地工蜂巢格網介面特性與鋪面設計成效評估

A Study of Interface Characteristics for Geocell and assessing the effectiveness of Pavement Design

邱太昌(Tai-Chang Chiou)

指導教授 ： 張達德

中原大學/工學院/土木工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500578

摘要

地工蜂巢格網為新興之地工合成材，於國內仍較少被使用，本研究目的即是希望能透過此一研究，對地工蜂巢格網在影響路基土壤承載力的提升與鋪面設計時可減少的舖築結構厚度，進行更詳盡之探討，以瞭解地工蜂巢格網應用於鋪面時的成效。

本研究前後可分為兩大階段，第一階段為以三種不同介面條件因子的地工蜂巢格網進行直剪試驗，剪動速率控制在1.0mm/min，砂土的相對密度控制為95%，以瞭解三種不同類型的材料與砂土的摩擦阻抗機制，並應用承載力公式，計算地工蜂巢格網加勁於砂土，可提升的承載力，研究結果顯示加勁後的砂土承載力比未加勁前的砂土承載力，上升至少2倍，由此可知當地工蜂巢格網應用於軟弱土層時，可提升承載力，增加施工的便利性。

第二階段為應用路基土壤強度MR值設計鋪面厚度，本階段透過對未加勁砂土施作回彈彈性模數試驗，得出原狀土壤的MR值，再透過路基土壤與上層級配複合而得的K值，經由前人的研究得出加勁後複合K值可能的上升範圍，轉換回加勁後的路基土壤強度MR值，應用此兩種不同的MR值設計鋪面厚度，交通量以都會區高速公路設計，由研究結果得出加勁後的基層厚度比勁前的基層結構層減少約24公分，地工蜂巢格網應用於舖面設計確實可有效減少舖築材料的使用，降低施工成本。

關鍵字

回彈彈性模數MR ； 直剪試驗 ； 地工蜂巢格網 ； 舖面厚度設計 ； 承載能力

並列摘要

Geocell is a new material of Geosynthetic, it is still less to be used in Taiwan. The purpose of this research is more detailed to probe into the influence of Geocell to improve the bearing capacity of subgrade and the thickness of pavement to be reduced at pavement design, so we can understand the effectiveness of Geocell to be used in pavement.
The research can be divided into two major stages from the beginning to the end. In the first stage I do direct shear test with three different interface terms factors of Geocell. The test speed is controlled in 1.0mm/min and the relative density of the sand is controlled in 95%. That is in order to understand the friction mechanisms about three kinds of different materials with sand. The bearing capacity formula is applied to calculate the bearing capacity of sand what is reinforced with Geocell. The result of the research shows that the bearing capacity of sand with mattress increasing twice more than the sand without mattress at least. Therefore we can know when Geocell to be applied to the weakness soil layer, the bearing capacity of sand can be improved and increase the convenience of constructing.
The second stage is applied the value of resilient modulus about subgrade to design the thickness of pavement. In this stage I do the resilient modulus test about the sand without mattress to get the value of resilient modulus about undisturbed soil and get the K value through subgrade combining with the higher gradation layer. Then I get the range about K value what may rise through the research of scholars to transform into the value of resilient modulus about subgrade with mattress. Using these two kinds of different value of resilient modulus designs the thickness of pavement with the city high way traffic. The result of this study shows that the thickness of base with mattress reduces about 24 cm than without mattress. So Geocell is applied to pavement design really can reduce building materials and lower the cost of constructing.

並列關鍵字

Geocell ； Bearing Capacity ； Thickness of Pavement Design ； Resilient Modulus ； Direct Shear Test

參考文獻

15.張達德、張家豪，“地工蜂巢格網加勁於砂土路基之承載能力研究”，碩士論文，私立中原大學土木工程研究所 (2004)。

5.Ezek Technology Group ,Inc. (2002).“EZ-CELL Cellular Confinement System”.

10.Koutsourais, M. M., and Sprague, C. J. (1991).“Interfacial Friction Study of Cap and Liner Components for Landfill Design”, Geotextiles and Geomembranes, Vol.10 , pp.531-548.

11.Evans, M. D., and Fennick, T. J. (1996).“Geosynthetic/Soil Interface Friction Angles Using a Rotating Shear Device”,Geotechnical Testing Journal, GTJODJ, Vol. 18, NO.2, June 1995, pp. 271-275.

16.Dash, S.K. Rajagopal, K. Krishnaswamy, N.R. (2001). “Strip footing on geocell reinforced sand beds with additional planar reinforcement”, Geotextiles and Geomembranes, v19, n8, p 529-538, December.