場鑄樁樁底承載力及壓載詮釋法之評估

Evaluation of Tip Resistance and Compression Interpretation Criteria for Drilled Shafts

方顗忠(Yi-Chung Fang)

指導教授 ： 陳逸駿

中原大學/工學院/土木工程學系/碩士(2007年)

https://doi.org/10.6840/cycu200700712

摘要

本研究係以蒐集國內外樁載重試驗資料，評估場鑄樁之軸向詮釋法及樁底承載力分析模式。壓載詮釋法及樁底承載力分析所用之樁載重試驗資料，分別依沿樁身土層及樁底土層之土壤性質區分為排水土層與不排水土層兩大類。分析所選用的大地工程參數以能真正的反應出現地樁破壞時的實際行為模式。
於壓載詮釋法之評估，所選用的詮釋法代表各個不同理論基礎，且能涵蓋上、中、下限的詮釋範圍。經由載重資料的回饋分析統計，建立各詮釋法的相互關係及其可靠度。
於樁底承載力分析，藉由一般所使用的承載力理論公式之理論預測值與樁載重之實際量測值進行比較，以了解分析模式的適用性並提出可能之修正。同時由樁底之量測結果直接與SPT-N 值所建立之關係式亦示於本文中，本研究亦與國內相關規範做一比較。
針對上述之評估，本研究提出場鑄樁壓載詮釋法及樁底承載力於工程上之設計建議，並輔以適當的統計資料以為使用者參考。

關鍵字

詮釋法 ； 軸向壓載重 ； 分析模式 ； 載重試驗 ； 場鑄樁

並列摘要

This study is a critical evaluation of compression interpretation capacity and tip resistance for the drilled shafts under axial loading. A wide variety of compression load test data are used and these data are divided into drained and undrained databases. The geotechnical and load test parameters were evaluated using updated methods that can properly reflect the field condition under a load test.

In compression interpretation capacity, representative interpretation criteria are examined to evaluate the capacity of drilled shaft foundations under axial compression loading. These selected criteria represent a distribution of interpreted results from the lower, middle, and higher ranges as found in practice. In addition, these criteria employ varied interpretation bases. The interrelationship and reliability of each interpretation model were established.

In compression tip resistance, representative analytical models are examined using both measured and predicted results to evaluate the tip capacity of drilled shafts. The analytical models include bearing capacity theory, SPT-N empirical equation, and local design criteria. The suitability and required correction of tip analytical model are presented.

Specific design recommendations for the use of compression interpretation and tip resistance of drilled shafts are developed and given with the appropriate statistics to describe the quality of these recommended models.

並列關鍵字

load test ； axial compression loading ； drilled shaft foundation ； interation ； analytical model

參考文獻

Chen, J.-R. and Kulhawy, F. H. (2002). “Axial uplift behavior of pressure-injected footings in cohesionless soil”, Deep Foundations (GSP 116), Ed. MW O'Neill and FC Townsend, ASCE, Florida, 1275-1289.

Chen, Y.-J. (2006). Evaluation of tip resistance for drilled shaft foundations, Annual report to National Science Council, Taipei.

Chen, Y.J. and Kulhawy, F.H. (1993). “Undrained Strength Interrelationships Among CICU, UU and UC Tests”, Journal of Geotechnical Eng., ASCE, Vol. 119, No. 11, 1732-1750.

Chen, Y.-J. and Kulhawy, F. H. (2002). “Evaluation of drained axial capacity of drilled shafts”, Deep Foundations 2002 (GSP 116), Ed. MW O'Neill and FC Townsend, ASCE, Florida, 1200-1214.

Chin, F.K. (1970). “Estimation of the Ultimate Load of Piles not Carried to Failure”, 2nd Southeast Asian Conference on Soil Engineering, Singapore, 81-90.