超高層建築基樁試樁效益分析及爭議探討以新北市三重區某企業總部大樓為例

國內超高層建築蓬勃發展，基礎型式多採用樁基礎設計，然而承載力多依據理論或經驗公式，分別計算樁身極限摩擦力及樁底極限點承力，為印證設計與實際地層狀況是否符合，並且回饋試樁結果作為結構樁的設計參數，確認工作樁之實際尺寸於現地地層狀況下之單樁承載力，另一方面又可以檢核設計合理性，同時利用試樁來檢核工法的適用性。試樁工程非屬基樁工程中的必要工程，僅有在建築技術規則要求和設計單位為求更經濟的目下規劃試樁工程，本次研究利用成本的角度分析，試樁工程的成本在技術規則中，因安全係數折減所帶來基樁工程的成本效益。超高層建築的試樁工程主要目的出於得到更安全且經濟的設計，試樁的結果也”非”必須符合設計值，重點是試樁結果是符合現地層條件狀況，因此，需要分析探討影響試樁結果的人為因素，作為將來釐清責任的依據，減少往後試樁工程發生爭議的機會。本次研究利用實際案例收集，並以目前國內主要基樁的施工方法探討成本效益與爭議分析。

關鍵字

超高層建築；試樁；經濟；回饋；成本；爭議

並列摘要

Domestic high-rise buildings booming, the foundation piles are widely designed and engineered. However, the foundation bearing capacity such as the ultimate friction and bottom limit point bearing strength may be calculated according to theory or empirical formulas applicable. In order to verify the actual ground conditions with calculations, test piles shall have the results which are able to feedback structure design parameters to the pile design and engineering. Thus, the actual bearing load of the piles of various sizes will be available for actual site work. On the other hand, it can be checked whether the pile design were reasonable or not. In addition, we may use test pile to verify the foundation design approach. Test piles might not be essential works for foundation design and engineering unless it is requested per building regulations or cost analysis per Design Architect. Our study is to assess the value engineering of test piles. After pile test, the safety factor might be lowered for foundation engineering and consequently achieve cost saving of foundation works. Ultra-high-rise buildings shall conduct the test piles to achieve more safe and economical design. Test pile results need not to meet the design value. Furthermore, the test pile results are consistent with soil foundation conditions. It is analyzed to assess the human factors and clarify the responsibilities and reduce the potential opportunities for engineering test pile dispute. Actual case studies collected and the current construction methods piles investigated are based on major domestic methods applicable and controversial cost-benefit analysis.