混凝土泵送這項技術，自發明伊始至今已經超過一百年，也已廣泛應用在土木工程界，使用在各個建設工地之中。但混凝土泵送過程目前並不是非常穩定，塞管、爆管、效率低下等等的問題偶發，且這些問題並沒有統一的理論解釋，僅能依靠施工者與工程人員的經驗處理。

本文藉由有限元素軟體FLOW-3D，以數值模擬計算方式，模擬在各種可能導至塞管的不利操作環境下，管路中的混凝土和礫石級配間的交互作用導致塞管，提供塞管的理論背景解釋，並與實際經驗依序相較。

有多本著作均曾提及混凝土的性質屬於賓漢流體，並且列出了各種狀態下的混凝土可以參考的物理參數，本文中也採取類似的方法。本文將粗骨材分離出來當作固體物件，視為獨立固體物來模擬；餘下的水、水泥粉和細骨材混合形成砂漿，在模擬中當作賓漢流體來模擬。

本文考慮五種不同的實務操作情況：粗糙管壁、管線斷面積突縮、管線底部殘留混凝土、管線急彎、管徑漸縮。模擬的結果顯示均發生了塞管，與實務操作經驗相符。更進一步模擬發現，塞管時管中有拱阻塞的現象發生，顆粒排列成拱狀，拱兩端的兩隻腳抵住管壁，兩者之間的摩擦力減慢了流動速度。而拱阻塞的力鍊之間會相互交纏形成網狀，進一步阻滯流動，最終導致阻塞。

SUMMARY
This study is tended to learn more about what is happening about pipe jamming during concrete pumping. This study, in first chapter, will introduce what is concrete pumping. And then, the second chapter will review some basic theorem of fluid mechanics, such as mass conservation, Bingham fluid and multi-phase flow, etc. The third chapter will described the computational software we used, and how the setting are being set. In the fourth chapter, we selected 5 cases which are known as the reasons may cause arch jamming during pumping. If the simulation can reproduce how arch jamming really happens in the pipeline, then by the assistance of computer, stress chain and stress web can also be located. Those stress chain touch the wall of pipe and cause friction force, slowing down the speed of concrete flow. In other words, they are the reason causes blocking during concrete pumping.

Key words: Bingham Fluid, Concrete Pumping, Arch Jamming

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