than 3 times in comparison with the one.