場鑄樁受側向載重之詮釋法評估

Evaluation of Lateral Interpretation Criteria for Drilled Shafts

李昀宣(Yun-Shiuan Lee)

指導教授 ： 陳逸駿

中原大學/工學院/土木工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200900263

摘要

本研究為藉由大量之側向樁載重試驗資料評估場鑄樁之側向載重詮釋法，各載重資料依樁-土相對勁度分為柔性及剛性基樁，再依沿樁長之土層分為排水土層及不排水土層等共四大羣分別評估分析。為使本分析能在較一致的基準面上進行，所選用的地工參數需能實際反應現地的載重行為。
各代表理論基礎的詮釋法用於本分析，這些代表性的詮釋法能廣泛涵蓋上限、中間及下限的詮釋範圍，以建立一套具可靠與一致性的各側向載重詮釋限度，並且能建立各詮釋法的相互關係及可靠度。依據本評估結果顯示不論柔性與剛性基樁在愈低的樁頭側向位移或轉動角限度，同樣有愈高的變異係數，且不排水載重資料羣的變異性略小於排水載重羣。柔性基樁與剛性基樁之載重-位移曲線於排水土層有相當一致的結果，但在不排水土層時剛性基樁之載重-位移曲線則顯示較易迅速發揮達到極限載重的現象。
本研究最後針對各代表性場鑄樁側向詮釋限度(樁頭位移量、樁徑百分比及樁頭轉動角)提出工程設計上的建議，並提出各詮釋法於設計上的最小安全係數設計建議值，這些建議均有輔以適當的統計資料以顯示其可靠度。

關鍵字

場鑄樁 ； 側向載重試驗 ； 詮釋法

並列摘要

This paper is a critical evaluation of lateral interpretation capacity for the drilled shafts under lateral loading. A wide variety of lateral load test data are used and these data are divided into drained and undrained databases. Each database is further divided into flexible and rigid shafts according to their shaft-soil relative rigidity. The geotechnical and load test parameters were evaluated using updated methods that can properly reflect the field condition under load test.
Representative interpretation criteria are applied to these load test data to establish a consistent lateral interpretation model. These selected criteria represent a wide distribution of interpreted results from the lower, middle, to higher ranges, and these criteria employ varied interpretation bases. Based on these analyses, the interrelationship and reliability of each interpretation model were established. The statistical results show that the smaller the displacement or rotation, the higher the coefficient of variation for both flexible and rigid shafts. Moreover, the undrained load test results show somehow less variability than the drained results. In addition, the load-displacement curves of flexible and rigid shafts present comparable trend for drained soils, however, the rigid shafts show faster capacity mobilization than flexible shafts for undrained soils.
Specific design recommendations for the use of lateral interpretation criteria of drilled shafts are developed, in terms of capacity, displacement, and rotation. The suggested minimum design safety factors for the straightforward interpretation criteria are also presented. These design recommendations are given with the appropriate statistics to describe the quality of these recommended models.

並列關鍵字

Drilled Shafts ； Lateral Load Test ； Interpretation Criteria

參考文獻

25. 陳逸駿，李志成 (民國89年)，「場鑄樁側向載重試驗詮釋法之探討」，地工技術，第80期，第39-50頁。

1. Bierschwale, MW, Coyle, HM and Bartoskewitz, RE (1981). “Lateral Load Tests on Drilled Shafts”, Drilled Piers and Caissons, ASCE, 98-113.

5. Carter, JP and Kulhawy, FH (1992). “Analysis of Lateral Loaded Shafts in Rock”, Journal of Geotechnical Engineering, ASCE, 118, 6, 839-855.

9. Gleser, S (1984). Panel Discussion, Laterally Loaded Deep Foundation (STP 835), ASTM, Philadelphia, 239-243.

12. Honjo, Y, Zaika, Y and Pokharel, G (2005). “Estimation of Subgrade Reaction Coefficient for Horizontally Loaded Piles by Statistical Analyses”, Soils and Foundations, 45(3), 51-70.