关键词: 地下综合管廊, 深基坑, 内支撑, 优化设计, 现场监测

Abstract: This paper presents a case history of Value Engineering design and analysis of the internal strut supported deep excavation for an integrated utility culvert in Pintan. The original excavation support option was the drilled and castinplace reinforced concrete piles with one castinplace reinforced concrete waler supporting system plus two layers of steel pipe strut supporting system. The first castinplace reinforced concrete waler system in the original design had the disadvantages of low construction efficiency and high cost, and therefore, the optimized design converted into steel pipe strut support. The excavation sequence was simulated through a threedimensional finite element analysis using PLAXIS software. The stressstrain in the original and new supporting system were compared. The results indicate that, the maximum bending moment in the optimized system was 637.6 kNm/m or varying from 0.82% to 3.09%. The lateral deflections at the supporting system were similar with only 0.33% to 1.36% reduction. It was therefore concluded that the stressstrain changes in both system were not significant. The new supporting system was applied in the construction. From the construction monitoring results, the safety of the excavation could be ensured and the internal supporting system was reliable and was cost effective. The construction schedule was also accelerated.

Key words: Integrated Utility Culvert, Deep Excavation, Internal Strut Support, Optimized Design, Construction Monitoring