비개착공법으로 건설된 지하구조물 주변 지반 응력이완영역 규명

For the development of areas around railway lines, subsurface construction using the non-open cut methodunder the railway has recently been increased. However, when a structure under a railway is constructed, the stressrelease of the ground is not considered an important factor in the design. In this study, laboratory tests were conductedto determine a zone of stress relaxation. Field tests using an inclinometer were performed to measure the horizontal displacementof the ground during non-open cut construction. The stress release zone and the subgrade stiffness wereinvestigated by numerical analysis. The results of the laboratory tests indicated that the failure zone in the ground wassimilar to a Rankine's active earth pressure zone. The measured data from the inclinometer in the field tests showed thatdisplacements started when a steel pipe was pushed into the ground. The results of numerical analysis show that lateralearth pressure was also close to Rankine’s active earth pressure. The roadbed support stiffness of the soil around thestructure decreased to 40% of the original value. The ground around the subsurface structure constructed using nonopencut methods should be reinforced to maintain the running stability of train.