경량기포토의 교대 뒷채움재 적용성 평가

Abstract

In this study, the numeral analysis has been conducted to verify the effect on behavior of abutment and under ground when Lightweight Air-trapped soil(ATS) is applied as abutment backfill. When the structure is installed on soft ground, because of trait change of ground, damage of subsidence of ground happens frequently before or after the construction. Especially, when the backfill of the structures such as abutment and retaining wall is conducted, as the lateral load acts on the piles top in abutment, with the piles, horizontal shifting of abutment happen so that the structural destruction of foundation happens. The light weight method is commonly used in the reinforcement methods that the weight of embankment material is being light so the ground is stabilized. EPS construction method is mostly used but because of characteristic of material, there are many problems such as long-term creep and settlement. To supplementing these problems, many researches have been conducted on ATS method which is a material mixing of air bubbles with the result of fluidization of compound of water and cement. However, until now there is little research on its field application domestically. Therefore, the numeral analysis is conducted to evaluate the applicability of abutment backfill of ATS. To identify the effect of an amount of ATS used, the reciprocal difference is analyzed by varying the slope(1:S) and distance(B/H). With this condition, the horizontal displacement on the upper abutment and the point in pile top, and horizontal displacement of the concept of inclinometer on the surface settlement and abutment backfill are calculated.

By the results of numeral analysis, it can be found that when the ATS is used as an abutment backfill, horizontal displacement and settlement are remarkably decreased even more than applying the soil. In addition, when embankment was done with a soil, settlement rapidly was happened at the abutment joint part, but, on the applying section of ATS, the settlement gently was occurred. With these results, It can be concluded that applying ATS is effective to control horizontal shifting of abutment and minimize the settlement. And it is expected that trafficability on the joint part with the abutment is satisfactory. Upon the variations on the slope(1:S) and distance(B/H), the influence on the abutment and under ground are varied so that when the ATS is used in construction field, it must be applied according to the environmental condition of construction field

constructability, economic, etc.

This thesis is only the result of numeral analysis, based on theoretical interpretation method, so conducting laboratory test and field test is needed to suggest the applicability of design criterion for the optimum capacity to apply ATS for field.